Chuansheng Liu c685689fd2 genirq: Remove racy waitqueue_active check ... We hit one rare case below: T1 calling disable_irq(), but hanging at synchronize_irq() always; The corresponding irq thread is in sleeping state; And all CPUs are in idle state; After analysis, we found there is one possible scenerio which causes T1 is waiting there forever: CPU0 CPU1 synchronize_irq() wait_event() spin_lock() atomic_dec_and_test(&threads_active) insert the __wait into queue spin_unlock() if(waitqueue_active) atomic_read(&threads_active) wake_up() Here after inserted the __wait into queue on CPU0, and before test if queue is empty on CPU1, there is no barrier, it maybe cause it is not visible for CPU1 immediately, although CPU0 has updated the queue list. It is similar for CPU0 atomic_read() threads_active also. So we'd need one smp_mb() before waitqueue_active.that, but removing the waitqueue_active() check solves it as wel l and it makes things simple and clear. Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com> Cc: Xiaoming Wang <xiaoming.wang@intel.com> Link: http://lkml.kernel.org/r/1393212590-32543-1-git-send-email-chuansheng.liu@intel.com Cc: stable@vger.kernel.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>		2014-02-27 10:54:16 +01:00
..
cpu	sched/preempt: Fix up missed PREEMPT_NEED_RESCHED folding	2014-01-13 17:38:55 +01:00
debug	kgdb/kdb: Fix no KDB config problem	2014-01-25 08:55:09 +01:00
events	This pull request has a new feature to ftrace, namely the trace event	2014-01-22 16:35:21 -08:00
gcov
irq	genirq: Remove racy waitqueue_active check	2014-02-27 10:54:16 +01:00
locking	Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2014-01-20 10:42:08 -08:00
power	arm, pm, vmpressure: add missing slab.h includes	2014-02-03 13:24:01 -05:00
printk	printk: fix syslog() overflowing user buffer	2014-02-17 12:24:45 -08:00
rcu	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2014-01-28 08:38:04 -08:00
sched	sched/deadline: Remove useless dl_nr_total	2014-02-21 21:27:10 +01:00
time	sched_clock: Prevent callers from seeing half-updated data	2014-02-19 17:07:22 +01:00
trace	ring-buffer: Fix first commit on sub-buffer having non-zero delta	2014-02-11 13:38:54 -05:00
.gitignore	Ignore generated file kernel/x509_certificate_list	2013-12-10 18:21:34 +00:00
acct.c
async.c
audit.c	audit: fix location of __net_initdata for audit_net_ops	2014-01-17 17:14:32 -05:00
audit.h	audit: Convert int limit uses to u32	2014-01-14 14:54:00 -05:00
audit_tree.c	fsnotify: remove pointless NULL initializers	2014-01-21 16:19:41 -08:00
audit_watch.c	fsnotify: remove pointless NULL initializers	2014-01-21 16:19:41 -08:00
auditfilter.c	audit: log on errors from filter user rules	2014-01-13 22:32:31 -05:00
auditsc.c	execve: use 'struct filename *' for executable name passing	2014-02-05 12:54:53 -08:00
backtracetest.c
bounds.c	mm: do not allocate page->ptl dynamically, if spinlock_t fits to long	2013-12-20 12:25:45 -08:00
capability.c	audit: Simplify and correct audit_log_capset	2014-01-13 22:26:48 -05:00
cgroup.c	cgroup: update cgroup_enable_task_cg_lists() to grab siglock	2014-02-18 18:23:18 -05:00
cgroup_freezer.c	cgroup: replace cftype->read_seq_string() with cftype->seq_show()	2013-12-05 12:28:04 -05:00
compat.c
configs.c
context_tracking.c	context_tracking: Wrap static key check into more intuitive function name	2013-12-02 20:43:14 +01:00
cpu.c
cpu_pm.c
