Commit Graph

6044 Commits

Author SHA1 Message Date
linke li
f1e30cb636 ring-buffer: use READ_ONCE() to read cpu_buffer->commit_page in concurrent environment
In function ring_buffer_iter_empty(), cpu_buffer->commit_page is read
while other threads may change it. It may cause the time_stamp that read
in the next line come from a different page. Use READ_ONCE() to avoid
having to reason about compiler optimizations now and in future.

Link: https://lore.kernel.org/linux-trace-kernel/tencent_DFF7D3561A0686B5E8FC079150A02505180A@qq.com

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: linke li <lilinke99@qq.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-03-17 07:58:53 -04:00
Vincent Donnefort
6b76323e5a ring-buffer: Zero ring-buffer sub-buffers
In preparation for the ring-buffer memory mapping where each subbuf will
be accessible to user-space, zero all the page allocations.

Link: https://lore.kernel.org/linux-trace-kernel/20240220202310.2489614-2-vdonnefort@google.com

Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-03-17 07:58:53 -04:00
Steven Rostedt (Google)
2cc621fd2e tracing: Move saved_cmdline code into trace_sched_switch.c
The code that handles saved_cmdlines is split between the trace.c file and
the trace_sched_switch.c. There's some history to this. The
trace_sched_switch.c was originally created to handle the sched_switch
tracer that was deprecated due to sched_switch trace event making it
obsolete. But that file did not get deleted as it had some code to help
with saved_cmdlines. But trace.c has grown tremendously since then. Just
move all the saved_cmdlines code into trace_sched_switch.c as that's the
only reason that file still exists, and trace.c has gotten too big.

No functional changes.

Link: https://lore.kernel.org/linux-trace-kernel/20240220140703.497966629@goodmis.org

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Vincent Donnefort <vdonnefort@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Mete Durlu <meted@linux.ibm.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-03-17 07:58:53 -04:00
Steven Rostedt (Google)
e85d471c2b tracing: Move open coded processing of tgid_map into helper function
In preparation of moving the saved_cmdlines logic out of trace.c and into
trace_sched_switch.c, replace the open coded manipulation of tgid_map in
set_tracer_flag() into a helper function trace_alloc_tgid_map() so that it
can be easily moved into trace_sched_switch.c without changing existing
functions in trace.c.

No functional changes.

Link: https://lore.kernel.org/linux-trace-kernel/20240220140703.338116216@goodmis.org

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Vincent Donnefort <vdonnefort@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Mete Durlu <meted@linux.ibm.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-03-17 07:58:52 -04:00
Steven Rostedt (Google)
0b18c852cc tracing: Have saved_cmdlines arrays all in one allocation
The saved_cmdlines have three arrays for mapping PIDs to COMMs:

 - map_pid_to_cmdline[]
 - map_cmdline_to_pid[]
 - saved_cmdlines

The map_pid_to_cmdline[] is PID_MAX_DEFAULT in size and holds the index
into the other arrays. The map_cmdline_to_pid[] is a mapping back to the
full pid as it can be larger than PID_MAX_DEFAULT. And the
saved_cmdlines[] just holds the COMMs associated to the pids.

Currently the map_pid_to_cmdline[] and saved_cmdlines[] are allocated
together (in reality the saved_cmdlines is just in the memory of the
rounding of the allocation of the structure as it is always allocated in
powers of two). The map_cmdline_to_pid[] array is allocated separately.

Since the rounding to a power of two is rather large (it allows for 8000
elements in saved_cmdlines), also include the map_cmdline_to_pid[] array.
(This drops it to 6000 by default, which is still plenty for most use
cases). This saves even more memory as the map_cmdline_to_pid[] array
doesn't need to be allocated.

Link: https://lore.kernel.org/linux-trace-kernel/20240212174011.068211d9@gandalf.local.home/
Link: https://lore.kernel.org/linux-trace-kernel/20240220140703.182330529@goodmis.org

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Vincent Donnefort <vdonnefort@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Mete Durlu <meted@linux.ibm.com>
Fixes: 44dc5c41b5 ("tracing: Fix wasted memory in saved_cmdlines logic")
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-03-17 07:58:52 -04:00
Linus Torvalds
63bd30f249 Tracing/ring-buffer fixes for 6.8 (to be applied in 6.9-rc):
- Do not update shortest_full in rb_watermark_hit() if the watermark
   is hit. The shortest_full field was being updated regardless if
   the task was going to wait or not. If the watermark is hit, then
   the task is not going to wait, so do not update the shortest_full
   field (used by the waker).
 
 - Update shortest_full field before setting the full_waiters_pending flag
 
   In the poll logic, the full_waiters_pending flag was being set
   before the shortest_full field was set. If the full_waiters_pending
   flag is set, writers will check the shortest_full field which has
   the least percentage of data that the ring buffer needs to be
   filled before waking up. The writer will check shortest_full if
   full_waiters_pending is set, and if the ring buffer percentage filled
   is greater than shortest full, then it will call the irq_work to
   wake up the waiters.
 
   The problem was that the poll logic set the full_waiters_pending flag
   before updating shortest_full, which when zero will always trigger
   the writer to call the irq_work to wake up the waiters. The irq_work
   will reset the shortest_full field back to zero as the woken waiters
   is suppose to reset it.
 
 - There's some optimized logic in the rb_watermark_hit() that is used
   in ring_buffer_wait(). Use that helper function in the poll logic
   as well.
 
 - Restructure ring_buffer_wait() to use wait_event_interruptible()
 
   The logic to wake up pending readers when the file descriptor is
   closed is racy. Restructure ring_buffer_wait() to allow callers
   to pass in conditions besides the ring buffer having enough data
   in it by using wait_event_interruptible().
 
 - Update the tracing_wait_on_pipe() to call ring_buffer_wait() with
   its own conditions to exit the wait loop.
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Merge tag 'trace-ring-buffer-v6.8-rc7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing updates from Steven Rostedt:

 - Do not update shortest_full in rb_watermark_hit() if the watermark is
   hit. The shortest_full field was being updated regardless if the task
   was going to wait or not. If the watermark is hit, then the task is
   not going to wait, so do not update the shortest_full field (used by
   the waker).

 - Update shortest_full field before setting the full_waiters_pending
   flag

   In the poll logic, the full_waiters_pending flag was being set before
   the shortest_full field was set. If the full_waiters_pending flag is
   set, writers will check the shortest_full field which has the least
   percentage of data that the ring buffer needs to be filled before
   waking up. The writer will check shortest_full if
   full_waiters_pending is set, and if the ring buffer percentage filled
   is greater than shortest full, then it will call the irq_work to wake
   up the waiters.

   The problem was that the poll logic set the full_waiters_pending flag
   before updating shortest_full, which when zero will always trigger
   the writer to call the irq_work to wake up the waiters. The irq_work
   will reset the shortest_full field back to zero as the woken waiters
   is suppose to reset it.

 - There's some optimized logic in the rb_watermark_hit() that is used
   in ring_buffer_wait(). Use that helper function in the poll logic as
   well.

 - Restructure ring_buffer_wait() to use wait_event_interruptible()

   The logic to wake up pending readers when the file descriptor is
   closed is racy. Restructure ring_buffer_wait() to allow callers to
   pass in conditions besides the ring buffer having enough data in it
   by using wait_event_interruptible().

 - Update the tracing_wait_on_pipe() to call ring_buffer_wait() with its
   own conditions to exit the wait loop.

* tag 'trace-ring-buffer-v6.8-rc7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing/ring-buffer: Fix wait_on_pipe() race
  ring-buffer: Use wait_event_interruptible() in ring_buffer_wait()
  ring-buffer: Reuse rb_watermark_hit() for the poll logic
  ring-buffer: Fix full_waiters_pending in poll
  ring-buffer: Do not set shortest_full when full target is hit
2024-03-14 16:25:01 -07:00
Linus Torvalds
01732755ee Probes updates for v6.9:
- x96/kprobes: Use boolean for some function return instead of 0 and 1.
  - x86/kprobes: Prohibit probing on INT/UD. This prevents user to put kprobe on
     INTn/INT1/INT3/INTO and UD0/UD1/UD2 because these are used for a special
     purpose in the kernel.
  - x86/kprobes: Boost Grp instructions. Because a few percent of kernel
     instructions are Grp 2/3/4/5 and those are safe to be executed without
     ip register fixup, allow those to be boosted (direct execution on the
     trampoline buffer with a JMP).
 
  - tracing/probes: Add function argument access from return events (kretprobe
     and fprobe). This allows user to compare how a data structure field is
     changed after executing a function. With BTF, return event also accepts
     function argument access by name. This also includes below patches;
   . Fix a wrong comment (using "Kretprobe" in fprobe)
   . Cleanup a big probe argument parser function into three parts, type
      parser, post-processing function, and main parser.
   . Cleanup to set nr_args field when initializing trace_probe instead of
      counting up it while parsing.
   . Cleanup a redundant #else block from tracefs/README source code.
   . Update selftests to check entry argument access from return probes.
   . Documentation update about entry argument access from return probes.
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Merge tag 'probes-v6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull probes updates from Masami Hiramatsu:
 "x86 kprobes:

   - Use boolean for some function return instead of 0 and 1

   - Prohibit probing on INT/UD. This prevents user to put kprobe on
     INTn/INT1/INT3/INTO and UD0/UD1/UD2 because these are used for a
     special purpose in the kernel

   - Boost Grp instructions. Because a few percent of kernel
     instructions are Grp 2/3/4/5 and those are safe to be executed
     without ip register fixup, allow those to be boosted (direct
     execution on the trampoline buffer with a JMP)

  tracing:

   - Add function argument access from return events (kretprobe and
     fprobe). This allows user to compare how a data structure field is
     changed after executing a function. With BTF, return event also
     accepts function argument access by name.

   - Fix a wrong comment (using "Kretprobe" in fprobe)

   - Cleanup a big probe argument parser function into three parts, type
     parser, post-processing function, and main parser

   - Cleanup to set nr_args field when initializing trace_probe instead
     of counting up it while parsing

   - Cleanup a redundant #else block from tracefs/README source code

   - Update selftests to check entry argument access from return probes

   - Documentation update about entry argument access from return
     probes"

* tag 'probes-v6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  Documentation: tracing: Add entry argument access at function exit
  selftests/ftrace: Add test cases for entry args at function exit
  tracing/probes: Support $argN in return probe (kprobe and fprobe)
  tracing: Remove redundant #else block for BTF args from README
  tracing/probes: cleanup: Set trace_probe::nr_args at trace_probe_init
  tracing/probes: Cleanup probe argument parser
  tracing/fprobe-event: cleanup: Fix a wrong comment in fprobe event
  x86/kprobes: Boost more instructions from grp2/3/4/5
  x86/kprobes: Prohibit kprobing on INT and UD
  x86/kprobes: Refactor can_{probe,boost} return type to bool
2024-03-14 16:16:33 -07:00
Linus Torvalds
9187210eee Networking changes for 6.9.
Core & protocols
 ----------------
 
  - Large effort by Eric to lower rtnl_lock pressure and remove locks:
 
    - Make commonly used parts of rtnetlink (address, route dumps etc.)
      lockless, protected by RCU instead of rtnl_lock.
 
    - Add a netns exit callback which already holds rtnl_lock,
      allowing netns exit to take rtnl_lock once in the core
      instead of once for each driver / callback.
 
    - Remove locks / serialization in the socket diag interface.
 
    - Remove 6 calls to synchronize_rcu() while holding rtnl_lock.
 
    - Remove the dev_base_lock, depend on RCU where necessary.
 
