| From e857e5c6addd0fea4d145e818e24b1a75e41550f Mon Sep 17 00:00:00 2001 |
| From: Sage Weil <sage@inktank.com> |
| Date: Mon, 30 Jul 2012 18:17:13 -0700 |
| Subject: libceph: avoid dropping con mutex before fault |
| |
| From: Sage Weil <sage@inktank.com> |
| |
| (cherry picked from commit 8636ea672f0c5ab7478c42c5b6705ebd1db7eb6a) |
| |
| 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> |
| Reviewed-by: Alex Elder <elder@inktank.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| net/ceph/messenger.c | 4 +--- |
| 1 file changed, 1 insertion(+), 3 deletions(-) |
| |
| --- 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", |
