RE: BUG: unable to handle kernel NULL pointer dereference at 0000000000000038 !//RE: kernel BUG at kernel/locking/rtmutex.c:1027

[Feng Feng24 Liu]

Hi, Sebastian
	I just add the RT patches, nothing else.

Thanks
Feng

>-----Original Message-----
>From: Sebastian Andrzej Siewior [mailto:sebastian.siewior@xxxxxxxxxxxxx]
>Sent: Monday, June 26, 2017 10:55 PM
>To: Steven Rostedt
>Cc: Feng Feng24 Liu; Mike Galbraith; linux-kernel@xxxxxxxxxxxxxxx;
>linux-rt-users@xxxxxxxxxxxxxxx; tmac@xxxxxx
>Subject: Re: BUG: unable to handle kernel NULL pointer dereference at
>0000000000000038 !//RE: kernel BUG at kernel/locking/rtmutex.c:1027
>
>On 2017-06-26 10:24:18 [-0400], Steven Rostedt wrote:
>> >  CPU: 17 PID: 1738811 Comm: ip Not tainted 4.4.70-thinkcloud-nfv #1
>> > Hardware name: LENOVO System x3650 M5: -[8871AC1]-/01GR174, BIOS
>> > -[TCE124M-2.10]- 06/23/2016
>> >  task: ffff881cda2c27c0 ti: ffff881ea0538000 task.ti:
>> > ffff881ea0538000
>> >  RIP: 0010:[<ffffffff810a2cb4>]  [<ffffffff810a2cb4>]
>> > __try_to_take_rt_mutex+0x34/0x160
>> >  RSP: 0018:ffff881ea053bb50  EFLAGS: 00010082
>> >  RAX: 0000000000000000 RBX: ffff881f805416a8 RCX: 0000000000000000
>> >  RDX: ffff881ea053bb98 RSI: ffff881cda2c27c0 RDI: ffff881f805416a8
>> >  RBP: ffff881ea053bb60 R08: 0000000000000001 R09: 0000000000000002
>> >  R10: 0000000000000a01 R11: 0000000000000001 R12: ffff881cda2c27c0
>> >  R13: ffff881cda2c27c0 R14: 0000000000000202 R15: ffff881f6b0c27c0
>> >  FS:  00007f28be315740(0000) GS:ffff88205f8c0000(0000)
>> > knlGS:0000000000000000
>> >  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> >  CR2: 0000000000000038 CR3: 0000001e9e479000 CR4: 00000000003406e0
>> >  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>> >  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>> >  Stack:
>> >   ffff881f805416a8 ffff881ea053bb98 ffff881ea053bc28 ffffffff81a8f03d
>> >   ffff881ea053c000 01ff881ea053bb90 ffff881cda2c27c0 ffff881f6b0c27c1
>> >   ffff881cda2c2eb0 0000000000000001 0000000000000000
>> > 0000000000000000  Call Trace:
>> >   [<ffffffff81a8f03d>] rt_spin_lock_slowlock+0x13d/0x390
>> >   [<ffffffff81a903bf>] rt_spin_lock+0x1f/0x30
>> >   [<ffffffff8141757f>] lockref_get_not_dead+0xf/0x50
>> >   [<ffffffff811e0a01>] ns_get_path+0x61/0x1d0
>>
>> Hmm, this is in the filesystem code. What were you doing when this
>> happened?
>
>and do you have any patches except the RT patch?
>
>>
>> > <4>Jun 24 10:01:19 node-1 kernel: [44959.446268]
>> > [<ffffffff8121eea9>] proc_ns_follow_link+0x89/0xa0
>>
>> Do you know what proc file it was reading?
>>
>> -- Steve
>
>Sebastian