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	[PATCH] time: rename clocksource functions	2006-06-26 09:58:21 -07:00
.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	[PATCH] sched: cleanup, remove task_t, convert to struct task_struct	2006-07-03 15:27:11 -07:00
compat.c	[PATCH] N32 sigset and __COMPAT_ENDIAN_SWAP__	2006-06-25 10:01:15 -07:00
configs.c	Remove obsolete #include <linux/config.h>	2006-06-30 19:25:36 +02:00
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	Remove obsolete #include <linux/config.h>	2006-06-30 19:25:36 +02:00
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	[POWERPC] Add the use of the firmware soft-reset-nmi to kdump.	2006-06-28 15:18:52 +10:00
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	Remove obsolete #include <linux/config.h>	2006-06-30 19:25:36 +02:00
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	[PATCH] lockdep: procfs	2006-07-03 15:27:04 -07:00
lockdep.c	[PATCH] lockdep: core, reduce per-lock class-cache size	2006-07-10 13:24:14 -07:00
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	[PATCH] lockdep: prove mutex locking correctness	2006-07-03 15:27:04 -07:00
mutex-debug.h	[PATCH] lockdep: better lock debugging	2006-07-03 15:27:01 -07:00
mutex.c	[PATCH] lockdep: prove mutex locking correctness	2006-07-03 15:27:04 -07:00
mutex.h	[PATCH] lockdep: prove mutex locking correctness	2006-07-03 15:27:04 -07:00
panic.c	[PATCH] lockdep: do not touch console state when tainting the kernel	2006-09-06 11:00:02 -07:00
params.c	Remove obsolete #include <linux/config.h>	2006-06-30 19:25:36 +02:00
pid.c	[PATCH] sched: cleanup, remove task_t, convert to struct task_struct	2006-07-03 15:27:11 -07:00
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	Remove obsolete #include <linux/config.h>	2006-06-30 19:25:36 +02:00
ptrace.c	[PATCH] sched: cleanup, remove task_t, convert to struct task_struct	2006-07-03 15:27:11 -07:00
rcupdate.c	[PATCH] rcu_do_batch: make ->qlen decrement irq safe	2006-09-13 07:32:14 -07:00
rcutorture.c	[PATCH] rcutorture: add call_rcu_bh() operations	2006-06-27 17:32:40 -07:00
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	[PATCH] pi-futex: futex_lock_pi/futex_unlock_pi support	2006-06-27 17:32:47 -07:00
rtmutex-debug.c	[PATCH] sched: cleanup, remove task_t, convert to struct task_struct	2006-07-03 15:27:11 -07:00
rtmutex-debug.h	[PATCH] lockdep: better lock debugging	2006-07-03 15:27:01 -07:00
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	[PATCH] lockdep: better lock debugging	2006-07-03 15:27:01 -07:00
rwsem.c	[PATCH] lockdep: prove rwsem locking correctness	2006-07-03 15:27:04 -07:00
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	[PATCH] lockdep: stacktrace subsystem, core	2006-07-03 15:27:02 -07:00
stop_machine.c	[PATCH] Remove redundant up() in stop_machine()	2006-08-27 11:01:31 -07:00
sys_ni.c
sys.c	[PATCH] Fix prctl privilege escalation and suid_dumpable (CVE-2006-2451)	2006-07-12 12:50:25 -07:00
sysctl.c	[PATCH] ZVC/zone_reclaim: Leave 1% of unmapped pagecache pages for file I/O	2006-07-03 15:26:59 -07:00
taskstats.c	[PATCH] taskstats: free skb, avoid returns in send_cpu_listeners	2006-07-31 13:28:37 -07:00
time.c	[PATCH] Time: Introduce arch generic time accessors	2006-06-26 09:58:20 -07:00
timer.c	[PATCH] sys_getppid oopses on debug kernel	2006-08-14 12:54:29 -07:00
uid16.c
unwind.c	[PATCH] x86_64: allow unwinder to build without module support	2006-06-26 10:48:18 -07:00
user.c
wait.c	[PATCH] uninline init_waitqueue_head()	2006-07-10 13:24:25 -07:00
workqueue.c	[PATCH] workqueue: remove lock_cpu_hotplug()	2006-08-14 12:54:29 -07:00