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__bpf_prog_enter_sleepable_recur does recursion check which is not applicable
to wq callback. The callback function is part of bpf program and bpf prog might
be running on the same cpu. So recursion check would incorrectly prevent
callback from running. The code can call __bpf_prog_enter_sleepable(), but
run_ctx would be fake, hence use explicit rcu_read_lock_trace();
migrate_disable(); to address this problem. Another reason to open code is
__bpf_prog_enter* are not available in !JIT configs.
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202404241719.IIGdpAku-lkp@intel.com/
Closes: https://lore.kernel.org/oe-kbuild-all/202404241811.FFV4Bku3-lkp@intel.com/
Fixes: eb48f6cd41 ("bpf: wq: add bpf_wq_init")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sentinels) which
will reduce the overall build time size of the kernel and run time
memory bloat by ~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)
Remove sentinel element from bpf_syscall_table.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Joel Granados <j.granados@samsung.com>
We need to teach the verifier about the second argument which is declared
as void * but which is of type KF_ARG_PTR_TO_MAP. We could have dropped
this extra case if we declared the second argument as struct bpf_map *,
but that means users will have to do extra casting to have their program
compile.
We also need to duplicate the timer code for the checking if the map
argument is matching the provided workqueue.
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-11-6c986a5a741f@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Introduce support for KF_ARG_PTR_TO_WORKQUEUE. The kfuncs will use bpf_wq
as argument and that will be recognized as workqueue argument by verifier.
bpf_wq_kern casting can happen inside kfunc, but using bpf_wq in
argument makes life easier for users who work with non-kern type in BPF
progs.
Duplicate process_timer_func into process_wq_func.
meta argument is only needed to ensure bpf_wq_init's workqueue and map
arguments are coming from the same map (map_uid logic is necessary for
correct inner-map handling), so also amend check_kfunc_args() to
match what helpers functions check is doing.
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-8-6c986a5a741f@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
To be able to add workqueues and reuse most of the timer code, we need
to make bpf_hrtimer more generic.
There is no code change except that the new struct gets a new u64 flags
attribute. We are still below 2 cache lines, so this shouldn't impact
the current running codes.
The ordering is also changed. Everything related to async callback
is now on top of bpf_hrtimer.
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-1-6c986a5a741f@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch addresses a latent unsoundness issue in the
scalar(32)_min_max_and/or/xor functions. While it is not a bugfix,
it ensures that the functions produce sound outputs for all inputs.
The issue occurs in these functions when setting signed bounds. The
following example illustrates the issue for scalar_min_max_and(),
but it applies to the other functions.
In scalar_min_max_and() the following clause is executed when ANDing
positive numbers:
/* ANDing two positives gives a positive, so safe to
* cast result into s64.
*/
dst_reg->smin_value = dst_reg->umin_value;
dst_reg->smax_value = dst_reg->umax_value;
However, if umin_value and umax_value of dst_reg cross the sign boundary
(i.e., if (s64)dst_reg->umin_value > (s64)dst_reg->umax_value), then we
will end up with smin_value > smax_value, which is unsound.
Previous works [1, 2] have discovered and reported this issue. Our tool
Agni [2, 3] consideres it a false positive. This is because, during the
verification of the abstract operator scalar_min_max_and(), Agni restricts
its inputs to those passing through reg_bounds_sync(). This mimics
real-world verifier behavior, as reg_bounds_sync() is invariably executed
at the tail of every abstract operator. Therefore, such behavior is
unlikely in an actual verifier execution.
However, it is still unsound for an abstract operator to set signed bounds
such that smin_value > smax_value. This patch fixes it, making the abstract
operator sound for all (well-formed) inputs.
It is worth noting that while the previous code updated the signed bounds
(using the output unsigned bounds) only when the *input signed* bounds
were positive, the new code updates them whenever the *output unsigned*
bounds do not cross the sign boundary.
An alternative approach to fix this latent unsoundness would be to
unconditionally set the signed bounds to unbounded [S64_MIN, S64_MAX], and
let reg_bounds_sync() refine the signed bounds using the unsigned bounds
and the tnum. We found that our approach produces more precise (tighter)
bounds.