  - Support busy polling on a per-epoll context basis. Poll length
    and budget parameters can be set independently of system defaults.
 
  - Introduce struct net_hotdata, to make sure read-mostly global config
    variables fit in as few cache lines as possible.
 
  - Add optional per-nexthop statistics to ease monitoring / debug
    of ECMP imbalance problems.
 
  - Support TCP_NOTSENT_LOWAT in MPTCP.
 
  - Ensure that IPv6 temporary addresses' preferred lifetimes are long
    enough, compared to other configured lifetimes, and at least 2 sec.
 
  - Support forwarding of ICMP Error messages in IPSec, per RFC 4301.
 
  - Add support for the independent control state machine for bonding
    per IEEE 802.1AX-2008 5.4.15 in addition to the existing coupled
    control state machine.
 
  - Add "network ID" to MCTP socket APIs to support hosts with multiple
    disjoint MCTP networks.
 
  - Re-use the mono_delivery_time skbuff bit for packets which user
    space wants to be sent at a specified time. Maintain the timing
    information while traversing veth links, bridge etc.
 
  - Take advantage of MSG_SPLICE_PAGES for RxRPC DATA and ACK packets.
 
  - Simplify many places iterating over netdevs by using an xarray
    instead of a hash table walk (hash table remains in place, for
    use on fastpaths).
 
  - Speed up scanning for expired routes by keeping a dedicated list.
 
  - Speed up "generic" XDP by trying harder to avoid large allocations.
 
  - Support attaching arbitrary metadata to netconsole messages.
 
 Things we sprinkled into general kernel code
 --------------------------------------------
 
  - Enforce VM_IOREMAP flag and range in ioremap_page_range and introduce
    VM_SPARSE kind and vm_area_[un]map_pages (used by bpf_arena).
 
  - Rework selftest harness to enable the use of the full range of
    ksft exit code (pass, fail, skip, xfail, xpass).
 
 Netfilter
 ---------
 
  - Allow userspace to define a table that is exclusively owned by a daemon
    (via netlink socket aliveness) without auto-removing this table when
    the userspace program exits. Such table gets marked as orphaned and
    a restarting management daemon can re-attach/regain ownership.
 
  - Speed up element insertions to nftables' concatenated-ranges set type.
    Compact a few related data structures.
 
 BPF
 ---
 
  - Add BPF token support for delegating a subset of BPF subsystem
    functionality from privileged system-wide daemons such as systemd
    through special mount options for userns-bound BPF fs to a trusted
    & unprivileged application.
 
  - Introduce bpf_arena which is sparse shared memory region between BPF
    program and user space where structures inside the arena can have
    pointers to other areas of the arena, and pointers work seamlessly
    for both user-space programs and BPF programs.
 
  - Introduce may_goto instruction that is a contract between the verifier
    and the program. The verifier allows the program to loop assuming it's
    behaving well, but reserves the right to terminate it.
 
  - Extend the BPF verifier to enable static subprog calls in spin lock
    critical sections.
 
  - Support registration of struct_ops types from modules which helps
    projects like fuse-bpf that seeks to implement a new struct_ops type.
 
  - Add support for retrieval of cookies for perf/kprobe multi links.
 
  - Support arbitrary TCP SYN cookie generation / validation in the TC
    layer with BPF to allow creating SYN flood handling in BPF firewalls.
 
  - Add code generation to inline the bpf_kptr_xchg() helper which
    improves performance when stashing/popping the allocated BPF objects.
 
 Wireless
 --------
 
  - Add SPP (signaling and payload protected) AMSDU support.
 
  - Support wider bandwidth OFDMA, as required for EHT operation.
 
 Driver API
 ----------
 
  - Major overhaul of the Energy Efficient Ethernet internals to support
    new link modes (2.5GE, 5GE), share more code between drivers
    (especially those using phylib), and encourage more uniform behavior.
    Convert and clean up drivers.
 
  - Define an API for querying per netdev queue statistics from drivers.
 
  - IPSec: account in global stats for fully offloaded sessions.
 
  - Create a concept of Ethernet PHY Packages at the Device Tree level,
    to allow parameterizing the existing PHY package code.
 
  - Enable Rx hashing (RSS) on GTP protocol fields.
 
 Misc
 ----
 
  - Improvements and refactoring all over networking selftests.
 
  - Create uniform module aliases for TC classifiers, actions,
    and packet schedulers to simplify creating modprobe policies.
 
  - Address all missing MODULE_DESCRIPTION() warnings in networking.
 
  - Extend the Netlink descriptions in YAML to cover message encapsulation
    or "Netlink polymorphism", where interpretation of nested attributes
    depends on link type, classifier type or some other "class type".
 
 Drivers
 -------
 
  - Ethernet high-speed NICs:
    - Add a new driver for Marvell's Octeon PCI Endpoint NIC VF.
    - Intel (100G, ice, idpf):
      - support E825-C devices
    - nVidia/Mellanox:
      - support devices with one port and multiple PCIe links
    - Broadcom (bnxt):
      - support n-tuple filters
      - support configuring the RSS key
    - Wangxun (ngbe/txgbe):
      - implement irq_domain for TXGBE's sub-interrupts
    - Pensando/AMD:
      - support XDP
      - optimize queue submission and wakeup handling (+17% bps)
      - optimize struct layout, saving 28% of memory on queues
 
  - Ethernet NICs embedded and virtual:
    - Google cloud vNIC:
      - refactor driver to perform memory allocations for new queue
        config before stopping and freeing the old queue memory
    - Synopsys (stmmac):
      - obey queueMaxSDU and implement counters required by 802.1Qbv
    - Renesas (ravb):
      - support packet checksum offload
      - suspend to RAM and runtime PM support
 
  - Ethernet switches:
    - nVidia/Mellanox:
      - support for nexthop group statistics
    - Microchip:
      - ksz8: implement PHY loopback
      - add support for KSZ8567, a 7-port 10/100Mbps switch
 
  - PTP:
    - New driver for RENESAS FemtoClock3 Wireless clock generator.
    - Support OCP PTP cards designed and built by Adva.
 
  - CAN:
    - Support recvmsg() flags for own, local and remote traffic
      on CAN BCM sockets.
    - Support for esd GmbH PCIe/402 CAN device family.
    - m_can:
      - Rx/Tx submission coalescing
      - wake on frame Rx
 
  - WiFi:
    - Intel (iwlwifi):
      - enable signaling and payload protected A-MSDUs
      - support wider-bandwidth OFDMA
      - support for new devices
      - bump FW API to 89 for AX devices; 90 for BZ/SC devices
    - MediaTek (mt76):
      - mt7915: newer ADIE version support
      - mt7925: radio temperature sensor support
    - Qualcomm (ath11k):
      - support 6 GHz station power modes: Low Power Indoor (LPI),
        Standard Power) SP and Very Low Power (VLP)
      - QCA6390 & WCN6855: support 2 concurrent station interfaces
      - QCA2066 support
    - Qualcomm (ath12k):
      - refactoring in preparation for Multi-Link Operation (MLO) support
      - 1024 Block Ack window size support
      - firmware-2.bin support
      - support having multiple identical PCI devices (firmware needs to
        have ATH12K_FW_FEATURE_MULTI_QRTR_ID)
      - QCN9274: support split-PHY devices
      - WCN7850: enable Power Save Mode in station mode
      - WCN7850: P2P support
    - RealTek:
      - rtw88: support for more rtw8811cu and rtw8821cu devices
      - rtw89: support SCAN_RANDOM_SN and SET_SCAN_DWELL
      - rtlwifi: speed up USB firmware initialization
      - rtwl8xxxu:
        - RTL8188F: concurrent interface support
        - Channel Switch Announcement (CSA) support in AP mode
    - Broadcom (brcmfmac):
      - per-vendor feature support
      - per-vendor SAE password setup
      - DMI nvram filename quirk for ACEPC W5 Pro
 
 Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Merge tag 'net-next-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next

Pull networking updates from Jakub Kicinski:
 "Core & protocols:

   - Large effort by Eric to lower rtnl_lock pressure and remove locks:

      - Make commonly used parts of rtnetlink (address, route dumps
        etc) lockless, protected by RCU instead of rtnl_lock.

      - Add a netns exit callback which already holds rtnl_lock,
        allowing netns exit to take rtnl_lock once in the core instead
        of once for each driver / callback.

      - Remove locks / serialization in the socket diag interface.

      - Remove 6 calls to synchronize_rcu() while holding rtnl_lock.

      - Remove the dev_base_lock, depend on RCU where necessary.

   - Support busy polling on a per-epoll context basis. Poll length and
     budget parameters can be set independently of system defaults.

   - Introduce struct net_hotdata, to make sure read-mostly global
     config variables fit in as few cache lines as possible.

   - Add optional per-nexthop statistics to ease monitoring / debug of
     ECMP imbalance problems.

   - Support TCP_NOTSENT_LOWAT in MPTCP.

   - Ensure that IPv6 temporary addresses' preferred lifetimes are long
     enough, compared to other configured lifetimes, and at least 2 sec.

   - Support forwarding of ICMP Error messages in IPSec, per RFC 4301.

   - Add support for the independent control state machine for bonding
     per IEEE 802.1AX-2008 5.4.15 in addition to the existing coupled
     control state machine.

   - Add "network ID" to MCTP socket APIs to support hosts with multiple
     disjoint MCTP networks.

   - Re-use the mono_delivery_time skbuff bit for packets which user
     space wants to be sent at a specified time. Maintain the timing
     information while traversing veth links, bridge etc.

   - Take advantage of MSG_SPLICE_PAGES for RxRPC DATA and ACK packets.

   - Simplify many places iterating over netdevs by using an xarray
     instead of a hash table walk (hash table remains in place, for use
     on fastpaths).

   - Speed up scanning for expired routes by keeping a dedicated list.

   - Speed up "generic" XDP by trying harder to avoid large allocations.

   - Support attaching arbitrary metadata to netconsole messages.

  Things we sprinkled into general kernel code:

   - Enforce VM_IOREMAP flag and range in ioremap_page_range and
     introduce VM_SPARSE kind and vm_area_[un]map_pages (used by
     bpf_arena).

   - Rework selftest harness to enable the use of the full range of ksft
     exit code (pass, fail, skip, xfail, xpass).

  Netfilter:

   - Allow userspace to define a table that is exclusively owned by a
     daemon (via netlink socket aliveness) without auto-removing this
     table when the userspace program exits. Such table gets marked as
     orphaned and a restarting management daemon can re-attach/regain
     ownership.

   - Speed up element insertions to nftables' concatenated-ranges set
     type. Compact a few related data structures.

  BPF:

   - Add BPF token support for delegating a subset of BPF subsystem
     functionality from privileged system-wide daemons such as systemd
     through special mount options for userns-bound BPF fs to a trusted
     & unprivileged application.

   - Introduce bpf_arena which is sparse shared memory region between
     BPF program and user space where structures inside the arena can
     have pointers to other areas of the arena, and pointers work
     seamlessly for both user-space programs and BPF programs.

   - Introduce may_goto instruction that is a contract between the
     verifier and the program. The verifier allows the program to loop
     assuming it's behaving well, but reserves the right to terminate
     it.

   - Extend the BPF verifier to enable static subprog calls in spin lock
     critical sections.

   - Support registration of struct_ops types from modules which helps
     projects like fuse-bpf that seeks to implement a new struct_ops
     type.

   - Add support for retrieval of cookies for perf/kprobe multi links.

   - Support arbitrary TCP SYN cookie generation / validation in the TC
     layer with BPF to allow creating SYN flood handling in BPF
     firewalls.

