4.19-stable review patch. If anyone has any objections, please let me know.
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From: Luiz Augusto von Dentz luiz.von.dentz@intel.com
[ Upstream commit 08d1914293dae38350b8088980e59fbc699a72fe ]
rfcomm_sk_state_change attempts to use sock_lock so it must never be called with it locked but rfcomm_sock_ioctl always attempt to lock it causing the following trace:
====================================================== WARNING: possible circular locking dependency detected 6.8.0-syzkaller-08951-gfe46a7dd189e #0 Not tainted ------------------------------------------------------ syz-executor386/5093 is trying to acquire lock: ffff88807c396258 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1671 [inline] ffff88807c396258 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: rfcomm_sk_state_change+0x5b/0x310 net/bluetooth/rfcomm/sock.c:73
but task is already holding lock: ffff88807badfd28 (&d->lock){+.+.}-{3:3}, at: __rfcomm_dlc_close+0x226/0x6a0 net/bluetooth/rfcomm/core.c:491
Reported-by: syzbot+d7ce59b06b3eb14fd218@syzkaller.appspotmail.com Tested-by: syzbot+d7ce59b06b3eb14fd218@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=d7ce59b06b3eb14fd218 Fixes: 3241ad820dbb ("[Bluetooth] Add timestamp support to L2CAP, RFCOMM and SCO") Signed-off-by: Luiz Augusto von Dentz luiz.von.dentz@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/bluetooth/rfcomm/sock.c | 2 -- 1 file changed, 2 deletions(-)
diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c index 78830efe89d73..8f53cc0d9682a 100644 --- a/net/bluetooth/rfcomm/sock.c +++ b/net/bluetooth/rfcomm/sock.c @@ -872,9 +872,7 @@ static int rfcomm_sock_ioctl(struct socket *sock, unsigned int cmd, unsigned lon
if (err == -ENOIOCTLCMD) { #ifdef CONFIG_BT_RFCOMM_TTY - lock_sock(sk); err = rfcomm_dev_ioctl(sk, cmd, (void __user *) arg); - release_sock(sk); #else err = -EOPNOTSUPP; #endif