For example, consider these inputs to BPF_AND:
/* dst_reg */
var_off.value: 8608032320201083347
var_off.mask: 615339716653692460
smin_value: 8070450532247928832
smax_value: 8070450532247928832
umin_value: 13206380674380886586
umax_value: 13206380674380886586
s32_min_value: -2110561598
s32_max_value: -133438816
u32_min_value: 4135055354
u32_max_value: 4135055354
/* src_reg */
var_off.value: 8584102546103074815
var_off.mask: 9862641527606476800
smin_value: 2920655011908158522
smax_value: 7495731535348625717
umin_value: 7001104867969363969
umax_value: 8584102543730304042
s32_min_value: -2097116671
s32_max_value: 71704632
u32_min_value: 1047457619
u32_max_value: 4268683090
After going through tnum_and() -> scalar32_min_max_and() ->
scalar_min_max_and() -> reg_bounds_sync(), our patch produces the following
bounds for s32:
s32_min_value: -1263875629
s32_max_value: -159911942
Whereas, setting the signed bounds to unbounded in scalar_min_max_and()
produces:
s32_min_value: -1263875629
s32_max_value: -1
As observed, our patch produces a tighter s32 bound. We also confirmed
using Agni and SMT verification that our patch always produces signed
bounds that are equal to or more precise than setting the signed bounds to
unbounded in scalar_min_max_and().
[1] https://sanjit-bhat.github.io/assets/pdf/ebpf-verifier-range-analysis22.pdf
[2] https://link.springer.com/chapter/10.1007/978-3-031-37709-9_12
[3] https://github.com/bpfverif/agni
Co-developed-by: Matan Shachnai <m.shachnai@rutgers.edu>
Signed-off-by: Matan Shachnai <m.shachnai@rutgers.edu>
Co-developed-by: Srinivas Narayana <srinivas.narayana@rutgers.edu>
Signed-off-by: Srinivas Narayana <srinivas.narayana@rutgers.edu>
Co-developed-by: Santosh Nagarakatte <santosh.nagarakatte@rutgers.edu>
Signed-off-by: Santosh Nagarakatte <santosh.nagarakatte@rutgers.edu>
Signed-off-by: Harishankar Vishwanathan <harishankar.vishwanathan@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240402212039.51815-1-harishankar.vishwanathan@gmail.com
Link: https://lore.kernel.org/bpf/20240416115303.331688-1-harishankar.vishwanathan@gmail.com
If the BTF code is enabled in the build configuration, the start/stop
BTF markers are guaranteed to exist. Only when CONFIG_DEBUG_INFO_BTF=n,
the references in btf_parse_vmlinux() will remain unsatisfied, relying
on the weak linkage of the external references to avoid breaking the
build.
Avoid GOT based relocations to these markers in the final executable by
dropping the weak attribute and instead, make btf_parse_vmlinux() return
ERR_PTR(-ENOENT) directly if CONFIG_DEBUG_INFO_BTF is not enabled to
begin with. The compiler will drop any subsequent references to
__start_BTF and __stop_BTF in that case, allowing the link to succeed.
Note that Clang will notice that taking the address of __start_BTF can
no longer yield NULL, so testing for that condition becomes unnecessary.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20240415162041.2491523-8-ardb+git@google.com
Long ago a map file descriptor in a pseudo ldimm64 instruction could
only be present as an immediate value insn[0].imm, and thus this value
was used in a verbose verifier message printed when the file descriptor
wasn't valid. Since addition of BPF_PSEUDO_MAP_IDX_VALUE/BPF_PSEUDO_MAP_IDX
the insn[0].imm field can also contain an index pointing to the file
descriptor in the attr.fd_array array. However, if the file descriptor
is invalid, the verifier still prints the verbose message containing
value of insn[0].imm. Patch the verifier message to always print the
actual file descriptor value.
Fixes: 387544bfa2 ("bpf: Introduce fd_idx")
Signed-off-by: Anton Protopopov <aspsk@isovalent.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240412141100.3562942-1-aspsk@isovalent.com
Add bpf_link support for sk_msg and sk_skb programs. We have an
internal request to support bpf_link for sk_msg programs so user
space can have a uniform handling with bpf_link based libbpf
APIs. Using bpf_link based libbpf API also has a benefit which
makes system robust by decoupling prog life cycle and
attachment life cycle.
Reviewed-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20240410043527.3737160-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Support atomics in bpf_arena that can be JITed as a single x86 instruction.
