Re: Crash in rbd, need advice

From: Ilya Dryomov
Date: Fri Apr 04 2014 - 07:08:55 EST


On Wed, Apr 2, 2014 at 12:18 AM, Hannes Landeholm <hannes@xxxxxxxxxxxxxx> wrote:
> Hello,
>
> We're running a couple of Arch Linux servers of version 3.13.5-1 in
> production and suddenly one of them had a strange problem after
> running for a few days. One process (pid 319) was running with a few
> threads, one of those threads (pid 322) was eating 100% cpu. I assumed
> it was stuck in an infinite loop (this was our own software so I
> assumed we had a bug) so I sent a SIGKILL to 319 which caused all
> other threads to exit and it turning into a zombie, but thread 322 was
> still running. After trying to stop some other services and failing I
> realized that sending any signals to any process now didn't work at
> all in the system.
>
> This was the process stack output:
>
> $ cat /proc/319/stack
> [<ffffffff810642fa>] do_exit+0x73a/0xa80
> [<ffffffff810646bf>] do_group_exit+0x3f/0xa0
> [<ffffffff81073295>] get_signal_to_deliver+0x295/0x5f0
> [<ffffffff810144a8>] do_signal+0x48/0x950
> [<ffffffff81014e18>] do_notify_resume+0x68/0xa0
> [<ffffffff8152326a>] int_signal+0x12/0x17
> [<ffffffffffffffff>] 0xffffffffffffffff
> $ cat /proc/319/task/322/stack
> [<ffffffff8151c11a>] error_exit+0x2a/0x60
> [<ffffffffffffffff>] 0xffffffffffffffff
>
> We're using ceph + rbd and this happened right after doing a rbd
> mapping (mounting it) or during the mapping itself, so we suspected
> rbd.
>
> A few days later (today) we had a server crash in another server, same
> version+distro and it had also just been running a few days as well.
> After starting it again we found the following in the system log:
>
> hostname kernel: BUG: unable to handle kernel paging request at ffff87fff75ad450
> hostname kernel: IP: [<ffffffffa018c196>] rbd_img_request_fill+0x126/0x930 [rbd]

Can you try gdb'ing that exact rbd.ko and

(gdb) list *rbd_img_request_fill+0x126

Also, the entire stack trace pertaining to rbd_img_request_fill would
help.

Thanks,

Ilya
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