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authorLinus Torvalds <torvalds@linux-foundation.org>2017-02-18 17:30:36 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-02-18 17:30:36 -0800
commite602e700842104096e96a7deee453183e4ed278a (patch)
treec828be96af44cae008f13a4e0d3711643fd20352
parent3dd9c12726ffd1d548ad5264731dfe7a785768ed (diff)
parentf222449c9dfad7c9bb8cb53e64c5c407b172ebbc (diff)
downloadlinux-stericsson-e602e700842104096e96a7deee453183e4ed278a.tar.gz
Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fixes from Thomas Gleixner: "Two small fixes:: - Prevent deadlock on the tick broadcast lock. Found and fixed by Mike. - Stop using printk() in the timekeeping debug code to prevent a deadlock against the scheduler" * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: timekeeping: Use deferred printk() in debug code tick/broadcast: Prevent deadlock on tick_broadcast_lock
-rw-r--r--kernel/time/tick-broadcast.c15
-rw-r--r--kernel/time/timekeeping_debug.c4
2 files changed, 9 insertions, 10 deletions
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index 3109204c87cc..17ac99b60ee5 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -347,17 +347,16 @@ static void tick_handle_periodic_broadcast(struct clock_event_device *dev)
*
* Called when the system enters a state where affected tick devices
* might stop. Note: TICK_BROADCAST_FORCE cannot be undone.
- *
- * Called with interrupts disabled, so clockevents_lock is not
- * required here because the local clock event device cannot go away
- * under us.
*/
void tick_broadcast_control(enum tick_broadcast_mode mode)
{
struct clock_event_device *bc, *dev;
struct tick_device *td;
int cpu, bc_stopped;
+ unsigned long flags;
+ /* Protects also the local clockevent device. */
+ raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
td = this_cpu_ptr(&tick_cpu_device);
dev = td->evtdev;
@@ -365,12 +364,11 @@ void tick_broadcast_control(enum tick_broadcast_mode mode)
* Is the device not affected by the powerstate ?
*/
if (!dev || !(dev->features & CLOCK_EVT_FEAT_C3STOP))
- return;
+ goto out;
if (!tick_device_is_functional(dev))
- return;
+ goto out;
- raw_spin_lock(&tick_broadcast_lock);
cpu = smp_processor_id();
bc = tick_broadcast_device.evtdev;
bc_stopped = cpumask_empty(tick_broadcast_mask);
@@ -420,7 +418,8 @@ void tick_broadcast_control(enum tick_broadcast_mode mode)
tick_broadcast_setup_oneshot(bc);
}
}
- raw_spin_unlock(&tick_broadcast_lock);
+out:
+ raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
}
EXPORT_SYMBOL_GPL(tick_broadcast_control);
diff --git a/kernel/time/timekeeping_debug.c b/kernel/time/timekeeping_debug.c
index ca9fb800336b..38bc4d2208e8 100644
--- a/kernel/time/timekeeping_debug.c
+++ b/kernel/time/timekeeping_debug.c
@@ -75,7 +75,7 @@ void tk_debug_account_sleep_time(struct timespec64 *t)
int bin = min(fls(t->tv_sec), NUM_BINS-1);
sleep_time_bin[bin]++;
- pr_info("Suspended for %lld.%03lu seconds\n", (s64)t->tv_sec,
- t->tv_nsec / NSEC_PER_MSEC);
+ printk_deferred(KERN_INFO "Suspended for %lld.%03lu seconds\n",
+ (s64)t->tv_sec, t->tv_nsec / NSEC_PER_MSEC);
}