Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753863Ab3ILNWZ (ORCPT ); Thu, 12 Sep 2013 09:22:25 -0400 Received: from sam.nabble.com ([216.139.236.26]:59387 "EHLO sam.nabble.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751327Ab3ILNWY (ORCPT ); Thu, 12 Sep 2013 09:22:24 -0400 Date: Thu, 12 Sep 2013 06:22:24 -0700 (PDT) From: johnflux To: linux-kernel@vger.kernel.org Message-ID: <1378992144394-718779.post@n7.nabble.com> In-Reply-To: <52308D47.409@hurleysoftware.com> References: <52308D47.409@hurleysoftware.com> Subject: Re: Deadlock in fb and tty MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1832 Lines: 54 The following seems to be better: >From d93c1e9761ff66365d658da7d8d0d33823aa946f Mon Sep 17 00:00:00 2001 From: John Tapsell 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? -- View this message in context: http://linux-kernel.2935.n7.nabble.com/Deadlock-in-fb-and-tty-tp717929p718779.html Sent from the Linux Kernel mailing list archive at Nabble.com. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/