From 2493c0c166565e36831196446af594eb07892daf Mon Sep 17 00:00:00 2001
From: Alan Cox <alan@linux.intel.com>
Date: Mon, 30 Nov 2009 13:17:46 +0000
Subject: [PATCH] tty: isicom: fix deadlock on shutdown
Alexander Strakh <strakh@ispras.ru> reported
KERNEL_VERSION: 2.6.31
DESCRIBE:
Driver drivers/char/isicom.c might sleep in atomic context, because it
calls
tty_port_xmit_buf under spin_lock.
./drivers/char/isicom.c:
1307 static void isicom_hangup(struct tty_struct *tty)
1308 {
...
1315 spin_lock_irqsave(&port->card->card_lock, flags);
1316 isicom_shutdown_port(port);
...
Path to might_sleep macro from isicom_hangup:
1. isicom_hangup calls spin_lock_irqsave (drivers/char/isicom.c:1315) and
then
calls isicom_shutdown_port.
2. isiscom_shutdown_port calls tty_port_free_xmit_buf at
drivers/char/isicom.c:906
3. tty_port_free_xmit_buf calls mutex_lock at drivers/char/tty_port:48
Found by Linux Driver Verification Project.
Reported-by: Alexander Strakh <strakh@ispras.ru>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
drivers/char/isicom.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/char/isicom.c b/drivers/char/isicom.c
index 1e91c302ee423..300d5bd6cd060 100644
--- a/drivers/char/isicom.c
+++ b/drivers/char/isicom.c
@@ -887,7 +887,6 @@ static void isicom_shutdown_port(struct isi_port *port)
{
struct isi_board *card = port->card;
- tty_port_free_xmit_buf(&port->port);
if (--card->count < 0) {
pr_dbg("isicom_shutdown_port: bad board(0x%lx) count %d.\n",
card->base, card->count);
@@ -927,6 +926,7 @@ static void isicom_shutdown(struct tty_port *port)
outw(card->port_status, card->base + 0x02);
isicom_shutdown_port(ip);
spin_unlock_irqrestore(&card->card_lock, flags);
+ tty_port_free_xmit_buf(port);
}
static void isicom_close(struct tty_struct *tty, struct file *filp)
--
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