On Wed, Aug 27, 2025 at 5:38 AM Menglong Dong <menglong8.dong@xxxxxxxxx> wrote: > > Preemption is disabled in ftrace graph, which indicate rcu_read_lock. So > the rcu_read_lock is not needed in fprobe_entry(), and it is not needed > in kprobe_multi_link_prog_run() neither. kprobe_busy_begin() doing preempt_disable() is an implementation detail that might change. Having explicit rcu_read_lock() doesn't hurt. It's a nop anyway in PREEMPT_NONE. pw-bot: cr > Signed-off-by: Menglong Dong <dongml2@xxxxxxxxxxxxxxx> > --- > kernel/trace/bpf_trace.c | 2 -- > 1 file changed, 2 deletions(-) > > diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c > index 606007c387c5..0e79fa84a634 100644 > --- a/kernel/trace/bpf_trace.c > +++ b/kernel/trace/bpf_trace.c > @@ -2741,12 +2741,10 @@ kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link, > goto out; > } > > - 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(); > > out: > __this_cpu_dec(bpf_prog_active); > -- > 2.51.0 >
