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This patch adds verifier core which simulates execution of every insn and
records the state of registers and program stack. Every branch instruction seen
during simulation is pushed into state stack. When verifier reaches BPF_EXIT,
it pops the state from the stack and continues until it reaches BPF_EXIT again.
For program:
1: bpf_mov r1, xxx
2: if (r1 == 0) goto 5
3: bpf_mov r0, 1
4: goto 6
5: bpf_mov r0, 2
6: bpf_exit
The verifier will walk insns: 1, 2, 3, 4, 6
then it will pop the state recorded at insn#2 and will continue: 5, 6
This way it walks all possible paths through the program and checks all
possible values of registers. While doing so, it checks for:
- invalid instructions
- uninitialized register access
- uninitialized stack access
- misaligned stack access
- out of range stack access
- invalid calling convention
- instruction encoding is not using reserved fields
Kernel subsystem configures the verifier with two callbacks:
- bool (*is_valid_access)(int off, int size, enum bpf_access_type type);
that provides information to the verifer which fields of 'ctx'
are accessible (remember 'ctx' is the first argument to eBPF program)
- const struct bpf_func_proto *(*get_func_proto)(enum bpf_func_id func_id);
returns argument constraints of kernel helper functions that eBPF program
may call, so that verifier can checks that R1-R5 types match the prototype
More details in Documentation/networking/filter.txt and in kernel/bpf/verifier.c
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
check that control flow graph of eBPF program is a directed acyclic graph
check_cfg() does:
- detect loops
- detect unreachable instructions
- check that program terminates with BPF_EXIT insn
- check that all branches are within program boundary
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
eBPF programs passed from userspace are using pseudo BPF_LD_IMM64 instructions
to refer to process-local map_fd. Scan the program for such instructions and
if FDs are valid, convert them to 'struct bpf_map' pointers which will be used
by verifier to check access to maps in bpf_map_lookup/update() calls.
If program passes verifier, convert pseudo BPF_LD_IMM64 into generic by dropping
BPF_PSEUDO_MAP_FD flag.
Note that eBPF interpreter is generic and knows nothing about pseudo insns.
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
add optional attributes for BPF_PROG_LOAD syscall:
union bpf_attr {
struct {
...
__u32 log_level; /* verbosity level of eBPF verifier */
__u32 log_size; /* size of user buffer */
__aligned_u64 log_buf; /* user supplied 'char *buffer' */
};
};
when log_level > 0 the verifier will return its verification log in the user
supplied buffer 'log_buf' which can be used by program author to analyze why
verifier rejected given program.
'Understanding eBPF verifier messages' section of Documentation/networking/filter.txt
provides several examples of these messages, like the program:
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_CALL_FUNC(BPF_FUNC_map_lookup_elem),
BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 1),
BPF_ST_MEM(BPF_DW, BPF_REG_0, 4, 0),
BPF_EXIT_INSN(),
will be rejected with the following multi-line message in log_buf:
0: (7a) *(u64 *)(r10 -8) = 0
1: (bf) r2 = r10
2: (07) r2 += -8
3: (b7) r1 = 0
4: (85) call 1
5: (15) if r0 == 0x0 goto pc+1
R0=map_ptr R10=fp
6: (7a) *(u64 *)(r0 +4) = 0
misaligned access off 4 size 8
The format of the output can change at any time as verifier evolves.
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
this patch adds all of eBPF verfier documentation and empty bpf_check()
The end goal for the verifier is to statically check safety of the program.
Verifier will catch:
- loops
- out of range jumps
- unreachable instructions
- invalid instructions
- uninitialized register access
- uninitialized stack access
- misaligned stack access
- out of range stack access
- invalid calling convention
More details in Documentation/networking/filter.txt
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
in native eBPF programs userspace is using pseudo BPF_CALL instructions
which encode one of 'enum bpf_func_id' inside insn->imm field.
Verifier checks that program using correct function arguments to given func_id.
