Re: perf_callchain_user oops

[Peter Zijlstra]

On Wed, Mar 22, 2017 at 10:58:04PM -0400, Dave Jones wrote:
> Not seen this one before..
> 
> Oops: 0002 [#1] PREEMPT SMP DEBUG_PAGEALLOC

That's a write fault reaching no_context() afaict.

> CPU: 1 PID: 24420 Comm: trinity-main Not tainted 4.11.0-rc3-think+ #3 
> task: ffff8804f4c85440 task.stack: ffffc90001d38000
> RIP: 0010:perf_callchain_user+0x11e/0x220
> RSP: 0000:ffffc90001d3ba98 EFLAGS: 00010246
> RAX: ffff88044c59c2a8 RBX: ffffc90001d3bae8 RCX: 0000562bce3f6e40
> RDX: 0000562bce3f6e40 RSI: 00007fffffffeff0 RDI: 0000000000000000
> RBP: ffffc90001d3bab8 R08: 00000000bffffff0 R09: 00000000ffffdff0
> R10: 0000000000002faa R11: 0000000000002fab R12: ffff8804f4c85440
> R13: ffffc90001d3bf58 R14: ffffc90001d3bf58 R15: 0000000000000000
> FS:  00007f34b3969b40(0000) GS:ffff880507a00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: ffff88044c5b4000 CR3: 000000044c584000 CR4: 00000000001406e0
> DR0: 00007f34b382e000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
> Call Trace:
>  get_perf_callchain+0x258/0x2b0
>  perf_callchain+0x79/0x80
>  perf_prepare_sample+0x27e/0x360
>  perf_event_output_forward+0x75/0x160

Any chance you could run scripts/faddr2line on this output?

I cannot seem to match the Code with a defconfig build of that function.