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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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