From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752843AbdHJPX4 (ORCPT ); Thu, 10 Aug 2017 11:23:56 -0400 Received: from mx2.suse.de ([195.135.220.15]:56697 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752168AbdHJPXz (ORCPT ); Thu, 10 Aug 2017 11:23:55 -0400 Date: Thu, 10 Aug 2017 17:23:52 +0200 From: Michal Hocko To: riel@redhat.com Cc: linux-kernel@vger.kernel.org, mike.kravetz@oracle.com, linux-mm@kvack.org, fweimer@redhat.com, colm@allcosts.net, akpm@linux-foundation.org, keescook@chromium.org, luto@amacapital.net, wad@chromium.org, mingo@kernel.org, kirill@shutemov.name, dave.hansen@intel.com Subject: Re: [PATCH 2/2] mm,fork: introduce MADV_WIPEONFORK Message-ID: <20170810152352.GZ23863@dhcp22.suse.cz> References: <20170806140425.20937-1-riel@redhat.com> <20170806140425.20937-3-riel@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170806140425.20937-3-riel@redhat.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun 06-08-17 10:04:25, Rik van Riel wrote: [...] > diff --git a/kernel/fork.c b/kernel/fork.c > index 17921b0390b4..db1fb2802ecc 100644 > --- a/kernel/fork.c > +++ b/kernel/fork.c > @@ -659,6 +659,13 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm, > tmp->vm_flags &= ~(VM_LOCKED | VM_LOCKONFAULT); > tmp->vm_next = tmp->vm_prev = NULL; > file = tmp->vm_file; > + > + /* With VM_WIPEONFORK, the child gets an empty VMA. */ > + if (tmp->vm_flags & VM_WIPEONFORK) { > + tmp->vm_file = file = NULL; > + tmp->vm_ops = NULL; > + } What about VM_SHARED/|VM)MAYSHARE flags. Is it OK to keep the around? At least do_anonymous_page SIGBUS on !vm_ops && VM_SHARED. Or do I miss where those flags are cleared? > + > if (file) { > struct inode *inode = file_inode(file); > struct address_space *mapping = file->f_mapping; -- Michal Hocko SUSE Labs