From: Alex Elder <elder@inktank.com>
To: Sage Weil <sage@inktank.com>
Cc: ceph-devel@vger.kernel.org
Subject: Re: [PATCH 6/8] libceph: avoid dropping con mutex before fault
Date: Mon, 30 Jul 2012 19:12:16 -0500 [thread overview]
Message-ID: <501722E0.1080203@inktank.com> (raw)
In-Reply-To: <1343663971-3221-7-git-send-email-sage@inktank.com>
On 07/30/2012 10:59 AM, Sage Weil wrote:
> The ceph_fault() function takes the con mutex, so we should avoid
> dropping it before calling it. This fixes a potential race with
> another thread calling ceph_con_close(), or _open(), or similar (we
> don't reverify con->state after retaking the lock).
>
> Add annotation so that lockdep realizes we will drop the mutex before
> returning.
>
> Signed-off-by: Sage Weil <sage@inktank.com>
Looks good.
Reviewed-by: Alex Elder <elder@inktank.com>
> ---
> net/ceph/messenger.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
> index feb5a2a..c3b628c 100644
> --- a/net/ceph/messenger.c
> +++ b/net/ceph/messenger.c
> @@ -2336,7 +2336,6 @@ done_unlocked:
> return;
>
> fault:
> - mutex_unlock(&con->mutex);
> ceph_fault(con); /* error/fault path */
> goto done_unlocked;
> }
> @@ -2347,9 +2346,8 @@ fault:
> * exponential backoff
> */
> static void ceph_fault(struct ceph_connection *con)
> + __releases(con->mutex)
> {
> - mutex_lock(&con->mutex);
> -
> pr_err("%s%lld %s %s\n", ENTITY_NAME(con->peer_name),
> ceph_pr_addr(&con->peer_addr.in_addr), con->error_msg);
> dout("fault %p state %lu to peer %s\n",
>
next prev parent reply other threads:[~2012-07-31 0:12 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-30 15:59 [PATCH 0/8] Last batch of messenger fixes, misc Sage Weil
2012-07-30 15:59 ` [PATCH 1/8] libceph: be less chatty about stray replies Sage Weil
2012-07-30 23:00 ` Alex Elder
2012-07-30 15:59 ` [PATCH 2/8] ceph: update MAINTAINERS file Sage Weil
2012-07-30 23:09 ` Alex Elder
2012-07-30 15:59 ` [PATCH 3/8] libceph: fix handling of immediate socket connect failure Sage Weil
2012-07-31 0:08 ` Alex Elder
2012-07-30 15:59 ` [PATCH 4/8] libceph: revoke mon_client messages on session restart Sage Weil
2012-07-31 0:09 ` Alex Elder
2012-07-30 15:59 ` [PATCH 5/8] libceph: verify state after retaking con lock after dispatch Sage Weil
2012-07-31 0:11 ` Alex Elder
2012-07-30 15:59 ` [PATCH 6/8] libceph: avoid dropping con mutex before fault Sage Weil
2012-07-31 0:12 ` Alex Elder [this message]
2012-07-30 15:59 ` [PATCH 7/8] libceph: change ceph_con_in_msg_alloc convention to be less weird Sage Weil
2012-07-31 0:25 ` Alex Elder
2012-07-31 1:09 ` Sage Weil
2012-07-30 15:59 ` [PATCH 8/8] libceph: recheck con state after allocating incoming message Sage Weil
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