From: Alan Cox <alan@linux.intel.com>
To: greg@kroah.com, linux-kernel@vger.kernel.org
Subject: [PATCH 05/12] isicom: fix deadlock on shutdown
Date: Wed, 18 Nov 2009 14:15:37 +0000 [thread overview]
Message-ID: <20091118141528.3346.41333.stgit@localhost.localdomain> (raw)
In-Reply-To: <20091118141354.3346.16910.stgit@localhost.localdomain>
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.
Signed-off-by: Alan Cox <alan@linux.intel.com>
---
drivers/char/isicom.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/drivers/char/isicom.c b/drivers/char/isicom.c
index 1e91c30..300d5bd 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)
next prev parent reply other threads:[~2009-11-18 14:32 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-18 14:14 [PATCH 00/12] Series short description Alan Cox
2009-11-18 14:14 ` [PATCH 01/12] isicom: switch to the new tty_port_open helper Alan Cox
2009-11-18 14:14 ` [PATCH 02/12] isicom: sort out the board init logic Alan Cox
2009-11-18 14:15 ` [PATCH 03/12] mxser: use the tty_port_open method Alan Cox
2009-11-18 14:15 ` [PATCH 04/12] mxser: Use the new locking rules to fix setserial properly Alan Cox
2009-11-20 12:08 ` Dan Carpenter
2009-11-18 14:15 ` Alan Cox [this message]
2009-11-18 14:15 ` [PATCH 06/12] moxa: Use more tty_port ops Alan Cox
2009-11-18 14:15 ` [PATCH 07/12] moxa: rework the locking a bit Alan Cox
2009-11-18 14:16 ` [PATCH 08/12] Locking clean up Alan Cox
2009-11-18 14:16 ` [PATCH 09/12] moxa: Kill off the throttle method Alan Cox
2009-11-18 14:16 ` [PATCH 10/12] moxa: Fix modem op locking Alan Cox
2009-11-18 14:16 ` [PATCH 11/12] moxa: Kill the use of lock_kernel Alan Cox
2009-11-18 14:17 ` [PATCH 12/12] moxa: split open lock Alan Cox
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