linux-kernel - [PATCH 2/3 v2] fb: udlfb: fix hang at disconnect

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Date:	Fri, 25 Jan 2013 19:49:27 +0100
From:	Alexander Holler <holler@...oftware.de>
To:	linux-kernel@...r.kernel.org
Cc:	linux-fbdev@...r.kernel.org,
	Florian Tobias Schandinat <FlorianSchandinat@....de>,
	Bernie Thompson <bernie@...gable.com>,
	Steve Glendinning <steve.glendinning@...well.net>,
	Alexander Holler <holler@...oftware.de>,
	<stable@...r.kernel.org>
Subject: [PATCH 2/3 v2] fb: udlfb: fix hang at disconnect

When a device was disconnected the driver may hang at waiting for urbs it never
will get. Fix this by using a timeout while waiting for the used semaphore.

There is still a memory leak if a timeout happens, but at least the driver
now continues his disconnect routine.

Cc: <stable@...r.kernel.org>
Signed-off-by: Alexander Holler <holler@...oftware.de>
---
 drivers/video/udlfb.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/video/udlfb.c b/drivers/video/udlfb.c
index 86d449e..db6cc66 100644
--- a/drivers/video/udlfb.c
+++ b/drivers/video/udlfb.c
@@ -1832,8 +1832,9 @@ static void dlfb_free_urb_list(struct dlfb_data *dev)
 	/* keep waiting and freeing, until we've got 'em all */
 	while (count--) {
 
-		/* Getting interrupted means a leak, but ok at disconnect */
-		ret = down_interruptible(&dev->urbs.limit_sem);
+		/* Timeout likely occurs at disconnect (resulting in a leak) */
+		ret = down_timeout_killable(&dev->urbs.limit_sem,
+						FREE_URB_TIMEOUT);
 		if (ret)
 			break;
 
-- 
1.7.11.7

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