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net: unix: allow set_peek_off to fail 

unix_dgram_recvmsg() will hold the readlock of the socket until recv
is complete.

In the same time, we may try to setsockopt(SO_PEEK_OFF) which will hang until
unix_dgram_recvmsg() will complete (which can take a while) without allowing
us to break out of it, triggering a hung task spew.

Instead, allow set_peek_off to fail, this way userspace will not hang.

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
wifi-calibration
Sasha Levin 2013-12-07 17:26:27 -05:00 committed by David S. Miller
parent 88b07b3660
commit 12663bfc97
3 changed files with 8 additions and 4 deletions
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2
include/linux/net.h
View File

@ -181,7 +181,7 @@ struct proto_ops {
int offset, size_t size, int flags);
ssize_t (*splice_read)(struct socket *sock, loff_t *ppos,
struct pipe_inode_info *pipe, size_t len, unsigned int flags);
void (*set_peek_off)(struct sock *sk, int val);
int (*set_peek_off)(struct sock *sk, int val);
};
#define DECLARE_SOCKADDR(type, dst, src) \

2
net/core/sock.c
View File

@ -882,7 +882,7 @@ set_rcvbuf:
case SO_PEEK_OFF:
if (sock->ops->set_peek_off)
sock->ops->set_peek_off(sk, val);
ret = sock->ops->set_peek_off(sk, val);
else
ret = -EOPNOTSUPP;
break;

8
net/unix/af_unix.c
View File

@ -530,13 +530,17 @@ static int unix_seqpacket_sendmsg(struct kiocb *, struct socket *,
static int unix_seqpacket_recvmsg(struct kiocb *, struct socket *,
struct msghdr *, size_t, int);
static void unix_set_peek_off(struct sock *sk, int val)
static int unix_set_peek_off(struct sock *sk, int val)
{
struct unix_sock *u = unix_sk(sk);
mutex_lock(&u->readlock);
if (mutex_lock_interruptible(&u->readlock))
return -EINTR;
sk->sk_peek_off = val;
mutex_unlock(&u->readlock);
return 0;
}