Messages in this thread | | | From | Vince Weaver <> | Date | Mon, 23 Feb 2015 22:33:05 -0500 (EST) | Subject | Re: perf: fuzzer gets CPU stuck in perf_callchain() |
| |
On Thu, 19 Feb 2015, Peter Zijlstra wrote:
> On Thu, Feb 19, 2015 at 11:54:40AM -0500, Vince Weaver wrote: > > > [ 7938.802139] [<ffffffff8115e114>] perf_tp_event+0xc4/0x210 > > [ 7938.861174] [<ffffffff810b4f8a>] perf_trace_lock+0x12a/0x160 > > [ 7938.882197] [<ffffffff810b7f10>] lock_release+0x130/0x260 > > [ 7938.888754] [<ffffffff816c7474>] _raw_spin_unlock_irqrestore+0x24/0x40 > > [ 7938.896510] [<ffffffff8107bb4d>] do_send_sig_info+0x5d/0x80 > > [ 7938.903240] [<ffffffff811f69df>] send_sigio_to_task+0x12f/0x1a0 > > [ 7938.923894] [<ffffffff811f71ce>] send_sigio+0xae/0x100 > > [ 7938.930132] [<ffffffff811f72b7>] kill_fasync+0x97/0xf0 > > [ 7938.942707] [<ffffffff8115d0b4>] perf_event_wakeup+0xd4/0xf0 > > [ 7938.956367] [<ffffffff8115d103>] perf_pending_event+0x33/0x60 > > [ 7938.963199] [<ffffffff8114e3fc>] irq_work_run_list+0x4c/0x80 > > [ 7938.969932] [<ffffffff8114e448>] irq_work_run+0x18/0x40 > > [ 7938.976212] [<ffffffff810196af>] smp_trace_irq_work_interrupt+0x3f/0xc0 > > [ 7938.983957] [<ffffffff816c99bd>] trace_irq_work_interrupt+0x6d/0x80 > > Ah, it looks like the never ending irq_work.. > > Could you try this?
sorry for the delay. I managed to reproduce this problem again on 4.0-rc1, verified it was reproducible, then applied the patch below and I could no longer trigger the issue.
Tested-by: Vince Weaver <vincent.weaver@maine.edu>
> > --- > kernel/events/core.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/kernel/events/core.c b/kernel/events/core.c > index f04daabfd1cf..088e81ae43cb 100644 > --- a/kernel/events/core.c > +++ b/kernel/events/core.c > @@ -4574,6 +4574,13 @@ static void perf_pending_event(struct irq_work *entry) > { > struct perf_event *event = container_of(entry, > struct perf_event, pending); > + int rctx; > + > + rctx = perf_swevent_get_recursion_context(); > + /* > + * If we 'fail' here, that's OK, it means recursion is already disabled > + * and we won't recurse 'further'. > + */ > > if (event->pending_disable) { > event->pending_disable = 0; > @@ -4584,6 +4591,9 @@ static void perf_pending_event(struct irq_work *entry) > event->pending_wakeup = 0; > perf_event_wakeup(event); > } > + > + if (rctx >= 0) > + perf_swevent_put_recursion_context(rctx); > } > > /*
| |