From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753439Ab0K2Ll1 (ORCPT ); Mon, 29 Nov 2010 06:41:27 -0500 Received: from mx1.redhat.com ([209.132.183.28]:25146 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751860Ab0K2Ll0 (ORCPT ); Mon, 29 Nov 2010 06:41:26 -0500 Date: Mon, 29 Nov 2010 12:33:57 +0100 From: Oleg Nesterov To: KOSAKI Motohiro Cc: Andrew Morton , Linus Torvalds , LKML , linux-mm , pageexec@freemail.hu, Solar Designer , Eugene Teo , Brad Spengler , Roland McGrath Subject: Re: [resend][PATCH 4/4] oom: don't ignore rss in nascent mm Message-ID: <20101129113357.GA30657@redhat.com> References: <20101125140253.GA29371@redhat.com> <20101125193659.GA14510@redhat.com> <20101129093803.829F.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20101129093803.829F.A69D9226@jp.fujitsu.com> 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 On 11/29, KOSAKI Motohiro wrote: > > > The patch is not complete, compat_copy_strings() needs changes. > > But, shouldn't it use get_arg_page() too? Otherwise, where do > > we check RLIMIT_STACK? > > Because NOMMU doesn't have variable length argv. Instead it is still > using MAX_ARG_STRLEN as old MMU code. > > 32 pages hard coded argv limitation naturally prevent this nascent mm > issue. Ah, I didn't mean NOMMU. I meant compat_execve()->compat_copy_strings(). If a 32bit process execs we seem to miss the RLIMIT_STACK check, no? > > The patch asks for the cleanups. In particular, I think exec_mmap() > > should accept bprm, not mm. But I'd prefer to do this later. > > > > Oleg. > > General request. Please consider to keep Brad's reported-by tag. Yes, yes, sure. > > +static void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) OK. > Please move this function into #ifdef CONFIG_MMU. nommu code doesn't use it. Well it does, to revert the MM_ANONPAGES counter. I'll add the empty function for NOMMU. > > +{ > > + struct mm_struct *mm = current->mm; > > + long diff = pages - bprm->vma_pages; > > I prefer to cast signed before assignment. It's safer more. OK. > > @@ -1003,6 +1024,7 @@ int flush_old_exec(struct linux_binprm * > > /* > > * Release all of the old mmap stuff > > */ > > + acct_arg_size(bprm, 0); > > Why do we need this unacct here? I mean 1) if exec_mmap() is success, > we don't need unaccount at all Yes, we already killed all sub-threads. But this doesn't mean nobody else can use current->mm, think about CLONE_VM. The simplest example is vfork(). > 2) if exec_mmap() is failure, an epilogue of > do_execve() does unaccount thing. Yes. Thanks Kosaki! I'll resend v2 today. I am still not sure about compat_copy_strings()... Oleg. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with SMTP id 531DB6B00AA for ; Mon, 29 Nov 2010 06:40:57 -0500 (EST) Date: Mon, 29 Nov 2010 12:33:57 +0100 From: Oleg Nesterov Subject: Re: [resend][PATCH 4/4] oom: don't ignore rss in nascent mm Message-ID: <20101129113357.GA30657@redhat.com> References: <20101125140253.GA29371@redhat.com> <20101125193659.GA14510@redhat.com> <20101129093803.829F.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20101129093803.829F.A69D9226@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org To: KOSAKI Motohiro Cc: Andrew Morton , Linus Torvalds , LKML , linux-mm , pageexec@freemail.hu, Solar Designer , Eugene Teo , Brad Spengler , Roland McGrath List-ID: On 11/29, KOSAKI Motohiro wrote: > > > The patch is not complete, compat_copy_strings() needs changes. > > But, shouldn't it use get_arg_page() too? Otherwise, where do > > we check RLIMIT_STACK? > > Because NOMMU doesn't have variable length argv. Instead it is still > using MAX_ARG_STRLEN as old MMU code. > > 32 pages hard coded argv limitation naturally prevent this nascent mm > issue. Ah, I didn't mean NOMMU. I meant compat_execve()->compat_copy_strings(). If a 32bit process execs we seem to miss the RLIMIT_STACK check, no? > > The patch asks for the cleanups. In particular, I think exec_mmap() > > should accept bprm, not mm. But I'd prefer to do this later. > > > > Oleg. > > General request. Please consider to keep Brad's reported-by tag. Yes, yes, sure. > > +static void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) OK. > Please move this function into #ifdef CONFIG_MMU. nommu code doesn't use it. Well it does, to revert the MM_ANONPAGES counter. I'll add the empty function for NOMMU. > > +{ > > + struct mm_struct *mm = current->mm; > > + long diff = pages - bprm->vma_pages; > > I prefer to cast signed before assignment. It's safer more. OK. > > @@ -1003,6 +1024,7 @@ int flush_old_exec(struct linux_binprm * > > /* > > * Release all of the old mmap stuff > > */ > > + acct_arg_size(bprm, 0); > > Why do we need this unacct here? I mean 1) if exec_mmap() is success, > we don't need unaccount at all Yes, we already killed all sub-threads. But this doesn't mean nobody else can use current->mm, think about CLONE_VM. The simplest example is vfork(). > 2) if exec_mmap() is failure, an epilogue of > do_execve() does unaccount thing. Yes. Thanks Kosaki! I'll resend v2 today. I am still not sure about compat_copy_strings()... Oleg. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . 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