linux/kernel
Anton Blanchard e9028b0ff2 [PATCH] fix scheduler deadlock
We have noticed lockups during boot when stress testing kexec on ppc64.
Two cpus would deadlock in scheduler code trying to grab already taken
spinlocks.

The double_rq_lock code uses the address of the runqueue to order the
taking of multiple locks.  This address is a per cpu variable:

	if (rq1 < rq2) {
		spin_lock(&rq1->lock);
		spin_lock(&rq2->lock);
	} else {
		spin_lock(&rq2->lock);
		spin_lock(&rq1->lock);
	}

On the other hand, the code in wake_sleeping_dependent uses the cpu id
order to grab locks:

	for_each_cpu_mask(i, sibling_map)
		spin_lock(&cpu_rq(i)->lock);

This means we rely on the address of per cpu data increasing as cpu ids
increase.  While this will be true for the generic percpu implementation it
may not be true for arch specific implementations.

One way to solve this is to always take runqueues in cpu id order. To do
this we add a cpu variable to the runqueue and check it in the
double runqueue locking functions.

Signed-off-by: Anton Blanchard <anton@samba.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-23 07:38:02 -08:00
..
irq [PATCH] kernel/: small cleanups 2006-01-08 20:13:48 -08:00
power [PATCH] swsusp: fix breakage with swap on LVM 2006-02-17 13:59:27 -08:00
.gitignore gitignore: ignore more generated files 2006-01-03 11:35:26 +01:00
acct.c [PATCH] move capable() to capability.h 2006-01-11 18:42:13 -08:00
audit.c [PATCH] EDAC: atomic scrub operations 2006-01-18 19:20:30 -08:00
auditsc.c Merge ../powerpc-merge 2006-02-24 14:05:47 +11:00
capability.c [PATCH] move capable() to capability.h 2006-01-11 18:42:13 -08:00
compat.c [PATCH] remove bogus asm/bug.h includes. 2006-02-07 20:56:35 -05:00
configs.c update the email address of Randy Dunlap 2006-01-03 13:37:51 +01:00
cpu.c [PATCH] clean up lock_cpu_hotplug() in cpufreq 2005-11-28 14:42:23 -08:00
cpuset.c [PATCH] cpuset: oops in exit on null cpuset fix 2006-02-15 15:32:21 -08:00
dma.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
exec_domain.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
exit.c [PATCH] don't do exit_io_context() until we know we won't be doing any IO 2006-03-18 18:33:46 -05:00
extable.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
fork.c [PATCH] unshare: Error if passed unsupported flags 2006-03-22 07:53:55 -08:00
futex.c [PATCH] FRV: Make futex code compilable on nommu [try #2] 2006-01-06 08:33:33 -08:00
hrtimer.c [PATCH] fix next_timer_interrupt() for hrtimer 2006-03-06 18:40:44 -08:00
intermodule.c [PATCH] missing license tag in intermodule 2006-02-05 11:06:52 -08:00
itimer.c [PATCH] hrtimers: fix oldvalue return in setitimer 2006-02-01 08:53:12 -08:00
kallsyms.c [PATCH] fix missing includes 2005-10-30 17:37:32 -08:00
Kconfig.hz [PATCH] i386: Selectable Frequency of the Timer Interrupt 2005-06-23 09:45:10 -07:00
Kconfig.preempt [PATCH] sched: voluntary kernel preemption 2005-06-25 16:24:45 -07:00
kexec.c [PATCH] move capable() to capability.h 2006-01-11 18:42:13 -08:00
kfifo.c [PATCH] gfp flags annotations - part 1 2005-10-08 15:00:57 -07:00
kmod.c [PATCH] Keys: Get rid of warning in kmod.c if keys disabled 2005-10-30 17:37:23 -08:00
kprobes.c [PATCH] Kprobes: Fix deadlock in function-return probes 2006-02-03 08:32:00 -08:00
ksysfs.c [PATCH] kobject: fix build error if CONFIG_SYSFS=n 2006-03-20 13:42:57 -08:00
kthread.c [PATCH] Add kthread_stop_sem() 2005-10-30 17:37:17 -08:00
Makefile [PATCH] build kernel/intermodule.c only when required 2006-01-16 23:15:26 -08:00
module.c [PATCH] fix module sysfs files reference counting 2006-03-20 13:42:58 -08:00
mutex-debug.c [PATCH] fix/simplify mutex debugging code 2006-01-11 08:14:16 -08:00
mutex-debug.h [PATCH] mutex subsystem, debugging code 2006-01-09 15:59:20 -08:00
mutex.c [PATCH] mutex: trivial whitespace cleanups 2006-01-10 14:27:59 -08:00
mutex.h [PATCH] mutex subsystem, core 2006-01-09 15:59:19 -08:00
panic.c [PATCH] prevent recursive panic from softlockup watchdog 2006-02-10 08:13:12 -08:00
params.c [PATCH] fix module sysfs files reference counting 2006-03-20 13:42:58 -08:00
pid.c [PATCH] RCU signal handling 2006-01-08 20:13:40 -08:00
posix-cpu-timers.c [PATCH] hrtimer: switch clock_nanosleep to hrtimer nanosleep API 2006-01-10 08:01:38 -08:00
posix-timers.c [PATCH] posix-timers: fix requeue accounting when signal is ignored 2006-03-17 07:51:25 -08:00
printk.c correct email address of Manfred Spraul 2006-01-15 02:43:54 +01:00
profile.c [PATCH] mostly_read data section 2005-07-07 18:23:46 -07:00
ptrace.c [PATCH] fix zap_thread's ptrace related problems 2006-02-15 11:05:43 -08:00
rcupdate.c [PATCH] add EXPORT_SYMBOL_GPL_FUTURE() to RCU subsystem 2006-03-20 13:42:58 -08:00
rcutorture.c [PATCH] rcu_torture_lock deadlock fix 2006-01-31 11:30:18 -08:00
resource.c [PATCH] kernel/resource.c: __check_region(): remove pointless __deprecated 2006-01-10 08:02:02 -08:00
sched.c [PATCH] fix scheduler deadlock 2006-03-23 07:38:02 -08:00
seccomp.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
signal.c [PATCH] do_sigaction: cleanup ->sa_mask manipulation 2006-02-09 16:17:36 -08:00
softirq.c [PATCH] on_each_cpu(): disable local interrupts 2006-03-22 07:53:59 -08:00
softlockup.c [PATCH] quieten softlockup at boot 2005-11-09 07:55:50 -08:00
spinlock.c [PATCH] spinlock consolidation 2005-09-10 10:06:21 -07:00
stop_machine.c [PATCH] Remove set_fs() in stop_machine() 2006-01-10 08:01:25 -08:00
sys_ni.c [PATCH] Fix compile for CONFIG_SYSVIPC=n or CONFIG_SYSCTL=n 2006-02-20 20:00:11 -08:00
sys.c [PATCH] kernel/sys.c NULL noise removal 2006-02-07 20:57:47 -05:00
sysctl.c [PATCH] fix file counting 2006-03-08 14:14:01 -08:00
time.c [PATCH] Normalize timespec for negative values in ns_to_timespec 2006-02-03 08:32:06 -08:00
timer.c [PATCH] time_interpolator: add __read_mostly 2006-03-17 07:51:25 -08:00
uid16.c [PATCH] move capable() to capability.h 2006-01-11 18:42:13 -08:00
user.c [PATCH] "Fix uidhash_lock <-> RXU deadlock" fix 2006-01-31 16:49:43 -08:00
wait.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
workqueue.c [SCSI] add execute_in_process_context() API 2006-02-27 23:34:40 -06:00