linux-kernel - [PATCH 08/16] [media] arv: fix sleep

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1393412516-3762435-9-git-send-email-arnd@arndb.de>
Date:	Wed, 26 Feb 2014 12:01:48 +0100
From:	Arnd Bergmann <arnd@...db.de>
To:	linux-kernel@...r.kernel.org
Cc:	Arnd Bergmann <arnd@...db.de>,
	Mauro Carvalho Chehab <m.chehab@...sung.com>,
	linux-media@...r.kernel.org
Subject: [PATCH 08/16] [media] arv: fix sleep_on race

interruptible_sleep_on is racy and going away. In the arv driver that
race has probably never caused problems since it would require a whole
video frame to be captured before the read function has a chance to
go to sleep, but using wait_event_interruptible lets us kill off the
old interface. In order to do this, we have to slightly adapt the
meaning of the ar->start_capture field to distinguish between not having
started a frame and having completed it.

Signed-off-by: Arnd Bergmann <arnd@...db.de>
Cc: Mauro Carvalho Chehab <m.chehab@...sung.com>
Cc: linux-media@...r.kernel.org
---
 drivers/media/platform/arv.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/media/platform/arv.c b/drivers/media/platform/arv.c
index e346d32d..e9410e4 100644
--- a/drivers/media/platform/arv.c
+++ b/drivers/media/platform/arv.c
@@ -109,7 +109,7 @@ extern struct cpuinfo_m32r	boot_cpu_data;
 struct ar {
 	struct v4l2_device v4l2_dev;
 	struct video_device vdev;
-	unsigned int start_capture;	/* duaring capture in INT. mode. */
+	int start_capture;	/* duaring capture in INT. mode. */
 #if USE_INT
 	unsigned char *line_buff;	/* DMA line buffer */
 #endif
@@ -307,11 +307,11 @@ static ssize_t ar_read(struct file *file, char *buf, size_t count, loff_t *ppos)
 	/*
 	 * Okay, kick AR LSI to invoke an interrupt
 	 */
-	ar->start_capture = 0;
+	ar->start_capture = -1;
 	ar_outl(arvcr1 | ARVCR1_HIEN, ARVCR1);
 	local_irq_restore(flags);
 	/* .... AR interrupts .... */
-	interruptible_sleep_on(&ar->wait);
+	wait_event_interruptible(ar->wait, ar->start_capture == 0);
 	if (signal_pending(current)) {
 		printk(KERN_ERR "arv: interrupted while get frame data.\n");
 		ret = -EINTR;
-- 
1.8.3.2

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/