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13 July 2024, 08:20:57 UTC
Revision 1f5e31d7e55ac7fbd4ec5e5b20c8868b0e4564c9 authored by Andrea Righi on 04 February 2009, 23:12:03 UTC, committed by Linus Torvalds on 05 February 2009, 20:56:46 UTC 
fbmem: don't call copy_from/to_user() with mutex held
 
Avoid calling copy_from/to_user() with fb_info->lock mutex held in fbmem
ioctl().

fb_mmap() is called under mm->mmap_sem (A) held, that also acquires
fb_info->lock (B); fb_ioctl() takes fb_info->lock (B) and does
copy_from/to_user() that might acquire mm->mmap_sem (A), causing a
deadlock.

NOTE: it doesn't push down the fb_info->lock in each own driver's
fb_ioctl(), so there are still potential deadlocks elsewhere.

Signed-off-by: Andrea Righi <righi.andrea@gmail.com>
Cc: Dave Jones <davej@redhat.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Johannes Weiner <hannes@saeurebad.de>
Cc: Krzysztof Helt <krzysztof.h1@wp.pl>
Cc: Harvey Harrison <harvey.harrison@gmail.com>
Cc: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent afd8d0f
History
Tip revision: 1f5e31d7e55ac7fbd4ec5e5b20c8868b0e4564c9 authored by Andrea Righi on 04 February 2009, 23:12:03 UTC
fbmem: don't call copy_from/to_user() with mutex held
Tip revision: 1f5e31d
File Mode Size
Documentation
arch
block
crypto
drivers
firmware
fs
include
init
ipc
kernel
lib
mm
net
samples
scripts
security
sound
usr
virt
.gitignore -rw-r--r-- 867 bytes
.mailmap -rw-r--r-- 3.9 KB
COPYING -rw-r--r-- 18.3 KB
CREDITS -rw-r--r-- 91.3 KB
Kbuild -rw-r--r-- 2.4 KB
MAINTAINERS -rw-r--r-- 106.5 KB
Makefile -rw-r--r-- 53.2 KB
README -rw-r--r-- 16.7 KB
REPORTING-BUGS -rw-r--r-- 3.1 KB

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