If all checks passed, kernel needs to fixup BPF_CALL->imm fields by
replacing func_id with in-kernel function pointer.
eBPF interpreter just calls the function.
In-kernel eBPF users continue to use generic BPF_CALL.
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
eBPF programs are similar to kernel modules. They are loaded by the user
process and automatically unloaded when process exits. Each eBPF program is
a safe run-to-completion set of instructions. eBPF verifier statically
determines that the program terminates and is safe to execute.
The following syscall wrapper can be used to load the program:
int bpf_prog_load(enum bpf_prog_type prog_type,
const struct bpf_insn *insns, int insn_cnt,
const char *license)
{
union bpf_attr attr = {
.prog_type = prog_type,
.insns = ptr_to_u64(insns),
.insn_cnt = insn_cnt,
.license = ptr_to_u64(license),
};
return bpf(BPF_PROG_LOAD, &attr, sizeof(attr));
}
where 'insns' is an array of eBPF instructions and 'license' is a string
that must be GPL compatible to call helper functions marked gpl_only
Upon succesful load the syscall returns prog_fd.
Use close(prog_fd) to unload the program.
User space tests and examples follow in the later patches
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
'maps' is a generic storage of different types for sharing data between kernel
and userspace.
The maps are accessed from user space via BPF syscall, which has commands:
- create a map with given type and attributes
fd = bpf(BPF_MAP_CREATE, union bpf_attr *attr, u32 size)
returns fd or negative error
- lookup key in a given map referenced by fd
err = bpf(BPF_MAP_LOOKUP_ELEM, union bpf_attr *attr, u32 size)
using attr->map_fd, attr->key, attr->value
returns zero and stores found elem into value or negative error
- create or update key/value pair in a given map
err = bpf(BPF_MAP_UPDATE_ELEM, union bpf_attr *attr, u32 size)
using attr->map_fd, attr->key, attr->value
returns zero or negative error
- find and delete element by key in a given map
err = bpf(BPF_MAP_DELETE_ELEM, union bpf_attr *attr, u32 size)
using attr->map_fd, attr->key
- iterate map elements (based on input key return next_key)
err = bpf(BPF_MAP_GET_NEXT_KEY, union bpf_attr *attr, u32 size)
using attr->map_fd, attr->key, attr->next_key
- close(fd) deletes the map
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
done as separate commit to ease conflict resolution
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
BPF syscall is a multiplexor for a range of different operations on eBPF.
This patch introduces syscall with single command to create a map.
Next patch adds commands to access maps.
'maps' is a generic storage of different types for sharing data between kernel
and userspace.
Userspace example:
/* this syscall wrapper creates a map with given type and attributes
* and returns map_fd on success.
* use close(map_fd) to delete the map
*/
int bpf_create_map(enum bpf_map_type map_type, int key_size,
int value_size, int max_entries)
{
union bpf_attr attr = {
.map_type = map_type,
.key_size = key_size,
.value_size = value_size,
.max_entries = max_entries
};
return bpf(BPF_MAP_CREATE, &attr, sizeof(attr));
}
'union bpf_attr' is backwards compatible with future extensions.
More details in Documentation/networking/filter.txt and in manpage
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Enable gcov support for ARM based on original patches by David
Singleton and George G. Davis
Riku - updated to patch to current mainline kernel. The patch
has been submitted in 2010, 2012 - for symmetry, now in 2014 too.
https://lwn.net/Articles/390419/http://marc.info/?l=linux-arm-kernel&m=133823081813044
v2: remove arch/arm/kernel from gcov disabled files
Cc: Andrey Ryabinin <a.ryabinin@samsung.com>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
Signed-off-by: Vincent Sanders <vincent.sanders@collabora.co.uk>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Various drivers implement architecture and/or device specific means to
restart (reset) the system. Various mechanisms have been implemented to
support those schemes. The best known mechanism is arm_pm_restart, which
is a function pointer to be set either from platform specific code or from
drivers. Another mechanism is to use hardware watchdogs to issue a reset;
this mechanism is used if there is no other method available to reset a
board or system. Two examples are alim7101_wdt, which currently uses the
reboot notifier to trigger a reset, and moxart_wdt, which registers the
arm_pm_restart function.
