Message-ID: <CAB7JpEHLJNsckzEnZ7rHLQfMfhRhSjYHf4MRN_A-CWmExi3gTA@mail.gmail.com>
Date:	Fri, 12 Aug 2016 20:54:49 +0300
From:	Alexander Shishkin <alexander.shishkin@...ux.intel.com>
To:	Vince Weaver <vincent.weaver@...ne.edu>
Cc:	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...hat.com>,
	Arnaldo Carvalho de Melo <acme@...nel.org>
Subject: Re: perf: WARNING: kernel/events/core.c:4893 perf_mmap_close

Yes, I tracked to a race between unmapping and set_output, trying to
come up with a good fix now.

On 12 August 2016 at 20:17, Vince Weaver <vincent.weaver@...ne.edu> wrote:
>
> On Tue, 9 Aug 2016, Alexander Shishkin wrote:
>
>>
>> Awesome, I'll have a look. Can you tell it it was messing around with
>> intel_bts driver from the fuzzer log?
>
>
> It's not just my Haswell machine either, my Core2 machine locked up with
> this (possibly related):
>
> [69117.178434] WARNING: CPU: 1 PID: 31160 at kernel/events/core.c:4831 ring_buffer_put+0x3c/0x4f
> [69117.178434] CPU: 1 PID: 31160 Comm: perf_fuzzer Tainted: G        W       4.8.0-rc1+ #208
> [69117.178434] Hardware name: AOpen   DE7000/nMCP7ALPx-DE R1.06 Oct.19.2012, BIOS 080015  10/19/2012
> [69117.178434]  0000000000000000 ffff88011932fb48 ffffffff812b7e50 0000000000000000
> [69117.178434]  0000000000000000 ffff88011932fb88 ffffffff8104cab6 000012df1932fc50
> [69117.178434]  ffff880119018000 ffff88011fc8b740 0000000000000000 ffff88003765d000
> [69117.178434] Call Trace:
> [69117.178434]  [<ffffffff812b7e50>] dump_stack+0x4d/0x63
> [69117.178434]  [<ffffffff8104cab6>] __warn+0xca/0xe5
> [69117.178434]  [<ffffffff8104cb8d>] warn_slowpath_null+0x1d/0x1f
> [69117.178434]  [<ffffffff810f000f>] ring_buffer_put+0x3c/0x4f
> [69117.178434]  [<ffffffff810f6625>] perf_aux_output_end+0xd2/0xd9
> [69117.178434]  [<ffffffff81008eba>] bts_event_stop+0xb2/0xfc
> [69117.178434]  [<ffffffff81008f17>] bts_event_del+0x13/0x15
> [69117.178434]  [<ffffffff810ef33e>] event_sched_out+0xb0/0x184
> [69117.178434]  [<ffffffff810ef43b>] group_sched_out+0x29/0x7a
> [69117.178434]  [<ffffffff810ef758>] ctx_sched_out+0x182/0x198
> [69117.178434]  [<ffffffff810ef7b9>] task_ctx_sched_out+0x4b/0x4d
> [69117.178434]  [<ffffffff810f2e7e>] ctx_resched+0x25/0x4d
> [69117.178434]  [<ffffffff810f2f61>] __perf_event_enable+0xbb/0xc4
> [69117.178434]  [<ffffffff810eb649>] event_function+0x107/0x122
> [69117.178434]  [<ffffffff810ec3b8>] ? perf_event_sysfs_show+0x22/0x22
> [69117.178434]  [<ffffffff810ec3cf>] remote_function+0x17/0x44
> [69117.178434]  [<ffffffff810a8fb4>] generic_exec_single+0x4e/0xce
> [69117.178434]  [<ffffffff810ec3b8>] ? perf_event_sysfs_show+0x22/0x22
> [69117.178434]  [<ffffffff810a90ed>] smp_call_function_single+0xb9/0xd9
> [69117.178434]  [<ffffffff810f2ea6>] ? ctx_resched+0x4d/0x4d
> [69117.178434]  [<ffffffff810eccda>] event_function_call+0xa1/0xfd
> [69117.178434]  [<ffffffff810f2ea6>] ? ctx_resched+0x4d/0x4d
