Re: [PATCH 1/1] perf tools: Add missing user space support for config1/config2

From: Cyrill Gorcunov
Date: Tue Apr 26 2011 - 17:33:56 EST


On 04/27/2011 01:25 AM, Don Zickus wrote:
> On Wed, Apr 27, 2011 at 01:19:07AM +0400, Cyrill Gorcunov wrote:
>> Vince I've not read the whole thread so no idea what is all about, but if you
>> have some p4 machines and have some will to help -- mind to test the patch below,
>> it should fix nmi-watchdog and cycles conflict. It's utter raw RFC (and i know there
>> is a nit i should update) but still might be interesting to see the results.
>> Untested.
>> --
>> perf, x86: P4 PMU -- Introduce alternate events v3
>
> Unfortunately it just panic'd for me when I ran
>
> perf record grep -r don /
>
> Thoughts?
>
> Cheers,
> Don
>
> redfish.lab.bos.redhat.com login: BUG: unable to handle kernel NULL
> pointer dereference at 0000000000000008
> IP: [<ffffffff8101ff60>] p4_pmu_schedule_events+0xb0/0x4c0
> PGD 2c603067 PUD 2d617067 PMD 0
> Oops: 0000 [#1] SMP
> last sysfs file: /sys/devices/system/cpu/online
> CPU 2
> Modules linked in: autofs4 sunrpc ipv6 dm_mirror dm_region_hash dm_log
> uinput ppdev e1000 parport_pc parport sg dcdbas pcspkr snd_intel8x0
> snd_ac97_codec ac97_bus snd_seq snd_seq_device snd_pcm sn]
>
> Pid: 1734, comm: grep Not tainted 2.6.39-rc3usb3-latest+ #339 Dell Inc.
> Precision WorkStation 470 /0P7996
> RIP: 0010:[<ffffffff8101ff60>] [<ffffffff8101ff60>]
> p4_pmu_schedule_events+0xb0/0x4c0
> RSP: 0018:ffff88003fb03b18 EFLAGS: 00010016
> RAX: 000000000000003c RBX: 0000000000000000 RCX: 0000000000000000
> RDX: ffff88003c30de00 RSI: 0000000000000004 RDI: 000000000000000f
> RBP: ffff88003fb03bb8 R08: 0000000000000001 R09: 0000000000000001
> R10: 000000000000006d R11: ffff88003acb4ae8 R12: ffff88002d490c00
> R13: ffff88003fb03b78 R14: 0000000000000001 R15: 0000000000000001
> FS: 0000000000000000(0000) GS:ffff88003fb00000(0000)
> knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000000000000008 CR3: 000000002d728000 CR4: 00000000000006e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> Process grep (pid: 1734, threadinfo ffff88002d648000, task
> ffff88003acb4240)
> Stack:
> ffff880000000014 ffff88003acb4b10 b00002030803c000 0000000000000003
> 0000000200000001 ffff88003fb03bc8 0000000100000002 ffff88003fb03bcc
> 0000000181a24ee0 ffff88003fb0cd48 0000000000000008 0000000000000000
> Call Trace:
> <IRQ>
> [<ffffffff8101b9e1>] ? x86_pmu_add+0xb1/0x170
> [<ffffffff8101b8bf>] x86_pmu_commit_txn+0x5f/0xb0
> [<ffffffff810ff0c4>] ? perf_event_update_userpage+0xa4/0xe0
> [<ffffffff810ff020>] ? perf_output_end+0x60/0x60
> [<ffffffff81100dca>] group_sched_in+0x8a/0x160
> [<ffffffff8110100b>] ctx_sched_in+0x16b/0x1d0
> [<ffffffff811017ce>] perf_event_task_tick+0x1de/0x260
> [<ffffffff8104fc1e>] scheduler_tick+0xde/0x2b0
> [<ffffffff81096e20>] ? tick_nohz_handler+0x100/0x100
>

Ouch, I bet p4_config_get_bind returned NULL and here we are. Weird,
seems I've missed something. Don, I'll continue tomorrow, ok? (kinda
sleep already).

--
Cyrill
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