Instructions that are JITed as loops are not supported at the moment,
since they require more complex extable and loop logic.
JITs can choose to do smarter things with bpf_jit_supports_insn().
Like arm64 may decide to support all bpf atomics instructions
when emit_lse_atomic is available and none in ll_sc mode.
bpf_jit_supports_percpu_insn(), bpf_jit_supports_ptr_xchg() and
other such callbacks can be replaced with bpf_jit_supports_insn()
in the future.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20240405231134.17274-1-alexei.starovoitov@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Currently, a set of core BPF kfuncs (e.g. bpf_task_*, bpf_cgroup_*,
bpf_cpumask_*, etc) cannot be invoked from BPF_PROG_TYPE_SYSCALL
programs. The whitelist approach taken for enabling kfuncs makes sense:
it not safe to call these kfuncs from every program type. For example,
it may not be safe to call bpf_task_acquire() in an fentry to
free_task().
BPF_PROG_TYPE_SYSCALL, on the other hand, is a perfectly safe program
type from which to invoke these kfuncs, as it's a very controlled
environment, and we should never be able to run into any of the typical
problems such as recursive invoations, acquiring references on freeing
kptrs, etc. Being able to invoke these kfuncs would be useful, as
BPF_PROG_TYPE_SYSCALL can be invoked with BPF_PROG_RUN, and would
therefore enable user space programs to synchronously call into BPF to
manipulate these kptrs.
This patch therefore enables invoking the aforementioned core kfuncs
from BPF_PROG_TYPE_SYSCALL progs.
Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/bpf/20240405143041.632519-2-void@manifault.com
Taking different maps within a single bpf_for_each_map_elem call is not
allowed before, because from the second map,
bpf_insn_aux_data->map_ptr_state will be marked as *poison*. In fact
both map_ptr and state are needed to support this use case: map_ptr is
used by set_map_elem_callback_state() while poison state is needed to
determine whether to use direct call.
Signed-off-by: Philo Lu <lulie@linux.alibaba.com>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20240405025536.18113-3-lulie@linux.alibaba.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Currently, bpf_insn_aux_data->map_ptr_state is used to store either
map_ptr or its poison state (i.e., BPF_MAP_PTR_POISON). Thus
BPF_MAP_PTR_POISON must be checked before reading map_ptr. In certain
cases, we may need valid map_ptr even in case of poison state.
This will be explained in next patch with bpf_for_each_map_elem()
helper.
This patch changes map_ptr_state into a new struct including both map
pointer and its state (poison/unpriv). It's in the same union with
struct bpf_loop_inline_state, so there is no extra memory overhead.
Besides, macros BPF_MAP_PTR_UNPRIV/BPF_MAP_PTR_POISON/BPF_MAP_PTR are no
longer needed.
This patch does not change any existing functionality.
Signed-off-by: Philo Lu <lulie@linux.alibaba.com>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20240405025536.18113-2-lulie@linux.alibaba.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The newly added code to handle bpf_get_branch_snapshot fails to link when
CONFIG_PERF_EVENTS is disabled:
aarch64-linux-ld: kernel/bpf/verifier.o: in function `do_misc_fixups':
verifier.c:(.text+0x1090c): undefined reference to `__SCK__perf_snapshot_branch_stack'
Add a build-time check for that Kconfig symbol around the code to
remove the link time dependency.
Fixes: 314a53623c ("bpf: inline bpf_get_branch_snapshot() helper")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20240405142637.577046-1-arnd@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
r10 is a special register that is not under BPF program's control and is
always effectively precise. The rest of precision logic assumes that
only r0-r9 SCALAR registers are marked as precise, so prevent r10 from
being marked precise.
This can happen due to signed cast instruction allowing to do something
like `r0 = (s8)r10;`, which later, if r0 needs to be precise, would lead
to an attempt to mark r10 as precise.
Prevent this with an extra check during instruction backtracking.
Fixes: 8100928c88 ("bpf: Support new sign-extension mov insns")
Reported-by: syzbot+148110ee7cf72f39f33e@syzkaller.appspotmail.com
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20240404214536.3551295-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Pull networking fixes from Jakub Kicinski:
"Including fixes from netfilter, bluetooth and bpf.
Fairly usual collection of driver and core fixes. The large selftest
accompanying one of the fixes is also becoming a common occurrence.