   - Add code generation to inline the bpf_kptr_xchg() helper which
     improves performance when stashing/popping the allocated BPF
     objects.

  Wireless:

   - Add SPP (signaling and payload protected) AMSDU support.

   - Support wider bandwidth OFDMA, as required for EHT operation.

  Driver API:

   - Major overhaul of the Energy Efficient Ethernet internals to
     support new link modes (2.5GE, 5GE), share more code between
     drivers (especially those using phylib), and encourage more
     uniform behavior. Convert and clean up drivers.

   - Define an API for querying per netdev queue statistics from
     drivers.

   - IPSec: account in global stats for fully offloaded sessions.

   - Create a concept of Ethernet PHY Packages at the Device Tree level,
     to allow parameterizing the existing PHY package code.

   - Enable Rx hashing (RSS) on GTP protocol fields.

  Misc:

   - Improvements and refactoring all over networking selftests.

   - Create uniform module aliases for TC classifiers, actions, and
     packet schedulers to simplify creating modprobe policies.

   - Address all missing MODULE_DESCRIPTION() warnings in networking.

   - Extend the Netlink descriptions in YAML to cover message
     encapsulation or "Netlink polymorphism", where interpretation of
     nested attributes depends on link type, classifier type or some
     other "class type".

  Drivers:

   - Ethernet high-speed NICs:
      - Add a new driver for Marvell's Octeon PCI Endpoint NIC VF.
      - Intel (100G, ice, idpf):
         - support E825-C devices
      - nVidia/Mellanox:
         - support devices with one port and multiple PCIe links
      - Broadcom (bnxt):
         - support n-tuple filters
         - support configuring the RSS key
      - Wangxun (ngbe/txgbe):
         - implement irq_domain for TXGBE's sub-interrupts
      - Pensando/AMD:
         - support XDP
         - optimize queue submission and wakeup handling (+17% bps)
         - optimize struct layout, saving 28% of memory on queues

   - Ethernet NICs embedded and virtual:
      - Google cloud vNIC:
         - refactor driver to perform memory allocations for new queue
           config before stopping and freeing the old queue memory
      - Synopsys (stmmac):
         - obey queueMaxSDU and implement counters required by 802.1Qbv
      - Renesas (ravb):
         - support packet checksum offload
         - suspend to RAM and runtime PM support

   - Ethernet switches:
      - nVidia/Mellanox:
         - support for nexthop group statistics
      - Microchip:
         - ksz8: implement PHY loopback
         - add support for KSZ8567, a 7-port 10/100Mbps switch

   - PTP:
      - New driver for RENESAS FemtoClock3 Wireless clock generator.
      - Support OCP PTP cards designed and built by Adva.

   - CAN:
      - Support recvmsg() flags for own, local and remote traffic on CAN
        BCM sockets.
      - Support for esd GmbH PCIe/402 CAN device family.
      - m_can:
         - Rx/Tx submission coalescing
         - wake on frame Rx

   - WiFi:
      - Intel (iwlwifi):
         - enable signaling and payload protected A-MSDUs
         - support wider-bandwidth OFDMA
         - support for new devices
         - bump FW API to 89 for AX devices; 90 for BZ/SC devices
      - MediaTek (mt76):
         - mt7915: newer ADIE version support
         - mt7925: radio temperature sensor support
      - Qualcomm (ath11k):
         - support 6 GHz station power modes: Low Power Indoor (LPI),
           Standard Power) SP and Very Low Power (VLP)
         - QCA6390 & WCN6855: support 2 concurrent station interfaces
         - QCA2066 support
      - Qualcomm (ath12k):
         - refactoring in preparation for Multi-Link Operation (MLO)
           support
         - 1024 Block Ack window size support
         - firmware-2.bin support
         - support having multiple identical PCI devices (firmware needs
           to have ATH12K_FW_FEATURE_MULTI_QRTR_ID)
         - QCN9274: support split-PHY devices
         - WCN7850: enable Power Save Mode in station mode
         - WCN7850: P2P support
      - RealTek:
         - rtw88: support for more rtw8811cu and rtw8821cu devices
         - rtw89: support SCAN_RANDOM_SN and SET_SCAN_DWELL
         - rtlwifi: speed up USB firmware initialization
         - rtwl8xxxu:
             - RTL8188F: concurrent interface support
             - Channel Switch Announcement (CSA) support in AP mode
      - Broadcom (brcmfmac):
         - per-vendor feature support
         - per-vendor SAE password setup
         - DMI nvram filename quirk for ACEPC W5 Pro"

* tag 'net-next-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2255 commits)
  nexthop: Fix splat with CONFIG_DEBUG_PREEMPT=y
  nexthop: Fix out-of-bounds access during attribute validation
  nexthop: Only parse NHA_OP_FLAGS for dump messages that require it
  nexthop: Only parse NHA_OP_FLAGS for get messages that require it
  bpf: move sleepable flag from bpf_prog_aux to bpf_prog
  bpf: hardcode BPF_PROG_PACK_SIZE to 2MB * num_possible_nodes()
  selftests/bpf: Add kprobe multi triggering benchmarks
  ptp: Move from simple ida to xarray
  vxlan: Remove generic .ndo_get_stats64
  vxlan: Do not alloc tstats manually
  devlink: Add comments to use netlink gen tool
  nfp: flower: handle acti_netdevs allocation failure
  net/packet: Add getsockopt support for PACKET_COPY_THRESH
  net/netlink: Add getsockopt support for NETLINK_LISTEN_ALL_NSID
  selftests/bpf: Add bpf_arena_htab test.
  selftests/bpf: Add bpf_arena_list test.
  selftests/bpf: Add unit tests for bpf_arena_alloc/free_pages
  bpf: Add helper macro bpf_addr_space_cast()
  libbpf: Recognize __arena global variables.
  bpftool: Recognize arena map type
  ...
2024-03-12 17:44:08 -07:00
Steven Rostedt (Google)
2aa043a55b tracing/ring-buffer: Fix wait_on_pipe() race
When the trace_pipe_raw file is closed, there should be no new readers on
the file descriptor. This is mostly handled with the waking and wait_index
fields of the iterator. But there's still a slight race.

     CPU 0                              CPU 1
     -----                              -----
                                   wait_index++;
   index = wait_index;
                                   ring_buffer_wake_waiters();
   wait_on_pipe()
     ring_buffer_wait();

The ring_buffer_wait() will miss the wakeup from CPU 1. The problem is
that the ring_buffer_wait() needs the logic of:

        prepare_to_wait();
        if (!condition)
                schedule();

Where the missing condition check is the iter->wait_index update.

Have the ring_buffer_wait() take a conditional callback function and a
data parameter that can be used within the wait_event_interruptible() of
the ring_buffer_wait() function.

In wait_on_pipe(), pass a condition function that will check if the
wait_index has been updated, if it has, it will return true to break out
of the wait_event_interruptible() loop.

Create a new field "closed" in the trace_iterator and set it in the
.flush() callback before calling ring_buffer_wake_waiters().
This will keep any new readers from waiting on a closed file descriptor.

Have the wait_on_pipe() condition callback also check the closed field.

Change the wait_index field of the trace_iterator to atomic_t. There's no
reason it needs to be 'long' and making it atomic and using
atomic_read_acquire() and atomic_fetch_inc_release() will provide the
necessary memory barriers.

Add a "woken" flag to tracing_buffers_splice_read() to exit the loop after
one more try to fetch data. That is, if it waited for data and something
woke it up, it should try to collect any new data and then exit back to
user space.

Link: https://lore.kernel.org/linux-trace-kernel/CAHk-=wgsNgewHFxZAJiAQznwPMqEtQmi1waeS2O1v6L4c_Um5A@mail.gmail.com/
Link: https://lore.kernel.org/linux-trace-kernel/20240312121703.557950713@goodmis.org

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linke li <lilinke99@qq.com>
Cc: Rabin Vincent <rabin@rab.in>
Fixes: f3ddb74ad0 ("tracing: Wake up ring buffer waiters on closing of the file")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-03-12 12:44:48 -04:00
Steven Rostedt (Google)
7af9ded0c2 ring-buffer: Use wait_event_interruptible() in ring_buffer_wait()
Convert ring_buffer_wait() over to wait_event_interruptible(). The default
condition is to execute the wait loop inside __wait_event() just once.

This does not change the ring_buffer_wait() prototype yet, but
restructures the code so that it can take a "cond" and "data" parameter
and will call wait_event_interruptible() with a helper function as the
condition.

The helper function (rb_wait_cond) takes the cond function and data
parameters. It will first check if the buffer hit the watermark defined by
the "full" parameter and then call the passed in condition parameter. If
either are true, it returns true.

If rb_wait_cond() does not return true, it will set the appropriate
"waiters_pending" flag and returns false.

Link: https://lore.kernel.org/linux-trace-kernel/CAHk-=wgsNgewHFxZAJiAQznwPMqEtQmi1waeS2O1v6L4c_Um5A@mail.gmail.com/
Link: https://lore.kernel.org/linux-trace-kernel/20240312121703.399598519@goodmis.org

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linke li <lilinke99@qq.com>
Cc: Rabin Vincent <rabin@rab.in>
Fixes: f3ddb74ad0 ("tracing: Wake up ring buffer waiters on closing of the file")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-03-12 12:44:35 -04:00
Steven Rostedt (Google)
e36f19a645 ring-buffer: Reuse rb_watermark_hit() for the poll logic
The check for knowing if the poll should wait or not is basically the
exact same logic as rb_watermark_hit(). The only difference is that
rb_watermark_hit() also handles the !full case. But for the full case, the
logic is the same. Just call that instead of duplicating the code in
ring_buffer_poll_wait().

Link: https://lore.kernel.org/linux-trace-kernel/20240312131952.802267543@goodmis.org

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-03-12 12:44:07 -04:00
Steven Rostedt (Google)
8145f1c35f ring-buffer: Fix full_waiters_pending in poll
If a reader of the ring buffer is doing a poll, and waiting for the ring
buffer to hit a specific watermark, there could be a case where it gets
into an infinite ping-pong loop.

The poll code has:

  rbwork->full_waiters_pending = true;
  if (!cpu_buffer->shortest_full ||
      cpu_buffer->shortest_full > full)
         cpu_buffer->shortest_full = full;

The writer will see full_waiters_pending and check if the ring buffer is
filled over the percentage of the shortest_full value. If it is, it calls
an irq_work to wake up all the waiters.

But the code could get into a circular loop:

	CPU 0					CPU 1
	-----					-----
 [ Poll ]
   [ shortest_full = 0 ]
   rbwork->full_waiters_pending = true;
					  if (rbwork->full_waiters_pending &&
					      [ buffer percent ] > shortest_full) {
					         rbwork->wakeup_full = true;
					         [ queue_irqwork ]

   cpu_buffer->shortest_full = full;

					  [ IRQ work ]
					  if (rbwork->wakeup_full) {
					        cpu_buffer->shortest_full = 0;
					        wakeup poll waiters;
  [woken]
   if ([ buffer percent ] > full)
      break;
   rbwork->full_waiters_pending = true;
					  if (rbwork->full_waiters_pending &&
					      [ buffer percent ] > shortest_full) {
					         rbwork->wakeup_full = true;
					         [ queue_irqwork ]

   cpu_buffer->shortest_full = full;

					  [ IRQ work ]
					  if (rbwork->wakeup_full) {
					        cpu_buffer->shortest_full = 0;
					        wakeup poll waiters;
  [woken]

 [ Wash, rinse, repeat! ]

In the poll, the shortest_full needs to be set before the
full_pending_waiters, as once that is set, the writer will compare the
current shortest_full (which is incorrect) to decide to call the irq_work,
which will reset the shortest_full (expecting the readers to update it).

