Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754871AbYLIS1w (ORCPT ); Tue, 9 Dec 2008 13:27:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754115AbYLIS1o (ORCPT ); Tue, 9 Dec 2008 13:27:44 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:43515 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753483AbYLIS1n (ORCPT ); Tue, 9 Dec 2008 13:27:43 -0500 Date: Tue, 9 Dec 2008 19:27:24 +0100 From: Ingo Molnar To: Brian King Cc: a.p.zijlstra@chello.nl, efault@gmx.de, vatsa@in.ibm.com, balbir@linux.vnet.ibm.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/1] sched: CPU remove deadlock fix Message-ID: <20081209182724.GB21698@elte.hu> References: <200812091548.mB9Fm0sm011959@d01av04.pok.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200812091548.mB9Fm0sm011959@d01av04.pok.ibm.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1812 Lines: 40 * Brian King wrote: > This patch fixes a possible deadlock scenario in the CPU remove path. > migration_call grabs rq->lock, then wakes up everything on > rq->migration_queue with the lock held. Then one of the tasks on the > migration queue ends up calling tg_shares_up which then also tries to > acquire the same rq->lock. > > [c000000058eab2e0] c000000000502078 ._spin_lock_irqsave+0x98/0xf0 > [c000000058eab370] c00000000008011c .tg_shares_up+0x10c/0x20c > [c000000058eab430] c00000000007867c .walk_tg_tree+0xc4/0xfc > [c000000058eab4d0] c0000000000840c8 .try_to_wake_up+0xb0/0x3c4 > [c000000058eab590] c0000000000799a0 .__wake_up_common+0x6c/0xe0 > [c000000058eab640] c00000000007ada4 .complete+0x54/0x80 > [c000000058eab6e0] c000000000509fa8 .migration_call+0x5fc/0x6f8 > [c000000058eab7c0] c000000000504074 .notifier_call_chain+0x68/0xe0 > [c000000058eab860] c000000000506568 ._cpu_down+0x2b0/0x3f4 > [c000000058eaba60] c000000000506750 .cpu_down+0xa4/0x108 > [c000000058eabb10] c000000000507e54 .store_online+0x44/0xa8 > [c000000058eabba0] c000000000396260 .sysdev_store+0x3c/0x50 > [c000000058eabc10] c0000000001a39b8 .sysfs_write_file+0x124/0x18c > [c000000058eabcd0] c00000000013061c .vfs_write+0xd0/0x1bc > [c000000058eabd70] c0000000001308a4 .sys_write+0x68/0x114 > [c000000058eabe30] c0000000000086b4 syscall_exit+0x0/0x40 > > Signed-off-by: Brian King > --- > > kernel/sched.c | 2 ++ > 1 file changed, 2 insertions(+) good catch - applied to tip/sched/urgent, thanks Brian! Ingo -- 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/