Current release - regressions:
- ipv6: fix infinite recursion in fib6_dump_done()
- net/rds: fix possible null-deref in newly added error path
Current release - new code bugs:
- net: do not consume a full cacheline for system_page_pool
- bpf: fix bpf_arena-related file descriptor leaks in the verifier
- drv: ice: fix freeing uninitialized pointers, fixing misuse of the
newfangled __free() auto-cleanup
Previous releases - regressions:
- x86/bpf: fixes the BPF JIT with retbleed=stuff
- xen-netfront: add missing skb_mark_for_recycle, fix page pool
accounting leaks, revealed by recently added explicit warning
- tcp: fix bind() regression for v6-only wildcard and v4-mapped-v6
non-wildcard addresses
- Bluetooth:
- replace "hci_qca: Set BDA quirk bit if fwnode exists in DT" with
better workarounds to un-break some buggy Qualcomm devices
- set conn encrypted before conn establishes, fix re-connecting to
some headsets which use slightly unusual sequence of msgs
- mptcp:
- prevent BPF accessing lowat from a subflow socket
- don't account accept() of non-MPC client as fallback to TCP
- drv: mana: fix Rx DMA datasize and skb_over_panic
- drv: i40e: fix VF MAC filter removal
Previous releases - always broken:
- gro: various fixes related to UDP tunnels - netns crossing
problems, incorrect checksum conversions, and incorrect packet
transformations which may lead to panics
- bpf: support deferring bpf_link dealloc to after RCU grace period
- nf_tables:
- release batch on table validation from abort path
- release mutex after nft_gc_seq_end from abort path
- flush pending destroy work before exit_net release
- drv: r8169: skip DASH fw status checks when DASH is disabled"
* tag 'net-6.9-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (81 commits)
netfilter: validate user input for expected length
net/sched: act_skbmod: prevent kernel-infoleak
net: usb: ax88179_178a: avoid the interface always configured as random address
net: dsa: sja1105: Fix parameters order in sja1110_pcs_mdio_write_c45()
net: ravb: Always update error counters
net: ravb: Always process TX descriptor ring
netfilter: nf_tables: discard table flag update with pending basechain deletion
netfilter: nf_tables: Fix potential data-race in __nft_flowtable_type_get()
netfilter: nf_tables: reject new basechain after table flag update
netfilter: nf_tables: flush pending destroy work before exit_net release
netfilter: nf_tables: release mutex after nft_gc_seq_end from abort path
netfilter: nf_tables: release batch on table validation from abort path
Revert "tg3: Remove residual error handling in tg3_suspend"
tg3: Remove residual error handling in tg3_suspend
net: mana: Fix Rx DMA datasize and skb_over_panic
net/sched: fix lockdep splat in qdisc_tree_reduce_backlog()
net: phy: micrel: lan8814: Fix when enabling/disabling 1-step timestamping
net: stmmac: fix rx queue priority assignment
net: txgbe: fix i2c dev name cannot match clkdev
net: fec: Set mac_managed_pm during probe
...
Inline bpf_get_branch_snapshot() helper using architecture-agnostic
inline BPF code which calls directly into underlying callback of
perf_snapshot_branch_stack static call. This callback is set early
during kernel initialization and is never updated or reset, so it's ok
to fetch actual implementation using static_call_query() and call
directly into it.
This change eliminates a full function call and saves one LBR entry
in PERF_SAMPLE_BRANCH_ANY LBR mode.
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20240404002640.1774210-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Using new per-CPU BPF instruction, partially inline
bpf_map_lookup_elem() helper for per-CPU hashmap BPF map. Just like for
normal HASH map, we still generate a call into __htab_map_lookup_elem(),
but after that we resolve per-CPU element address using a new
instruction, saving on extra functions calls.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/r/20240402021307.1012571-5-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add a new BPF instruction for resolving absolute addresses of per-CPU
data from their per-CPU offsets. This instruction is internal-only and
users are not allowed to use them directly. They will only be used for
internal inlining optimizations for now between BPF verifier and BPF JITs.
We use a special BPF_MOV | BPF_ALU64 | BPF_X form with insn->off field
set to BPF_ADDR_PERCPU = -1. I used negative offset value to distinguish
them from positive ones used by user-exposed instructions.