The existing mechanisms have a number of drawbacks. Typically only one
scheme to restart the system is supported (at least if arm_pm_restart is
used). At least in theory there can be multiple means to restart the
system, some of which may be less desirable (for example one mechanism may
only reset the CPU, while another may reset the entire system). Using
arm_pm_restart can also be racy if the function pointer is set from a
driver, as the driver may be in the process of being unloaded when
arm_pm_restart is called. Using the reboot notifier is always racy, as it
is unknown if and when other functions using the reboot notifier have
completed execution by the time the watchdog fires.
Introduce a system restart handler call chain to solve the described
problems. This call chain is expected to be executed from the
architecture specific machine_restart() function. Drivers providing
system restart functionality (such as the watchdog drivers mentioned
above) are expected to register with this call chain. By using the
priority field in the notifier block, callers can control restart handler
execution sequence and thus ensure that the restart handler with the
optimal restart capabilities for a given system is called first.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Wim Van Sebroeck <wim@iguana.be>
Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Jonas Jensen <jonas.jensen@gmail.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This reverts commit 0c7bf3e8cab7900e17ce7f97104c39927d835469.
If there are child cgroups in the cgroupfs and then we umount it,
the superblock will be destroyed but the cgroup_root will be kept
around. When we mount it again, cgroup_mount() will find this
cgroup_root and allocate a new sb for it.
So with this commit we will be trapped in a dead loop in the case
described above, because kernfs_pin_sb() keeps returning NULL.
Currently I don't see how we can avoid using both pinned_sb and
new_sb, so just revert it.
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Reported-by: Andrey Wagin <avagin@gmail.com>
Signed-off-by: Zefan Li <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
- Revert of a recent hibernation core commit that introduced
a NULL pointer dereference during resume for at least one user
(Rafael J Wysocki).
- Fix for the ACPI LPSS (Low-Power Subsystem) driver to disable
asynchronous PM callback execution for LPSS devices during system
suspend/resume (introduced in 3.16) which turns out to break
ordering expectations on some systems. From Fu Zhonghui.
- cpufreq core fix related to the handling of sysfs nodes during
system suspend/resume that has been broken for intel_pstate
since 3.15 from Lan Tianyu.
- Restore the generation of "online" uevents for ACPI container
devices that was removed in 3.14, but some user space utilities
turn out to need them (Rafael J Wysocki).
- The cpufreq core fails to release a lock in an error code path
after changes made in 3.14. Fix from Prarit Bhargava.
- ACPICA and ACPI/GPIO fixes to make the handling of ACPI GPIO
operation regions (which means AML using GPIOs) work correctly
in all cases from Bob Moore and Srinivas Pandruvada.
- Fix for a wrong sign of the ACPI core's create_modalias() return
value in case of an error from Mika Westerberg.
- ACPI backlight blacklist entry for ThinkPad X201s from Aaron Lu.
/
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Merge tag 'pm+acpi-3.17-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull ACPI and power management fixes from Rafael Wysocki:
"These are regression fixes (ACPI hotplug, cpufreq, hibernation, ACPI
LPSS driver), fixes for stuff that never worked correctly (ACPI GPIO
support in some cases and a wrong sign of an error code in the ACPI
core in one place), and one blacklist item for ACPI backlight
handling.
Specifics:
- Revert of a recent hibernation core commit that introduced a NULL
pointer dereference during resume for at least one user (Rafael J
Wysocki).
- Fix for the ACPI LPSS (Low-Power Subsystem) driver to disable
asynchronous PM callback execution for LPSS devices during system
suspend/resume (introduced in 3.16) which turns out to break
ordering expectations on some systems. From Fu Zhonghui.
