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authorIngo Molnar <mingo@elte.hu>2008-11-12 19:05:50 (GMT)
committerIngo Molnar <mingo@elte.hu>2008-11-12 19:05:50 (GMT)
commit5cbd54ef470d880fc37fbe4b21eb514806d51e0d (patch)
treedb9a73e605e0a2e7cfa13bd9697a113b5f6649eb /kernel
parenta2d477778e82a60a0b7114cefdb70aa43af28782 (diff)
downloadlinux-5cbd54ef470d880fc37fbe4b21eb514806d51e0d.tar.xz
sched: fix init_idle()'s use of sched_clock()
Maciej Rutecki reported: > I have this bug during suspend to disk: > > [ 188.592151] Enabling non-boot CPUs ... > [ 188.592151] SMP alternatives: switching to SMP code > [ 188.666058] BUG: using smp_processor_id() in preemptible > [00000000] > code: suspend_to_disk/2934 > [ 188.666064] caller is native_sched_clock+0x2b/0x80 Which, as noted by Linus, was caused by me, via: 7cbaef9c "sched: optimize sched_clock() a bit" Move the rq locking a bit earlier in the initialization sequence, that will make the sched_clock() call in init_idle() non-preemptible. Reported-by: Maciej Rutecki <maciej.rutecki@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sched.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index 3bafbe3..c94baf2 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -5870,6 +5870,8 @@ void __cpuinit init_idle(struct task_struct *idle, int cpu)
struct rq *rq = cpu_rq(cpu);
unsigned long flags;
+ spin_lock_irqsave(&rq->lock, flags);
+
__sched_fork(idle);
idle->se.exec_start = sched_clock();
@@ -5877,7 +5879,6 @@ void __cpuinit init_idle(struct task_struct *idle, int cpu)
idle->cpus_allowed = cpumask_of_cpu(cpu);
__set_task_cpu(idle, cpu);
- spin_lock_irqsave(&rq->lock, flags);
rq->curr = rq->idle = idle;
#if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
idle->oncpu = 1;