From: Alan Cox Date: Mon, 30 Nov 2009 13:17:46 +0000 (+0000) Subject: tty: isicom: fix deadlock on shutdown X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=2493c0c166565e36831196446af594eb07892daf;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git tty: isicom: fix deadlock on shutdown Alexander Strakh 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 Signed-off-by: Alan Cox Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/char/isicom.c b/drivers/char/isicom.c index 1e91c302ee42..300d5bd6cd06 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)