From: David Vernet void@manifault.com

commit 80dcee695143255261f30c7cc2a041ba413717a4 upstream.

The rcutorture module has an rcu_torture_writer task that repeatedly performs writes, synchronizations, and deletes. There is a corner-case check in rcu_torture_writer() wherein if nsynctypes is 0, a warning is issued and the task waits to be stopped via a call to torture_kthread_stopping() rather than performing any work.

There should be a return statement following this call to torture_kthread_stopping(), as the intention with issuing the call to torture_kthread_stopping() in the first place is to avoid the rcu_torture_writer task from performing any work. Some of the work may even be dangerous to perform, such as potentially causing a #DE due to nsynctypes being used in a modulo operator when querying for sync updates to issue.

This patch adds the missing return call. As a bonus, it also fixes a checkpatch warning that was emitted due to the WARN_ONCE() call using the name of the function rather than __func__.

Signed-off-by: David Vernet void@manifault.com Signed-off-by: Paul E. McKenney paulmck@kernel.org Signed-off-by: Daniil Dulov d.dulov@aladdin.ru --- 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 d820ef615475..a76399bd43b9 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -1165,7 +1165,7 @@ rcu_torture_writer(void *arg) " GP expediting controlled from boot/sysfs for %s.\n", torture_type, cur_ops->name); if (WARN_ONCE(nsynctypes == 0, - "rcu_torture_writer: No update-side primitives.\n")) { + "%s: No update-side primitives.\n", __func__)) { /* * No updates primitives, so don't try updating. * The resulting test won't be testing much, hence the @@ -1173,6 +1173,7 @@ rcu_torture_writer(void *arg) */ rcu_torture_writer_state = RTWS_STOPPING; torture_kthread_stopping("rcu_torture_writer"); + return 0; }

do {