Re: question on kernel stack trace

["Mkrtchyan, Tigran" <tigran.mkrtchyan@desy.de>]

Hi Dave,

Thanks for the reply. I am confused by line:

ext4_mark_inode_dirty+0x83/0x1d0 [ext4]

Is it in ext4 module or just an unfortunate stack trace?

Thanks,
   Tigran.


----- Original Message -----
> From: "David Wysochanski" <dwysocha@redhat.com>
> To: "Tigran Mkrtchyan" <tigran.mkrtchyan@desy.de>, "linux-nfs" <linux-nfs=
@vger.kernel.org>
> Sent: Wednesday, February 21, 2018 8:44:10 PM
> Subject: Re: question on kernel stack trace

> On Wed, 2018-02-21 at 11:46 +0100, Mkrtchyan, Tigran wrote:
>> On one of our nodes we got the following stack trace:
>>=20
>>=20
>> Feb 19 16:55:53 nafhh kernel: updatedb=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0D 000000000000000f=C2=A0=C2=A0=C2=A0=C2=A0=C2=A00
>> 32087=C2=A0=C2=A032081 0x00000080
>> Feb 19 16:55:53 nafhh kernel: ffff880852d13a88 0000000000000082
>> 0000000000000000 ffffffffa00bfe13
>> Feb 19 16:55:53 nafhh kernel: 0000000000000050 0000000300000001
>> 000d5a7576495a7a 0000000000000286
>> Feb 19 16:55:53 nafhh kernel: 0000000000000286 00000001dfd51213
>> ffff8810207c5068 ffff880852d13fd8
>> Feb 19 16:55:53 nafhh kernel: Call Trace:
>> Feb 19 16:55:53 nafhh kernel: [<ffffffffa00bfe13>] ?
>> ext4_mark_inode_dirty+0x83/0x1d0 [ext4]
>> Feb 19 16:55:53 nafhh kernel: [<ffffffffa029b1e4>] ?
>> __rpc_sleep_on_priority+0xf4/0x330 [sunrpc]
>> Feb 19 16:55:53 nafhh kernel: [<ffffffffa029a5b0>] ?
>> rpc_wait_bit_killable+0x0/0xa0 [sunrpc]
>> Feb 19 16:55:53 nafhh kernel: [<ffffffffa029a5f2>]
>> rpc_wait_bit_killable+0x42/0xa0 [sunrpc]
>> Feb 19 16:55:53 nafhh kernel: [<ffffffff8154ca7f>]
>> __wait_on_bit+0x5f/0x90
>> Feb 19 16:55:53 nafhh kernel: [<ffffffffa0294217>] ?
>> xprt_reserve_xprt+0x87/0x110 [sunrpc]
>> Feb 19 16:55:53 nafhh kernel: [<ffffffffa029a5b0>] ?
>> rpc_wait_bit_killable+0x0/0xa0 [sunrpc]
>> Feb 19 16:55:53 nafhh kernel: [<ffffffff8154cb28>]
>> out_of_line_wait_on_bit+0x78/0x90
>> Feb 19 16:55:53 nafhh kernel: [<ffffffff810a7220>] ?
>> wake_bit_function+0x0/0x50
>> Feb 19 16:55:53 nafhh kernel: [<ffffffffa029ab35>]
>> __rpc_execute+0xf5/0x350 [sunrpc]
>> Feb 19 16:55:53 nafhh kernel: [<ffffffff810a7027>] ?
>> bit_waitqueue+0x17/0xd0
>> Feb 19 16:55:53 nafhh kernel: [<ffffffffa029adf1>]
>> rpc_execute+0x61/0xa0 [sunrpc]
>> Feb 19 16:55:53 nafhh kernel: [<ffffffffa0291475>]
>> rpc_run_task+0x75/0x90 [sunrpc]
>> Feb 19 16:55:53 nafhh kernel: [<ffffffffa0291592>]
>> rpc_call_sync+0x42/0x70 [sunrpc]
>> Feb 19 16:55:53 nafhh kernel: [<ffffffffa035cf2e>]
>> _nfs4_call_sync+0x3e/0x40 [nfs]
>> Feb 19 16:55:53 nafhh kernel: [<ffffffffa035574c>]
>> _nfs4_proc_getattr+0xac/0xc0 [nfs]
>> Feb 19 16:55:53 nafhh kernel: [<ffffffffa0358796>]
>> nfs4_proc_getattr+0x56/0x80 [nfs]
>> Feb 19 16:55:53 nafhh kernel: [<ffffffffa033e293>]
>> __nfs_revalidate_inode+0xe3/0x220 [nfs]
>> Feb 19 16:55:53 nafhh kernel: [<ffffffffa033f12e>]
>> nfs_getattr+0xde/0x210 [nfs]
>> Feb 19 16:55:53 nafhh kernel: [<ffffffff811a0391>]
>> vfs_getattr+0x51/0x80
>> Feb 19 16:55:53 nafhh kernel: [<ffffffff811a01d4>] ?
>> cp_new_stat+0xe4/0x100
>> Feb 19 16:55:53 nafhh kernel: [<ffffffff811a0424>]
>> vfs_fstatat+0x64/0xa0
>> Feb 19 16:55:53 nafhh kernel: [<ffffffff811a04ce>]
>> vfs_lstat+0x1e/0x20
>> Feb 19 16:55:53 nafhh kernel: [<ffffffff811a04f4>]
>> sys_newlstat+0x24/0x50
>> Feb 19 16:55:53 nafhh kernel: [<ffffffff81556627>] ?
>> system_call_after_swapgs+0x187/0x220
>> Feb 19 16:55:53 nafhh kernel: [<ffffffff81556620>] ?
>> system_call_after_swapgs+0x180/0x220
>> Feb 19 16:55:53 nafhh kernel: [<ffffffff810eeef7>] ?
>> audit_syscall_entry+0x1d7/0x200
>> Feb 19 16:55:53 nafhh kernel: [<ffffffff8155660b>] ?
>> system_call_after_swapgs+0x16b/0x220
>> Feb 19 16:55:53 nafhh kernel: [<ffffffff81556604>] ?
>> system_call_after_swapgs+0x164/0x220
>> Feb 19 16:55:53 nafhh kernel: [<ffffffff815565fd>] ?
>> system_call_after_swapgs+0x15d/0x220
>> Feb 19 16:55:53 nafhh kernel: [<ffffffff815565f6>] ?
>> system_call_after_swapgs+0x156/0x220
>> Feb 19 16:55:53 nafhh kernel: [<ffffffff815565ef>] ?
>> system_call_after_swapgs+0x14f/0x220
>> Feb 19 16:55:53 nafhh kernel: [<ffffffff815566d6>]
>> system_call_fastpath+0x16/0x1b
>> Feb 19 16:55:53 nafhh kernel: [<ffffffff8155656a>] ?
>> system_call_after_swapgs+0xca/0x220
>>=20
>>=20
>> I am surprised, that top of the stack trace is in ext4 module. Can
>> some one put a light on it?
>>=20
>=20
> Ignore the symbols with '?' next to them as they are not reliable.
>=20
> If you want to map this to code use something like 'eu-addr2line' and
> see if the symbols make sense in terms of source code lines.
>=20
> This looks like the process is just blocked for a long time waiting on
> an NFS4 GETATTR to complete, and does not look unusual to me.
>=20
> --
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