From: "Paul E. McKenney" paulmck@kernel.org
[ Upstream commit c09929031018913b5783872a8b8cdddef4a543c7 ]
KCSAN reports data races between the rcu_segcblist_clear_flags() and rcu_segcblist_set_flags() functions, though misreporting the latter as a call to rcu_segcblist_is_enabled() from call_rcu(). This commit converts the updates of this field to WRITE_ONCE(), relying on the resulting unmarked reads to continue to detect buggy concurrent writes to this field.
Reported-by: Zhouyi Zhou zhouzhouyi@gmail.com Signed-off-by: Paul E. McKenney paulmck@kernel.org Cc: Frederic Weisbecker frederic@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/rcu/rcu_segcblist.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/rcu/rcu_segcblist.h b/kernel/rcu/rcu_segcblist.h index 9a19328ff251..5d405943823e 100644 --- a/kernel/rcu/rcu_segcblist.h +++ b/kernel/rcu/rcu_segcblist.h @@ -56,13 +56,13 @@ static inline long rcu_segcblist_n_cbs(struct rcu_segcblist *rsclp) static inline void rcu_segcblist_set_flags(struct rcu_segcblist *rsclp, int flags) { - rsclp->flags |= flags; + WRITE_ONCE(rsclp->flags, rsclp->flags | flags); }
static inline void rcu_segcblist_clear_flags(struct rcu_segcblist *rsclp, int flags) { - rsclp->flags &= ~flags; + WRITE_ONCE(rsclp->flags, rsclp->flags & ~flags); }
static inline bool rcu_segcblist_test_flags(struct rcu_segcblist *rsclp,