Pavel Emelianov f72fa70760 [PATCH] Fix misrouted interrupts deadlocks ... While testing kernel on machine with "irqpoll" option I've caught such a lockup: __do_IRQ() spin_lock(&desc->lock); desc->chip->ack(); /* IRQ is ACKed */ note_interrupt() misrouted_irq() handle_IRQ_event() if (...) local_irq_enable_in_hardirq(); /* interrupts are enabled from now */ ... __do_IRQ() /* same IRQ we've started from */ spin_lock(&desc->lock); /* LOCKUP */ Looking at misrouted_irq() code I've found that a potential deadlock like this can also take place: 1CPU: __do_IRQ() spin_lock(&desc->lock); /* irq = A */ misrouted_irq() for (i = 1; i < NR_IRQS; i++) { spin_lock(&desc->lock); /* irq = B */ if (desc->status & IRQ_INPROGRESS) { 2CPU: __do_IRQ() spin_lock(&desc->lock); /* irq = B */ misrouted_irq() for (i = 1; i < NR_IRQS; i++) { spin_lock(&desc->lock); /* irq = A */ if (desc->status & IRQ_INPROGRESS) { As the second lock on both CPUs is taken before checking that this irq is being handled in another processor this may cause a deadlock. This issue is only theoretical. I propose the attached patch to fix booth problems: when trying to handle misrouted IRQ active desc->lock may be unlocked. Acked-by: Ingo Molnar <mingo@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>		2006-11-13 07:40:43 -08:00
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irq	[PATCH] Fix misrouted interrupts deadlocks	2006-11-13 07:40:43 -08:00
power	[PATCH] swsusp: debugging	2006-11-03 12:27:58 -08:00
time
.gitignore
acct.c
audit.c
audit.h
auditfilter.c
auditsc.c
capability.c
compat.c	[PATCH] Create compat_sys_migrate_pages	2006-11-03 12:27:59 -08:00
configs.c
cpu.c	[PATCH] Fix the spurious unlock_cpu_hotplug false warnings	2006-11-06 01:46:22 -08:00
cpuset.c
delayacct.c	[PATCH] lockdep: fix delayacct locking bug	2006-11-06 01:46:23 -08:00
dma.c
exec_domain.c
exit.c
extable.c
fork.c	[PATCH] fix Data Acess error in dup_fd	2006-11-13 07:40:43 -08:00
futex_compat.c
futex.c
hrtimer.c
itimer.c
kallsyms.c
Kconfig.hz
Kconfig.preempt
kexec.c
kfifo.c
kmod.c
kprobes.c
ksysfs.c
kthread.c
latency.c
lockdep_internals.h
lockdep_proc.c
lockdep.c
Makefile
module.c
mutex-debug.c
mutex-debug.h
mutex.c
mutex.h
nsproxy.c
panic.c
params.c
pid.c
posix-cpu-timers.c
posix-timers.c
printk.c
profile.c
ptrace.c
rcupdate.c
rcutorture.c
relay.c
resource.c
rtmutex_common.h
rtmutex-debug.c
rtmutex-debug.h
rtmutex-tester.c
rtmutex.c
rtmutex.h
rwsem.c
sched.c
seccomp.c
signal.c	Make sure "user->sigpending" count is in sync	2006-11-04 13:03:00 -08:00
softirq.c
softlockup.c
spinlock.c
srcu.c
stacktrace.c
stop_machine.c
sys_ni.c	[PATCH] Create compat_sys_migrate_pages	2006-11-03 12:27:59 -08:00
sys.c
sysctl.c	[PATCH] sysctl: allow a zero ctl_name in the middle of a sysctl table	2006-11-06 01:46:23 -08:00
taskstats.c
time.c
timer.c
tsacct.c
uid16.c
unwind.c
user.c	Fix unlikely (but possible) race condition on task->user access	2006-11-04 10:06:02 -08:00
utsname.c
wait.c
workqueue.c