From patchwork Wed Jul 28 18:45:57 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 488598 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED autolearn=ham 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 D2926C4320A for ; Wed, 28 Jul 2021 18:46:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AE45660EBD for ; Wed, 28 Jul 2021 18:46:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229769AbhG1SqB (ORCPT ); Wed, 28 Jul 2021 14:46:01 -0400 Received: from mail.kernel.org ([198.145.29.99]:35834 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229577AbhG1SqB (ORCPT ); Wed, 28 Jul 2021 14:46:01 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id EC33E60525; Wed, 28 Jul 2021 18:45:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1627497958; bh=RjAgnQkk/Psy9Gs4coi2GKJyu5o6SGoC86V4MpiCPE4=; h=Date:From:To:Subject:From; b=OoX/9USH4OowkA7gO83Jp8xCJGKjyOyksANR+/CvfR5rw5azxzlNmshjiXzI2FpDl xThDlMtBTePYlzcNUAdY+JMYOmwKd25cF6EnU6RoBN/WO0zRd6up/jcS3cFdYu+Y5a 5ZWoOtIhQ42bzggX2lAVE2lreSYy+aHf26GUuFjQ= Date: Wed, 28 Jul 2021 11:45:57 -0700 From: akpm@linux-foundation.org To: mm-commits@vger.kernel.org, wangkefeng.wang@huawei.com, vbabka@suse.cz, stable@vger.kernel.org, shakeelb@google.com, rientjes@google.com, penberg@kernel.org, mhocko@suse.com, iamjoonsoo.kim@lge.com, hannes@cmpxchg.org, guro@fb.com, cl@linux.com, ast@kernel.org, wanghai38@huawei.com Subject: + mm-memcg-fix-null-pointer-dereference-in-memcg_slab_free_hook.patch added to -mm tree Message-ID: <20210728184557.xaKCu%akpm@linux-foundation.org> User-Agent: s-nail v14.9.10 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch titled Subject: mm/memcg: fix NULL pointer dereference in memcg_slab_free_hook() has been added to the -mm tree. Its filename is mm-memcg-fix-null-pointer-dereference-in-memcg_slab_free_hook.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-memcg-fix-null-pointer-dereference-in-memcg_slab_free_hook.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-memcg-fix-null-pointer-dereference-in-memcg_slab_free_hook.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Wang Hai Subject: mm/memcg: fix NULL pointer dereference in memcg_slab_free_hook() When I use kfree_rcu() to free a large memory allocated by kmalloc_node(), the following dump occurs. BUG: kernel NULL pointer dereference, address: 0000000000000020 [...] Oops: 0000 [#1] SMP [...] Workqueue: events kfree_rcu_work RIP: 0010:__obj_to_index include/linux/slub_def.h:182 [inline] RIP: 0010:obj_to_index include/linux/slub_def.h:191 [inline] RIP: 0010:memcg_slab_free_hook+0x120/0x260 mm/slab.h:363 [...] Call Trace: kmem_cache_free_bulk+0x58/0x630 mm/slub.c:3293 kfree_bulk include/linux/slab.h:413 [inline] kfree_rcu_work+0x1ab/0x200 kernel/rcu/tree.c:3300 process_one_work+0x207/0x530 kernel/workqueue.c:2276 worker_thread+0x320/0x610 kernel/workqueue.c:2422 kthread+0x13d/0x160 kernel/kthread.c:313 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 When kmalloc_node() a large memory, page is allocated, not slab, so when freeing memory via kfree_rcu(), this large memory should not be used by memcg_slab_free_hook(), because memcg_slab_free_hook() is is used for slab. Using page_objcgs_check() instead of page_objcgs() in memcg_slab_free_hook() to fix this bug. Link: https://lkml.kernel.org/r/20210728145655.274476-1-wanghai38@huawei.com Fixes: 270c6a71460e ("mm: memcontrol/slab: Use helpers to access slab page's memcg_data") Signed-off-by: Wang Hai Reviewed-by: Shakeel Butt Acked-by: Michal Hocko Cc: Christoph Lameter Cc: Pekka Enberg Cc: Roman Gushchin Cc: David Rientjes Cc: Joonsoo Kim Cc: Vlastimil Babka Cc: Johannes Weiner Cc: Alexei Starovoitov Cc: Kefeng Wang Cc: Signed-off-by: Andrew Morton --- mm/slab.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/slab.h~mm-memcg-fix-null-pointer-dereference-in-memcg_slab_free_hook +++ a/mm/slab.h @@ -346,7 +346,7 @@ static inline void memcg_slab_free_hook( continue; page = virt_to_head_page(p[i]); - objcgs = page_objcgs(page); + objcgs = page_objcgs_check(page); if (!objcgs) continue;