From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx128.postini.com [74.125.245.128]) by kanga.kvack.org (Postfix) with SMTP id A71946B0044 for ; Mon, 2 Apr 2012 12:27:39 -0400 (EDT) Received: by bkwq16 with SMTP id q16so3165448bkw.14 for ; Mon, 02 Apr 2012 09:27:37 -0700 (PDT) Date: Mon, 2 Apr 2012 20:27:33 +0400 From: Cyrill Gorcunov Subject: Re: [PATCH 6/7] mm: kill vma flag VM_EXECUTABLE Message-ID: <20120402162733.GI7607@moon> References: <20120331091049.19373.28994.stgit@zurg> <20120331092929.19920.54540.stgit@zurg> <20120331201324.GA17565@redhat.com> <20120331203912.GB687@moon> <4F79755B.3030703@openvz.org> <20120402144821.GA3334@redhat.com> <4F79D1AF.7080100@openvz.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4F79D1AF.7080100@openvz.org> Sender: owner-linux-mm@kvack.org List-ID: To: Konstantin Khlebnikov , Oleg Nesterov Cc: "linux-mm@kvack.org" , Andrew Morton , "linux-kernel@vger.kernel.org" , Eric Paris On Mon, Apr 02, 2012 at 08:19:59PM +0400, Konstantin Khlebnikov wrote: > Oleg Nesterov wrote: > >On 04/02, Konstantin Khlebnikov wrote: > >> > >>In this patch I leave mm->exe_file lockless. > >>After exec/fork we can change it only for current task and only if mm->mm_users == 1. > >> > >>something like this: > >> > >>task_lock(current); > > > >OK, this protects against the race with get_task_mm() > > > >>if (atomic_read(¤t->mm->mm_users) == 1) > > > >this means PR_SET_MM_EXE_FILE can fail simply because someone did > >get_task_mm(). Or the caller is multithreaded. > > This is sad, seems like we should keep mm->exe_file protection by mm->mmap_sem. > So, I'll rework this patch... Ah, it's about locking. I misundertand it at first. Oleg, forget about my email then. Cyrill -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org