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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 74DC4C6FA82 for ; Tue, 13 Sep 2022 03:42:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229744AbiIMDmT (ORCPT ); Mon, 12 Sep 2022 23:42:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33398 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229610AbiIMDmP (ORCPT ); Mon, 12 Sep 2022 23:42:15 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 85A0513D31 for ; Mon, 12 Sep 2022 20:42:14 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 1ECA9B80CB1 for ; Tue, 13 Sep 2022 03:42:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C2227C433C1; Tue, 13 Sep 2022 03:42:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1663040531; bh=VUeq6MUzXB3MhRWXQ1REV1K4QwHMVaOsxFDEM74s2JM=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=EQ7adyotaOphDX46uv9SLP9FXSj7XTK0+OvL+hiaeepzepf6FMmqcAZJuORYxsoqL QGKm+7lx121CEUPtZ6WN21dExX2Ju8x2yQ60Nx7xcP6obu3F6QerPdFMyXPyXQsXXQ VwcSjxRwCkWCkj3SZdqV2MGXjUaXtdLW4cQ5q6ZabcLYDZx+NuswOALS4ALnihXCSQ bAYATikAnNwroYqQ3LDlXlPAJm58OycpOnN5RWm0u4R9JjmIzdVYDcg/AncOVws4Ft 91/nAde33ArG3aT5zPxKXYRn4kXXG8b0/Rbx2ZiyYihQ6kqKxQYQ6AwhGiEMi44/XM 6yE/2b/TtQW4g== Message-ID: Date: Tue, 13 Sep 2022 11:42:04 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Subject: Re: [PATCH] mm/slub: fix to return errno if kmalloc() fails Content-Language: en-US To: Christophe JAILLET , "Vlastimil Babka (SUSE)" , linux-mm@kvack.org Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, Chao Yu , muchun.song@linux.dev References: <20220830141009.150075-1-chao@kernel.org> <2025305d-16db-abdf-6cd3-1fb93371c2b4@wanadoo.fr> From: Chao Yu In-Reply-To: <2025305d-16db-abdf-6cd3-1fb93371c2b4@wanadoo.fr> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022/9/10 0:47, Christophe JAILLET wrote: > Le 30/08/2022 à 16:10, Chao Yu a écrit : >> From: Chao Yu >> >> In create_unique_id(), kmalloc(, GFP_KERNEL) can fail due to >> out-of-memory, if it fails, return errno correctly rather than >> triggering panic via BUG_ON(); >> >> kernel BUG at mm/slub.c:5893! >> Internal error: Oops - BUG: 0 [#1] PREEMPT SMP >> >> Call trace: >>   sysfs_slab_add+0x258/0x260 mm/slub.c:5973 >>   __kmem_cache_create+0x60/0x118 mm/slub.c:4899 >>   create_cache mm/slab_common.c:229 [inline] >>   kmem_cache_create_usercopy+0x19c/0x31c mm/slab_common.c:335 >>   kmem_cache_create+0x1c/0x28 mm/slab_common.c:390 >>   f2fs_kmem_cache_create fs/f2fs/f2fs.h:2766 [inline] >>   f2fs_init_xattr_caches+0x78/0xb4 fs/f2fs/xattr.c:808 >>   f2fs_fill_super+0x1050/0x1e0c fs/f2fs/super.c:4149 >>   mount_bdev+0x1b8/0x210 fs/super.c:1400 >>   f2fs_mount+0x44/0x58 fs/f2fs/super.c:4512 >>   legacy_get_tree+0x30/0x74 fs/fs_context.c:610 >>   vfs_get_tree+0x40/0x140 fs/super.c:1530 >>   do_new_mount+0x1dc/0x4e4 fs/namespace.c:3040 >>   path_mount+0x358/0x914 fs/namespace.c:3370 >>   do_mount fs/namespace.c:3383 [inline] >>   __do_sys_mount fs/namespace.c:3591 [inline] >>   __se_sys_mount fs/namespace.c:3568 [inline] >>   __arm64_sys_mount+0x2f8/0x408 fs/namespace.c:3568 >> >> Cc: >> Reported-by: syzbot+81684812ea68216e08c5@syzkaller.appspotmail.com >> Signed-off-by: Chao Yu >> --- >>   mm/slub.c | 5 ++++- >>   1 file changed, 4 insertions(+), 1 deletion(-) >> >> diff --git a/mm/slub.c b/mm/slub.c >> index 862dbd9af4f5..e6f3727b9ad2 100644 >> --- a/mm/slub.c >> +++ b/mm/slub.c >> @@ -5890,7 +5890,8 @@ static char *create_unique_id(struct kmem_cache *s) >>       char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL); > > Hi, > > looks that ID_STR_LENGTH could even be reduced to 32 or 16. > > The 2nd BUG_ON at the end of the function could certainly be just removed as well or remplaced by a: >        if (p > name + ID_STR_LENGTH - 1) { >         kfree(name); >         return -E; >     } Hi Christophe, Vlastimil, Should I include this in v3? or may be in another patch? Thanks, > > Just my 2c, > > CJ > >>       char *p = name; >> -    BUG_ON(!name); >> +    if (!name) >> +        return ERR_PTR(-ENOMEM); >>       *p++ = ':'; >>       /* >> @@ -5948,6 +5949,8 @@ static int sysfs_slab_add(struct kmem_cache *s) >>            * for the symlinks. >>            */ >>           name = create_unique_id(s); >> +        if (IS_ERR(name)) >> +            return PTR_ERR(name); >>       } >>       s->kobj.kset = kset; >