crypto: cryptd - disable softirqs in cryptd_queue_worker to prevent data corruption

cryptd_queue_worker attempts to prevent simultaneous accesses to crypto
workqueue by cryptd_enqueue_request using preempt_disable/preempt_enable.
However cryptd_enqueue_request might be called from softirq context,
so add local_bh_disable/local_bh_enable to prevent data corruption and
panics.

Bug report at http://marc.info/?l=linux-crypto-vger&m=134858649616319&w=2

v2:
 - Disable software interrupts instead of hardware interrupts

Cc: stable@vger.kernel.org
Reported-by: Gurucharan Shetty <gurucharan.shetty@gmail.com>
Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/crypto/cryptd.c b/crypto/cryptd.c
index 671d4d6d14df106b3b0278364340ef3290d7a185..7bdd61b867c899901ed846ed5a229bc6ab31653b 100644 (file)
--- a/crypto/cryptd.c
+++ b/crypto/cryptd.c
@@ -137,13 +137,18 @@ static void cryptd_queue_worker(struct work_struct *work)
        struct crypto_async_request *req, *backlog;
 
        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() */
+       /*
+        * 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)
                return;