From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752618AbeFEOss (ORCPT ); Tue, 5 Jun 2018 10:48:48 -0400 Received: from mail-it0-f65.google.com ([209.85.214.65]:33073 "EHLO mail-it0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752432AbeFEOsq (ORCPT ); Tue, 5 Jun 2018 10:48:46 -0400 X-Google-Smtp-Source: ADUXVKLYPQ8yIdXaanmpbDf58TiIUcHmm5WnVPsMnpNOUOeBGeMx5lertN0mD81loRoRJGMy5IXFRQ== Subject: Re: dm: Use kzalloc for all structs with embedded biosets/mempools To: Mike Snitzer Cc: Kent Overstreet , torvalds@linux-foundation.org, linux-kernel@vger.kernel.org References: <20180605092633.29583-1-kent.overstreet@gmail.com> <20180605144506.GA13100@redhat.com> From: Jens Axboe Message-ID: <7373e0e8-c3b9-2fed-b0a1-88fb4934d82d@kernel.dk> Date: Tue, 5 Jun 2018 08:48:42 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.0 MIME-Version: 1.0 In-Reply-To: <20180605144506.GA13100@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/5/18 8:45 AM, Mike Snitzer wrote: > On Tue, Jun 05 2018 at 10:22P -0400, > Jens Axboe wrote: > >> On 6/5/18 3:26 AM, Kent Overstreet wrote: >>> mempool_init()/bioset_init() require that the mempools/biosets be zeroed >>> first; they probably should not _require_ this, but not allocating those >>> structs with kzalloc is a fairly nonsensical thing to do (calling >>> mempool_exit()/bioset_exit() on an uninitialized mempool/bioset is legal >>> and safe, but only works if said memory was zeroed.) >>> >>> Signed-off-by: Kent Overstreet >>> --- >>> >>> Linus, >>> >>> I fucked up majorly on the bioset/mempool conversion - I forgot to check that >>> everything biosets/mempools were being embedded in was actually being zeroed on >>> allocation. Device mapper currently explodes, you'll probably want to apply this >>> patch post haste. >>> >>> I have now done that auditing, for every single conversion - this patch fixes >>> everything I found. There do not seem to be any incorrect ones outside of device >>> mapper... >>> >>> We'll probably want a second patch that either a) changes >>> bioset_init()/mempool_init() to zero the passed in bioset/mempool first, or b) >>> my preference, WARN() or BUG() if they're passed memory that isn't zeroed. >> >> Odd, haven't seen a crash, but probably requires kasan or poisoning to >> trigger anything? Mike's tree also had the changes, since they were based >> on the block tree. >> >> I can queue this up and ship it later today. Mike, you want to review >> this one? > > Yes, looks good. > > From the start of revisiting these changes last week, Kent and I > discussed whether it was safe to call mempool_exit() even if > mempool_init() failed or was never called. He advised that it was so > long as the containing structure was zeroed. But I forgot to audit that > aspect. So this was an oversight by both of us. > > DM core uses kvzalloc_node for struct mapped_device and cache, crypt, > integrity, verity-fec and zoned targets are already using kzalloc as > needed. > > Acked-by: Mike Snitzer Thanks Mike, I'll push this out this morning. -- Jens Axboe