Re: [PATCH] perf powerpc: Don't call perf_event_disable from atomic context

[Jan Stancek]

----- Original Message -----
> From: "Michael Ellerman" <mpe@xxxxxxxxxxxxxx>
> To: "Jiri Olsa" <jolsa@xxxxxxxxxx>, "Peter Zijlstra" <a.p.zijlstra@xxxxxxxxx>
> Cc: "lkml" <linux-kernel@xxxxxxxxxxxxxxx>, "Ingo Molnar" <mingo@xxxxxxxxxx>, "Michael Neuling" <mikey@xxxxxxxxxxx>,
> "Paul Mackerras" <paulus@xxxxxxxxx>, "Alexander Shishkin" <alexander.shishkin@xxxxxxxxxxxxxxx>, "Jan Stancek"
> <jstancek@xxxxxxxxxx>
> Sent: Tuesday, 4 October, 2016 6:08:27 AM
> Subject: Re: [PATCH] perf powerpc: Don't call perf_event_disable from atomic context
> 
> Jiri Olsa <jolsa@xxxxxxxxxx> writes:
> 
> > The trinity syscall fuzzer triggered following WARN on powerpc:
> >   WARNING: CPU: 9 PID: 2998 at arch/powerpc/kernel/hw_breakpoint.c:278
> >   ...
> >   NIP [c00000000093aedc] .hw_breakpoint_handler+0x28c/0x2b0
> >   LR [c00000000093aed8] .hw_breakpoint_handler+0x288/0x2b0
> >   Call Trace:
> >   [c0000002f7933580] [c00000000093aed8] .hw_breakpoint_handler+0x288/0x2b0
> >   (unreliable)
> >   [c0000002f7933630] [c0000000000f671c] .notifier_call_chain+0x7c/0xf0
> >   [c0000002f79336d0] [c0000000000f6abc]
> >   .__atomic_notifier_call_chain+0xbc/0x1c0
> >   [c0000002f7933780] [c0000000000f6c40] .notify_die+0x70/0xd0
> >   [c0000002f7933820] [c00000000001a74c] .do_break+0x4c/0x100
> >   [c0000002f7933920] [c0000000000089fc] handle_dabr_fault+0x14/0x48
> 
> Is that the full stack trace? It doesn't look like it.
> 
> And were you running trinity as root or regular user?

As regular user:

# adduser dummy
# su dummy /mnt/testarea/trinity --children $proc_num -m --syslog -q -T DIE

Regards,
Jan