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| author |   Kumar Kartikeya Dwivedi <memxor@gmail.com> | 2025-07-03 13:48:13 -0700 |
|---|---|---|
| committer |   Alexei Starovoitov <ast@kernel.org> | 2025-07-03 19:30:07 -0700 |
| commit | e8d01330225210a8af55f5683fb2ca726717ee16 (patch) | |
| tree | 4b6f759988246033d473c0c1293a7bd17b77d326 | |
| parent | bpf: Add dump_stack() analogue to print to BPF stderr (diff) | |
| download | wireguard-linux-e8d01330225210a8af55f5683fb2ca726717ee16.tar.xz wireguard-linux-e8d01330225210a8af55f5683fb2ca726717ee16.zip | |
bpf: Report may_goto timeout to BPF stderr
Begin reporting may_goto timeouts to BPF program's stderr stream.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20250703204818.925464-8-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
| -rw-r--r-- | kernel/bpf/core.c | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 037d67cf5fb1..fe8a53f3c5bc 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -3168,6 +3168,22 @@ u64 __weak arch_bpf_timed_may_goto(void) return 0; } +static noinline void bpf_prog_report_may_goto_violation(void) +{ +#ifdef CONFIG_BPF_SYSCALL + struct bpf_stream_stage ss; + struct bpf_prog *prog; + + prog = bpf_prog_find_from_stack(); + if (!prog) + return; + bpf_stream_stage(ss, prog, BPF_STDERR, ({ + bpf_stream_printk(ss, "ERROR: Timeout detected for may_goto instruction\n"); + bpf_stream_dump_stack(ss); + })); +#endif +} + u64 bpf_check_timed_may_goto(struct bpf_timed_may_goto *p) { u64 time = ktime_get_mono_fast_ns(); @@ -3178,8 +3194,10 @@ u64 bpf_check_timed_may_goto(struct bpf_timed_may_goto *p) return BPF_MAX_TIMED_LOOPS; } /* Check if we've exhausted our time slice, and zero count. */ - if (time - p->timestamp >= (NSEC_PER_SEC / 4)) + if (unlikely(time - p->timestamp >= (NSEC_PER_SEC / 4))) { + bpf_prog_report_may_goto_violation(); return 0; + } /* Refresh the count for the stack frame. */ return BPF_MAX_TIMED_LOOPS; } |