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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2009-09-24 11:29:52 -0400
committerIngo Molnar <mingo@elte.hu>2009-09-24 16:37:53 -0400
commit89133f93508137231251543d1732da638e6022e1 (patch)
tree8f94df8c650bbe2ec765de89ce70b9e762a5ba2f /kernel
parent94a8d5caba74211ec76dac80fc6e2d5c391530df (diff)
clocksource: Resume clocksource without taking the clocksource mutex
git commit 75c5158f70c065b9 converted the clocksource spinlock to a mutex. This causes the following BUG: BUG: sleeping function called from invalid context at kernel/mutex.c:280 in_atomic(): 0, irqs_disabled(): 1, pid: 2473, name: pm-suspend 2 locks held by pm-suspend/2473: #0: (&buffer->mutex){......}, at: [<ffffffff8115ab13>] sysfs_write_file+0x3c/0x137 #1: (pm_mutex){......}, at: [<ffffffff810865b5>] enter_state+0x39/0x130 Pid: 2473, comm: pm-suspend Not tainted 2.6.31 #1 Call Trace: [<ffffffff810792f0>] ? __debug_show_held_locks+0x22/0x24 [<ffffffff8104a2ef>] __might_sleep+0x107/0x10b [<ffffffff8141fca9>] mutex_lock_nested+0x25/0x43 [<ffffffff81073537>] clocksource_resume+0x1c/0x60 [<ffffffff81072902>] timekeeping_resume+0x1e/0x1c8 [<ffffffff812aee62>] __sysdev_resume+0x25/0xcf [<ffffffff812aef79>] sysdev_resume+0x6d/0xae [<ffffffff810864f8>] suspend_devices_and_enter+0x12b/0x1af [<ffffffff8108665b>] enter_state+0xdf/0x130 [<ffffffff81085dc3>] state_store+0xb6/0xd3 [<ffffffff81204c73>] kobj_attr_store+0x17/0x19 [<ffffffff8115abd2>] sysfs_write_file+0xfb/0x137 [<ffffffff811057d2>] vfs_write+0xae/0x10b [<ffffffff81208392>] ? __up_read+0x1a/0x7f [<ffffffff811058ef>] sys_write+0x4a/0x6e [<ffffffff81011b82>] system_call_fastpath+0x16/0x1b clocksource_resume is called early in the resume process, there is only one cpu, no processes are running and the interrupts are disabled. It is therefore possible to resume the clocksources without taking the clocksource mutex. Reported-by: Xiaotian Feng <xtfeng@gmail.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Tested-by: Michal Schmidt <mschmidt@redhat.com> Cc: Xiaotian Feng <xtfeng@gmail.com> Cc: John Stultz <johnstul@us.ibm.com> LKML-Reference: <20090924172952.49697825@mschwide.boeblingen.de.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/time/clocksource.c4
1 files changed, 0 insertions, 4 deletions
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index 09113347d328..5e18c6ab2c6a 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -394,15 +394,11 @@ void clocksource_resume(void)
394{ 394{
395 struct clocksource *cs; 395 struct clocksource *cs;
396 396
397 mutex_lock(&clocksource_mutex);
398
399 list_for_each_entry(cs, &clocksource_list, list) 397 list_for_each_entry(cs, &clocksource_list, list)
400 if (cs->resume) 398 if (cs->resume)
401 cs->resume(); 399 cs->resume();
402 400
403 clocksource_resume_watchdog(); 401 clocksource_resume_watchdog();
404
405 mutex_unlock(&clocksource_mutex);
406} 402}
407 403
408/** 404/**