Such instruction performs a resolution of a per-CPU offset stored in
a register to a valid kernel address which can be dereferenced. It is
useful in any use case where absolute address of a per-CPU data has to
be resolved (e.g., in inlining bpf_map_lookup_elem()).
BPF disassembler is also taught to recognize them to support dumping
final BPF assembly code (non-JIT'ed version).
Add arch-specific way for BPF JITs to mark support for this instructions.
This patch also adds support for these instructions in x86-64 BPF JIT.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/r/20240402021307.1012571-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
strncpy() is deprecated for use on NUL-terminated destination strings
[1] and as such we should prefer more robust and less ambiguous string
interfaces.
bpf sym names get looked up and compared/cleaned with various string
apis. This suggests they need to be NUL-terminated (strncpy() suggests
this but does not guarantee it).
| static int compare_symbol_name(const char *name, char *namebuf)
| {
| cleanup_symbol_name(namebuf);
| return strcmp(name, namebuf);
| }
| static void cleanup_symbol_name(char *s)
| {
| ...
| res = strstr(s, ".llvm.");
| ...
| }
Use strscpy() as this method guarantees NUL-termination on the
destination buffer.
This patch also replaces two uses of strncpy() used in log.c. These are
simple replacements as postfix has been zero-initialized on the stack
and has source arguments with a size less than the destination's size.
Note that this patch uses the new 2-argument version of strscpy
introduced in commit e6584c3964 ("string: Allow 2-argument strscpy()").
Signed-off-by: Justin Stitt <justinstitt@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2]
Link: https://github.com/KSPP/linux/issues/90
Link: https://lore.kernel.org/bpf/20240402-strncpy-kernel-bpf-core-c-v1-1-7cb07a426e78@google.com
This patch improves the run-time calculation for program stats by
capturing the duration as soon as possible after the program returns.
Previously, the duration included u64_stats_t operations. While the
instrumentation overhead is part of the total time spent when stats are
enabled, distinguishing between the program's native execution time and
the time spent due to instrumentation is crucial for accurate
performance analysis.
By making this change, the patch facilitates more precise optimization
of BPF programs, enabling users to understand their performance in
environments without stats enabled.
I used a virtualized environment to measure the run-time over one minute
for a basic raw_tracepoint/sys_enter program, which just increments a
local counter. Although the virtualization introduced some performance
degradation that could affect the results, I observed approximately a
16% decrease in average run-time reported by stats with this change
(310 -> 260 nsec).
Signed-off-by: Jose Fernandez <josef@netflix.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240402034010.25060-1-josef@netflix.com
Pull Kbuild fixes from Masahiro Yamada:
- Deduplicate Kconfig entries for CONFIG_CXL_PMU
- Fix unselectable choice entry in MIPS Kconfig, and forbid this
structure
- Remove unused include/asm-generic/export.h
- Fix a NULL pointer dereference bug in modpost
- Enable -Woverride-init warning consistently with W=1
- Drop KCSAN flags from *.mod.c files
* tag 'kbuild-fixes-v6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kconfig: Fix typo HEIGTH to HEIGHT
Documentation/llvm: Note s390 LLVM=1 support with LLVM 18.1.0 and newer
kbuild: Disable KCSAN for autogenerated *.mod.c intermediaries
kbuild: make -Woverride-init warnings more consistent
modpost: do not make find_tosym() return NULL
export.h: remove include/asm-generic/export.h
kconfig: do not reparent the menu inside a choice block
MIPS: move unselectable FIT_IMAGE_FDT_EPM5 out of the "System type" choice
cxl: remove CONFIG_CXL_PMU entry in drivers/cxl/Kconfig
The -Woverride-init warn about code that may be intentional or not,
but the inintentional ones tend to be real bugs, so there is a bit of
disagreement on whether this warning option should be enabled by default
and we have multiple settings in scripts/Makefile.extrawarn as well as
individual subsystems.
Older versions of clang only supported -Wno-initializer-overrides with
the same meaning as gcc's -Woverride-init, though all supported versions
now work with both. Because of this difference, an earlier cleanup of
mine accidentally turned the clang warning off for W=1 builds and only
left it on for W=2, while it's still enabled for gcc with W=1.
There is also one driver that only turns the warning off for newer
versions of gcc but not other compilers, and some but not all the
Makefiles still use a cc-disable-warning conditional that is no
longer needed with supported compilers here.
