From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 774ECC76186 for ; Wed, 17 Jul 2019 05:09:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4DA0A208C0 for ; Wed, 17 Jul 2019 05:09:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563340177; bh=YzI1pD2gTwbW8D6/QGw/v3A2j7p4mjkpexVdaYSJZkc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=aXCQT0MDWPDiGydKI1utrOqknaTdP0xT35RVMTWNOavhVfEJ4C+xS8SNP/MSMeTI3 Mx4THk3BFZDlXyd0B4Y6xgs6wwQec3TOCrFumORpf0MSOZjfqEtnK7BAe+DyEULXhj 0ut+PT6Dk9DqjWiZAUoCo0yyRHSnxtZduWTCe5eA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726852AbfGQFJg (ORCPT ); Wed, 17 Jul 2019 01:09:36 -0400 Received: from mx2.suse.de ([195.135.220.15]:54080 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726775AbfGQFJf (ORCPT ); Wed, 17 Jul 2019 01:09:35 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 679C6AC68; Wed, 17 Jul 2019 05:09:33 +0000 (UTC) Date: Wed, 17 Jul 2019 07:09:32 +0200 From: Michal Hocko To: Yang Shi Cc: catalin.marinas@arm.com, dvyukov@google.com, rientjes@google.com, willy@infradead.org, cai@lca.pw, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] Revert "kmemleak: allow to coexist with fault injection" Message-ID: <20190717050932.GB16284@dhcp22.suse.cz> References: <1563299431-111710-1-git-send-email-yang.shi@linux.alibaba.com> <20190717050711.GA16284@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190717050711.GA16284@dhcp22.suse.cz> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 17-07-19 07:07:11, Michal Hocko wrote: > On Wed 17-07-19 01:50:31, Yang Shi wrote: > > When running ltp's oom test with kmemleak enabled, the below warning was > > triggerred since kernel detects __GFP_NOFAIL & ~__GFP_DIRECT_RECLAIM is > > passed in: > > > > WARNING: CPU: 105 PID: 2138 at mm/page_alloc.c:4608 __alloc_pages_nodemask+0x1c31/0x1d50 > > Modules linked in: loop dax_pmem dax_pmem_core ip_tables x_tables xfs virtio_net net_failover virtio_blk failover ata_generic virtio_pci virtio_ring virtio libata > > CPU: 105 PID: 2138 Comm: oom01 Not tainted 5.2.0-next-20190710+ #7 > > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 > > RIP: 0010:__alloc_pages_nodemask+0x1c31/0x1d50 > > ... > > kmemleak_alloc+0x4e/0xb0 > > kmem_cache_alloc+0x2a7/0x3e0 > > ? __kmalloc+0x1d6/0x470 > > ? ___might_sleep+0x9c/0x170 > > ? mempool_alloc+0x2b0/0x2b0 > > mempool_alloc_slab+0x2d/0x40 > > mempool_alloc+0x118/0x2b0 > > ? __kasan_check_read+0x11/0x20 > > ? mempool_resize+0x390/0x390 > > ? lock_downgrade+0x3c0/0x3c0 > > bio_alloc_bioset+0x19d/0x350 > > ? __swap_duplicate+0x161/0x240 > > ? bvec_alloc+0x1b0/0x1b0 > > ? do_raw_spin_unlock+0xa8/0x140 > > ? _raw_spin_unlock+0x27/0x40 > > get_swap_bio+0x80/0x230 > > ? __x64_sys_madvise+0x50/0x50 > > ? end_swap_bio_read+0x310/0x310 > > ? __kasan_check_read+0x11/0x20 > > ? check_chain_key+0x24e/0x300 > > ? bdev_write_page+0x55/0x130 > > __swap_writepage+0x5ff/0xb20 > > > > The mempool_alloc_slab() clears __GFP_DIRECT_RECLAIM, however kmemleak has > > __GFP_NOFAIL set all the time due to commit > > d9570ee3bd1d4f20ce63485f5ef05663866fe6c0 ("kmemleak: allow to coexist > > with fault injection"). But, it doesn't make any sense to have > > __GFP_NOFAIL and ~__GFP_DIRECT_RECLAIM specified at the same time. > > > > According to the discussion on the mailing list, the commit should be > > reverted for short term solution. Catalin Marinas would follow up with a better > > solution for longer term. > > > > The failure rate of kmemleak metadata allocation may increase in some > > circumstances, but this should be expected side effect. > > > > Suggested-by: Catalin Marinas > > Cc: Michal Hocko > > Cc: Dmitry Vyukov > > Cc: David Rientjes > > Cc: Matthew Wilcox > > Cc: Qian Cai > > Signed-off-by: Yang Shi > > I forgot > Acked-by: Michal Hocko Btw. If this leads to early allocation failures too often then dropping __GFP_NORETRY should help for now until a better solution is available. It could lead to OOM killer invocation which is probably the reason why it has been added but probably better than completely disabling kmemleak altogether. Up to Catalin I guess. > > --- > > mm/kmemleak.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/mm/kmemleak.c b/mm/kmemleak.c > > index 9dd581d..884a5e3 100644 > > --- a/mm/kmemleak.c > > +++ b/mm/kmemleak.c > > @@ -114,7 +114,7 @@ > > /* GFP bitmask for kmemleak internal allocations */ > > #define gfp_kmemleak_mask(gfp) (((gfp) & (GFP_KERNEL | GFP_ATOMIC)) | \ > > __GFP_NORETRY | __GFP_NOMEMALLOC | \ > > - __GFP_NOWARN | __GFP_NOFAIL) > > + __GFP_NOWARN) > > > > /* scanning area inside a memory block */ > > struct kmemleak_scan_area { > > -- > > 1.8.3.1 > > -- > Michal Hocko > SUSE Labs -- Michal Hocko SUSE Labs