This is a note to let you know that I've just added the patch titled
rcutorture: Fix rcu_torture_one_read() pipe_count overflow comment
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
rcutorture-fix-rcu_torture_one_read-pipe_count-overf.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 6fc847b530e2b49b645958fe51c56a5a6e87e364
Author: Paul E. McKenney <paulmck@xxxxxxxxxx>
Date: Wed Mar 6 19:21:47 2024 -0800
rcutorture: Fix rcu_torture_one_read() pipe_count overflow comment
[ Upstream commit 8b9b443fa860276822b25057cb3ff3b28734dec0 ]
The "pipe_count > RCU_TORTURE_PIPE_LEN" check has a comment saying "Should
not happen, but...". This is only true when testing an RCU whose grace
periods are always long enough. This commit therefore fixes this comment.
Reported-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Closes: https://lore.kernel.org/lkml/CAHk-=wi7rJ-eGq+xaxVfzFEgbL9tdf6Kc8Z89rCpfcQOKm74Tw@xxxxxxxxxxxxxx/
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 0b7af7e2bcbb1..8986ef3a95888 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -1334,7 +1334,8 @@ static bool rcu_torture_one_read(struct torture_random_state *trsp)
preempt_disable();
pipe_count = p->rtort_pipe_count;
if (pipe_count > RCU_TORTURE_PIPE_LEN) {
- /* Should not happen, but... */
+ // Should not happen in a correct RCU implementation,
+ // happens quite often for torture_type=busted.
pipe_count = RCU_TORTURE_PIPE_LEN;
}
completed = cur_ops->get_gp_seq();
