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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

19
drivers/video/fbmem.c
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@@ -1097,8 +1097,11 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
return -EINVAL;
con2fb.framebuffer = -1;
event.data = &con2fb;
if (!lock_fb_info(info))
return -ENODEV;
event.info = info;
fb_notifier_call_chain(FB_EVENT_GET_CONSOLE_MAP, &event);
unlock_fb_info(info);
ret = copy_to_user(argp, &con2fb, sizeof(con2fb)) ? -EFAULT : 0;
break;
case FBIOPUT_CON2FBMAP:
@@ -1115,8 +1118,11 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
break;
}
event.data = &con2fb;
if (!lock_fb_info(info))
return -ENODEV;
event.info = info;
ret = fb_notifier_call_chain(FB_EVENT_SET_CONSOLE_MAP, &event);
unlock_fb_info(info);
break;
case FBIOBLANK:
if (!lock_fb_info(info))
@@ -1521,7 +1527,10 @@ register_framebuffer(struct fb_info *fb_info)
registered_fb[i] = fb_info;
event.info = fb_info;
if (!lock_fb_info(fb_info))
return -ENODEV;
fb_notifier_call_chain(FB_EVENT_FB_REGISTERED, &event);
unlock_fb_info(fb_info);
return 0;
}
@@ -1555,8 +1564,12 @@ unregister_framebuffer(struct fb_info *fb_info)
goto done;
}
if (!lock_fb_info(fb_info))
return -ENODEV;
event.info = fb_info;
ret = fb_notifier_call_chain(FB_EVENT_FB_UNBIND, &event);
unlock_fb_info(fb_info);
if (ret) {
ret = -EINVAL;
@@ -1590,6 +1603,8 @@ void fb_set_suspend(struct fb_info *info, int state)
{
struct fb_event event;
if (!lock_fb_info(info))
return;
event.info = info;
if (state) {
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;
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;
if (!list_empty(&info->modelist)) {
if (!lock_fb_info(info))
return -ENODEV;
event.info = info;
err = fb_notifier_call_chain(FB_EVENT_NEW_MODELIST, &event);
unlock_fb_info(info);
}
return err;