Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757878Ab0HQQPf (ORCPT ); Tue, 17 Aug 2010 12:15:35 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:40307 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751957Ab0HQQPd convert rfc822-to-8bit (ORCPT ); Tue, 17 Aug 2010 12:15:33 -0400 MIME-Version: 1.0 In-Reply-To: <20100816.211218.189709876.davem@davemloft.net> References: <20100816.211218.189709876.davem@davemloft.net> From: Linus Torvalds Date: Tue, 17 Aug 2010 09:14:37 -0700 Message-ID: Subject: Re: tasks getting stuck on mmap_sem? To: David Miller , Michel Lespinasse , David Howells , Andrew Morton Cc: linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2170 Lines: 45 On Mon, Aug 16, 2010 at 9:12 PM, David Miller wrote: > > I just started seeing this with current GIT, is it related > to the page table locking shuffle of a few days ago? No. Looks like the rwsem changes broke sparc too. ia64 had some problems too. ia64 had the type problems, but even after they were fixed there was reports of something similar. So I am starting to suspect that there is something more serious going on here - possibly hidden on x86 due to the strong memory ordering. And possibly just because mmap_sem is _mostly_ just used by a single thread. Threaded apps are still uncommon. Adding the guilty parties to the cc, leaving your backtrace quoted. Linus --- > [21029.265646] INFO: task git:16643 blocked for more than 120 seconds. > [21029.267054] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > [21029.268412] git ? ? ? ? ? D 000000000072f804 ? ? 0 16643 ?16273 0x210001101000080 > [21029.269809] Call Trace: > [21029.271062] ?[000000000072f778] rwsem_down_failed_common+0x90/0xb8 > [21029.272390] ?[000000000072f804] __down_read+0x30/0x40 > [21029.273689] ?[0000000000731148] do_sparc64_fault+0x238/0x788 > [21029.274996] ?[00000000004079e8] sparc64_realfault_common+0x10/0x20 > [21029.276347] INFO: task git:16644 blocked for more than 120 seconds. > [21029.277655] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > [21029.278993] git ? ? ? ? ? D 000000000072f874 ? ? 0 16644 ?16273 0x210041101000080 > [21029.280348] Call Trace: > [21029.281542] ?[000000000072f778] rwsem_down_failed_common+0x90/0xb8 > [21029.282818] ?[000000000072f874] __down_write+0x34/0x44 > [21029.284057] ?[00000000004d9c44] SyS_mmap_pgoff+0xc8/0x118 > [21029.285293] ?[0000000000406154] linux_sparc_syscall32+0x34/0x40 > ?... > > etc. ?it's a set of git threads computing deltas for a remote pull > request to the machine. > -- 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/