From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753636AbeDRLdE (ORCPT ); Wed, 18 Apr 2018 07:33:04 -0400 Received: from mx2.suse.de ([195.135.220.15]:53603 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753520AbeDRLdD (ORCPT ); Wed, 18 Apr 2018 07:33:03 -0400 Date: Wed, 18 Apr 2018 13:33:01 +0200 From: Michal Hocko To: Tetsuo Handa Cc: Andrew Morton , linux-mm@kvack.org, LKML Subject: Re: [PATCH 2/2] fs, elf: drop MAP_FIXED usage from elf_map Message-ID: <20180418113301.GY17484@dhcp22.suse.cz> References: <20171213092550.2774-1-mhocko@kernel.org> <20171213092550.2774-3-mhocko@kernel.org> <0b5c541a-91ee-220b-3196-f64264f9f0bc@I-love.SAKURA.ne.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0b5c541a-91ee-220b-3196-f64264f9f0bc@I-love.SAKURA.ne.jp> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 18-04-18 19:51:05, Tetsuo Handa wrote: > >From 0ba20dcbbc40b703413c9a6907a77968b087811b Mon Sep 17 00:00:00 2001 > From: Tetsuo Handa > Date: Wed, 18 Apr 2018 15:31:48 +0900 > Subject: [PATCH] fs, elf: don't complain MAP_FIXED_NOREPLACE if mapping > failed. > > Commit 4ed28639519c7bad ("fs, elf: drop MAP_FIXED usage from elf_map") is > printing spurious messages under memory pressure due to map_addr == -ENOMEM. > > 9794 (a.out): Uhuuh, elf segment at 00007f2e34738000(fffffffffffffff4) requested but the memory is mapped already > 14104 (a.out): Uhuuh, elf segment at 00007f34fd76c000(fffffffffffffff4) requested but the memory is mapped already > 16843 (a.out): Uhuuh, elf segment at 00007f930ecc7000(fffffffffffffff4) requested but the memory is mapped already Hmm this is ENOMEM. > Don't complain if IS_ERR_VALUE(), this is simply wrong. We do want to warn on the failure because this is when the actual clash happens. We should just warn on EEXIST. > and use %px for printing the address. > > Signed-off-by: Tetsuo Handa > Cc: Michal Hocko > Cc: Andrei Vagin > Cc: Khalid Aziz > Cc: Michael Ellerman > Cc: Kees Cook > Cc: Abdul Haleem > Cc: Joel Stanley > Cc: Anshuman Khandual > --- > fs/binfmt_elf.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c > index 41e0418..559d35b 100644 > --- a/fs/binfmt_elf.c > +++ b/fs/binfmt_elf.c > @@ -377,10 +377,10 @@ static unsigned long elf_map(struct file *filep, unsigned long addr, > } else > map_addr = vm_mmap(filep, addr, size, prot, type, off); > > - if ((type & MAP_FIXED_NOREPLACE) && BAD_ADDR(map_addr)) > - pr_info("%d (%s): Uhuuh, elf segment at %p requested but the memory is mapped already\n", > - task_pid_nr(current), current->comm, > - (void *)addr); > + if ((type & MAP_FIXED_NOREPLACE) && BAD_ADDR(map_addr) && > + !IS_ERR_VALUE(map_addr)) > + pr_info("%d (%s): Uhuuh, elf segment at %px requested but the memory is mapped already\n", > + task_pid_nr(current), current->comm, (void *)addr); > > return(map_addr); > } > -- > 1.8.3.1 > > -- Michal Hocko SUSE Labs