[ 3.5.y.z extended stable ] Patch "crypto: cryptd - disable softirqs in cryptd_queue_worker to" has been added to staging queue

[Herton Ronaldo Krzesinski]

This is a note to let you know that I have just added a patch titled

    crypto: cryptd - disable softirqs in cryptd_queue_worker to

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Herton

------

>From 95b83e9c4a245eba62f6341336e9c51336dab125 Mon Sep 17 00:00:00 2001
From: Jussi Kivilinna <jussi.kivilinna at mbnet.fi>
Date: Sun, 21 Oct 2012 20:42:28 +0300
Subject: [PATCH] crypto: cryptd - disable softirqs in cryptd_queue_worker to
 prevent data corruption
X-Extended-Stable: 3.5

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 at gmail.com>
Signed-off-by: Jussi Kivilinna <jussi.kivilinna at mbnet.fi>
Signed-off-by: Herbert Xu <herbert at gondor.apana.org.au>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski at canonical.com>
---
 crypto/cryptd.c |   11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/crypto/cryptd.c b/crypto/cryptd.c
index 671d4d6..7bdd61b 100644
--- 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;
--
1.7.9.5