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| author | Paul E. McKenney <paul.mckenney@linaro.org> | 2012-01-12 22:08:18 +0100 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2012-02-21 18:03:45 +0100 |
| commit | c44e2cddacc2cf299186bad5697d738ea19668b7 (patch) | |
| tree | 5346f0dbee43202bf4049e3cda955f3d0cf97cfb /kernel/rcutree.c | |
| parent | rcu: Clean up straggling rcu_preempt_needs_cpu() name (diff) | |
| download | linux-c44e2cddacc2cf299186bad5697d738ea19668b7.tar.xz linux-c44e2cddacc2cf299186bad5697d738ea19668b7.zip | |
rcu: Check for idle-loop entry while in RCU read-side critical section
The inner idle loop is an extended quiescent state for all flavors
of RCU, but there have been recent bug involving use of RCU read-side
primitives from within the idle loop. Therefore, this commit enlists
lockdep-RCU to detect attempts to enter the inner idle loop while in
an RCU read-side critical section, emitting a lockdep-RCU splat if so.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcutree.c')
| -rw-r--r-- | kernel/rcutree.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 0569ba11e35a..195bf1fb59ea 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -366,6 +366,17 @@ static void rcu_idle_enter_common(struct rcu_dynticks *rdtp, long long oldval) atomic_inc(&rdtp->dynticks); smp_mb__after_atomic_inc(); /* Force ordering with next sojourn. */ WARN_ON_ONCE(atomic_read(&rdtp->dynticks) & 0x1); + + /* + * The idle task is not permitted to enter the idle loop while + * in an RCU read-side critical section. + */ + rcu_lockdep_assert(!lock_is_held(&rcu_lock_map), + "Illegal idle entry in RCU read-side critical section."); + rcu_lockdep_assert(!lock_is_held(&rcu_bh_lock_map), + "Illegal idle entry in RCU-bh read-side critical section."); + rcu_lockdep_assert(!lock_is_held(&rcu_sched_lock_map), + "Illegal idle entry in RCU-sched read-side critical section."); } /** |