Messages in this thread Patch in this message | | | Date | Sun, 29 Jun 2008 15:05:54 +0200 | From | Ingo Molnar <> | Subject | Re: -tip: WARNING: at kernel/lockdep.c:2738 |
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* Vegard Nossum <vegard.nossum@gmail.com> wrote:
> Hi, > > I just got this on the latest tip/master shortly after finishing initcalls: > > ------------[ cut here ]------------ > WARNING: at kernel/lockdep.c:2738 check_flags+0x142/0x160() > Pid: 5, comm: watchdog/0 Not tainted 2.6.26-rc8-tip-00206-g3248a70-dirty #49 > [<c0139684>] warn_on_slowpath+0x54/0x70 > [<c015be00>] ? trace_hardirqs_off_caller+0x40/0xe0 > [<c010a7c5>] ? native_sched_clock+0xb5/0x110 > [<c018076e>] ? ftrace_record_ip+0x12e/0x240 > [<c05ab8c8>] ? _spin_unlock_irqrestore+0x48/0x80 > [<c029ffd3>] ? debug_locks_off+0x3/0x50 > [<c018076e>] ? ftrace_record_ip+0x12e/0x240 > [<c0104f6b>] ? mcount_call+0x5/0xa > [<c015b322>] check_flags+0x142/0x160 > [<c015f6e9>] lock_acquire+0x59/0xd0 > [<c01769f1>] ? watchdog+0xb1/0x1e0 > [<c05ab2fd>] _read_lock+0x3d/0x70 > [<c01769f1>] ? watchdog+0xb1/0x1e0 > [<c01769f1>] watchdog+0xb1/0x1e0 > [<c05ab8c8>] ? _spin_unlock_irqrestore+0x48/0x80 > [<c012bae9>] ? complete+0x49/0x60 > [<c0176940>] ? watchdog+0x0/0x1e0 > [<c014e637>] kthread+0x47/0x80 > [<c014e5f0>] ? kthread+0x0/0x80 > [<c0104f53>] kernel_thread_helper+0x7/0x10 > ======================= > ---[ end trace 8e23f95b45fa05f7 ]--- > possible reason: unannotated irqs-on. > irq event stamp: 18 > hardirqs last enabled at (17): [<c015e02b>] trace_hardirqs_on+0xb/0x10 > hardirqs last disabled at (18): [<c015beab>] trace_hardirqs_off+0xb/0x10 > softirqs last enabled at (0): [<c0137cd8>] copy_process+0x268/0x10b0 > softirqs last disabled at (0): [<00000000>] 0x0 > > I hope this wasn't caused by any of my patches :-S > > $ addr2line -e vmlinux -i c01769f1 > kernel/softlockup.c:232 > kernel/softlockup.c:271 > > It seems that Andrew reported this too, > http://lkml.org/lkml/2008/6/9/41, but I already have the fix, > > commit 040ec23d07f95285e9777a85cda29cb339a3065b > Author: Ingo Molnar <mingo@elte.hu> > Date: Mon Jun 9 01:45:29 2008 -0700 > > sched: sched_clock() lockdep fix > > so it can't be the same one. > > (It seems to be something ftrace-related, adding Steven to Cc.)
perhaps caused by this one:
| commit 76a2a6ee8a0660a29127f05989ac59ae1ce865fa | Author: Peter Zijlstra <a.p.zijlstra@chello.nl> | Date: Fri Jun 27 13:41:15 2008 +0200 | | sched: sched_clock_cpu() based cpu_clock()
?
Does the patch below (or the tip/master i just pushed out) fix it?
Ingo
-------------> commit 2d452c9b10caeec455eb5e56a0ef4ed485178213 Author: Ingo Molnar <mingo@elte.hu> Date: Sun Jun 29 15:01:59 2008 +0200
sched: sched_clock_cpu() based cpu_clock(), lockdep fix Vegard Nossum reported: > WARNING: at kernel/lockdep.c:2738 check_flags+0x142/0x160() which happens due to: unsigned long long cpu_clock(int cpu) { unsigned long long clock; unsigned long flags; raw_local_irq_save(flags); as lower level functions can take locks, we must not do that, use proper lockdep-annotated irq save/restore. Reported-by: Vegard Nossum <vegard.nossum@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/sched_clock.c b/kernel/sched_clock.c index ed5a8c4..60094e2 100644 --- a/kernel/sched_clock.c +++ b/kernel/sched_clock.c @@ -250,9 +250,9 @@ unsigned long long cpu_clock(int cpu) unsigned long long clock; unsigned long flags; - raw_local_irq_save(flags); + local_irq_save(flags); clock = sched_clock_cpu(cpu); - raw_local_irq_restore(flags); + local_irq_restore(flags); return clock; }
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