Ingo Molnar 86998aa653 [PATCH] genirq core: fix handle_level_irq() ... while porting the -rt tree to 2.6.18-rc7 i noticed the following screaming-IRQ scenario on an SMP system: 2274 0Dn.:1 0.001ms: do_IRQ+0xc/0x103 <= (ret_from_intr+0x0/0xf) 2274 0Dn.:1 0.010ms: do_IRQ+0xc/0x103 <= (ret_from_intr+0x0/0xf) 2274 0Dn.:1 0.020ms: do_IRQ+0xc/0x103 <= (ret_from_intr+0x0/0xf) 2274 0Dn.:1 0.029ms: do_IRQ+0xc/0x103 <= (ret_from_intr+0x0/0xf) 2274 0Dn.:1 0.039ms: do_IRQ+0xc/0x103 <= (ret_from_intr+0x0/0xf) 2274 0Dn.:1 0.048ms: do_IRQ+0xc/0x103 <= (ret_from_intr+0x0/0xf) 2274 0Dn.:1 0.058ms: do_IRQ+0xc/0x103 <= (ret_from_intr+0x0/0xf) 2274 0Dn.:1 0.068ms: do_IRQ+0xc/0x103 <= (ret_from_intr+0x0/0xf) 2274 0Dn.:1 0.077ms: do_IRQ+0xc/0x103 <= (ret_from_intr+0x0/0xf) 2274 0Dn.:1 0.087ms: do_IRQ+0xc/0x103 <= (ret_from_intr+0x0/0xf) 2274 0Dn.:1 0.097ms: do_IRQ+0xc/0x103 <= (ret_from_intr+0x0/0xf) as it turns out, the bug is caused by handle_level_irq(), which if it races with another CPU already handling this IRQ, it _unmasks_ the IRQ line on the way out. This is not how 2.6.17 works, and we introduced this bug in one of the early genirq cleanups right before it went into -mm. (the bug was not in the genirq patchset for a long time, and we didnt notice the bug due to the lack of -rt rebase to the new genirq code. -rt, and hardirq-preemption in particular opens up such races much wider than anything else.) Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>		2006-09-19 07:57:20 -07:00
..
irq	[PATCH] genirq core: fix handle_level_irq()	2006-09-19 07:57:20 -07:00
power	[PATCH] prevent swsusp with PAE	2006-09-06 11:00:02 -07:00
time
.gitignore
acct.c	[PATCH] Fix sighand->siglock usage in kernel/acct.c	2006-07-14 21:53:54 -07:00
audit.c	[PATCH] sanity check audit_buffer	2006-09-11 13:32:17 -04:00
audit.h	[PATCH] audit: AUDIT_PERM support	2006-09-11 13:32:30 -04:00
auditfilter.c	[PATCH] audit: AUDIT_PERM support	2006-09-11 13:32:30 -04:00
auditsc.c	[PATCH] audit: AUDIT_PERM support	2006-09-11 13:32:30 -04:00
capability.c
compat.c
configs.c
cpu.c	cpu hotplug: simplify and hopefully fix locking	2006-07-23 12:12:16 -07:00
cpuset.c	[PATCH] cpuset: oom panic fix	2006-08-27 11:01:32 -07:00
delayacct.c	[PATCH] task delay accounting fixes	2006-09-01 11:39:08 -07:00
dma.c
exec_domain.c
exit.c	[PATCH] eligible_child: remove an obsolete ->tgid check	2006-09-02 14:51:27 -07:00
extable.c
fork.c	[PATCH] task delay accounting fixes	2006-09-01 11:39:08 -07:00
futex_compat.c	[PATCH] futex: Apply recent futex fixes to futex_compat	2006-08-06 08:57:49 -07:00
futex.c	[PATCH] Use the correct restart option for futex_lock_pi	2006-09-08 10:22:50 -07:00
hrtimer.c	[PATCH] fix hrtimer percpu usage typo	2006-08-14 12:54:28 -07:00
itimer.c
kallsyms.c	[PATCH] null-terminate over-long /proc/kallsyms symbols	2006-07-14 21:53:52 -07:00
Kconfig.hz
Kconfig.preempt
kexec.c
kfifo.c
kmod.c	[PATCH] bug fix in kernel/kmod.c	2006-09-16 12:54:32 -07:00
kprobes.c	[PATCH] IA64: kprobe invalidate icache of jump buffer	2006-07-31 13:28:38 -07:00
ksysfs.c
kthread.c	[PATCH] remove kernel/kthread.c:kthread_stop_sem()	2006-07-14 21:53:52 -07:00
lockdep_internals.h	[PATCH] lockdep: double the number of stack-trace entries	2006-09-13 07:32:14 -07:00
lockdep_proc.c
lockdep.c
Makefile	[PATCH] per-task-delay-accounting: taskstats interface	2006-07-14 21:53:56 -07:00
module.c	[PATCH] null-terminate over-long /proc/kallsyms symbols	2006-07-14 21:53:52 -07:00
mutex-debug.c
mutex-debug.h
mutex.c
mutex.h
panic.c	[PATCH] lockdep: do not touch console state when tainting the kernel	2006-09-06 11:00:02 -07:00
params.c
pid.c
posix-cpu-timers.c
posix-timers.c
printk.c	[PATCH] vt: printk: Fix framebuffer console triggering might_sleep assertion	2006-08-06 08:57:47 -07:00
profile.c
ptrace.c
rcupdate.c	[PATCH] rcu_do_batch: make ->qlen decrement irq safe	2006-09-13 07:32:14 -07:00
rcutorture.c
relay.c
resource.c	[PATCH] memory hotadd fixes: find_next_system_ram catch range fix	2006-08-06 08:57:48 -07:00
rtmutex_common.h
rtmutex-debug.c
rtmutex-debug.h
rtmutex-tester.c	[PATCH] Add try_to_freeze() to rt-test kthreads	2006-07-14 21:53:53 -07:00
rtmutex.c	[PATCH] reference rt-mutex-design in rtmutex.c	2006-07-31 13:28:43 -07:00
rtmutex.h
rwsem.c
sched.c	[PATCH] revert "Drop tasklist lock in do_sched_setscheduler"	2006-08-27 11:01:29 -07:00
seccomp.c
signal.c	Fix force_sig_info() semantics after cleanups	2006-08-02 20:17:49 -07:00
softirq.c	[PATCH] Reducing local_bh_enable/disable overhead in irqtrace	2006-07-31 13:28:42 -07:00
softlockup.c	[PATCH] cpu hotplug: replace __devinit* with __cpuinit* for cpu notifications	2006-07-31 13:28:39 -07:00
spinlock.c	[PATCH] lockdep ifdef fix	2006-09-06 11:00:01 -07:00
stacktrace.c
stop_machine.c	[PATCH] Remove redundant up() in stop_machine()	2006-08-27 11:01:31 -07:00
sys_ni.c
sys.c
sysctl.c
taskstats.c	[PATCH] taskstats: free skb, avoid returns in send_cpu_listeners	2006-07-31 13:28:37 -07:00
time.c
timer.c	[PATCH] sys_getppid oopses on debug kernel	2006-08-14 12:54:29 -07:00
uid16.c
unwind.c
user.c
wait.c
workqueue.c	[PATCH] workqueue: remove lock_cpu_hotplug()	2006-08-14 12:54:29 -07:00