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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

3
drivers/video/backlight/backlight.c
View File

@@ -35,8 +35,6 @@ static int fb_notifier_callback(struct notifier_block *self,
return 0; return 0;
bd = container_of(self, struct backlight_device, fb_notif); bd = container_of(self, struct backlight_device, fb_notif);
if (!lock_fb_info(evdata->info))
return -ENODEV;
mutex_lock(&bd->ops_lock); mutex_lock(&bd->ops_lock);
if (bd->ops) if (bd->ops)
if (!bd->ops->check_fb || if (!bd->ops->check_fb ||
@@ -49,7 +47,6 @@ static int fb_notifier_callback(struct notifier_block *self,
backlight_update_status(bd); backlight_update_status(bd);
} }
mutex_unlock(&bd->ops_lock); mutex_unlock(&bd->ops_lock);
unlock_fb_info(evdata->info);
return 0; return 0;
} }

3
drivers/video/backlight/lcd.c
View File

@@ -40,8 +40,6 @@ static int fb_notifier_callback(struct notifier_block *self,
if (!ld->ops) if (!ld->ops)
return 0; return 0;
if (!lock_fb_info(evdata->info))
return -ENODEV;
mutex_lock(&ld->ops_lock); mutex_lock(&ld->ops_lock);
if (!ld->ops->check_fb || ld->ops->check_fb(ld, evdata->info)) { if (!ld->ops->check_fb || ld->ops->check_fb(ld, evdata->info)) {
if (event == FB_EVENT_BLANK) { if (event == FB_EVENT_BLANK) {
@@ -53,7 +51,6 @@ static int fb_notifier_callback(struct notifier_block *self,
} }
} }
mutex_unlock(&ld->ops_lock); mutex_unlock(&ld->ops_lock);
unlock_fb_info(evdata->info);
return 0; return 0;
} }

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

19
drivers/video/fbmem.c
View File

@@ -1097,8 +1097,11 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
return -EINVAL; return -EINVAL;
con2fb.framebuffer = -1; con2fb.framebuffer = -1;
event.data = &con2fb; event.data = &con2fb;
if (!lock_fb_info(info))
return -ENODEV;
event.info = info; event.info = info;
fb_notifier_call_chain(FB_EVENT_GET_CONSOLE_MAP, &event); fb_notifier_call_chain(FB_EVENT_GET_CONSOLE_MAP, &event);
unlock_fb_info(info);
ret = copy_to_user(argp, &con2fb, sizeof(con2fb)) ? -EFAULT : 0; ret = copy_to_user(argp, &con2fb, sizeof(con2fb)) ? -EFAULT : 0;
break; break;
case FBIOPUT_CON2FBMAP: case FBIOPUT_CON2FBMAP:
@@ -1115,8 +1118,11 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
break; break;
} }
event.data = &con2fb; event.data = &con2fb;
if (!lock_fb_info(info))
return -ENODEV;
event.info = info; event.info = info;
ret = fb_notifier_call_chain(FB_EVENT_SET_CONSOLE_MAP, &event); ret = fb_notifier_call_chain(FB_EVENT_SET_CONSOLE_MAP, &event);
unlock_fb_info(info);
break; break;
case FBIOBLANK: case FBIOBLANK:
if (!lock_fb_info(info)) if (!lock_fb_info(info))
@@ -1521,7 +1527,10 @@ register_framebuffer(struct fb_info *fb_info)
registered_fb[i] = fb_info; registered_fb[i] = fb_info;
event.info = fb_info; event.info = fb_info;
if (!lock_fb_info(fb_info))
return -ENODEV;
fb_notifier_call_chain(FB_EVENT_FB_REGISTERED, &event); fb_notifier_call_chain(FB_EVENT_FB_REGISTERED, &event);
unlock_fb_info(fb_info);
return 0; return 0;
} }
@@ -1555,8 +1564,12 @@ unregister_framebuffer(struct fb_info *fb_info)
goto done; goto done;
} }
if (!lock_fb_info(fb_info))
return -ENODEV;
event.info = fb_info; event.info = fb_info;
ret = fb_notifier_call_chain(FB_EVENT_FB_UNBIND, &event); ret = fb_notifier_call_chain(FB_EVENT_FB_UNBIND, &event);
unlock_fb_info(fb_info);
if (ret) { if (ret) {
ret = -EINVAL; ret = -EINVAL;
@@ -1590,6 +1603,8 @@ void fb_set_suspend(struct fb_info *info, int state)
{ {
struct fb_event event; struct fb_event event;
if (!lock_fb_info(info))
return;
event.info = info; event.info = info;
if (state) { if (state) {
fb_notifier_call_chain(FB_EVENT_SUSPEND, &event); fb_notifier_call_chain(FB_EVENT_SUSPEND, &event);
@@ -1598,6 +1613,7 @@ void fb_set_suspend(struct fb_info *info, int state)
info->state = FBINFO_STATE_RUNNING; info->state = FBINFO_STATE_RUNNING;
fb_notifier_call_chain(FB_EVENT_RESUME, &event); fb_notifier_call_chain(FB_EVENT_RESUME, &event);
} }
unlock_fb_info(info);
} }
/** /**
@@ -1667,8 +1683,11 @@ int fb_new_modelist(struct fb_info *info)
err = 1; err = 1;
if (!list_empty(&info->modelist)) { if (!list_empty(&info->modelist)) {
if (!lock_fb_info(info))
return -ENODEV;
event.info = info; event.info = info;
err = fb_notifier_call_chain(FB_EVENT_NEW_MODELIST, &event); err = fb_notifier_call_chain(FB_EVENT_NEW_MODELIST, &event);
unlock_fb_info(info);
} }
return err; return err;