Re: perf: fuzzer causes stack going in wrong direction warnings

From: Vince Weaver
Date: Sat May 05 2018 - 11:38:38 EST


On Fri, 4 May 2018, Josh Poimboeuf wrote:
>
> The 'nmi_restore' warning points to a bug in my patch, but the others
> are head scratchers. Here's a patch which combines the first two
> patches, plus improves the existing warnings a bit. Can you try it?

with that updated patch I hit

May 4 21:51:20 haswell kernel: [19245.450607] WARNING: stack recursion on stack type 2
May 4 22:21:29 haswell kernel: [21055.268717] WARNING: can't dereference registers at 000000006546ba71 for ip ret_from_intr+0x6/0x1d
May 4 22:36:22 haswell kernel: [21948.106762] WARNING: stack going in the wrong direction? ip=native_sched_clock+0xe/0x90
May 4 22:36:22 haswell kernel: [21948.115377] WARNING: stack going in the wrong direction? ip=native_sched_clock+0xe/0x90
May 4 22:36:22 haswell kernel: [21948.124086] WARNING: stack going in the wrong direction? ip=native_sched_clock+0xd/0x90
May 4 22:36:22 haswell kernel: [21948.124088] WARNING: stack going in the wrong direction? ip=intel_pmu_handle_irq+0x12/0x4a0
May 4 22:36:22 haswell kernel: [21948.124097] WARNING: stack going in the wrong direction? ip=native_sched_clock+0xe/0x90
May 4 22:36:22 haswell kernel: [21948.150189] WARNING: stack going in the wrong direction? ip=native_sched_clock+0xe/0x90
May 4 22:36:22 haswell kernel: [21948.150199] WARNING: stack going in the wrong direction? ip=intel_pmu_handle_irq+0xe/0x4a0

the last bit repeated for a few minutes (flooding the log with a few
thousand entries that look mostly similar)

Vince