From: Jussi Kivilinna <jussi.kivilinna@xxxxxxxx>
-------------------
This is a commit scheduled for the next v2.6.34 longterm release.
http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git
If you see a problem with using this for longterm, please comment.
-------------------
commit 9efade1b3e981f5064f9db9ca971b4dc7557ae42 upstream.
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
Reported-by: Gurucharan Shetty <gurucharan.shetty@xxxxxxxxx>
Signed-off-by: Jussi Kivilinna <jussi.kivilinna@xxxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
---
crypto/cryptd.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/crypto/cryptd.c b/crypto/cryptd.c
index ef71318976c7..6e241640219d 100644
--- a/crypto/cryptd.c
+++ b/crypto/cryptd.c
@@ -116,13 +116,18 @@ 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;
--
1.8.5.2
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