From e6fb1fc1085e5b5155bc8f3d3385c48b8bdde95e Mon Sep 17 00:00:00 2001 From: Artem Savkov Date: Sun, 7 Feb 2016 13:31:39 +0100 Subject: [PATCH] rcuperf: Do not wake up shutdown wait queue if "shutdown" is false. After finishing its tests rcuperf tries to wake up shutdown_wq even if "shutdown" param is set to false, resulting in a wake_up() call on an unitialized wait_queue_head_t which leads to "BUG: spinlock bad magic" and "BUG: unable to handle kernel NULL pointer dereference". Fix by checking "shutdown" param before waking up the queue. Signed-off-by: Artem Savkov --- kernel/rcu/rcuperf.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/rcu/rcuperf.c b/kernel/rcu/rcuperf.c index 4c0572859ff0..3cee0d8393ed 100644 --- a/kernel/rcu/rcuperf.c +++ b/kernel/rcu/rcuperf.c @@ -423,8 +423,10 @@ rcu_perf_writer(void *arg) b_rcu_perf_writer_finished = cur_ops->completed(); } - smp_mb(); /* Assign before wake. */ - wake_up(&shutdown_wq); + if (shutdown) { + smp_mb(); /* Assign before wake. */ + wake_up(&shutdown_wq); + } } } if (done && !alldone && -- 2.34.1