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Date: Thu, 06 Jun 2024 06:13:35 -0700
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Subject: Re: [syzbot] Re: 000000000000fcfa6406141cc8ac@google.com
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Subject: Re: 000000000000fcfa6406141cc8ac@google.com
Author: wojciech.gladysz@infogain.com

#syz test: https://linux.googlesource.com/linux/kernel/git/torvalds/linux e=
377d803b65ee4130213b3c041fc25fdfec1bd90

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 2d29bc0f21cc..75fdb8e3abaa 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -2393,12 +2393,21 @@ void __bpf_trace_run(struct bpf_raw_tp_link *link, =
u64 *args)
       cant_sleep();

       // return if instrumentation disabled, see: bpf_disable_instrumentat=
ion
-       if (unlikely(__this_cpu_read(bpf_prog_active))) {
+       int instrumentation =3D unlikely(__this_cpu_read(bpf_prog_active));
+       if (instrumentation) {
+               printk("SKIP FOR INSTRUMENTATION: %s > %s > %p /%i =3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D\n",
+                               prog->aux->name,
+                               link->btp->tp->name, prog, instrumentation)=
;
               bpf_prog_inc_misses_counter(prog);
               return;
       }

-       if (unlikely(this_cpu_inc_return(*(prog->active)) !=3D 1)) {
+       int active =3D this_cpu_inc_return(*(prog->active));
+       // printk("%s > %s > %p /%i\n", prog->aux->name, link->btp->tp->nam=
e, prog, active);
+       if (active !=3D 1) {
+               printk("SKIP FOR ACTIVE: %s > %s > %p /%i =3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D\n",
+                               prog->aux->name,
+                               link->btp->tp->name, prog, active);
               bpf_prog_inc_misses_counter(prog);
               goto out;
       }
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index 8d1507dd0724..e756262d8df7 100644
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -298,6 +308,8 @@ static enum tp_func_state nr_func_state(const struct tr=
acepoint_func *tp_funcs)
{
       if (!tp_funcs)
               return TP_FUNC_0;
+       if (!tp_funcs[0].func)
+               return TP_FUNC_0;
       if (!tp_funcs[1].func)
               return TP_FUNC_1;
       if (!tp_funcs[2].func)

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