- cpufreq core fix related to the handling of sysfs nodes during
system suspend/resume that has been broken for intel_pstate since
3.15 from Lan Tianyu.
- Restore the generation of "online" uevents for ACPI container
devices that was removed in 3.14, but some user space utilities
turn out to need them (Rafael J Wysocki).
- The cpufreq core fails to release a lock in an error code path
after changes made in 3.14. Fix from Prarit Bhargava.
- ACPICA and ACPI/GPIO fixes to make the handling of ACPI GPIO
operation regions (which means AML using GPIOs) work correctly in
all cases from Bob Moore and Srinivas Pandruvada.
- Fix for a wrong sign of the ACPI core's create_modalias() return
value in case of an error from Mika Westerberg.
- ACPI backlight blacklist entry for ThinkPad X201s from Aaron Lu"
* tag 'pm+acpi-3.17-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
Revert "PM / Hibernate: Iterate over set bits instead of PFNs in swsusp_free()"
gpio / ACPI: Use pin index and bit length
ACPICA: Update to GPIO region handler interface.
ACPI / platform / LPSS: disable async suspend/resume of LPSS devices
cpufreq: release policy->rwsem on error
cpufreq: fix cpufreq suspend/resume for intel_pstate
ACPI / scan: Correct error return value of create_modalias()
ACPI / video: disable native backlight for ThinkPad X201s
ACPI / hotplug: Generate online uevents for ACPI containers
In commit c1221321b7c25b53204447cff9949a6d5a7ddddc
sched: Allow wait_on_bit_action() functions to support a timeout
I suggested that a "wait_on_bit_timeout()" interface would not meet my
need. This isn't true - I was just over-engineering.
Including a 'private' field in wait_bit_key instead of a focused
"timeout" field was just premature generalization. If some other
use is ever found, it can be generalized or added later.
So this patch renames "private" to "timeout" with a meaning "stop
waiting when "jiffies" reaches or passes "timeout",
and adds two of the many possible wait..bit..timeout() interfaces:
wait_on_page_bit_killable_timeout(), which is the one I want to use,
and out_of_line_wait_on_bit_timeout() which is a reasonably general
example. Others can be added as needed.
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NeilBrown <neilb@suse.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
When we change cpuset.memory_spread_{page,slab}, cpuset will flip
PF_SPREAD_{PAGE,SLAB} bit of tsk->flags for each task in that cpuset.
This should be done using atomic bitops, but currently we don't,
which is broken.
Tetsuo reported a hard-to-reproduce kernel crash on RHEL6, which happened
when one thread tried to clear PF_USED_MATH while at the same time another
thread tried to flip PF_SPREAD_PAGE/PF_SPREAD_SLAB. They both operate on
the same task.
Here's the full report:
https://lkml.org/lkml/2014/9/19/230
To fix this, we make PF_SPREAD_PAGE and PF_SPREAD_SLAB atomic flags.
v4:
- updated mm/slab.c. (Fengguang Wu)
- updated Documentation.
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Miao Xie <miaox@cn.fujitsu.com>
Cc: Kees Cook <keescook@chromium.org>
Fixes: 950592f7b991 ("cpusets: update tasks' page/slab spread flags in time")
Cc: <stable@vger.kernel.org> # 2.6.31+
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Zefan Li <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Also adds a class type PM_QOS_SUM that aggregates the values by summing them.
It can be used by memory controllers to calculate the optimum clock frequency
based on the bandwidth needs of the different memory clients.
Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
With the recent addition of percpu_ref_reinit(), percpu_ref now can be
used as a persistent switch which can be turned on and off repeatedly
where turning off maps to killing the ref and waiting for it to drain;
however, there currently isn't a way to initialize a percpu_ref in its
off (killed and drained) state, which can be inconvenient for certain
persistent switch use cases.
Similarly, percpu_ref_switch_to_atomic/percpu() allow dynamic
selection of operation mode; however, currently a newly initialized
percpu_ref is always in percpu mode making it impossible to avoid the
latency overhead of switching to atomic mode.
