From: Sebastian Andrzej Siewior bigeasy@linutronix.de
[ Upstream commit 91e8bcd7b4da182e09ea19a2c73167345fe14c98 ]
The access to cryptd_queue::cpu_queue is synchronized by disabling preemption in cryptd_enqueue_request() and disabling BH in cryptd_queue_worker(). This implies that access is allowed from BH.
If cryptd_enqueue_request() is invoked from preemptible context _and_ soft interrupt then this can lead to list corruption since cryptd_enqueue_request() is not protected against access from soft interrupt.
Replace get_cpu() in cryptd_enqueue_request() with local_bh_disable() to ensure BH is always disabled. Remove preempt_disable() from cryptd_queue_worker() since it is not needed because local_bh_disable() ensures synchronisation.
Fixes: 254eff771441 ("crypto: cryptd - Per-CPU thread implementation...") Signed-off-by: Sebastian Andrzej Siewior bigeasy@linutronix.de Signed-off-by: Herbert Xu herbert@gondor.apana.org.au Signed-off-by: Sasha Levin sashal@kernel.org --- crypto/cryptd.c | 23 +++++++++++------------ 1 file changed, 11 insertions(+), 12 deletions(-)
diff --git a/crypto/cryptd.c b/crypto/cryptd.c index 927760b316a4..43a1a855886b 100644 --- a/crypto/cryptd.c +++ b/crypto/cryptd.c @@ -39,6 +39,10 @@ struct cryptd_cpu_queue { };
struct cryptd_queue { + /* + * Protected by disabling BH to allow enqueueing from softinterrupt and + * dequeuing from kworker (cryptd_queue_worker()). + */ struct cryptd_cpu_queue __percpu *cpu_queue; };
@@ -125,28 +129,28 @@ static void cryptd_fini_queue(struct cryptd_queue *queue) static int cryptd_enqueue_request(struct cryptd_queue *queue, struct crypto_async_request *request) { - int cpu, err; + int err; struct cryptd_cpu_queue *cpu_queue; refcount_t *refcnt;
- cpu = get_cpu(); + local_bh_disable(); cpu_queue = this_cpu_ptr(queue->cpu_queue); err = crypto_enqueue_request(&cpu_queue->queue, request);
refcnt = crypto_tfm_ctx(request->tfm);
if (err == -ENOSPC) - goto out_put_cpu; + goto out;
- queue_work_on(cpu, cryptd_wq, &cpu_queue->work); + queue_work_on(smp_processor_id(), cryptd_wq, &cpu_queue->work);
if (!refcount_read(refcnt)) - goto out_put_cpu; + goto out;
refcount_inc(refcnt);
-out_put_cpu: - put_cpu(); +out: + local_bh_enable();
return err; } @@ -162,15 +166,10 @@ static void cryptd_queue_worker(struct work_struct *work) cpu_queue = container_of(work, struct cryptd_cpu_queue, work); /* * Only handle one request at a time to avoid hogging crypto workqueue. - * preempt_disable/enable is used to prevent being preempted by - * cryptd_enqueue_request(). local_bh_disable/enable is used to prevent - * cryptd_enqueue_request() being accessed from software interrupts. */ local_bh_disable(); - preempt_disable(); backlog = crypto_get_backlog(&cpu_queue->queue); req = crypto_dequeue_request(&cpu_queue->queue); - preempt_enable(); local_bh_enable();
if (!req)