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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2012-07-07 05:57:03 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2012-09-23 07:41:55 -0700
commit661a85dc0d2ec0404e3b80909e413a9d5e42a239 (patch)
tree8ea9545a62835d8cd47978fd31ede669f988b43a /kernel/rcutree.c
parent5d4b86594984d8746b01487c768d8548463c173f (diff)
rcu: Add random PROVE_RCU_DELAY to grace-period initialization
Preemption greatly raised the probability of certain types of race conditions, so this commit adds an anti-heisenbug to greatly increase the collision cross section, also known as the probability of occurrence. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Diffstat (limited to 'kernel/rcutree.c')
-rw-r--r--kernel/rcutree.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 145f27fe3a1..f0f3a18c0a2 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -52,6 +52,7 @@
#include <linux/prefetch.h>
#include <linux/delay.h>
#include <linux/stop_machine.h>
+#include <linux/random.h>
#include "rcutree.h"
#include <trace/events/rcu.h>
@@ -1087,6 +1088,10 @@ static int rcu_gp_init(struct rcu_state *rsp)
rnp->level, rnp->grplo,
rnp->grphi, rnp->qsmask);
raw_spin_unlock_irq(&rnp->lock);
+#ifdef CONFIG_PROVE_RCU_DELAY
+ if ((random32() % (rcu_num_nodes * 8)) == 0)
+ schedule_timeout_uninterruptible(2);
+#endif /* #ifdef CONFIG_PROVE_RCU_DELAY */
cond_resched();
}