This patch adds @flags to percpu_ref_init() and implements the
following flags.
* PERCPU_REF_INIT_ATOMIC : start ref in atomic mode
* PERCPU_REF_INIT_DEAD : start ref killed and drained
These flags should be able to serve the above two use cases.
v2: target_core_tpg.c conversion was missing. Fixed.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
This is to receive 0a30288da1ae ("blk-mq, percpu_ref: implement a
kludge for SCSI blk-mq stall during probe") which implements
__percpu_ref_kill_expedited() to work around SCSI blk-mq stall. The
commit reverted and patches to implement proper fix will be added.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>
This reverts commit 1f9a7268c67f0290837aada443d28fd953ddca90.
With the fix of the initial state for the cloned event we now correctly
handle the error described in:
1f9a7268c67f perf: Do not allow optimized switch for non-cloned events
so we can revert it.
I made an automated test for this, but its not suitable for automated
perf tests framework. It needs to be customized for each machine (the
more cpu the higher numbers for GROUPS/WORKERS/BYTES) and it could take
longer time to hit the issue.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140910143535.GD2409@krava.brq.redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently we initialize the child event based on the original
parent state. This is wrong, because the original parent event
(and its state) is not related to current fork and also could
be already gone.
We need to initialize the child state based on the immediate
parent event state.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1410520708-19275-2-git-send-email-jolsa@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently we return POLLHUP in event polling if the monitored
process is done, but we didn't consider possible children,
that might be still running and producing data.
Before returning POLLHUP making sure that:
1) the monitored task has exited and that
2) we don't have any children to monitor
Also adding parent wakeup when the child event is gone.
Suggested-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1410520708-19275-1-git-send-email-jolsa@kernel.org
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Some time ago PREEMPT_NEED_RESCHED was implemented,
so reschedule technics is a little more difficult now.
Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140922183642.11015.66039.stgit@localhost
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Probability of use-after-free isn't zero in this place.
Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@vger.kernel.org> # v3.14+
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140922183636.11015.83611.stgit@localhost
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Nothing is locked there, so label's name only confuses a reader.
Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140922183630.11015.59500.stgit@localhost
Signed-off-by: Ingo Molnar <mingo@kernel.org>
dl_bw_of() dereferences rq->rd which has to have RCU read lock held.
Probability of use-after-free isn't zero here.
Also add lockdep assert into dl_bw_cpus().
Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@vger.kernel.org> # v3.14+
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140922183624.11015.71558.stgit@localhost
Signed-off-by: Ingo Molnar <mingo@kernel.org>
read_lock_irqsave(tasklist_lock) in print_rq() looks strange. We do
not need to disable irqs, and they are already disabled by the caller.
And afaics this lock buys nothing, we can rely on rcu_read_lock().
In this case it makes sense to also move rcu_read_lock/unlock from
the caller to print_rq().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140921193341.GA28628@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
1. read_lock(tasklist_lock) does not need to disable irqs.
2. ->mm != NULL is a common mistake, use PF_KTHREAD.
3. The second ->mm check can be simply removed.
4. task_rq_lock() looks better than raw_spin_lock(&p->pi_lock) +
__task_rq_lock().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140921193338.GA28621@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
tg_has_rt_tasks() wants to find an RT task in this task_group, but
task_rq(p)->rt.tg wrongly checks the root rt_rq.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Link: http://lkml.kernel.org/r/20140921193336.GA28618@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The code in find_idlest_cpu() looks for the CPU with the smallest load.
However, if multiple CPUs are idle, the first idle CPU is selected
irrespective of the depth of its idle state.
Among the idle CPUs we should pick the one with with the shallowest idle
state, or the latest to have gone idle if all idle CPUs are in the same
state. The later applies even when cpuidle is configured out.
This patch doesn't cover the following issues:
- The idle exit latency of a CPU might be larger than the time needed
to migrate the waking task to an already running CPU with sufficient
capacity, and therefore performance would benefit from task packing
in such case (in most cases task packing is about power saving).
