Patchwork [3.5.yuz,extended,stable] Patch "libceph: fix mutex coverage for ceph_con_close" has been added to staging queue

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Submitter Herton Ronaldo Krzesinski
Date Nov. 20, 2012, 5:18 p.m.
Message ID <1353431885-9836-1-git-send-email-herton.krzesinski@canonical.com>
Download mbox | patch
Permalink /patch/200457/
State New
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Herton Ronaldo Krzesinski - Nov. 20, 2012, 5:18 p.m.
This is a note to let you know that I have just added a patch titled

    libceph: fix mutex coverage for ceph_con_close

to the linux-3.5.y-queue branch of the 3.5.yuz 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.yuz tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Herton

------

From 1c8f127afee6cdbd1e11873267c3e1555fd6658e Mon Sep 17 00:00:00 2001
From: Sage Weil <sage@inktank.com>
Date: Mon, 30 Jul 2012 16:24:37 -0700
Subject: [PATCH 49/78] libceph: fix mutex coverage for ceph_con_close

commit 8c50c817566dfa4581f82373aac39f3e608a7dc8 upstream.

Hold the mutex while twiddling all of the state bits to avoid possible
races.  While we're here, make not of why we cannot close the socket
directly.

Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Alex Elder <elder@inktank.com>
Reviewed-by: Yehuda Sadeh <yehuda@inktank.com>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
---
 net/ceph/messenger.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

--
1.7.9.5

Patch

diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 6e2f678..e65b15d 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -503,6 +503,7 @@  static void reset_connection(struct ceph_connection *con)
  */
 void ceph_con_close(struct ceph_connection *con)
 {
+	mutex_lock(&con->mutex);
 	dout("con_close %p peer %s\n", con,
 	     ceph_pr_addr(&con->peer_addr.in_addr));
 	clear_bit(NEGOTIATING, &con->state);
@@ -515,11 +516,16 @@  void ceph_con_close(struct ceph_connection *con)
 	clear_bit(KEEPALIVE_PENDING, &con->flags);
 	clear_bit(WRITE_PENDING, &con->flags);

-	mutex_lock(&con->mutex);
 	reset_connection(con);
 	con->peer_global_seq = 0;
 	cancel_delayed_work(&con->work);
 	mutex_unlock(&con->mutex);
+
+	/*
+	 * We cannot close the socket directly from here because the
+	 * work threads use it without holding the mutex.  Instead, let
+	 * con_work() do it.
+	 */
 	queue_con(con);
 }
 EXPORT_SYMBOL(ceph_con_close);