> [69117.178434]  [<ffffffff810eb542>] ? perf_ctx_lock+0x22/0x22
> [69117.178434]  [<ffffffff810ecda7>] ? perf_event_disable+0x27/0x27
> [69117.178434]  [<ffffffff810ece00>] _perf_event_enable+0x59/0x5e
> [69117.178434]  [<ffffffff810eb831>] perf_event_for_each_child+0x59/0x94
> [69117.178434]  [<ffffffff810efa77>] perf_event_task_enable+0x6b/0xa1
> [69117.178434]  [<ffffffff8105d140>] SyS_prctl+0x157/0x3b2
> [69117.178434]  [<ffffffff81582cdf>] entry_SYSCALL_64_fastpath+0x17/0x93
> [69117.178434] ---[ end trace 6960c0c785736820 ]---
> [69117.431157] BUG: unable to handle kernel NULL pointer dereference at 0000000000000088
> [69117.435117] IP: [<ffffffff810f1ed5>] perf_mmap_close+0x2d/0x252
> [69117.435117] PGD 1192d5067 PUD 119be7067 PMD 0
> [69117.435117] Oops: 0000 [#1] SMP
> [69117.435117] task: ffff8801198b40c0 task.stack: ffff88011932c000
> [69117.435117] RIP: 0010:[<ffffffff810f1ed5>]  [<ffffffff810f1ed5>] perf_mmap_close+0x2d/0x252
> [69117.435117] RSP: 0018:ffff88011932fe60  EFLAGS: 00010246
> [69117.435117] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
> [69117.435117] RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff880119018000
> [69117.435117] RBP: ffff88011932fea0 R08: 0000000000000000 R09: 0000000000000000
> [69117.435117] R10: 000000000001af54 R11: 000000000001af08 R12: ffff88003765d000
> [69117.435117] R13: ffff880037536900 R14: ffff880119af6a80 R15: ffff880119af6a80
> [69117.435117] FS:  00007f40dc148700(0000) GS:ffff88011fc00000(0000) knlGS:0000000000000000
> [69117.435117] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [69117.435117] CR2: 0000000000000088 CR3: 000000011a8ef000 CR4: 00000000000407f0
> [69117.435117] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [69117.435117] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
> [69117.435117] Stack:
> [69117.435117]  ffffffff8111e2c0 ffff880037536920 0000000000000000 ffff880119af6a80
> [69117.435117]  0000000000000000 ffff880037536900 ffff880119af6a80 ffff880119af6a80
> [69117.435117]  ffff88011932fec0 ffffffff8111e7da ffff88003748d3c0 0000000000000000
> [69117.435117] Call Trace:
> [69117.435117]  [<ffffffff8111e2c0>] ? vma_gap_callbacks_propagate+0x1b/0x33
> [69117.435117]  [<ffffffff8111e7da>] remove_vma+0x32/0x66
> [69117.435117]  [<ffffffff811206cf>] do_munmap+0x2bf/0x2e3
> [69117.435117]  [<ffffffff81120bd6>] SyS_munmap+0x50/0x69
> [69117.435117]  [<ffffffff81582cdf>] entry_SYSCALL_64_fastpath+0x17/0x93
> [69117.435117] Code: 89 e5 41 57 41 56 41 55 41 54 49 89 fe 53 48 83 ec 18 48 8b 87 a0 00 00 00 4c 8b a0 c8 00 00 00 4c 89 e7 e8 d0 e0 ff ff 48 89 c3 <4c> 8b a8 88 00 00 00 48 8b 80 80 00 00 00 48 89 45 d0 8b 43 18
> [69117.435117] RIP  [<ffffffff810f1ed5>] perf_mmap_close+0x2d/0x252
> [69117.435117]  RSP <ffff88011932fe60>
> [69117.435117] CR2: 0000000000000088
> [69117.677732] ---[ end trace 6960c0c785736821 ]---
>

Powered by blists - more mailing lists