diff options
| author | Tao Chen <chen.dylane@linux.dev> | 2025-08-14 20:14:29 +0800 |
|---|---|---|
| committer | Andrii Nakryiko <andrii@kernel.org> | 2025-08-15 16:49:31 -0700 |
| commit | abdaf49be5424db74e19d167c10d7dad79a0efc2 (patch) | |
| tree | d6cb730018f6048f9a892f4b6cfc69c097bc2b5f /kernel/trace | |
| parent | c80d79720647ed77ebc0198abd5a0807efdaff0b (diff) | |
bpf: Remove migrate_disable in kprobe_multi_link_prog_run
Graph tracer framework ensures we won't migrate, kprobe_multi_link_prog_run
called all the way from graph tracer, which disables preemption in
function_graph_enter_regs, as Jiri and Yonghong suggested, there is no
need to use migrate_disable. As a result, some overhead may will be reduced.
And add cant_sleep check for __this_cpu_inc_return.
Fixes: 0dcac2725406 ("bpf: Add multi kprobe link")
Signed-off-by: Tao Chen <chen.dylane@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250814121430.2347454-1-chen.dylane@linux.dev
Diffstat (limited to 'kernel/trace')
| -rw-r--r-- | kernel/trace/bpf_trace.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 3ae52978cae6..606007c387c5 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -2728,20 +2728,25 @@ kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link, struct pt_regs *regs; int err; + /* + * graph tracer framework ensures we won't migrate, so there is no need + * to use migrate_disable for bpf_prog_run again. The check here just for + * __this_cpu_inc_return. + */ + cant_sleep(); + if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) { bpf_prog_inc_misses_counter(link->link.prog); err = 1; goto out; } - migrate_disable(); rcu_read_lock(); regs = ftrace_partial_regs(fregs, bpf_kprobe_multi_pt_regs_ptr()); old_run_ctx = bpf_set_run_ctx(&run_ctx.session_ctx.run_ctx); err = bpf_prog_run(link->link.prog, regs); bpf_reset_run_ctx(old_run_ctx); rcu_read_unlock(); - migrate_enable(); out: __this_cpu_dec(bpf_prog_active); |