Also move the setting of full_waiters_pending after the check if the ring
buffer has the required percentage filled. There's no reason to tell the
writer to wake up waiters if there are no waiters.

Link: https://lore.kernel.org/linux-trace-kernel/20240312131952.630922155@goodmis.org

Cc: stable@vger.kernel.org
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: 42fb0a1e84 ("tracing/ring-buffer: Have polling block on watermark")
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-03-12 12:43:30 -04:00
Steven Rostedt (Google)
761d9473e2 ring-buffer: Do not set shortest_full when full target is hit
The rb_watermark_hit() checks if the amount of data in the ring buffer is
above the percentage level passed in by the "full" variable. If it is, it
returns true.

But it also sets the "shortest_full" field of the cpu_buffer that informs
writers that it needs to call the irq_work if the amount of data on the
ring buffer is above the requested amount.

The rb_watermark_hit() always sets the shortest_full even if the amount in
the ring buffer is what it wants. As it is not going to wait, because it
has what it wants, there's no reason to set shortest_full.

Link: https://lore.kernel.org/linux-trace-kernel/20240312115641.6aa8ba08@gandalf.local.home

Cc: stable@vger.kernel.org
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fixes: 42fb0a1e84 ("tracing/ring-buffer: Have polling block on watermark")
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-03-12 12:40:28 -04:00
Linus Torvalds
685d982112 Core x86 changes for v6.9:
- The biggest change is the rework of the percpu code,
   to support the 'Named Address Spaces' GCC feature,
   by Uros Bizjak:
 
    - This allows C code to access GS and FS segment relative
      memory via variables declared with such attributes,
      which allows the compiler to better optimize those accesses
      than the previous inline assembly code.
 
    - The series also includes a number of micro-optimizations
      for various percpu access methods, plus a number of
      cleanups of %gs accesses in assembly code.
 
    - These changes have been exposed to linux-next testing for
      the last ~5 months, with no known regressions in this area.
 
 - Fix/clean up __switch_to()'s broken but accidentally
   working handling of FPU switching - which also generates
   better code.
 
 - Propagate more RIP-relative addressing in assembly code,
   to generate slightly better code.
 
 - Rework the CPU mitigations Kconfig space to be less idiosyncratic,
   to make it easier for distros to follow & maintain these options.
 
 - Rework the x86 idle code to cure RCU violations and
   to clean up the logic.
 
 - Clean up the vDSO Makefile logic.
 
 - Misc cleanups and fixes.
 
 [ Please note that there's a higher number of merge commits in
   this branch (three) than is usual in x86 topic trees. This happened
   due to the long testing lifecycle of the percpu changes that
   involved 3 merge windows, which generated a longer history
   and various interactions with other core x86 changes that we
   felt better about to carry in a single branch. ]
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-core-2024-03-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull core x86 updates from Ingo Molnar:

 - The biggest change is the rework of the percpu code, to support the
   'Named Address Spaces' GCC feature, by Uros Bizjak:

      - This allows C code to access GS and FS segment relative memory
        via variables declared with such attributes, which allows the
        compiler to better optimize those accesses than the previous
        inline assembly code.

      - The series also includes a number of micro-optimizations for
        various percpu access methods, plus a number of cleanups of %gs
        accesses in assembly code.

      - These changes have been exposed to linux-next testing for the
        last ~5 months, with no known regressions in this area.

 - Fix/clean up __switch_to()'s broken but accidentally working handling
   of FPU switching - which also generates better code

 - Propagate more RIP-relative addressing in assembly code, to generate
   slightly better code

 - Rework the CPU mitigations Kconfig space to be less idiosyncratic, to
   make it easier for distros to follow & maintain these options

 - Rework the x86 idle code to cure RCU violations and to clean up the
   logic

 - Clean up the vDSO Makefile logic

 - Misc cleanups and fixes

* tag 'x86-core-2024-03-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (52 commits)
  x86/idle: Select idle routine only once
  x86/idle: Let prefer_mwait_c1_over_halt() return bool
  x86/idle: Cleanup idle_setup()
  x86/idle: Clean up idle selection
  x86/idle: Sanitize X86_BUG_AMD_E400 handling
  sched/idle: Conditionally handle tick broadcast in default_idle_call()
  x86: Increase brk randomness entropy for 64-bit systems
  x86/vdso: Move vDSO to mmap region
  x86/vdso/kbuild: Group non-standard build attributes and primary object file rules together
  x86/vdso: Fix rethunk patching for vdso-image-{32,64}.o
  x86/retpoline: Ensure default return thunk isn't used at runtime
  x86/vdso: Use CONFIG_COMPAT_32 to specify vdso32
  x86/vdso: Use $(addprefix ) instead of $(foreach )
  x86/vdso: Simplify obj-y addition
  x86/vdso: Consolidate targets and clean-files
  x86/bugs: Rename CONFIG_RETHUNK              => CONFIG_MITIGATION_RETHUNK
  x86/bugs: Rename CONFIG_CPU_SRSO             => CONFIG_MITIGATION_SRSO
  x86/bugs: Rename CONFIG_CPU_IBRS_ENTRY       => CONFIG_MITIGATION_IBRS_ENTRY
  x86/bugs: Rename CONFIG_CPU_UNRET_ENTRY      => CONFIG_MITIGATION_UNRET_ENTRY
  x86/bugs: Rename CONFIG_SLS                  => CONFIG_MITIGATION_SLS
  ...
2024-03-11 19:53:15 -07:00
Jakub Kicinski
5f20e6ab1f for-netdev
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Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Alexei Starovoitov says:

====================
pull-request: bpf-next 2024-03-11

We've added 59 non-merge commits during the last 9 day(s) which contain
a total of 88 files changed, 4181 insertions(+), 590 deletions(-).

The main changes are:

1) Enforce VM_IOREMAP flag and range in ioremap_page_range and introduce
   VM_SPARSE kind and vm_area_[un]map_pages to be used in bpf_arena,
   from Alexei.

2) Introduce bpf_arena which is sparse shared memory region between bpf
   program and user space where structures inside the arena can have
   pointers to other areas of the arena, and pointers work seamlessly for
   both user-space programs and bpf programs, from Alexei and Andrii.

3) Introduce may_goto instruction that is a contract between the verifier
   and the program. The verifier allows the program to loop assuming it's
   behaving well, but reserves the right to terminate it, from Alexei.

4) Use IETF format for field definitions in the BPF standard
   document, from Dave.

5) Extend struct_ops libbpf APIs to allow specify version suffixes for
   stuct_ops map types, share the same BPF program between several map
   definitions, and other improvements, from Eduard.

6) Enable struct_ops support for more than one page in trampolines,
   from Kui-Feng.

7) Support kCFI + BPF on riscv64, from Puranjay.

8) Use bpf_prog_pack for arm64 bpf trampoline, from Puranjay.

9) Fix roundup_pow_of_two undefined behavior on 32-bit archs, from Toke.
====================

Link: https://lore.kernel.org/r/20240312003646.8692-1-alexei.starovoitov@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-03-11 18:06:04 -07:00
Andrii Nakryiko
66c8473135 bpf: move sleepable flag from bpf_prog_aux to bpf_prog
prog->aux->sleepable is checked very frequently as part of (some) BPF
program run hot paths. So this extra aux indirection seems wasteful and
on busy systems might cause unnecessary memory cache misses.

Let's move sleepable flag into prog itself to eliminate unnecessary
pointer dereference.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Message-ID: <20240309004739.2961431-1-andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-03-11 16:41:25 -07:00
Linus Torvalds
fa4b851b4a Tracing fixes for v6.8-rc7:
- Do not allow large strings (> 4096) as single write to trace_marker
 
   The size of a string written into trace_marker was determined by
   the size of the sub-buffer in the ring buffer. That size is
   dependent on the PAGE_SIZE of the architecture as it can be mapped
   into user space. But on PowerPC, where PAGE_SIZE is 64K, that made
   the limit of the string of writing into trace_marker 64K.
 
   One of the selftests looks at the size of the ring buffer sub-buffers
   and writes that plus more into the trace_marker. The write will take
   what it can and report back what it consumed so that the user space
   application (like echo) will write the rest of the string. The string
   is stored in the ring buffer and can be read via the "trace" or
   "trace_pipe" files.
 
   The reading of the ring buffer uses vsnprintf(), which uses a precision
   "%.*s" to make sure it only reads what is stored in the buffer, as
   a bug could cause the string to be non terminated.
 
   With the combination of the precision change and the PAGE_SIZE of 64K
   allowing huge strings to be added into the ring buffer, plus the test
   that would actually stress that limit, a bug was reported that
   the precision used was too big for "%.*s" as the string was close to
   64K in size and the max precision of vsnprintf is 32K.
 
   Linus suggested not to have that precision as it could hide a bug
   if the string was again stored without a nul byte.
 
   Another issue that was brought up is that the trace_seq buffer is
   also based on PAGE_SIZE even though it is not tied to the architecture
   limit like the ring buffer sub-buffer is. Having it be 64K * 2 is
   simply just too big and wasting memory on systems with 64K page sizes.
   It is now hardcoded to 8K which is what all other architectures with
   4K PAGE_SIZE has.
 
   Finally, the write to trace_marker is now limited to 4K as there is no
   reason to write larger strings into trace_marker.
 
 - ring_buffer_wait() should not loop.
   The ring_buffer_wait() does not have the full context (yet) on if it
   should loop or not. Just exit the loop as soon as its woken up and
   let the callers decide to loop or not (they already do, so it's a bit
   redundant).
 
 - Fix shortest_full field to be the smallest amount in the ring buffer that
   a waiter is waiting for. The "shortest_full" field is updated when a new
   waiter comes in and wants to wait for a smaller amount of data in the
   ring buffer than other waiters. But after all waiters are woken up, it's
   not reset, so if another waiter comes in wanting to wait for more data,
   it will be woken up when the ring buffer has a smaller amount from what
   the previous waiters were waiting for.
 
 - The wake up all waiters on close is incorrectly called frome .release()
   and not from .flush() so it will never wake up any waiters as the
   .release() will not get called until all .read() calls are finished. And the
   wakeup is for the waiters in those .read() calls.
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Merge tag 'trace-ring-buffer-v6.8-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing fixes from Steven Rostedt:

 - Do not allow large strings (> 4096) as single write to trace_marker

   The size of a string written into trace_marker was determined by the
   size of the sub-buffer in the ring buffer. That size is dependent on
   the PAGE_SIZE of the architecture as it can be mapped into user
   space. But on PowerPC, where PAGE_SIZE is 64K, that made the limit of
   the string of writing into trace_marker 64K.

   One of the selftests looks at the size of the ring buffer sub-buffers
   and writes that plus more into the trace_marker. The write will take
   what it can and report back what it consumed so that the user space
   application (like echo) will write the rest of the string. The string
   is stored in the ring buffer and can be read via the "trace" or
   "trace_pipe" files.

   The reading of the ring buffer uses vsnprintf(), which uses a
   precision "%.*s" to make sure it only reads what is stored in the
   buffer, as a bug could cause the string to be non terminated.

   With the combination of the precision change and the PAGE_SIZE of 64K
   allowing huge strings to be added into the ring buffer, plus the test
   that would actually stress that limit, a bug was reported that the
   precision used was too big for "%.*s" as the string was close to 64K
   in size and the max precision of vsnprintf is 32K.

