Re: 2.6.20-git15 BUG: soft lockup detected on CPU#0! - timers?

From: Ingo Molnar
Date: Fri Feb 23 2007 - 05:15:51 EST

* Ingo Molnar <mingo@xxxxxxx> wrote:

> could you please try the patch below? This is pretty much the only
> condition under which we can silently 'leak' pending softirqs, and
> trigger the new warning: if something does cond_resched_softirq() in
> non-runnable state. (which is a no-no, but nothing enforced this, so
> it could in theory happen.) So the question is, with this patch
> applied, do you get these new warnings from sched.c?

it just triggered on one of my boxes:

BUG: at kernel/sched.c:4692 cond_resched_softirq()
[<c03ce128>] cond_resched_softirq+0x5f/0x7b
[<c0369078>] release_sock+0x42/0x81
[<c03693bc>] sk_wait_data+0x57/0x9d
[<c0129a00>] autoremove_wake_function+0x0/0x33
[<c03942ff>] tcp_recvmsg+0x39c/0x973
[<c0368e39>] sock_common_recvmsg+0x3e/0x54
[<c0367903>] sock_aio_read+0x106/0x112
[<c0159b0c>] do_sync_read+0xc8/0x105
[<c0129a00>] autoremove_wake_function+0x0/0x33
[<c0159e82>] vfs_read+0xc1/0x15a
[<c015a7d2>] sys_read+0x41/0x67
[<c0103c10>] syscall_call+0x7/0xb

so tcp_recvmsg() definitely gets into this condition.

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