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Tue, 6 Dec 2022 12:04:18 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap1.suse-dmz.suse.de with ESMTPSA id rMLKKsIvj2PgWgAAGKfGzw (envelope-from ); Tue, 06 Dec 2022 12:04:18 +0000 Received: by quack3.suse.cz (Postfix, from userid 1000) id 07A92A0725; Tue, 6 Dec 2022 13:04:17 +0100 (CET) Date: Tue, 6 Dec 2022 13:04:17 +0100 From: Jan Kara To: Ye Bin Cc: tytso@mit.edu, adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, jack@suse.cz, Ye Bin , syzbot+4d99a966fd74bdeeec36@syzkaller.appspotmail.com Subject: Re: [PATCH -next 1/6] ext4: fix WARNING in ext4_expand_extra_isize_ea Message-ID: <20221206120417.225uxtlg255bzph4@quack3> References: <20221206015806.3420321-1-yebin@huaweicloud.com> <20221206015806.3420321-2-yebin@huaweicloud.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221206015806.3420321-2-yebin@huaweicloud.com> Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Tue 06-12-22 09:58:01, Ye Bin wrote: > From: Ye Bin > > Syzbot found the following issue: > ------------[ cut here ]------------ > WARNING: CPU: 1 PID: 3631 at mm/page_alloc.c:5534 __alloc_pages+0x30a/0x560 mm/page_alloc.c:5534 > Modules linked in: > CPU: 1 PID: 3631 Comm: syz-executor261 Not tainted 6.1.0-rc6-syzkaller-00308-g644e9524388a #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 > RIP: 0010:__alloc_pages+0x30a/0x560 mm/page_alloc.c:5534 > RSP: 0018:ffffc90003ccf080 EFLAGS: 00010246 > RAX: ffffc90003ccf0e0 RBX: 000000000000000c RCX: 0000000000000000 > RDX: 0000000000000028 RSI: 0000000000000000 RDI: ffffc90003ccf108 > RBP: ffffc90003ccf198 R08: dffffc0000000000 R09: ffffc90003ccf0e0 > R10: fffff52000799e21 R11: 1ffff92000799e1c R12: 0000000000040c40 > R13: 1ffff92000799e18 R14: dffffc0000000000 R15: 1ffff92000799e14 > FS: 0000555555c10300(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007ffc36f70000 CR3: 00000000744ad000 CR4: 00000000003506e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > > __alloc_pages_node include/linux/gfp.h:223 [inline] > alloc_pages_node include/linux/gfp.h:246 [inline] > __kmalloc_large_node+0x8a/0x1a0 mm/slab_common.c:1096 > __do_kmalloc_node mm/slab_common.c:943 [inline] > __kmalloc+0xfe/0x1a0 mm/slab_common.c:968 > kmalloc include/linux/slab.h:558 [inline] > ext4_xattr_move_to_block fs/ext4/xattr.c:2558 [inline] > ext4_xattr_make_inode_space fs/ext4/xattr.c:2673 [inline] > ext4_expand_extra_isize_ea+0xe3f/0x1cd0 fs/ext4/xattr.c:2765 > __ext4_expand_extra_isize+0x2b8/0x3f0 fs/ext4/inode.c:5857 > ext4_try_to_expand_extra_isize fs/ext4/inode.c:5900 [inline] > __ext4_mark_inode_dirty+0x51a/0x670 fs/ext4/inode.c:5978 > ext4_inline_data_truncate+0x548/0xd00 fs/ext4/inline.c:2021 > ext4_truncate+0x341/0xeb0 fs/ext4/inode.c:4221 > ext4_process_orphan+0x1aa/0x2d0 fs/ext4/orphan.c:339 > ext4_orphan_cleanup+0xb60/0x1340 fs/ext4/orphan.c:474 > __ext4_fill_super fs/ext4/super.c:5515 [inline] > ext4_fill_super+0x80ed/0x8610 fs/ext4/super.c:5643 > get_tree_bdev+0x400/0x620 fs/super.c:1324 > vfs_get_tree+0x88/0x270 fs/super.c:1531 > do_new_mount+0x289/0xad0 fs/namespace.c:3040 > do_mount fs/namespace.c:3383 [inline] > __do_sys_mount fs/namespace.c:3591 [inline] > __se_sys_mount+0x2d3/0x3c0 fs/namespace.c:3568 > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > > > Reason is allocate 16M memory by kmalloc, but MAX_ORDER is 11, kmalloc > can allocate maxium size memory is 4M. > XATTR_SIZE_MAX is currently 64k, but EXT4_XATTR_SIZE_MAX is '(1 << 24)', > so 'ext4_xattr_check_entries()' regards this length as legal. Then trigger > warning in 'ext4_xattr_move_to_block()'. > To solve above issue, according to Jan Kara's suggestion use kvmalloc() > to allocate memory in ext4_xattr_move_to_block(). > > Reported-by: syzbot+4d99a966fd74bdeeec36@syzkaller.appspotmail.com > Fixes: 54dd0e0a1b25 ("ext4: add extra checks to ext4_xattr_block_get()") > Signed-off-by: Ye Bin The changelog speak about kvmalloc() while your patch changes EXT4_XATTR_SIZE_MAX. This needs to be fixed. If Ted is find with this change, I have no problem with it either but I remember there were some discussions about what EXT4_XATTR_SIZE_MAX should be when ea_inode feature has been developed. Ted might remember. Also the change from kmalloc() to kvmalloc() is a desirable one anyway. It is not always easy to find physically contiguous 64k of memory so kvmalloc() makes the allocation much more likely to succeed. Honza -- Jan Kara SUSE Labs, CR