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authorAndrea Righi <righi.andrea@gmail.com>2009-04-13 14:39:39 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-04-13 15:04:28 -0700
commit513adb58685615b0b1d47a3f0d40f5352beff189 (patch)
tree80afe08d17f24bbf3d5ad48d62df2e143d00ae95 /drivers/video/backlight
parentb52bb3712a64c404846f30300b339cfd01e316be (diff)
fbdev: fix info->lock deadlock in fbcon_event_notify()
fb_notifier_call_chain() is called with info->lock held, i.e. in do_fb_ioctl() => FBIOPUT_VSCREENINFO => fb_set_var() and the some notifier callbacks, like fbcon_event_notify(), try to re-acquire info->lock again. Remove the lock/unlock_fb_info() in all the framebuffer notifier callbacks' and be sure to always call fb_notifier_call_chain() with info->lock held. Reported-by: Pavel Roskin <proski@gnu.org> Reported-by: Eric Miao <eric.y.miao@gmail.com> Signed-off-by: Andrea Righi <righi.andrea@gmail.com> Cc: Stefan Richter <stefanr@s5r6.in-berlin.de> Cc: Krzysztof Helt <krzysztof.h1@poczta.fm> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/video/backlight')
-rw-r--r--drivers/video/backlight/backlight.c3
-rw-r--r--drivers/video/backlight/lcd.c3
2 files changed, 0 insertions, 6 deletions
diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c
index dd37cbcaf8c..157057c79ca 100644
--- a/drivers/video/backlight/backlight.c
+++ b/drivers/video/backlight/backlight.c
@@ -35,8 +35,6 @@ static int fb_notifier_callback(struct notifier_block *self,
return 0;
bd = container_of(self, struct backlight_device, fb_notif);
- if (!lock_fb_info(evdata->info))
- return -ENODEV;
mutex_lock(&bd->ops_lock);
if (bd->ops)
if (!bd->ops->check_fb ||
@@ -49,7 +47,6 @@ static int fb_notifier_callback(struct notifier_block *self,
backlight_update_status(bd);
}
mutex_unlock(&bd->ops_lock);
- unlock_fb_info(evdata->info);
return 0;
}
diff --git a/drivers/video/backlight/lcd.c b/drivers/video/backlight/lcd.c
index 0bb13df0fa8..b6449470106 100644
--- a/drivers/video/backlight/lcd.c
+++ b/drivers/video/backlight/lcd.c
@@ -40,8 +40,6 @@ static int fb_notifier_callback(struct notifier_block *self,
if (!ld->ops)
return 0;
- if (!lock_fb_info(evdata->info))
- return -ENODEV;
mutex_lock(&ld->ops_lock);
if (!ld->ops->check_fb || ld->ops->check_fb(ld, evdata->info)) {
if (event == FB_EVENT_BLANK) {
@@ -53,7 +51,6 @@ static int fb_notifier_callback(struct notifier_block *self,
}
}
mutex_unlock(&ld->ops_lock);
- unlock_fb_info(evdata->info);
return 0;
}