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fbdev: fix info->lock deadlock in fbcon_event_notify()

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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>
This commit is contained in:
Andrea Righi
2009-04-13 14:39:39 -07:00
committed by Linus Torvalds
parent b52bb3712a
commit 513adb5868
4 changed files with 22 additions and 58 deletions
Download Patch File Download Diff File Expand all files Collapse all files

55
drivers/video/console/fbcon.c
View File

@@ -2263,9 +2263,12 @@ static void fbcon_generic_blank(struct vc_data *vc, struct fb_info *info,
}
if (!lock_fb_info(info))
return;
event.info = info;
event.data = &blank;
fb_notifier_call_chain(FB_EVENT_CONBLANK, &event);
unlock_fb_info(info);
}
static int fbcon_blank(struct vc_data *vc, int blank, int mode_switch)
@@ -2956,8 +2959,6 @@ static int fbcon_fb_unregistered(struct fb_info *info)
{
int i, idx;
if (!lock_fb_info(info))
return -ENODEV;
idx = info->node;
for (i = first_fb_vc; i <= last_fb_vc; i++) {
if (con2fb_map[i] == idx)
@@ -2985,8 +2986,6 @@ static int fbcon_fb_unregistered(struct fb_info *info)
if (primary_device == idx)
primary_device = -1;
unlock_fb_info(info);
if (!num_registered_fb)
unregister_con_driver(&fb_con);
@@ -3027,11 +3026,8 @@ static int fbcon_fb_registered(struct fb_info *info)
{
int ret = 0, i, idx;
if (!lock_fb_info(info))
return -ENODEV;
idx = info->node;
fbcon_select_primary(info);
unlock_fb_info(info);
if (info_idx == -1) {
for (i = first_fb_vc; i <= last_fb_vc; i++) {
@@ -3152,53 +3148,23 @@ static int fbcon_event_notify(struct notifier_block *self,
switch(action) {
case FB_EVENT_SUSPEND:
if (!lock_fb_info(info)) {
ret = -ENODEV;
goto done;
}
fbcon_suspended(info);
unlock_fb_info(info);
break;
case FB_EVENT_RESUME:
if (!lock_fb_info(info)) {
ret = -ENODEV;
goto done;
}
fbcon_resumed(info);
unlock_fb_info(info);
break;
case FB_EVENT_MODE_CHANGE:
if (!lock_fb_info(info)) {
ret = -ENODEV;
goto done;
}
fbcon_modechanged(info);
unlock_fb_info(info);
break;
case FB_EVENT_MODE_CHANGE_ALL:
if (!lock_fb_info(info)) {
ret = -ENODEV;
goto done;
}
fbcon_set_all_vcs(info);
unlock_fb_info(info);
break;
case FB_EVENT_MODE_DELETE:
mode = event->data;
if (!lock_fb_info(info)) {
ret = -ENODEV;
goto done;
}
ret = fbcon_mode_deleted(info, mode);
unlock_fb_info(info);
break;
case FB_EVENT_FB_UNBIND:
if (!lock_fb_info(info)) {
ret = -ENODEV;
goto done;
}
idx = info->node;
unlock_fb_info(info);
ret = fbcon_fb_unbind(idx);
break;
case FB_EVENT_FB_REGISTERED:
@@ -3217,29 +3183,14 @@ static int fbcon_event_notify(struct notifier_block *self,
con2fb->framebuffer = con2fb_map[con2fb->console - 1];
break;
case FB_EVENT_BLANK:
if (!lock_fb_info(info)) {
ret = -ENODEV;
goto done;
}
fbcon_fb_blanked(info, *(int *)event->data);
unlock_fb_info(info);
break;
case FB_EVENT_NEW_MODELIST:
if (!lock_fb_info(info)) {
ret = -ENODEV;
goto done;
}
fbcon_new_modelist(info);
unlock_fb_info(info);
break;
case FB_EVENT_GET_REQ:
caps = event->data;
if (!lock_fb_info(info)) {
ret = -ENODEV;
goto done;
}
fbcon_get_requirement(info, caps);
unlock_fb_info(info);
break;
}
done: