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Date: Fri, 23 Feb 2007 11:10:25 +0100
From: Ingo Molnar <mingo@elte.hu>
To: Michal Piotrowski <michal.k.k.piotrowski@gmail.com>
Cc: Michal Piotrowski <michal.k.k.piotrowski@googlemail.com>,
       tglx@linutronix.de, LKML <linux-kernel@vger.kernel.org>
Subject: Re: 2.6.20-git15 BUG: soft lockup detected on CPU#0! - timers?
Message-ID: <20070223101025.GA21127@elte.hu>
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* Ingo Molnar <mingo@elte.hu> 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.

	Ingo
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