[PATCH AUTOSEL 6.1 5/9] rcutorture: Fix rcu_torture_one_read() pipe_count overflow comment

Sasha Levin
2024-05-26T09:43:20Z

From: "Paul E. McKenney" <paulmck@kernel.org>

[ 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@linux-foundation.org>
Closes: https://lore.kernel.org/lkml/CAHk-=wi7rJ-eGq+xaxVfzFEgbL9tdf6Kc8Z89rCpfcQOKm74Tw@mail.gmail.com/
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
kernel/rcu/rcutorture.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 503c2aa845a4a..2f6c52a863f2e 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -1946,7 +1946,8 @@ static bool rcu_torture_one_read(struct torture_random_state *trsp, long myid)
preempt_disable();
pipe_count = READ_ONCE(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();
--
2.43.0