Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756091Ab1DMMTN (ORCPT ); Wed, 13 Apr 2011 08:19:13 -0400 Received: from mail-pz0-f46.google.com ([209.85.210.46]:50140 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755673Ab1DMMTL convert rfc822-to-8bit (ORCPT ); Wed, 13 Apr 2011 08:19:11 -0400 MIME-Version: 1.0 In-Reply-To: References: <20110412182809.GA1218@redhat.com> <20110412192059.GA14360@redhat.com> Date: Wed, 13 Apr 2011 14:19:10 +0200 Message-ID: Subject: Re: Processes hang in an unkillable state From: =?UTF-8?B?Um9iZXJ0IMWad2nEmWNraQ==?= To: Linus Torvalds Cc: Oleg Nesterov , =?UTF-8?Q?Am=C3=A9rico_Wang?= , linux-kernel@vger.kernel.org, Hugh Dickins , Miklos Szeredi Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1539 Lines: 34 On Wed, Apr 13, 2011 at 12:43 AM, Linus Torvalds wrote: >> btw, here might be another path which hits this (at least I think so). > > So both mprotect and mlock will do the same "split/merge vma's as > necessary", but neither of them should actually ever _expand_ a > mapping or change the vm_pgoff of a vma (except to fix up the pgoff as > a vma is split). > > So what I think is happening is that a previous vma operation (like > the mremap or the stack expansion) did the expand and created a vma > with a wrapping vm_pgoff. But nothing bad happened, because nobody > really _cares_ about the wrapping until later, when we split the vma. > > So I think (and hope) that your mprotect issue is exactly the same as > your mlock issue, and that the deeper problem was the earlier stack > expansion. So, after ~12h of testing I don't see any crashes. Currently, I'm testing with 2.6.39-rc3 with 2 of your patches applied (1st patching mlock.c/memory.c, 2nd: mmap.c). It's still crashing with sys_madvise (as reported earlier), and I'm going to re-enable all syscalls now (madvise, getdents(64), readdir), which were disabled before. If something unrelated to the problems discussed in this thread happens, I'll report it in another thread. -- Robert Święcki -- 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/