From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Ilya Dryomov <idryomov@gmail.com>,
Sasha Levin <sashal@kernel.org>,
ceph-devel@vger.kernel.org, netdev@vger.kernel.org
Subject: [PATCH AUTOSEL 3.18 08/16] libceph: avoid KEEPALIVE_PENDING races in ceph_con_keepalive()
Date: Thu, 14 Feb 2019 21:15:38 -0500 [thread overview]
Message-ID: <20190215021546.179605-8-sashal@kernel.org> (raw)
In-Reply-To: <20190215021546.179605-1-sashal@kernel.org>
From: Ilya Dryomov <idryomov@gmail.com>
[ Upstream commit 4aac9228d16458cedcfd90c7fb37211cf3653ac3 ]
con_fault() can transition the connection into STANDBY right after
ceph_con_keepalive() clears STANDBY in clear_standby():
libceph user thread ceph-msgr worker
ceph_con_keepalive()
mutex_lock(&con->mutex)
clear_standby(con)
mutex_unlock(&con->mutex)
mutex_lock(&con->mutex)
con_fault()
...
if KEEPALIVE_PENDING isn't set
set state to STANDBY
...
mutex_unlock(&con->mutex)
set KEEPALIVE_PENDING
set WRITE_PENDING
This triggers warnings in clear_standby() when either ceph_con_send()
or ceph_con_keepalive() get to clearing STANDBY next time.
I don't see a reason to condition queue_con() call on the previous
value of KEEPALIVE_PENDING, so move the setting of KEEPALIVE_PENDING
into the critical section -- unlike WRITE_PENDING, KEEPALIVE_PENDING
could have been a non-atomic flag.
Reported-by: syzbot+acdeb633f6211ccdf886@syzkaller.appspotmail.com
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Tested-by: Myungho Jung <mhjungk@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/ceph/messenger.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 2dc4e064bea3..45bd78f3e28f 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -3068,9 +3068,10 @@ void ceph_con_keepalive(struct ceph_connection *con)
dout("con_keepalive %p\n", con);
mutex_lock(&con->mutex);
clear_standby(con);
+ con_flag_set(con, CON_FLAG_KEEPALIVE_PENDING);
mutex_unlock(&con->mutex);
- if (con_flag_test_and_set(con, CON_FLAG_KEEPALIVE_PENDING) == 0 &&
- con_flag_test_and_set(con, CON_FLAG_WRITE_PENDING) == 0)
+
+ if (con_flag_test_and_set(con, CON_FLAG_WRITE_PENDING) == 0)
queue_con(con);
}
EXPORT_SYMBOL(ceph_con_keepalive);
--
2.19.1
next prev parent reply other threads:[~2019-02-15 2:17 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20190215021546.179605-1-sashal@kernel.org>
2019-02-15 2:15 ` [PATCH AUTOSEL 3.18 07/16] mac80211: fix miscounting of ttl-dropped frames Sasha Levin
2019-02-15 2:15 ` Sasha Levin [this message]
2019-02-15 2:15 ` [PATCH AUTOSEL 3.18 11/16] net: altera_tse: fix connect_local_phy error path Sasha Levin
2019-02-15 2:15 ` [PATCH AUTOSEL 3.18 12/16] sfc: suppress duplicate nvmem partition types in efx_ef10_mtd_probe Sasha Levin
2019-02-19 9:22 ` Bert Kenward
2019-02-15 2:15 ` [PATCH AUTOSEL 3.18 13/16] ibmveth: Do not process frames after calling napi_reschedule Sasha Levin
2019-02-15 2:15 ` [PATCH AUTOSEL 3.18 14/16] mac80211: don't initiate TDLS connection if station is not associated to AP Sasha Levin
2019-02-15 2:15 ` [PATCH AUTOSEL 3.18 15/16] cfg80211: extend range deviation for DMG Sasha Levin
2019-02-15 12:31 ` Johannes Berg
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190215021546.179605-8-sashal@kernel.org \
--to=sashal@kernel.org \
--cc=ceph-devel@vger.kernel.org \
--cc=idryomov@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=stable@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).