Messages in this thread Patch in this message | | | Date | Thu, 12 Sep 2013 06:22:24 -0700 (PDT) | From | johnflux <> | Subject | Re: Deadlock in fb and tty |
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The following seems to be better:
From d93c1e9761ff66365d658da7d8d0d33823aa946f Mon Sep 17 00:00:00 2001 From: John Tapsell <johnflux@gmail.com> Date: Thu, 12 Sep 2013 09:16:12 +0100 Subject: [PATCH] Fix deadlock between fb_info and console. Do not lock fb_info when calling sending the FB_EVENT_CONBLANK
In fbmem.c, the semantics are that we acquire the lock_fb_info first, and then console_lock. However when fbcon.c fbcon_generic_blank() is called, the console lock could already be held. Locking fb_info can thus cause a deadlock.
fbmem.c sends the FB_EVENT_BLANK without locking lock_fb_info first, so this change introduces similar behaviour. --- drivers/video/console/fbcon.c | 4 ---- 1 file changed, 4 deletions(-)
diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c index 6b4fb5c..8546441 100644 --- a/drivers/video/console/fbcon.c +++ b/drivers/video/console/fbcon.c @@ -2333,13 +2333,9 @@ static void fbcon_generic_blank(struct vc_data *vc, struct fb_info *info, vc->vc_video_erase_char = oldc; } - - if (!lock_fb_info(info)) - return; event.info = info; event.data = ␣ 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) -- 1.8.1.2
How can I get this reviewed/acked please?
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