Messages in this thread Patch in this message | | | Date | Thu, 24 May 2007 09:45:34 +0200 | From | Ingo Molnar <> | Subject | Re: [BUG] local_softirq_pending storm |
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* Chuck Ebbert <cebbert@redhat.com> wrote:
> > if (need_resched() && system_state == SYSTEM_RUNNING) { > > - raw_local_irq_disable(); > > - _local_bh_enable(); > > - raw_local_irq_enable(); > > + local_bh_enable(); > > __cond_resched(); > > local_bh_disable(); > > return 1; > > We may have a problem with that: > > BUG: warning at kernel/softirq.c:138/local_bh_enable() (Not tainted) > [<c042b2ef>] local_bh_enable+0x45/0x92 > [<c06036b7>] cond_resched_softirq+0x2c/0x42 > [<c059d5d0>] release_sock+0x54/0xa3 > [<c05c9428>] tcp_sendmsg+0x91b/0xa0c > [<c05e1bb9>] inet_sendmsg+0x3b/0x45 > [<c059af34>] sock_aio_write+0xf9/0x105 > [<c0476035>] do_sync_write+0xc7/0x10a > [<c0437265>] autoremove_wake_function+0x0/0x35 > [<c047688e>] vfs_write+0xbc/0x154 > [<c0476e8c>] sys_write+0x41/0x67 > [<c0404f70>] syscall_call+0x7/0xb
hm, this place really shouldnt call cond_resched_softirq() with hardirqs disabled.
perhaps a buggy ->sk_backlog_rcv() handler disabled interrupts without restoring them?
could you enable CONFIG_PROVE_LOCKING and apply the patch below - which location is printed as having last disabled hardirqs?
Ingo
---------------------> Subject: [patch] softirqs: print out irq-trace events From: Ingo Molnar <mingo@elte.hu>
some code is fiddling with softirqs but hardirqs are disabled, so try to figure out who disabled hardirqs.
Signed-off-by: Ingo Molnar <mingo@elte.hu> --- kernel/softirq.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)
Index: linux/kernel/softirq.c =================================================================== --- linux.orig/kernel/softirq.c +++ linux/kernel/softirq.c @@ -135,7 +135,15 @@ void local_bh_enable(void) WARN_ON_ONCE(in_irq()); #endif - WARN_ON_ONCE(irqs_disabled()); + if (irqs_disabled()) { + static int once = 1; + + if (once) { + once = 0; + print_irqtrace_events(current); + WARN_ON(1); + } + } #ifdef CONFIG_TRACE_IRQFLAGS local_irq_save(flags); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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