linux-kernel - [PATCH] [drivers/video/fb] Eliminate recursive mutex in compat fb ioctl path

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 for Android: free password hash cracker in your pocket

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

Date:	Sun,  2 Nov 2008 23:06:50 -0800
From:	Keith Packard <keithp@...thp.com>
To:	linux-kernel@...r.kernel.org
Cc:	Keith Packard <keithp@...thp.com>
Subject: [PATCH] [drivers/video/fb] Eliminate recursive mutex in compat fb ioctl path

fb_compat_ioctl grabbed the fb mutex and then called fb_ioctl, which also
grabs the same mutex. I traced through all existing fb_compat_ioctl
functions in the various fb drivers and found that they also transform their
arguments and call the native fb_ioctl function. So, it is correct to just
remove the mutex_lock/mutex_unlock pair in the top-level compat path.

Signed-off-by: Keith Packard <keithp@...thp.com>
---
 drivers/video/fbmem.c |    2 --
 1 files changed, 0 insertions(+), 2 deletions(-)

diff --git a/drivers/video/fbmem.c b/drivers/video/fbmem.c
index cd5f20d..548cf26 100644
--- a/drivers/video/fbmem.c
+++ b/drivers/video/fbmem.c
@@ -1253,7 +1253,6 @@ fb_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	struct fb_ops *fb = info->fbops;
 	long ret = -ENOIOCTLCMD;
 
-	mutex_lock(&info->lock);
 	switch(cmd) {
 	case FBIOGET_VSCREENINFO:
 	case FBIOPUT_VSCREENINFO:
@@ -1279,7 +1278,6 @@ fb_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 			ret = fb->fb_compat_ioctl(info, cmd, arg);
 		break;
 	}
-	mutex_unlock(&info->lock);
 	return ret;
 }
 #endif
-- 
1.5.6.5

--
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/