   Linus suggested not to have that precision as it could hide a bug if
   the string was again stored without a nul byte.

   Another issue that was brought up is that the trace_seq buffer is
   also based on PAGE_SIZE even though it is not tied to the
   architecture limit like the ring buffer sub-buffer is. Having it be
   64K * 2 is simply just too big and wasting memory on systems with 64K
   page sizes. It is now hardcoded to 8K which is what all other
   architectures with 4K PAGE_SIZE has.

   Finally, the write to trace_marker is now limited to 4K as there is
   no reason to write larger strings into trace_marker.

 - ring_buffer_wait() should not loop.

   The ring_buffer_wait() does not have the full context (yet) on if it
   should loop or not. Just exit the loop as soon as its woken up and
   let the callers decide to loop or not (they already do, so it's a bit
   redundant).

 - Fix shortest_full field to be the smallest amount in the ring buffer
   that a waiter is waiting for. The "shortest_full" field is updated
   when a new waiter comes in and wants to wait for a smaller amount of
   data in the ring buffer than other waiters. But after all waiters are
   woken up, it's not reset, so if another waiter comes in wanting to
   wait for more data, it will be woken up when the ring buffer has a
   smaller amount from what the previous waiters were waiting for.

 - The wake up all waiters on close is incorrectly called frome
   .release() and not from .flush() so it will never wake up any waiters
   as the .release() will not get called until all .read() calls are
   finished. And the wakeup is for the waiters in those .read() calls.

* tag 'trace-ring-buffer-v6.8-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing: Use .flush() call to wake up readers
  ring-buffer: Fix resetting of shortest_full
  ring-buffer: Fix waking up ring buffer readers
  tracing: Limit trace_marker writes to just 4K
  tracing: Limit trace_seq size to just 8K and not depend on architecture PAGE_SIZE
  tracing: Remove precision vsnprintf() check from print event
2024-03-10 11:53:21 -07:00
Steven Rostedt (Google)
e5d7c19165 tracing: Use .flush() call to wake up readers
The .release() function does not get called until all readers of a file
descriptor are finished.

If a thread is blocked on reading a file descriptor in ring_buffer_wait(),
and another thread closes the file descriptor, it will not wake up the
other thread as ring_buffer_wake_waiters() is called by .release(), and
that will not get called until the .read() is finished.

The issue originally showed up in trace-cmd, but the readers are actually
other processes with their own file descriptors. So calling close() would wake
up the other tasks because they are blocked on another descriptor then the
one that was closed(). But there's other wake ups that solve that issue.

When a thread is blocked on a read, it can still hang even when another
thread closed its descriptor.

This is what the .flush() callback is for. Have the .flush() wake up the
readers.

Link: https://lore.kernel.org/linux-trace-kernel/20240308202432.107909457@goodmis.org

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linke li <lilinke99@qq.com>
Cc: Rabin Vincent <rabin@rab.in>
Fixes: f3ddb74ad0 ("tracing: Wake up ring buffer waiters on closing of the file")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-03-10 12:27:47 -04:00
Steven Rostedt (Google)
68282dd930 ring-buffer: Fix resetting of shortest_full
The "shortest_full" variable is used to keep track of the waiter that is
waiting for the smallest amount on the ring buffer before being woken up.
When a tasks waits on the ring buffer, it passes in a "full" value that is
a percentage. 0 means wake up on any data. 1-100 means wake up from 1% to
100% full buffer.

As all waiters are on the same wait queue, the wake up happens for the
waiter with the smallest percentage.

The problem is that the smallest_full on the cpu_buffer that stores the
smallest amount doesn't get reset when all the waiters are woken up. It
does get reset when the ring buffer is reset (echo > /sys/kernel/tracing/trace).

This means that tasks may be woken up more often then when they want to
be. Instead, have the shortest_full field get reset just before waking up
all the tasks. If the tasks wait again, they will update the shortest_full
before sleeping.

Also add locking around setting of shortest_full in the poll logic, and
change "work" to "rbwork" to match the variable name for rb_irq_work
structures that are used in other places.

Link: https://lore.kernel.org/linux-trace-kernel/20240308202431.948914369@goodmis.org

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linke li <lilinke99@qq.com>
Cc: Rabin Vincent <rabin@rab.in>
Fixes: 2c2b0a78b3 ("ring-buffer: Add percentage of ring buffer full to wake up reader")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-03-10 12:27:40 -04:00
Steven Rostedt (Google)
b359457368 ring-buffer: Fix waking up ring buffer readers
A task can wait on a ring buffer for when it fills up to a specific
watermark. The writer will check the minimum watermark that waiters are
waiting for and if the ring buffer is past that, it will wake up all the
waiters.

The waiters are in a wait loop, and will first check if a signal is
pending and then check if the ring buffer is at the desired level where it
should break out of the loop.

If a file that uses a ring buffer closes, and there's threads waiting on
the ring buffer, it needs to wake up those threads. To do this, a
"wait_index" was used.

Before entering the wait loop, the waiter will read the wait_index. On
wakeup, it will check if the wait_index is different than when it entered
the loop, and will exit the loop if it is. The waker will only need to
update the wait_index before waking up the waiters.

This had a couple of bugs. One trivial one and one broken by design.

The trivial bug was that the waiter checked the wait_index after the
schedule() call. It had to be checked between the prepare_to_wait() and
the schedule() which it was not.

The main bug is that the first check to set the default wait_index will
always be outside the prepare_to_wait() and the schedule(). That's because
the ring_buffer_wait() doesn't have enough context to know if it should
break out of the loop.

The loop itself is not needed, because all the callers to the
ring_buffer_wait() also has their own loop, as the callers have a better
sense of what the context is to decide whether to break out of the loop
or not.

Just have the ring_buffer_wait() block once, and if it gets woken up, exit
the function and let the callers decide what to do next.

Link: https://lore.kernel.org/all/CAHk-=whs5MdtNjzFkTyaUy=vHi=qwWgPi0JgTe6OYUYMNSRZfg@mail.gmail.com/
Link: https://lore.kernel.org/linux-trace-kernel/20240308202431.792933613@goodmis.org

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linke li <lilinke99@qq.com>
Cc: Rabin Vincent <rabin@rab.in>
Fixes: e30f53aad2 ("tracing: Do not busy wait in buffer splice")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-03-10 12:24:59 -04:00
Jakub Kicinski
e3afe5dd3a Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Cross-merge networking fixes after downstream PR.

No conflicts.

Adjacent changes:

net/core/page_pool_user.c
  0b11b1c5c3 ("netdev: let netlink core handle -EMSGSIZE errors")
  429679dcf7 ("page_pool: fix netlink dump stop/resume")

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-03-07 10:29:36 -08:00
Steven Rostedt (Google)
095fe48912 tracing: Limit trace_marker writes to just 4K
Limit the max print event of trace_marker to just 4K string size. This must
also be less than the amount that can be held by a trace_seq along with
the text that is before the output (like the task name, PID, CPU, state,
etc). As trace_seq is made to handle large events (some greater than 4K).
Make the max size of a trace_marker write event be 4K which is guaranteed
to fit in the trace_seq buffer.

Link: https://lore.kernel.org/linux-trace-kernel/20240304223433.4ba47dff@gandalf.local.home

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-03-06 13:27:26 -05:00
Steven Rostedt (Google)
5efd3e2aef tracing: Remove precision vsnprintf() check from print event
This reverts 60be76eeab ("tracing: Add size check when printing
trace_marker output"). The only reason the precision check was added
was because of a bug that miscalculated the write size of the string into
the ring buffer and it truncated it removing the terminating nul byte. On
reading the trace it crashed the kernel. But this was due to the bug in
the code that happened during development and should never happen in
practice. If anything, the precision can hide bugs where the string in the
ring buffer isn't nul terminated and it will not be checked.

Link: https://lore.kernel.org/all/C7E7AF1A-D30F-4D18-B8E5-AF1EF58004F5@linux.ibm.com/
Link: https://lore.kernel.org/linux-trace-kernel/20240227125706.04279ac2@gandalf.local.home
Link: https://lore.kernel.org/all/20240302111244.3a1674be@gandalf.local.home/
Link: https://lore.kernel.org/linux-trace-kernel/20240304174341.2a561d9f@gandalf.local.home

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Fixes: 60be76eeab ("tracing: Add size check when printing trace_marker output")
Reported-by: Sachin Sant <sachinp@linux.ibm.com>
Tested-by: Sachin Sant <sachinp@linux.ibm.com>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-03-06 13:26:26 -05:00
Masami Hiramatsu (Google)
25f00e40ce tracing/probes: Support $argN in return probe (kprobe and fprobe)
Support accessing $argN in the return probe events. This will help users to
record entry data in function return (exit) event for simplfing the function
entry/exit information in one event, and record the result values (e.g.
allocated object/initialized object) at function exit.

For example, if we have a function `int init_foo(struct foo *obj, int param)`
sometimes we want to check how `obj` is initialized. In such case, we can
define a new return event like below;

 # echo 'r init_foo retval=$retval param=$arg2 field1=+0($arg1)' >> kprobe_events

Thus it records the function parameter `param` and its result `obj->field1`
(the dereference will be done in the function exit timing) value at once.

This also support fprobe, BTF args and'$arg*'. So if CONFIG_DEBUG_INFO_BTF
is enabled, we can trace both function parameters and the return value
by following command.

 # echo 'f target_function%return $arg* $retval' >> dynamic_events

Link: https://lore.kernel.org/all/170952365552.229804.224112990211602895.stgit@devnote2/

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2024-03-07 00:27:34 +09:00
Masami Hiramatsu (Google)
c18f9eabee tracing: Remove redundant #else block for BTF args from README
Remove redundant #else block for BTF args from README message.
This is a cleanup, so no change on the message.

Link: https://lore.kernel.org/all/170952364558.229804.17285528811097152410.stgit@devnote2/

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-03-07 00:27:25 +09:00
Masami Hiramatsu (Google)
035ba76014 tracing/probes: cleanup: Set trace_probe::nr_args at trace_probe_init
Instead of incrementing the trace_probe::nr_args, init it at
trace_probe_init(). Without this change, there is no way to get the number
of trace_probe arguments while parsing it.
This is a cleanup, so the behavior is not changed.

Link: https://lore.kernel.org/all/170952363585.229804.13060759900346411951.stgit@devnote2/

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2024-03-07 00:27:15 +09:00
Masami Hiramatsu (Google)
032330abd0 tracing/probes: Cleanup probe argument parser
Cleanup traceprobe_parse_probe_arg_body() to split out the
type parser and post-processing part of fetch_insn.
This makes no functional change.

Link: https://lore.kernel.org/all/170952362603.229804.9942703761682605372.stgit@devnote2/

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-03-07 00:27:06 +09:00
Masami Hiramatsu (Google)
7e37b6bc3c tracing/fprobe-event: cleanup: Fix a wrong comment in fprobe event
Despite the fprobe event,  "Kretprobe" was commented. So fix it.

Link: https://lore.kernel.org/all/170952361630.229804.10832200172327797860.stgit@devnote2/

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-03-07 00:26:57 +09:00
Jakub Kicinski
4b2765ae41 bpf-next-for-netdev
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Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Daniel Borkmann says:

====================
pull-request: bpf-next 2024-02-29

We've added 119 non-merge commits during the last 32 day(s) which contain
a total of 150 files changed, 3589 insertions(+), 995 deletions(-).

The main changes are:

1) Extend the BPF verifier to enable static subprog calls in spin lock
   critical sections, from Kumar Kartikeya Dwivedi.

