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authorArnd Bergmann <arnd@arndb.de>2014-01-02 13:07:40 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-01-07 17:05:21 -0800
commitb8c98ae49e8d53344b1d62417eea05ebc3cdbd78 (patch)
treed50982086efec947214cc960d123afc616429dc9
parent591cee0a35632031cd925392a1bce507dcfe9ea8 (diff)
tty: synclink: avoid sleep_on race
The four variants of the synclink driver use the same code in their open() callback to wait for a port in process of being closed, using interruptible_sleep_on, which is racy and going away soon. Making things worse, these functions hold the BTM while doing so, which means that if we ever enter this code path, we cannot actually continue since the other thread that is in process of closing the port can no longer get the BTM. This addresses both issues by using wait_event_interruptible_tty() instead. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/char/pcmcia/synclink_cs.c4
-rw-r--r--drivers/tty/synclink.c4
-rw-r--r--drivers/tty/synclink_gt.c4
-rw-r--r--drivers/tty/synclinkmp.c4
4 files changed, 8 insertions, 8 deletions
diff --git a/drivers/char/pcmcia/synclink_cs.c b/drivers/char/pcmcia/synclink_cs.c
index d39cca659a3..8320abd1ef1 100644
--- a/drivers/char/pcmcia/synclink_cs.c
+++ b/drivers/char/pcmcia/synclink_cs.c
@@ -2511,8 +2511,8 @@ static int mgslpc_open(struct tty_struct *tty, struct file * filp)
/* If port is closing, signal caller to try again */
if (tty_hung_up_p(filp) || port->flags & ASYNC_CLOSING){
- if (port->flags & ASYNC_CLOSING)
- interruptible_sleep_on(&port->close_wait);
+ wait_event_interruptible_tty(tty, port->close_wait,
+ !(port->flags & ASYNC_CLOSING));
retval = ((port->flags & ASYNC_HUP_NOTIFY) ?
-EAGAIN : -ERESTARTSYS);
goto cleanup;
diff --git a/drivers/tty/synclink.c b/drivers/tty/synclink.c
index e1ce141bad5..5ae14b46cce 100644
--- a/drivers/tty/synclink.c
+++ b/drivers/tty/synclink.c
@@ -3404,8 +3404,8 @@ static int mgsl_open(struct tty_struct *tty, struct file * filp)
/* If port is closing, signal caller to try again */
if (tty_hung_up_p(filp) || info->port.flags & ASYNC_CLOSING){
- if (info->port.flags & ASYNC_CLOSING)
- interruptible_sleep_on(&info->port.close_wait);
+ wait_event_interruptible_tty(tty, info->port.close_wait,
+ !(info->port.flags & ASYNC_CLOSING));
retval = ((info->port.flags & ASYNC_HUP_NOTIFY) ?
-EAGAIN : -ERESTARTSYS);
goto cleanup;
diff --git a/drivers/tty/synclink_gt.c b/drivers/tty/synclink_gt.c
index 1abf946463f..c359a91f734 100644
--- a/drivers/tty/synclink_gt.c
+++ b/drivers/tty/synclink_gt.c
@@ -674,8 +674,8 @@ static int open(struct tty_struct *tty, struct file *filp)
/* If port is closing, signal caller to try again */
if (tty_hung_up_p(filp) || info->port.flags & ASYNC_CLOSING){
- if (info->port.flags & ASYNC_CLOSING)
- interruptible_sleep_on(&info->port.close_wait);
+ wait_event_interruptible_tty(tty, info->port.close_wait,
+ !(info->port.flags & ASYNC_CLOSING));
retval = ((info->port.flags & ASYNC_HUP_NOTIFY) ?
-EAGAIN : -ERESTARTSYS);
goto cleanup;
diff --git a/drivers/tty/synclinkmp.c b/drivers/tty/synclinkmp.c
index dc6e96996ea..144202eef6f 100644
--- a/drivers/tty/synclinkmp.c
+++ b/drivers/tty/synclinkmp.c
@@ -754,8 +754,8 @@ static int open(struct tty_struct *tty, struct file *filp)
/* If port is closing, signal caller to try again */
if (tty_hung_up_p(filp) || info->port.flags & ASYNC_CLOSING){
- if (info->port.flags & ASYNC_CLOSING)
- interruptible_sleep_on(&info->port.close_wait);
+ wait_event_interruptible_tty(tty, info->port.close_wait,
+ !(info->port.flags & ASYNC_CLOSING));
retval = ((info->port.flags & ASYNC_HUP_NOTIFY) ?
-EAGAIN : -ERESTARTSYS);
goto cleanup;