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authorPaul E. McKenney <paulmck@kernel.org>2020-01-20 15:29:04 -0800
committerPaul E. McKenney <paulmck@kernel.org>2020-02-20 15:58:23 -0800
commit59881bcd85a06565c53fd13ce3b0ad7fa55e560c (patch)
tree675ba755b0405c7967b28e4235c56eca27a7f699 /kernel/rcu
parent57721fd15a02f7df9dad1f3cca27f21e03ee118f (diff)
downloadlinux-59881bcd85a06565c53fd13ce3b0ad7fa55e560c.tar.bz2
rcu: Add WRITE_ONCE() to rcu_state ->gp_start
The rcu_state structure's ->gp_start field is read locklessly, so this commit adds the WRITE_ONCE() to an update in order to provide proper documentation and READ_ONCE()/WRITE_ONCE() pairing. This data race was reported by KCSAN. Not appropriate for backporting due to failure being unlikely. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/rcu')
-rw-r--r--kernel/rcu/tree_stall.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h
index bca637b274fb..488b71d03030 100644
--- a/kernel/rcu/tree_stall.h
+++ b/kernel/rcu/tree_stall.h
@@ -102,7 +102,7 @@ static void record_gp_stall_check_time(void)
unsigned long j = jiffies;
unsigned long j1;
- rcu_state.gp_start = j;
+ WRITE_ONCE(rcu_state.gp_start, j);
j1 = rcu_jiffies_till_stall_check();
/* Record ->gp_start before ->jiffies_stall. */
smp_store_release(&rcu_state.jiffies_stall, j + j1); /* ^^^ */