Re: Blocked in keyctl(...) ??? - RCU related ???

From: ããããããã
Date: Fri Mar 16 2012 - 04:43:36 EST


Hello,

On Mon, 12 Mar 2012 17:03:01 +0100
Paul Rolland (ããããããã) <rol@xxxxxxxxx> wrote:

> Sometimes, my applications start "locking": nothing happens anymore, can't
> kill them...
> I manage to strace them, to find that they are executing the following
> syscall:
>
> 13686 keyctl(0x1, 0, 0xffffffffffffffff, 0x7fa90fd6a2c0, 0
>
> and that syscall never returns.

OK, this happened again, while running 3.3-rc7... I've used sysrq to
collect some informations and what I can see from that is the following :

Mar 16 08:40:02 tux kernel: Call Trace:
Mar 16 08:40:02 tux kernel: [<ffffffff813b8771>] ? extract_buf+0x91/0x140
Mar 16 08:40:02 tux kernel: [<ffffffff8166fd5a>] schedule+0x3a/0x50
Mar 16 08:40:02 tux kernel: [<ffffffff8166e09d>] schedule_timeout+0x1ed/0x260
Mar 16 08:40:02 tux kernel: [<ffffffff810636c1>] ? get_parent_ip+0x11/0x50
Mar 16 08:40:02 tux kernel: [<ffffffff810636c1>] ? get_parent_ip+0x11/0x50
Mar 16 08:40:02 tux kernel: [<ffffffff810636c1>] ? get_parent_ip+0x11/0x50
Mar 16 08:40:02 tux kernel: [<ffffffff8166f100>] wait_for_common+0xc0/0x160
Mar 16 08:40:02 tux kernel: [<ffffffff81062150>] ? try_to_wake_up+0x2e0/0x2e0
Mar 16 08:40:02 tux kernel: [<ffffffff810ad020>] ? __call_rcu+0x150/0x150
Mar 16 08:40:02 tux kernel: [<ffffffff8166f1b8>] wait_for_completion+0x18/0x20
Mar 16 08:40:02 tux kernel: [<ffffffff81054628>] wait_rcu_gp+0x48/0x50
Mar 16 08:40:02 tux kernel: [<ffffffff81054630>] ? wait_rcu_gp+0x50/0x50
Mar 16 08:40:02 tux kernel: [<ffffffff810ac09c>] synchronize_rcu+0x1c/0x20
Mar 16 08:40:02 tux kernel: [<ffffffff812ba6a9>] install_session_keyring_to_cred+0x59/0xc0
Mar 16 08:40:02 tux kernel: [<ffffffff812bac3a>] join_session_keyring+0x12a/0x170
Mar 16 08:40:02 tux kernel: [<ffffffff812b8cd2>] keyctl_join_session_keyring+0x32/0x60
Mar 16 08:40:02 tux kernel: [<ffffffff812ba278>] sys_keyctl+0x168/0x180
Mar 16 08:40:02 tux kernel: [<ffffffff81671b62>]
system_call_fastpath+0x16/0x1b

The complete traces collected in /var/log/messages is attached to this email.

Is there anything I can do to investigate this ?

Paul


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