Messages in this thread Patch in this message | | | Date | Wed, 23 Nov 2022 16:06:17 +0100 | From | Peter Zijlstra <> | Subject | Re: [Syzkaller & bisect] There is "__perf_event_overflow" WARNING in v6.1-rc5 kernel in guest |
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On Wed, Nov 23, 2022 at 04:05:14PM +0100, Peter Zijlstra wrote: > @@ -9330,7 +9350,7 @@ static int __perf_event_overflow(struct > } > > event->pending_addr = 0; > - if (data->sample_flags & PERF_SAMPLE_ADDR) > + if (valid_sample && (data->sample_flags & PERF_SAMPLE_ADDR)) > event->pending_addr = data->addr; > irq_work_queue(&event->pending_irq); > }
That is the result of this patch; also found in that branch:
--- Subject: perf: Fixup SIGTRAP and sample_flags interaction From: Peter Zijlstra <peterz@infradead.org> Date: Mon Nov 21 15:57:44 CET 2022
The perf_event_attr::sigtrap functionality relies on data->addr being set. However commit 7b0846301531 ("perf: Use sample_flags for addr") changed this to only initialize data->addr when not 0.
Fixes: 7b0846301531 ("perf: Use sample_flags for addr") Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- kernel/events/core.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
--- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -9328,7 +9328,10 @@ static int __perf_event_overflow(struct */ WARN_ON_ONCE(event->pending_sigtrap != pending_id); } - event->pending_addr = data->addr; + + event->pending_addr = 0; + if (data->sample_flags & PERF_SAMPLE_ADDR) + event->pending_addr = data->addr; irq_work_queue(&event->pending_irq); }
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