Commit 7246240c authored Oct 25, 2012 by Sage Weil Committed by Alex Elder Oct 26, 2012

libceph: avoid NULL kref_put from NULL alloc_msg return

The ceph_on_in_msg_alloc() method calls the ->alloc_msg() helper which
may return NULL.  It also drops con->mutex while it allocates a message,
which means that the connection state may change (e.g., get closed).  If
that happens, we clean up and bail out.  Avoid calling ceph_msg_put() on
a NULL return value and triggering a crash.

This was observed when an ->alloc_msg() call races with a timeout that
resends a zillion messages and resets the connection, and ->alloc_msg()
returns NULL (because the request was resent to another target).

Fixes http://tracker.newdream.net/issues/3342



Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Alex Elder <elder@inktank.com>

parent 0f9831a8

net/ceph/messenger.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -2742,6 +2742,7 @@ static int ceph_con_in_msg_alloc(struct ceph_connection con, int skip)
		msg = con->ops->alloc_msg(con, hdr, skip);
		mutex_lock(&con->mutex);
		if (con->state != CON_STATE_OPEN) {
		if (msg)
		ceph_msg_put(msg);
		return -EAGAIN;
		}

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