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Subject[ 083/184] crypto: cryptd - disable softirqs in
2.6.32-longterm review patch.  If anyone has any objections, please let me know.

------------------
cryptd_queue_worker to prevent data corruption

From: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>

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@gmail.com>
Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>
---
crypto/cryptd.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/crypto/cryptd.c b/crypto/cryptd.c
index 3533582..9e1bf69 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;
--
1.7.12.2.21.g234cd45.dirty




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