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authorLinus Torvalds <torvalds@linux-foundation.org>2010-10-21 12:54:12 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-10-21 12:54:12 -0700
commit888a6f77e0418b049f83d37547c209b904d30af4 (patch)
tree42cdb9f781d2177e6b380e69a66a27ec7705f51f /kernel/sched.c
parent31b7eab27a314b153d8fa07ba9e9ec00a98141e1 (diff)
parent6506cf6ce68d78a5470a8360c965dafe8e4b78e3 (diff)
downloadlwn-888a6f77e0418b049f83d37547c209b904d30af4.tar.gz
lwn-888a6f77e0418b049f83d37547c209b904d30af4.zip
Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (52 commits) sched: fix RCU lockdep splat from task_group() rcu: using ACCESS_ONCE() to observe the jiffies_stall/rnp->qsmask value sched: suppress RCU lockdep splat in task_fork_fair net: suppress RCU lockdep false positive in sock_update_classid rcu: move check from rcu_dereference_bh to rcu_read_lock_bh_held rcu: Add advice to PROVE_RCU_REPEATEDLY kernel config parameter rcu: Add tracing data to support queueing models rcu: fix sparse errors in rcutorture.c rcu: only one evaluation of arg in rcu_dereference_check() unless sparse kernel: Remove undead ifdef CONFIG_DEBUG_LOCK_ALLOC rcu: fix _oddness handling of verbose stall warnings rcu: performance fixes to TINY_PREEMPT_RCU callback checking rcu: upgrade stallwarn.txt documentation for CPU-bound RT processes vhost: add __rcu annotations rcu: add comment stating that list_empty() applies to RCU-protected lists rcu: apply TINY_PREEMPT_RCU read-side speedup to TREE_PREEMPT_RCU rcu: combine duplicate code, courtesy of CONFIG_PREEMPT_RCU rcu: Upgrade srcu_read_lock() docbook about SRCU grace periods rcu: document ways of stalling updates in low-memory situations rcu: repair code-duplication FIXMEs ...
Diffstat (limited to 'kernel/sched.c')
-rw-r--r--kernel/sched.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index df6579d9b4df..0bba34a48d10 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -5337,7 +5337,19 @@ void __cpuinit init_idle(struct task_struct *idle, int cpu)
idle->se.exec_start = sched_clock();
cpumask_copy(&idle->cpus_allowed, cpumask_of(cpu));
+ /*
+ * We're having a chicken and egg problem, even though we are
+ * holding rq->lock, the cpu isn't yet set to this cpu so the
+ * lockdep check in task_group() will fail.
+ *
+ * Similar case to sched_fork(). / Alternatively we could
+ * use task_rq_lock() here and obtain the other rq->lock.
+ *
+ * Silence PROVE_RCU
+ */
+ rcu_read_lock();
__set_task_cpu(idle, cpu);
+ rcu_read_unlock();
rq->curr = rq->idle = idle;
#if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)