- Some idle states have a non negligible and non abortable entry latency
which needs to run to completion before the exit latency can start.
A concurrent patch series is making this info available to the cpuidle
core. Once available, the entry latency with the idle timestamp could
determine when the exit latency may be effective.
Those issues will be handled in due course. In the mean time, what
is implemented here should improve things already compared to the current
state of affairs.
Based on an initial patch from Daniel Lezcano.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-pm@vger.kernel.org
Cc: linaro-kernel@lists.linaro.org
Link: http://lkml.kernel.org/n/tip-@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When the cpu enters idle, it stores the cpuidle state pointer in its
struct rq instance which in turn could be used to make a better decision
when balancing tasks.
As soon as the cpu exits its idle state, the struct rq reference is
cleared.
There are a couple of situations where the idle state pointer could be changed
while it is being consulted:
1. For x86/acpi with dynamic c-states, when a laptop switches from battery
to AC that could result on removing the deeper idle state. The acpi driver
triggers:
'acpi_processor_cst_has_changed'
'cpuidle_pause_and_lock'
'cpuidle_uninstall_idle_handler'
'kick_all_cpus_sync'.
All cpus will exit their idle state and the pointed object will be set to
NULL.
2. The cpuidle driver is unloaded. Logically that could happen but not
in practice because the drivers are always compiled in and 95% of them are
not coded to unregister themselves. In any case, the unloading code must
call 'cpuidle_unregister_device', that calls 'cpuidle_pause_and_lock'
leading to 'kick_all_cpus_sync' as mentioned above.
A race can happen if we use the pointer and then one of these two scenarios
occurs at the same moment.
In order to be safe, the idle state pointer stored in the rq must be
used inside a rcu_read_lock section where we are protected with the
'rcu_barrier' in the 'cpuidle_uninstall_idle_handler' function. The
idle_get_state() and idle_put_state() accessors should be used to that
effect.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: linux-pm@vger.kernel.org
Cc: linaro-kernel@lists.linaro.org
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Users can perform clustered scheduling using the cpuset facility.
After an exclusive cpuset is created, task migrations happen only
between CPUs belonging to the same cpuset. Inter- cpuset migrations
can only happen when the user requires so, moving a task between
different cpusets. This behaviour is broken in SCHED_DEADLINE, as
currently spurious inter- cpuset migration may happen without user
intervention.
This patch fix the problem (and shuffles the code a bit to improve
clarity).
Signed-off-by: Juri Lelli <juri.lelli@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: raistlin@linux.it
Cc: michael@amarulasolutions.com
Cc: fchecconi@gmail.com
Cc: daniel.wagner@bmw-carit.de
Cc: vincent@legout.info
Cc: luca.abeni@unitn.it
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1411118561-26323-4-git-send-email-juri.lelli@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When a task is using SCHED_DEADLINE and the user setschedules it to a
different class its sched_dl_entity static parameters are not cleaned
up. This causes a bug if the user sets it back to SCHED_DEADLINE with
the same parameters again. The problem resides in the check we
perform at the very beginning of dl_overflow():
if (new_bw == p->dl.dl_bw)
return 0;
This condition is met in the case depicted above, so the function
returns and dl_b->total_bw is not updated (the p->dl.dl_bw is not
added to it). After this, admission control is broken.
This patch fixes the thing, properly clearing static parameters for a
task that ceases to use SCHED_DEADLINE.