2) Fix confusing and incorrect inference of PTR_TO_CTX argument type
   in BPF global subprogs, from Andrii Nakryiko.

3) Larger batch of riscv BPF JIT improvements and enabling inlining
   of the bpf_kptr_xchg() for RV64, from Pu Lehui.

4) Allow skeleton users to change the values of the fields in struct_ops
   maps at runtime, from Kui-Feng Lee.

5) Extend the verifier's capabilities of tracking scalars when they
   are spilled to stack, especially when the spill or fill is narrowing,
   from Maxim Mikityanskiy & Eduard Zingerman.

6) Various BPF selftest improvements to fix errors under gcc BPF backend,
   from Jose E. Marchesi.

7) Avoid module loading failure when the module trying to register
   a struct_ops has its BTF section stripped, from Geliang Tang.

8) Annotate all kfuncs in .BTF_ids section which eventually allows
   for automatic kfunc prototype generation from bpftool, from Daniel Xu.

9) Several updates to the instruction-set.rst IETF standardization
   document, from Dave Thaler.

10) Shrink the size of struct bpf_map resp. bpf_array,
    from Alexei Starovoitov.

11) Initial small subset of BPF verifier prepwork for sleepable bpf_timer,
    from Benjamin Tissoires.

12) Fix bpftool to be more portable to musl libc by using POSIX's
    basename(), from Arnaldo Carvalho de Melo.

13) Add libbpf support to gcc in CORE macro definitions,
    from Cupertino Miranda.

14) Remove a duplicate type check in perf_event_bpf_event,
    from Florian Lehner.

15) Fix bpf_spin_{un,}lock BPF helpers to actually annotate them
    with notrace correctly, from Yonghong Song.

16) Replace the deprecated bpf_lpm_trie_key 0-length array with flexible
    array to fix build warnings, from Kees Cook.

17) Fix resolve_btfids cross-compilation to non host-native endianness,
    from Viktor Malik.

* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (119 commits)
  selftests/bpf: Test if shadow types work correctly.
  bpftool: Add an example for struct_ops map and shadow type.
  bpftool: Generated shadow variables for struct_ops maps.
  libbpf: Convert st_ops->data to shadow type.
  libbpf: Set btf_value_type_id of struct bpf_map for struct_ops.
  bpf: Replace bpf_lpm_trie_key 0-length array with flexible array
  bpf, arm64: use bpf_prog_pack for memory management
  arm64: patching: implement text_poke API
  bpf, arm64: support exceptions
  arm64: stacktrace: Implement arch_bpf_stack_walk() for the BPF JIT
  bpf: add is_async_callback_calling_insn() helper
  bpf: introduce in_sleepable() helper
  bpf: allow more maps in sleepable bpf programs
  selftests/bpf: Test case for lacking CFI stub functions.
  bpf: Check cfi_stubs before registering a struct_ops type.
  bpf: Clarify batch lookup/lookup_and_delete semantics
  bpf, docs: specify which BPF_ABS and BPF_IND fields were zero
  bpf, docs: Fix typos in instruction-set.rst
  selftests/bpf: update tcp_custom_syncookie to use scalar packet offset
  bpf: Shrink size of struct bpf_map/bpf_array.
  ...
====================

Link: https://lore.kernel.org/r/20240301001625.8800-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-03-02 20:50:59 -08:00
Linus Torvalds
161671a6eb Probes fixes for v6.8-rc5:
- fprobe: Fix to allocate entry_data_size buffer for each rethook
     instance. This fixes a buffer overrun bug (which leads a kernel
     crash) when fprobe user uses its entry_data in the entry_handler.
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Merge tag 'probes-fixes-v6.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull fprobe fix from Masami Hiramatsu:

 - allocate entry_data_size buffer for each rethook instance.

   This fixes a buffer overrun bug (which leads a kernel crash)
   when fprobe user uses its entry_data in the entry_handler.

* tag 'probes-fixes-v6.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  fprobe: Fix to allocate entry_data_size buffer with rethook instances
2024-03-01 11:17:23 -08:00
Masami Hiramatsu (Google)
6572786006 fprobe: Fix to allocate entry_data_size buffer with rethook instances
Fix to allocate fprobe::entry_data_size buffer with rethook instances.
If fprobe doesn't allocate entry_data_size buffer for each rethook instance,
fprobe entry handler can cause a buffer overrun when storing entry data in
entry handler.

Link: https://lore.kernel.org/all/170920576727.107552.638161246679734051.stgit@devnote2/

Reported-by: Jiri Olsa <olsajiri@gmail.com>
Closes: https://lore.kernel.org/all/Zd9eBn2FTQzYyg7L@krava/
Fixes: 4bbd934556 ("kprobes: kretprobe scalability improvement")
Cc: stable@vger.kernel.org
Tested-by: Jiri Olsa <olsajiri@gmail.com>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2024-03-01 09:18:24 +09:00
Jakub Kicinski
fecc51559a Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Cross-merge networking fixes after downstream PR.

Conflicts:

net/ipv4/udp.c
  f796feabb9 ("udp: add local "peek offset enabled" flag")
  56667da739 ("net: implement lockless setsockopt(SO_PEEK_OFF)")

Adjacent changes:

net/unix/garbage.c
  aa82ac51d6 ("af_unix: Drop oob_skb ref before purging queue in GC.")
  11498715f2 ("af_unix: Remove io_uring code for GC.")

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-02-22 15:29:26 -08:00
Steven Rostedt (Google)
e78fb4eac8 ring-buffer: Do not let subbuf be bigger than write mask
The data on the subbuffer is measured by a write variable that also
contains status flags. The counter is just 20 bits in length. If the
subbuffer is bigger than then counter, it will fail.

Make sure that the subbuffer can not be set to greater than the counter
that keeps track of the data on the subbuffer.

Link: https://lore.kernel.org/linux-trace-kernel/20240220095112.77e9cb81@gandalf.local.home

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fixes: 2808e31ec1 ("ring-buffer: Add interface for configuring trace sub buffer size")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-02-21 09:15:23 -05:00
Linus Torvalds
ad645dea35 Probes fixes for v6.8-rc4:
- tracing/probes: Fix BTF structure member finder to find the members
     which are placed after any anonymous union member correctly.
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Merge tag 'probes-fixes-v6.8-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull probes fix from Masami Hiramatsu:

 - tracing/probes: Fix BTF structure member finder to find the members
   which are placed after any anonymous union member correctly.

* tag 'probes-fixes-v6.8-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing/probes: Fix to search structure fields correctly
2024-02-17 07:59:47 -08:00
Masami Hiramatsu (Google)
9704669c38 tracing/probes: Fix to search structure fields correctly
Fix to search a field from the structure which has anonymous union
correctly.
Since the reference `type` pointer was updated in the loop, the search
loop suddenly aborted where it hits an anonymous union. Thus it can not
find the field after the anonymous union. This avoids updating the
cursor `type` pointer in the loop.

Link: https://lore.kernel.org/all/170791694361.389532.10047514554799419688.stgit@devnote2/

Fixes: 302db0f5b3 ("tracing/probes: Add a function to search a member of a struct/union")
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2024-02-17 21:25:42 +09:00
Linus Torvalds
4b6f7c624e Tracing fixes for v6.8:
- Fix the #ifndef that didn't have CONFIG_ on HAVE_DYNAMIC_FTRACE_WITH_REGS
   The fix to have dynamic trampolines work with x86 broke arm64 as
   the config used in the #ifdef was HAVE_DYNAMIC_FTRACE_WITH_REGS and not
   CONFIG_HAVE_DYNAMIC_FTRACE_WITH_REGS which removed the fix that the
   previous fix was to fix.
 
 - Fix tracing_on state
   The code to test if "tracing_on" is set used ring_buffer_record_is_on()
   which returns false if the ring buffer isn't able to be written to.
   But the ring buffer disable has several bits that disable it.
   One is internal disabling which is used for resizing and other
   modifications of the ring buffer. But the "tracing_on" user space
   visible flag should only report if tracing is actually on and not
   internally disabled, as this can cause confusion as writing "1"
   when it is disabled will not enable it.
 
   Instead use ring_buffer_record_is_set_on() which shows the user space
   visible settings.
 
 - Fix a false positive kmemleak on saved cmdlines
   Now that the saved_cmdlines structure is allocated via alloc_page()
   and not via kmalloc() it has become invisible to kmemleak.
   The allocation done to one of its pointers was flagged as a
   dangling allocation leak. Make kmemleak aware of this allocation
   and free.
 
 - Fix synthetic event dynamic strings.
   A update that cleaned up the synthetic event code removed the
   return value of trace_string(), and had it return zero instead
   of the length, causing dynamic strings in the synthetic event
   to always have zero size.
 
 - Clean up documentation and header files for seq_buf
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Merge tag 'trace-v6.8-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing fixes from Steven Rostedt:

 - Fix the #ifndef that didn't have the 'CONFIG_' prefix on
   HAVE_DYNAMIC_FTRACE_WITH_REGS

   The fix to have dynamic trampolines work with x86 broke arm64 as the
   config used in the #ifdef was HAVE_DYNAMIC_FTRACE_WITH_REGS and not
   CONFIG_HAVE_DYNAMIC_FTRACE_WITH_REGS which removed the fix that the
   previous fix was to fix.

 - Fix tracing_on state

   The code to test if "tracing_on" is set incorrectly used
   ring_buffer_record_is_on() which returns false if the ring buffer
   isn't able to be written to.

   But the ring buffer disable has several bits that disable it. One is
   internal disabling which is used for resizing and other modifications
   of the ring buffer. But the "tracing_on" user space visible flag
   should only report if tracing is actually on and not internally
   disabled, as this can cause confusion as writing "1" when it is
   disabled will not enable it.

   Instead use ring_buffer_record_is_set_on() which shows the user space
   visible settings.

 - Fix a false positive kmemleak on saved cmdlines

   Now that the saved_cmdlines structure is allocated via alloc_page()
   and not via kmalloc() it has become invisible to kmemleak. The
   allocation done to one of its pointers was flagged as a dangling
   allocation leak. Make kmemleak aware of this allocation and free.

 - Fix synthetic event dynamic strings

   An update that cleaned up the synthetic event code removed the return
   value of trace_string(), and had it return zero instead of the
   length, causing dynamic strings in the synthetic event to always have
   zero size.

 - Clean up documentation and header files for seq_buf

* tag 'trace-v6.8-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  seq_buf: Fix kernel documentation
  seq_buf: Don't use "proxy" headers
  tracing/synthetic: Fix trace_string() return value
  tracing: Inform kmemleak of saved_cmdlines allocation
  tracing: Use ring_buffer_record_is_set_on() in tracer_tracing_is_on()
  tracing: Fix HAVE_DYNAMIC_FTRACE_WITH_REGS ifdef
2024-02-16 10:33:51 -08:00
Jakub Kicinski
73be9a3aab Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Cross-merge networking fixes after downstream PR.

No conflicts.

Adjacent changes:

net/core/dev.c
  9f30831390 ("net: add rcu safety to rtnl_prop_list_size()")
  723de3ebef ("net: free altname using an RCU callback")

net/unix/garbage.c
  11498715f2 ("af_unix: Remove io_uring code for GC.")
  25236c91b5 ("af_unix: Fix task hung while purging oob_skb in GC.")

drivers/net/ethernet/renesas/ravb_main.c
  ed4adc0720 ("net: ravb: Count packets instead of descriptors in GbEth RX path"
)
  c2da940857 ("ravb: Add Rx checksum offload support for GbEth")

net/mptcp/protocol.c
  bdd70eb689 ("mptcp: drop the push_pending field")
  28e5c13805 ("mptcp: annotate lockless accesses around read-mostly fields")

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-02-15 16:20:04 -08:00
Thorsten Blum
9b6326354c tracing/synthetic: Fix trace_string() return value
Fix trace_string() by assigning the string length to the return variable
which got lost in commit ddeea494a1 ("tracing/synthetic: Use union
instead of casts") and caused trace_string() to always return 0.