cpuset.c	cgroup: replace cftype->read_seq_string() with cftype->seq_show()	2013-12-05 12:28:04 -05:00
crash_dump.c
cred.c
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c	introduce for_each_thread() to replace the buggy while_each_thread()	2014-01-21 16:19:46 -08:00
extable.c	kernel/extable: fix address-checks for core_kernel and init areas	2013-11-28 09:49:41 -08:00
fork.c	exec: kill task_struct->did_exec	2014-01-23 16:37:02 -08:00
freezer.c	libata, freezer: avoid block device removal while system is frozen	2013-12-19 13:50:32 -05:00
futex.c	Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2014-01-20 10:42:08 -08:00
futex_compat.c
groups.c
hrtimer.c	sched/deadline: Add SCHED_DEADLINE structures & implementation	2014-01-13 13:41:06 +01:00
hung_task.c	hung_task: Display every hung task warning	2014-01-25 12:13:33 +01:00
irq_work.c
itimer.c
jump_label.c
kallsyms.c
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kexec.c	kernel/kexec.c: use vscnprintf() instead of vsnprintf() in vmcoreinfo_append_str()	2014-01-27 21:02:40 -08:00
kmod.c	execve: use 'struct filename *' for executable name passing	2014-02-05 12:54:53 -08:00
kprobes.c
ksysfs.c	kdump: fix exported size of vmcoreinfo note	2014-01-23 16:37:03 -08:00
kthread.c
latencytop.c
Makefile	KEYS: Remove files generated when SYSTEM_TRUSTED_KEYRING=y	2013-12-13 15:59:11 +00:00
module-internal.h
module.c	module: Add missing newline in printk call.	2014-01-21 09:59:16 +10:30
module_signing.c
notifier.c
nsproxy.c
padata.c	padata: Fix wrong usage of rcu_dereference()	2013-12-05 21:28:42 +08:00
panic.c	panic: Make panic_timeout configurable	2013-11-26 12:12:26 +01:00
params.c	params: improve standard definitions	2013-12-04 14:09:46 +10:30
pid.c
pid_namespace.c
posix-cpu-timers.c	posix-timers: Convert abuses of BUG_ON to WARN_ON	2013-12-09 16:56:29 +01:00
posix-timers.c
profile.c
ptrace.c
range.c
reboot.c	kexec: migrate to reboot cpu	2013-12-18 19:04:50 -08:00
relay.c
res_counter.c
resource.c
seccomp.c
signal.c	kernel/signal.c: change do_signal_stop/do_sigaction to use while_each_thread()	2014-01-23 16:37:02 -08:00
smp.c	kernel/smp.c: remove cpumask_ipi	2014-01-30 16:56:54 -08:00
smpboot.c
smpboot.h
softirq.c	Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2014-01-31 09:02:51 -08:00
stacktrace.c
stop_machine.c
sys.c	kernel/sys.c: k_getrusage() can use while_each_thread()	2014-01-23 16:37:02 -08:00
sys_ni.c
sysctl.c	Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2014-01-31 08:59:46 -08:00
sysctl_binary.c
system_certificates.S	KEYS: correct alignment of system_certificate_list content in assembly file	2013-12-10 18:25:28 +00:00
system_keyring.c	KEYS: correct alignment of system_certificate_list content in assembly file	2013-12-10 18:25:28 +00:00
task_work.c
taskstats.c	genetlink: only pass array to genl_register_family_with_ops()	2013-11-19 16:39:05 -05:00
test_kprobes.c
time.c
timeconst.bc
timer.c	timer: Convert kmalloc_node(...GFP_ZERO...) to kzalloc_node(...)	2013-11-19 14:59:50 +01:00
tracepoint.c
tsacct.c
uid16.c
up.c
user-return-notifier.c
user.c	KEYS: fix uninitialized persistent_keyring_register_sem	2013-12-13 15:59:11 +00:00
user_namespace.c	user_namespace.c: Remove duplicated word in comment	2014-02-20 11:58:35 -08:00
utsname.c
utsname_sysctl.c
watchdog.c
workqueue.c	workqueue: ensure @task is valid across kthread_stop()	2014-02-18 16:35:20 -05:00
workqueue_internal.h