Reported-by: Daniele Alessandrelli <daniele.alessandrelli@gmail.com>
Reported-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Reported-by: Vincent Legout <vincent@legout.info>
Tested-by: Luca Abeni <luca.abeni@unitn.it>
Tested-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Tested-by: Vincent Legout <vincent@legout.info>
Signed-off-by: Juri Lelli <juri.lelli@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Fabio Checconi <fchecconi@gmail.com>
Cc: Dario Faggioli <raistlin@linux.it>
Cc: Michael Trimarchi <michael@amarulasolutions.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1411118561-26323-2-git-send-email-juri.lelli@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
current->state == TASK_DEAD means that the task is doing its
last schedule(), page fault is obviously impossible at this
stage.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140921194743.GA30114@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When task->comm is passed directly to audit_log_untrustedstring() without
getting a copy or using the task_lock, there is a race that could happen that
would output a NULL (\0) in the output string that would effectively truncate
the rest of the report text after the comm= field in the audit, losing fields.
Use get_task_comm() to get a copy while acquiring the task_lock to prevent
this and to prevent the result from being a mixture of old and new values of
comm.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
When an AUDIT_GET_FEATURE message is sent from userspace to the kernel, it
should reply with a message tagged as an AUDIT_GET_FEATURE type with a struct
audit_feature. The current reply is a message tagged as an AUDIT_GET
type with a struct audit_feature.
This appears to have been a cut-and-paste-eo in commit b0fed40.
Reported-by: Steve Grubb <sgrubb@redhat.com>
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Report:
Looking at your example code in
http://people.redhat.com/rbriggs/audit-multicast-listen/audit-multicast-listen.c,
it seems that nlmsg_len field in the received messages is supposed to
contain the length of the header + payload, but it is always set to the
size of the header only, i.e. 16. The example program works, because
the printf format specifies the minimum width, not "precision", so it
simply prints out the payload until the first zero byte. This isn't too
much of a problem, but precludes the use of recvmmsg, iiuc?
(gdb) p *(struct nlmsghdr*)nlh
$14 = {nlmsg_len = 16, nlmsg_type = 1100, nlmsg_flags = 0, nlmsg_seq = 0, nlmsg_pid = 9910}
The only time nlmsg_len would have been updated was at audit_buffer_alloc()
inside audit_log_start() and never updated after. It should arguably be done
in audit_log_vformat(), but would be more efficient in audit_log_end().
Reported-by: Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Since only one of val, uid, gid and lsm* are used at any given time, combine
them to reduce the size of the struct audit_field.
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Various audit events dealing with adding, removing and updating rules result in
invalid values set for the op keys which result in embedded spaces in op=
values.
The invalid values are
op="add rule" set in kernel/auditfilter.c
op="remove rule" set in kernel/auditfilter.c
op="remove rule" set in kernel/audit_tree.c
op="updated rules" set in kernel/audit_watch.c
op="remove rule" set in kernel/audit_watch.c
Replace the space in the above values with an underscore character ('_').
Coded-by: Burn Alting <burn@swtf.dyndns.org>
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Since there is already a primitive to do this operation in the atomic_t, use it
to simplify audit_serial().
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Use kernel.h definition.
Cc: Eric Paris <eparis@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Since the arch is found locally in __audit_syscall_entry(), there is no need to
pass it in as a parameter. Delete it from the parameter list.
x86* was the only arch to call __audit_syscall_entry() directly and did so from
assembly code.
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-audit@redhat.com
Signed-off-by: Eric Paris <eparis@redhat.com>
---
As this patch relies on changes in the audit tree, I think it
appropriate to send it through my tree rather than the x86 tree.
The AUDIT_SECCOMP record looks something like this:
type=SECCOMP msg=audit(1373478171.953:32775): auid=4325 uid=4325 gid=4325 ses=1 subj=unconfined_u:unconfined_r:unconfined_t:s0 pid=12381 comm="test" sig=31 syscall=231 compat=0 ip=0x39ea8bca89 code=0x0
In order to determine what syscall 231 maps to, we need to have the arch= field right before it.
To see the event, compile this test.c program:
=====
int main(void)
{
return seccomp_load(seccomp_init(SCMP_ACT_KILL));
}
=====
gcc -g test.c -o test -lseccomp
After running the program, find the record by: ausearch --start recent -m SECCOMP -i
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
signed-off-by: Eric Paris <eparis@redhat.com>
