Messages in this thread | | | Date | Sun, 6 Apr 2008 23:48:14 -0700 | From | Andrew Morton <> | Subject | Re: 2.6.25-rc8-mm1 - BUG: scheduling while atomic: swapper/0/0xffffffff |
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On Mon, 07 Apr 2008 02:21:22 -0400 Valdis.Kletnieks@vt.edu wrote:
> On Tue, 01 Apr 2008 21:32:14 PDT, Andrew Morton said: > > ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.25-rc8/2.6.25-rc8-mm1/ > > Been seeing these crop up once in a while - can take hours after a reboot > before I see the first one, but once I see one, I'm likely to see more, at > a frequency of anywhere from ~5seconds to ~10 minutes between BUG msgs. > > BUG: scheduling while atomic: swapper/0/0xffffffff > Pid: 0, comm: swapper Tainted: P 2.6.25-rc8-mm1 #4 > > Call Trace: > [<ffffffff8020b2f4>] ? default_idle+0x0/0x74 > [<ffffffff8022be19>] __schedule_bug+0x5d/0x61 > [<ffffffff80552aea>] schedule+0x11a/0x9e4 > [<ffffffff805536ce>] ? preempt_schedule+0x3c/0xaa > [<ffffffff802480f1>] ? hrtimer_forward+0x82/0x96 > [<ffffffff804600a4>] ? cpuidle_idle_call+0x0/0xd5 > [<ffffffff8020b2f4>] ? default_idle+0x0/0x74 > [<ffffffff8020b2e0>] cpu_idle+0xf6/0x10a > [<ffffffff80540cb2>] rest_init+0x86/0x8a > > Eventually, I end up with a basically hung system, and need to alt-sysrq-B. > > Yes, I know it's tainted, and it's possible the root cause is a self-inflicted > buggy module - but the traceback above seems odd. Did some of my code manage > to idle the CPU while is_atomic was set, or is the path from cpu_idle on down > doing something it shouldn't be?
I'd say that there's an unlock missing somewhere.
> (I admit being confused - if my code was the source of the is_atomic error, > shouldn't it have been caught on the *previous* call to schedule - the one > that ran through all the queues and decided we should invoke idle?
Sounds sane. Perhaps preempt_count is getting mucked up in interrupt context?
iirc there's some toy in either the recently-added tracing code or still in the -rt tree which would help find a missed unlock, but I forget what it was. Ingo will know...
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