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authorFrederic Weisbecker <fweisbec@gmail.com>2011-10-07 16:22:08 (GMT)
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2011-12-11 18:31:37 (GMT)
commite37e112de3ac64032df45c2db0dbe1e8f1af86b4 (patch)
tree688ac406d7edb9766f07aa7dd308d62ae1d73044 /arch/x86/kernel/process_64.c
parent2bbb6817c0ac1b5f2a68d720f364f98eeb1ac4fd (diff)
x86: Enter rcu extended qs after idle notifier call
The idle notifier, called by enter_idle(), enters into rcu read side critical section but at that time we already switched into the RCU-idle window (rcu_idle_enter() has been called). And it's illegal to use rcu_read_lock() in that state. This results in rcu reporting its bad mood: [ 1.275635] WARNING: at include/linux/rcupdate.h:194 __atomic_notifier_call_chain+0xd2/0x110() [ 1.275635] Hardware name: AMD690VM-FMH [ 1.275635] Modules linked in: [ 1.275635] Pid: 0, comm: swapper Not tainted 3.0.0-rc6+ #252 [ 1.275635] Call Trace: [ 1.275635] [<ffffffff81051c8a>] warn_slowpath_common+0x7a/0xb0 [ 1.275635] [<ffffffff81051cd5>] warn_slowpath_null+0x15/0x20 [ 1.275635] [<ffffffff817d6f22>] __atomic_notifier_call_chain+0xd2/0x110 [ 1.275635] [<ffffffff817d6f71>] atomic_notifier_call_chain+0x11/0x20 [ 1.275635] [<ffffffff810018a0>] enter_idle+0x20/0x30 [ 1.275635] [<ffffffff81001995>] cpu_idle+0xa5/0x110 [ 1.275635] [<ffffffff817a7465>] rest_init+0xe5/0x140 [ 1.275635] [<ffffffff817a73c8>] ? rest_init+0x48/0x140 [ 1.275635] [<ffffffff81cc5ca3>] start_kernel+0x3d1/0x3dc [ 1.275635] [<ffffffff81cc5321>] x86_64_start_reservations+0x131/0x135 [ 1.275635] [<ffffffff81cc5412>] x86_64_start_kernel+0xed/0xf4 [ 1.275635] ---[ end trace a22d306b065d4a66 ]--- Fix this by entering rcu extended quiescent state later, just before the CPU goes to sleep. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Diffstat (limited to 'arch/x86/kernel/process_64.c')
-rw-r--r--arch/x86/kernel/process_64.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 18e8cf3..64e926c 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -122,7 +122,7 @@ void cpu_idle(void)
/* endless idle loop with no priority at all */
while (1) {
- tick_nohz_idle_enter_norcu();
+ tick_nohz_idle_enter();
while (!need_resched()) {
rmb();
@@ -139,8 +139,14 @@ void cpu_idle(void)
enter_idle();
/* Don't trace irqs off for idle */
stop_critical_timings();
+
+ /* enter_idle() needs rcu for notifiers */
+ rcu_idle_enter();
+
if (cpuidle_idle_call())
pm_idle();
+
+ rcu_idle_exit();
start_critical_timings();
/* In many cases the interrupt that ended idle
@@ -149,7 +155,7 @@ void cpu_idle(void)
__exit_idle();
}
- tick_nohz_idle_exit_norcu();
+ tick_nohz_idle_exit();
preempt_enable_no_resched();
schedule();
preempt_disable();

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