Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762186Ab2FHRDt (ORCPT ); Fri, 8 Jun 2012 13:03:49 -0400 Received: from mx1.redhat.com ([209.132.183.28]:62070 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761333Ab2FHRDr (ORCPT ); Fri, 8 Jun 2012 13:03:47 -0400 Date: Fri, 8 Jun 2012 19:01:52 +0200 From: Oleg Nesterov To: Konstantin Khlebnikov Cc: Hugh Dickins , Linus Torvalds , "akpm@linux-foundation.org" , Linux Kernel Mailing List , linux-mm , "kamezawa.hiroyu@jp.fujitsu.com" , "markus@trippelsdorf.de" , "stable@vger.kernel.org" Subject: Re: [patch 12/12] mm: correctly synchronize rss-counters at exit/exec Message-ID: <20120608170152.GA30975@redhat.com> References: <20120607212114.E4F5AA02F8@akpm.mtv.corp.google.com> <4FD1D1F7.2090503@openvz.org> <20120608122459.GB23147@redhat.com> <4FD1FE20.40600@openvz.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4FD1FE20.40600@openvz.org> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1132 Lines: 29 On 06/08, Konstantin Khlebnikov wrote: > > Oleg Nesterov wrote: >> On 06/08, Konstantin Khlebnikov wrote: >>> >>> As result you can see "BUG: Bad rss-counter state mm:ffff88040783a680 idx:1 val:-1" in dmesg >>> >>> There left only one problem: nobody calls sync_mm_rss() after put_user() in mm_release(). >> >> Both callers call sync_mm_rss() to make check_mm() happy. But please >> see the changelog, I think we should move it into mm_release(). See >> the patch below (on top of v2 I sent). I need to recheck. > > Patch below broken: it removes one hunk from kernel/exit.c twice. > And it does not add anything into mm_release(). Yes, sorry. But I guess you understand the intent, mm_release() should simply do sync_mm_rss() after put_user(clear_child_tid) unconditionally. If task->mm == NULL but task->rss_stat, then there is something wrong and probably OOPS makes sense. Oleg. -- 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/