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Date:   Tue, 6 Sep 2022 14:34:01 -0700 (PDT)
From:   David Rientjes <rientjes@google.com>
To:     Chao Yu <chao@kernel.org>
cc:     linux-mm@kvack.org, akpm@linux-foundation.org,
        linux-kernel@vger.kernel.org, jaegeuk@kernel.org,
        Chao Yu <chao.yu@oppo.com>, stable@kernel.org,
        syzbot+81684812ea68216e08c5@syzkaller.appspotmail.com,
        Muchun Song <songmuchun@bytedance.com>,
        Hyeonggon Yoo <42.hyeyoo@gmail.com>
Subject: Re: [PATCH v2] mm/slub: fix to return errno if kmalloc() fails
In-Reply-To: <20220831145454.858200-1-chao@kernel.org>
Message-ID: <996c5407-711e-18e5-79e1-995afbd6c151@google.com>
References: <20220831145454.858200-1-chao@kernel.org>
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On Wed, 31 Aug 2022, Chao Yu wrote:

> From: Chao Yu <chao.yu@oppo.com>
> 
> 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: <stable@kernel.org>
> Fixes: 81819f0fc8285 ("SLUB core")
> Reported-by: syzbot+81684812ea68216e08c5@syzkaller.appspotmail.com
> Reviewed-by: Muchun Song <songmuchun@bytedance.com>
> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> Signed-off-by: Chao Yu <chao.yu@oppo.com>

Acked-by: David Rientjes <rientjes@google.com>