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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id CCC84ECAAD3 for ; Fri, 9 Sep 2022 16:47:55 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1676C6B0071; Fri, 9 Sep 2022 12:47:55 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 116C66B0072; Fri, 9 Sep 2022 12:47:55 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F217E8D0001; Fri, 9 Sep 2022 12:47:54 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id DFF516B0071 for ; Fri, 9 Sep 2022 12:47:54 -0400 (EDT) Received: from smtpin28.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 9D6A1AB6D6 for ; Fri, 9 Sep 2022 16:47:54 +0000 (UTC) X-FDA: 79893128868.28.5015646 Received: from smtp.smtpout.orange.fr (smtp03.smtpout.orange.fr [80.12.242.125]) by imf04.hostedemail.com (Postfix) with ESMTP id F33D040081 for ; Fri, 9 Sep 2022 16:47:52 +0000 (UTC) Received: from [192.168.1.18] ([90.11.190.129]) by smtp.orange.fr with ESMTPA id WhATopmnsPMmaWhAToUQN3; Fri, 09 Sep 2022 18:47:51 +0200 X-ME-Helo: [192.168.1.18] X-ME-Auth: Y2hyaXN0b3BoZS5qYWlsbGV0QHdhbmFkb28uZnI= X-ME-Date: Fri, 09 Sep 2022 18:47:51 +0200 X-ME-IP: 90.11.190.129 Message-ID: <2025305d-16db-abdf-6cd3-1fb93371c2b4@wanadoo.fr> Date: Fri, 9 Sep 2022 18:47:49 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Subject: Re: [PATCH] mm/slub: fix to return errno if kmalloc() fails Content-Language: fr To: Chao Yu , linux-mm@kvack.org Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, jaegeuk@kernel.org, Chao Yu , vbabka@kernel.org, muchun.song@linux.dev References: <20220830141009.150075-1-chao@kernel.org> From: Christophe JAILLET In-Reply-To: <20220830141009.150075-1-chao@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1662742073; a=rsa-sha256; cv=none; b=1JeLg0YRnmF9F+tnTNyOQom7gRJTTVjlYjYT6EuZSB+UVlJrBHFDX8nFPJ2Mr3WmMAc3Md 4fJfpZOnL8TU2FJMKkWkhBEJXM/xP/CuR6QJikogNWQ5Na+3pr0P6C3nwyxdXJM+0K5j88 Xz+TpFOXTJnQHUlEa0m6ZdPOob2qje8= ARC-Authentication-Results: i=1; imf04.hostedemail.com; dkim=none; dmarc=none; spf=pass (imf04.hostedemail.com: domain of christophe.jaillet@wanadoo.fr designates 80.12.242.125 as permitted sender) smtp.mailfrom=christophe.jaillet@wanadoo.fr ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1662742073; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=YeklOwzIjtLiwF9/UtmxiN6stBYPUGstsfhRz5EbvkE=; b=6DTDFh1lOVT4zm/0wkX8SRHUwR7iCOEkNwvYE4HfzClNbRM0uDCZ/7yR3iXaVf8Ve9dlx9 dG/qSOxTORyF4cWTvjToB6bVY5UrN2yQh4Ih4ZYIsU926plP3CbWQwf09UJfNOlzW1tKFA 9NodsXVl3P/sgibQSjYKWlesTEqGpxc= X-Stat-Signature: up4srhqfwn8e3m3m44xxhmrpj68tgnc8 X-Rspamd-Queue-Id: F33D040081 X-Rspam-User: Authentication-Results: imf04.hostedemail.com; dkim=none; dmarc=none; spf=pass (imf04.hostedemail.com: domain of christophe.jaillet@wanadoo.fr designates 80.12.242.125 as permitted sender) smtp.mailfrom=christophe.jaillet@wanadoo.fr X-Rspamd-Server: rspam02 X-HE-Tag: 1662742072-422516 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000126, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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; } 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;