Link: https://lore.kernel.org/linux-trace-kernel/20240214220555.711598-1-thorsten.blum@toblux.com

Cc: stable@vger.kernel.org
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fixes: ddeea494a1 ("tracing/synthetic: Use union instead of casts")
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-02-15 11:40:01 -05:00
Steven Rostedt (Google)
2394ac4145 tracing: Inform kmemleak of saved_cmdlines allocation
The allocation of the struct saved_cmdlines_buffer structure changed from:

        s = kmalloc(sizeof(*s), GFP_KERNEL);
	s->saved_cmdlines = kmalloc_array(TASK_COMM_LEN, val, GFP_KERNEL);

to:

	orig_size = sizeof(*s) + val * TASK_COMM_LEN;
	order = get_order(orig_size);
	size = 1 << (order + PAGE_SHIFT);
	page = alloc_pages(GFP_KERNEL, order);
	if (!page)
		return NULL;

	s = page_address(page);
	memset(s, 0, sizeof(*s));

	s->saved_cmdlines = kmalloc_array(TASK_COMM_LEN, val, GFP_KERNEL);

Where that s->saved_cmdlines allocation looks to be a dangling allocation
to kmemleak. That's because kmemleak only keeps track of kmalloc()
allocations. For allocations that use page_alloc() directly, the kmemleak
needs to be explicitly informed about it.

Add kmemleak_alloc() and kmemleak_free() around the page allocation so
that it doesn't give the following false positive:

unreferenced object 0xffff8881010c8000 (size 32760):
  comm "swapper", pid 0, jiffies 4294667296
  hex dump (first 32 bytes):
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff  ................
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff  ................
  backtrace (crc ae6ec1b9):
    [<ffffffff86722405>] kmemleak_alloc+0x45/0x80
    [<ffffffff8414028d>] __kmalloc_large_node+0x10d/0x190
    [<ffffffff84146ab1>] __kmalloc+0x3b1/0x4c0
    [<ffffffff83ed7103>] allocate_cmdlines_buffer+0x113/0x230
    [<ffffffff88649c34>] tracer_alloc_buffers.isra.0+0x124/0x460
    [<ffffffff8864a174>] early_trace_init+0x14/0xa0
    [<ffffffff885dd5ae>] start_kernel+0x12e/0x3c0
    [<ffffffff885f5758>] x86_64_start_reservations+0x18/0x30
    [<ffffffff885f582b>] x86_64_start_kernel+0x7b/0x80
    [<ffffffff83a001c3>] secondary_startup_64_no_verify+0x15e/0x16b

Link: https://lore.kernel.org/linux-trace-kernel/87r0hfnr9r.fsf@kernel.org/
Link: https://lore.kernel.org/linux-trace-kernel/20240214112046.09a322d6@gandalf.local.home

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Fixes: 44dc5c41b5 ("tracing: Fix wasted memory in saved_cmdlines logic")
Reported-by: Kalle Valo <kvalo@kernel.org>
Tested-by: Kalle Valo <kvalo@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-02-14 12:36:34 -05:00
Ingo Molnar
4589f199eb Merge branch 'x86/bugs' into x86/core, to pick up pending changes before dependent patches
Merge in pending alternatives patching infrastructure changes, before
applying more patches.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2024-02-14 10:49:37 +01:00
Sven Schnelle
a6eaa24f1c tracing: Use ring_buffer_record_is_set_on() in tracer_tracing_is_on()
tracer_tracing_is_on() checks whether record_disabled is not zero. This
checks both the record_disabled counter and the RB_BUFFER_OFF flag.
Reading the source it looks like this function should only check for
the RB_BUFFER_OFF flag. Therefore use ring_buffer_record_is_set_on().
This fixes spurious fails in the 'test for function traceon/off triggers'
test from the ftrace testsuite when the system is under load.

Link: https://lore.kernel.org/linux-trace-kernel/20240205065340.2848065-1-svens@linux.ibm.com

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Tested-By: Mete Durlu <meted@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-02-13 12:04:17 -05:00
Petr Pavlu
bdbddb109c tracing: Fix HAVE_DYNAMIC_FTRACE_WITH_REGS ifdef
Commit a8b9cf62ad ("ftrace: Fix DIRECT_CALLS to use SAVE_REGS by
default") attempted to fix an issue with direct trampolines on x86, see
its description for details. However, it wrongly referenced the
HAVE_DYNAMIC_FTRACE_WITH_REGS config option and the problem is still
present.

Add the missing "CONFIG_" prefix for the logic to work as intended.

Link: https://lore.kernel.org/linux-trace-kernel/20240213132434.22537-1-petr.pavlu@suse.com

Fixes: a8b9cf62ad ("ftrace: Fix DIRECT_CALLS to use SAVE_REGS by default")
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-02-13 11:56:49 -05:00
Linus Torvalds
ca8a66738a Tracing fixes for v6.8-rc3:
- Fix broken direct trampolines being called when another callback is
   attached the same function. ARM 64 does not support FTRACE_WITH_REGS, and
   when it added direct trampoline calls from ftrace, it removed the
   "WITH_REGS" flag from the ftrace_ops for direct trampolines. This broke
   x86 as x86 requires direct trampolines to have WITH_REGS. This wasn't
   noticed because direct trampolines work as long as the function it is
   attached to is not shared with other callbacks (like the function tracer).
   When there's other callbacks, a helper trampoline is called, to call all
   the non direct callbacks and when it returns, the direct trampoline is
   called. For x86, the direct trampoline sets a flag in the regs field to
   tell the x86 specific code to call the direct trampoline. But this only
   works if the ftrace_ops had WITH_REGS set. ARM does things differently
   that does not require this. For now, set WITH_REGS if the arch supports
   WITH_REGS (which ARM does not), and this makes it work for both ARM64 and
   x86.
 
 - Fix wasted memory in the saved_cmdlines logic.
 
   The saved_cmdlines is a cache that maps PIDs to COMMs that tracing can
   use. Most trace events only save the PID in the event. The saved_cmdlines
   file lists PIDs to COMMs so that the tracing tools can show an actual name
   and not just a PID for each event. There's an array of PIDs that map to a
   small set of saved COMM strings. The array is set to PID_MAX_DEFAULT which
   is usually set to 32768. When a PID comes in, it will add itself to this
   array along with the index into the COMM array (note if the system allows
   more than PID_MAX_DEFAULT, this cache is similar to cache lines as an
   update of a PID that has the same PID_MAX_DEFAULT bits set will flush out
   another task with the same matching bits set).
 
   A while ago, the size of this cache was changed to be dynamic and the
   array was moved into a structure and created with kmalloc(). But this
   new structure had the size of 131104 bytes, or 0x20020 in hex. As kmalloc
   allocates in powers of two, it was actually allocating 0x40000 bytes
   (262144) leaving 131040 bytes of wasted memory. The last element of this
   structure was a pointer to the COMM string array which defaulted to just
   saving 128 COMMs.
 
   By changing the last field of this structure to a variable length string,
   and just having it round up to fill the allocated memory, the default
   size of the saved COMM cache is now 8190. This not only uses the wasted
   space, but actually saves space by removing the extra allocation for the
   COMM names.
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Merge tag 'trace-v6.8-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing fixes from Steven Rostedt:

 - Fix broken direct trampolines being called when another callback is
   attached the same function.

   ARM 64 does not support FTRACE_WITH_REGS, and when it added direct
   trampoline calls from ftrace, it removed the "WITH_REGS" flag from
   the ftrace_ops for direct trampolines. This broke x86 as x86 requires
   direct trampolines to have WITH_REGS.

   This wasn't noticed because direct trampolines work as long as the
   function it is attached to is not shared with other callbacks (like
   the function tracer). When there are other callbacks, a helper
   trampoline is called, to call all the non direct callbacks and when
   it returns, the direct trampoline is called.

   For x86, the direct trampoline sets a flag in the regs field to tell
   the x86 specific code to call the direct trampoline. But this only
   works if the ftrace_ops had WITH_REGS set. ARM does things
   differently that does not require this. For now, set WITH_REGS if the
   arch supports WITH_REGS (which ARM does not), and this makes it work
   for both ARM64 and x86.

 - Fix wasted memory in the saved_cmdlines logic.

   The saved_cmdlines is a cache that maps PIDs to COMMs that tracing
   can use. Most trace events only save the PID in the event. The
   saved_cmdlines file lists PIDs to COMMs so that the tracing tools can
   show an actual name and not just a PID for each event. There's an
   array of PIDs that map to a small set of saved COMM strings. The
   array is set to PID_MAX_DEFAULT which is usually set to 32768. When a
   PID comes in, it will add itself to this array along with the index
   into the COMM array (note if the system allows more than
   PID_MAX_DEFAULT, this cache is similar to cache lines as an update of
   a PID that has the same PID_MAX_DEFAULT bits set will flush out
   another task with the same matching bits set).

   A while ago, the size of this cache was changed to be dynamic and the
   array was moved into a structure and created with kmalloc(). But this
   new structure had the size of 131104 bytes, or 0x20020 in hex. As
   kmalloc allocates in powers of two, it was actually allocating
   0x40000 bytes (262144) leaving 131040 bytes of wasted memory. The
   last element of this structure was a pointer to the COMM string array
   which defaulted to just saving 128 COMMs.

   By changing the last field of this structure to a variable length
   string, and just having it round up to fill the allocated memory, the
   default size of the saved COMM cache is now 8190. This not only uses
   the wasted space, but actually saves space by removing the extra
   allocation for the COMM names.

* tag 'trace-v6.8-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing: Fix wasted memory in saved_cmdlines logic
  ftrace: Fix DIRECT_CALLS to use SAVE_REGS by default
2024-02-09 11:13:19 -08:00
Steven Rostedt (Google)
44dc5c41b5 tracing: Fix wasted memory in saved_cmdlines logic
While looking at improving the saved_cmdlines cache I found a huge amount
of wasted memory that should be used for the cmdlines.

The tracing data saves pids during the trace. At sched switch, if a trace
occurred, it will save the comm of the task that did the trace. This is
saved in a "cache" that maps pids to comms and exposed to user space via
the /sys/kernel/tracing/saved_cmdlines file. Currently it only caches by
default 128 comms.

The structure that uses this creates an array to store the pids using
PID_MAX_DEFAULT (which is usually set to 32768). This causes the structure
to be of the size of 131104 bytes on 64 bit machines.

In hex: 131104 = 0x20020, and since the kernel allocates generic memory in
powers of two, the kernel would allocate 0x40000 or 262144 bytes to store
this structure. That leaves 131040 bytes of wasted space.

Worse, the structure points to an allocated array to store the comm names,
which is 16 bytes times the amount of names to save (currently 128), which
is 2048 bytes. Instead of allocating a separate array, make the structure
end with a variable length string and use the extra space for that.

This is similar to a recommendation that Linus had made about eventfs_inode names:

  https://lore.kernel.org/all/20240130190355.11486-5-torvalds@linux-foundation.org/

Instead of allocating a separate string array to hold the saved comms,
have the structure end with: char saved_cmdlines[]; and round up to the
next power of two over sizeof(struct saved_cmdline_buffers) + num_cmdlines * TASK_COMM_LEN
It will use this extra space for the saved_cmdline portion.

