Messages in this thread Patch in this message | | | Date | Fri, 3 May 2013 20:32:58 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: clockevents_program_event WARN_ON preventing boot. |
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On Fri, 3 May 2013, Dave Jones wrote: > On Fri, May 03, 2013 at 12:49:20AM +0200, Thomas Gleixner wrote: > > > I'm fundamentally confused and Daves observation about slub debug does > > not make it less confusing. > > > > It'd be nice if you could add some more instrumentation or bisect the > > issue. > > Here's what I ended up with.. > b352bc1cbc29134a356b5c16ee2281807a7b984e is the first bad commit > commit b352bc1cbc29134a356b5c16ee2281807a7b984e > Author: Thomas Gleixner <tglx@linutronix.de> > Date: Tue Mar 5 14:25:32 2013 +0100 > > tick: Convert broadcast cpu bitmaps to cpumask_var_t > > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > Link: http://lkml.kernel.org/r/20130306111537.366394000@linutronix.de > Cc: Rusty Russell <rusty@rustcorp.com.au> >
I bet you have CONFIG_CPUMASK_OFFSTACK enabled.
/me is a moron and rumages for a brown paperbag.
Patch below.
Thanks,
tglx
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Subject: tick: Use zalloc_cpumask_var for allocating offstack cpumasks From: Thomas Gleixner <tglx@linutronix.de> Date: Fri, 03 May 2013 20:22:36 +0200
commit b352bc1cbc (tick: Convert broadcast cpu bitmaps to cpumask_var_t) broke CONFIG_CPUMASK_OFFSTACK in a very subtle way.
Instead of allocating the cpumasks with zalloc_cpumask_var it uses alloc_cpumask_var, so we can get random data there, which of course confuses the logic completely and causes random failures.
Reported-by: Dave Jones <davej@redhat.com> Reported-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> --- kernel/time/tick-broadcast.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)
Index: linux-2.6/kernel/time/tick-broadcast.c =================================================================== --- linux-2.6.orig/kernel/time/tick-broadcast.c +++ linux-2.6/kernel/time/tick-broadcast.c @@ -785,11 +785,11 @@ bool tick_broadcast_oneshot_available(vo void __init tick_broadcast_init(void) { - alloc_cpumask_var(&tick_broadcast_mask, GFP_NOWAIT); - alloc_cpumask_var(&tmpmask, GFP_NOWAIT); + zalloc_cpumask_var(&tick_broadcast_mask, GFP_NOWAIT); + zalloc_cpumask_var(&tmpmask, GFP_NOWAIT); #ifdef CONFIG_TICK_ONESHOT - alloc_cpumask_var(&tick_broadcast_oneshot_mask, GFP_NOWAIT); - alloc_cpumask_var(&tick_broadcast_pending_mask, GFP_NOWAIT); - alloc_cpumask_var(&tick_broadcast_force_mask, GFP_NOWAIT); + zalloc_cpumask_var(&tick_broadcast_oneshot_mask, GFP_NOWAIT); + zalloc_cpumask_var(&tick_broadcast_pending_mask, GFP_NOWAIT); + zalloc_cpumask_var(&tick_broadcast_force_mask, GFP_NOWAIT); #endif }
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