Address all of the above by removing the special cases for clang
and always turning the warning off unconditionally where it got
in the way, using the syntax that is supported by both compilers.
Fixes: 2cd3271b7a ("kbuild: avoid duplicate warning options")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Andrew Jeffery <andrew@codeconstruct.com.au>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
syzbot reported the following lock sequence:
cpu 2:
grabs timer_base lock
spins on bpf_lpm lock
cpu 1:
grab rcu krcp lock
spins on timer_base lock
cpu 0:
grab bpf_lpm lock
spins on rcu krcp lock
bpf_lpm lock can be the same.
timer_base lock can also be the same due to timer migration.
but rcu krcp lock is always per-cpu, so it cannot be the same lock.
Hence it's a false positive.
To avoid lockdep complaining move kfree_rcu() after spin_unlock.
Reported-by: syzbot+1fa663a2100308ab6eab@syzkaller.appspotmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240329171439.37813-1-alexei.starovoitov@gmail.com
BPF link for some program types is passed as a "context" which can be
used by those BPF programs to look up additional information. E.g., for
multi-kprobes and multi-uprobes, link is used to fetch BPF cookie values.
Because of this runtime dependency, when bpf_link refcnt drops to zero
there could still be active BPF programs running accessing link data.
This patch adds generic support to defer bpf_link dealloc callback to
after RCU GP, if requested. This is done by exposing two different
deallocation callbacks, one synchronous and one deferred. If deferred
one is provided, bpf_link_free() will schedule dealloc_deferred()
callback to happen after RCU GP.
BPF is using two flavors of RCU: "classic" non-sleepable one and RCU
tasks trace one. The latter is used when sleepable BPF programs are
used. bpf_link_free() accommodates that by checking underlying BPF
program's sleepable flag, and goes either through normal RCU GP only for
non-sleepable, or through RCU tasks trace GP *and* then normal RCU GP
(taking into account rcu_trace_implies_rcu_gp() optimization), if BPF
program is sleepable.
We use this for multi-kprobe and multi-uprobe links, which dereference
link during program run. We also preventively switch raw_tp link to use
deferred dealloc callback, as upcoming changes in bpf-next tree expose
raw_tp link data (specifically, cookie value) to BPF program at runtime
as well.
Fixes: 0dcac27254 ("bpf: Add multi kprobe link")
Fixes: 89ae89f53d ("bpf: Add multi uprobe link")
Reported-by: syzbot+981935d9485a560bfbcb@syzkaller.appspotmail.com
Reported-by: syzbot+2cb5a6c573e98db598cc@syzkaller.appspotmail.com
Reported-by: syzbot+62d8b26793e8a2bd0516@syzkaller.appspotmail.com
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20240328052426.3042617-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Following the recent upgrade of one of our BPF programs, we encountered
significant latency spikes affecting other applications running on the same
host. After thorough investigation, we identified that these spikes were
primarily caused by the prolonged duration required to free a
non-preallocated htab with approximately 2 million keys.
Notably, our kernel configuration lacks the presence of CONFIG_PREEMPT. In
scenarios where kernel execution extends excessively, other threads might
be starved of CPU time, resulting in latency issues across the system. To
mitigate this, we've adopted a proactive approach by incorporating
cond_resched() calls within the kernel code. This ensures that during
lengthy kernel operations, the scheduler is invoked periodically to provide
opportunities for other threads to execute.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20240327032022.78391-1-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add a simple bpf_modify_return_test_tp() kfunc, available to all program
types, that is useful for various testing and benchmarking scenarios, as
it allows to trigger most tracing BPF program types from BPF side,
allowing to do complex testing and benchmarking scenarios.
It is also attachable to for fmod_ret programs, making it a good and
simple way to trigger fmod_ret program under test/benchmark.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240326162151.3981687-6-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
BPF verifier emits "unknown func" message when given BPF program type
does not support BPF helper. This message may be confusing for users, as
important context that helper is unknown only to current program type is
not provided.
This patch changes message to "program of this type cannot use helper "
and aligns dependent code in libbpf and tests. Any suggestions on
improving/changing this message are welcome.
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Quentin Monnet <qmo@kernel.org>
Link: https://lore.kernel.org/r/20240325152210.377548-1-yatsenko@meta.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