Now, instead of saving only 128 comms by default, by using this wasted
space at the end of the structure it can save over 8000 comms and even
saves space by removing the need for allocating the other array.

Link: https://lore.kernel.org/linux-trace-kernel/20240209063622.1f7b6d5f@rorschach.local.home

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Vincent Donnefort <vdonnefort@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Mete Durlu <meted@linux.ibm.com>
Fixes: 939c7a4f04 ("tracing: Introduce saved_cmdlines_size file")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-02-09 06:43:21 -05:00
Masami Hiramatsu (Google)
a8b9cf62ad ftrace: Fix DIRECT_CALLS to use SAVE_REGS by default
The commit 60c8971899 ("ftrace: Make DIRECT_CALLS work WITH_ARGS
and !WITH_REGS") changed DIRECT_CALLS to use SAVE_ARGS when there
are multiple ftrace_ops at the same function, but since the x86 only
support to jump to direct_call from ftrace_regs_caller, when we set
the function tracer on the same target function on x86, ftrace-direct
does not work as below (this actually works on arm64.)

At first, insmod ftrace-direct.ko to put a direct_call on
'wake_up_process()'.

 # insmod kernel/samples/ftrace/ftrace-direct.ko
 # less trace
...
          <idle>-0       [006] ..s1.   564.686958: my_direct_func: waking up rcu_preempt-17
          <idle>-0       [007] ..s1.   564.687836: my_direct_func: waking up kcompactd0-63
          <idle>-0       [006] ..s1.   564.690926: my_direct_func: waking up rcu_preempt-17
          <idle>-0       [006] ..s1.   564.696872: my_direct_func: waking up rcu_preempt-17
          <idle>-0       [007] ..s1.   565.191982: my_direct_func: waking up kcompactd0-63

Setup a function filter to the 'wake_up_process' too, and enable it.

 # cd /sys/kernel/tracing/
 # echo wake_up_process > set_ftrace_filter
 # echo function > current_tracer
 # less trace
...
          <idle>-0       [006] ..s3.   686.180972: wake_up_process <-call_timer_fn
          <idle>-0       [006] ..s3.   686.186919: wake_up_process <-call_timer_fn
          <idle>-0       [002] ..s3.   686.264049: wake_up_process <-call_timer_fn
          <idle>-0       [002] d.h6.   686.515216: wake_up_process <-kick_pool
          <idle>-0       [002] d.h6.   686.691386: wake_up_process <-kick_pool

Then, only function tracer is shown on x86.
But if you enable 'kprobe on ftrace' event (which uses SAVE_REGS flag)
on the same function, it is shown again.

 # echo 'p wake_up_process' >> dynamic_events
 # echo 1 > events/kprobes/p_wake_up_process_0/enable
 # echo > trace
 # less trace
...
          <idle>-0       [006] ..s2.  2710.345919: p_wake_up_process_0: (wake_up_process+0x4/0x20)
          <idle>-0       [006] ..s3.  2710.345923: wake_up_process <-call_timer_fn
          <idle>-0       [006] ..s1.  2710.345928: my_direct_func: waking up rcu_preempt-17
          <idle>-0       [006] ..s2.  2710.349931: p_wake_up_process_0: (wake_up_process+0x4/0x20)
          <idle>-0       [006] ..s3.  2710.349934: wake_up_process <-call_timer_fn
          <idle>-0       [006] ..s1.  2710.349937: my_direct_func: waking up rcu_preempt-17

To fix this issue, use SAVE_REGS flag for multiple ftrace_ops flag of
direct_call by default.

Link: https://lore.kernel.org/linux-trace-kernel/170484558617.178953.1590516949390270842.stgit@devnote2

Fixes: 60c8971899 ("ftrace: Make DIRECT_CALLS work WITH_ARGS and !WITH_REGS")
Cc: stable@vger.kernel.org
Cc: Florent Revest <revest@chromium.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com> [arm64]
Acked-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-02-09 04:58:22 -05:00
Jakub Kicinski
3be042cf46 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Cross-merge networking fixes after downstream PR.

No conflicts.

Adjacent changes:

drivers/net/ethernet/stmicro/stmmac/common.h
  38cc3c6dcc ("net: stmmac: protect updates of 64-bit statistics counters")
  fd5a6a7131 ("net: stmmac: est: Per Tx-queue error count for HLBF")
  c5c3e1bfc9 ("net: stmmac: Offload queueMaxSDU from tc-taprio")

drivers/net/wireless/microchip/wilc1000/netdev.c
  c901388028 ("wifi: fill in MODULE_DESCRIPTION()s for wilc1000")
  328efda22a ("wifi: wilc1000: do not realloc workqueue everytime an interface is added")

net/unix/garbage.c
  11498715f2 ("af_unix: Remove io_uring code for GC.")
  1279f9d9de ("af_unix: Call kfree_skb() for dead unix_(sk)->oob_skb in GC.")

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-02-08 15:30:33 -08:00
Masami Hiramatsu (Google)
9a571c1e27 tracing/probes: Fix to set arg size and fmt after setting type from BTF
Since the BTF type setting updates probe_arg::type, the type size
calculation and setting print-fmt should be done after that.
Without this fix, the argument size and print-fmt can be wrong.

Link: https://lore.kernel.org/all/170602218196.215583.6417859469540955777.stgit@devnote2/

Fixes: b576e09701 ("tracing/probes: Support function parameters if BTF is available")
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2024-02-08 23:26:25 +09:00
Masami Hiramatsu (Google)
8c427cc2fa tracing/probes: Fix to show a parse error for bad type for $comm
Fix to show a parse error for bad type (non-string) for $comm/$COMM and
immediate-string. With this fix, error_log file shows appropriate error
message as below.

 /sys/kernel/tracing # echo 'p vfs_read $comm:u32' >> kprobe_events
sh: write error: Invalid argument
 /sys/kernel/tracing # echo 'p vfs_read \"hoge":u32' >> kprobe_events
sh: write error: Invalid argument
 /sys/kernel/tracing # cat error_log

[   30.144183] trace_kprobe: error: $comm and immediate-string only accepts string type
  Command: p vfs_read $comm:u32
                            ^
[   62.618500] trace_kprobe: error: $comm and immediate-string only accepts string type
  Command: p vfs_read \"hoge":u32
                              ^
Link: https://lore.kernel.org/all/170602215411.215583.2238016352271091852.stgit@devnote2/

Fixes: 3dd1f7f24f ("tracing: probeevent: Fix to make the type of $comm string")
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2024-02-08 23:26:13 +09:00
Jakub Kicinski
cf244463a2 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Cross-merge networking fixes after downstream PR.

No conflicts or adjacent changes.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-02-01 15:12:37 -08:00
Daniel Bristot de Oliveira
1389358bb0 tracing/timerlat: Move hrtimer_init to timerlat_fd open()
Currently, the timerlat's hrtimer is initialized at the first read of
timerlat_fd, and destroyed at close(). It works, but it causes an error
if the user program open() and close() the file without reading.

Here's an example:

 # echo NO_OSNOISE_WORKLOAD > /sys/kernel/debug/tracing/osnoise/options
 # echo timerlat > /sys/kernel/debug/tracing/current_tracer

 # cat <<EOF > ./timerlat_load.py
 # !/usr/bin/env python3

 timerlat_fd = open("/sys/kernel/tracing/osnoise/per_cpu/cpu0/timerlat_fd", 'r')
 timerlat_fd.close();
 EOF

 # ./taskset -c 0 ./timerlat_load.py
<BOOM>

 BUG: kernel NULL pointer dereference, address: 0000000000000010
 #PF: supervisor read access in kernel mode
 #PF: error_code(0x0000) - not-present page
 PGD 0 P4D 0
 Oops: 0000 [#1] PREEMPT SMP NOPTI
 CPU: 1 PID: 2673 Comm: python3 Not tainted 6.6.13-200.fc39.x86_64 #1
 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-1.fc39 04/01/2014
 RIP: 0010:hrtimer_active+0xd/0x50
 Code: 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 0f 1f 44 00 00 48 8b 57 30 <8b> 42 10 a8 01 74 09 f3 90 8b 42 10 a8 01 75 f7 80 7f 38 00 75 1d
 RSP: 0018:ffffb031009b7e10 EFLAGS: 00010286
 RAX: 000000000002db00 RBX: ffff9118f786db08 RCX: 0000000000000000
 RDX: 0000000000000000 RSI: ffff9117a0e64400 RDI: ffff9118f786db08
 RBP: ffff9118f786db80 R08: ffff9117a0ddd420 R09: ffff9117804d4f70
 R10: 0000000000000000 R11: 0000000000000000 R12: ffff9118f786db08
 R13: ffff91178fdd5e20 R14: ffff9117840978c0 R15: 0000000000000000
 FS:  00007f2ffbab1740(0000) GS:ffff9118f7840000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000000000010 CR3: 00000001b402e000 CR4: 0000000000750ee0
 PKRU: 55555554
 Call Trace:
  <TASK>
  ? __die+0x23/0x70
  ? page_fault_oops+0x171/0x4e0
  ? srso_alias_return_thunk+0x5/0x7f
  ? avc_has_extended_perms+0x237/0x520
  ? exc_page_fault+0x7f/0x180
  ? asm_exc_page_fault+0x26/0x30
  ? hrtimer_active+0xd/0x50
  hrtimer_cancel+0x15/0x40
  timerlat_fd_release+0x48/0xe0
  __fput+0xf5/0x290
  __x64_sys_close+0x3d/0x80
  do_syscall_64+0x60/0x90
  ? srso_alias_return_thunk+0x5/0x7f
  ? __x64_sys_ioctl+0x72/0xd0
  ? srso_alias_return_thunk+0x5/0x7f
  ? syscall_exit_to_user_mode+0x2b/0x40
  ? srso_alias_return_thunk+0x5/0x7f
  ? do_syscall_64+0x6c/0x90
  ? srso_alias_return_thunk+0x5/0x7f
  ? exit_to_user_mode_prepare+0x142/0x1f0
  ? srso_alias_return_thunk+0x5/0x7f
  ? syscall_exit_to_user_mode+0x2b/0x40
  ? srso_alias_return_thunk+0x5/0x7f
  ? do_syscall_64+0x6c/0x90
  entry_SYSCALL_64_after_hwframe+0x6e/0xd8
 RIP: 0033:0x7f2ffb321594
 Code: 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 80 3d d5 cd 0d 00 00 74 13 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 3c c3 0f 1f 00 55 48 89 e5 48 83 ec 10 89 7d
 RSP: 002b:00007ffe8d8eef18 EFLAGS: 00000202 ORIG_RAX: 0000000000000003
 RAX: ffffffffffffffda RBX: 00007f2ffba4e668 RCX: 00007f2ffb321594
 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
 RBP: 00007ffe8d8eef40 R08: 0000000000000000 R09: 0000000000000000
 R10: 55c926e3167eae79 R11: 0000000000000202 R12: 0000000000000003
 R13: 00007ffe8d8ef030 R14: 0000000000000000 R15: 00007f2ffba4e668
  </TASK>
 CR2: 0000000000000010
 ---[ end trace 0000000000000000 ]---

Move hrtimer_init to timerlat_fd open() to avoid this problem.

Link: https://lore.kernel.org/linux-trace-kernel/7324dd3fc0035658c99b825204a66049389c56e3.1706798888.git.bristot@kernel.org

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: stable@vger.kernel.org
Fixes: e88ed227f6 ("tracing/timerlat: Add user-space interface")
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-02-01 11:50:13 -05:00