[PATCH 3.12 21/77] net: unix: allow bind to fail on mutex lock

From: Greg Kroah-Hartman
Date: Mon Jan 13 2014 - 19:35:12 EST


3.12-stable review patch. If anyone has any objections, please let me know.

------------------

From: Sasha Levin <sasha.levin@xxxxxxxxxx>

[ Upstream commit 37ab4fa7844a044dc21fde45e2a0fc2f3c3b6490 ]

This is similar to the set_peek_off patch where calling bind while the
socket is stuck in unix_dgram_recvmsg() will block and cause a hung task
spew after a while.

This is also the last place that did a straightforward mutex_lock(), so
there shouldn't be any more of these patches.

Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/unix/af_unix.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -718,7 +718,9 @@ static int unix_autobind(struct socket *
int err;
unsigned int retries = 0;

- mutex_lock(&u->readlock);
+ err = mutex_lock_interruptible(&u->readlock);
+ if (err)
+ return err;

err = 0;
if (u->addr)
@@ -877,7 +879,9 @@ static int unix_bind(struct socket *sock
goto out;
addr_len = err;

- mutex_lock(&u->readlock);
+ err = mutex_lock_interruptible(&u->readlock);
+ if (err)
+ goto out;

err = -EINVAL;
if (u->addr)


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