From 89133f93508137231251543d1732da638e6022e1 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Thu, 24 Sep 2009 17:29:52 +0200 Subject: [PATCH] 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: [] sysfs_write_file+0x3c/0x137 #1: (pm_mutex){......}, at: [] enter_state+0x39/0x130 Pid: 2473, comm: pm-suspend Not tainted 2.6.31 #1 Call Trace: [] ? __debug_show_held_locks+0x22/0x24 [] __might_sleep+0x107/0x10b [] mutex_lock_nested+0x25/0x43 [] clocksource_resume+0x1c/0x60 [] timekeeping_resume+0x1e/0x1c8 [] __sysdev_resume+0x25/0xcf [] sysdev_resume+0x6d/0xae [] suspend_devices_and_enter+0x12b/0x1af [] enter_state+0xdf/0x130 [] state_store+0xb6/0xd3 [] kobj_attr_store+0x17/0x19 [] sysfs_write_file+0xfb/0x137 [] vfs_write+0xae/0x10b [] ? __up_read+0x1a/0x7f [] sys_write+0x4a/0x6e [] 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 Signed-off-by: Martin Schwidefsky Tested-by: Michal Schmidt Cc: Xiaotian Feng Cc: John Stultz LKML-Reference: <20090924172952.49697825@mschwide.boeblingen.de.ibm.com> Signed-off-by: Ingo Molnar --- kernel/time/clocksource.c | 4 ---- 1 file changed, 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) { struct clocksource *cs; - mutex_lock(&clocksource_mutex); - list_for_each_entry(cs, &clocksource_list, list) if (cs->resume) cs->resume(); clocksource_resume_watchdog(); - - mutex_unlock(&clocksource_mutex); } /** -- 2.20.1