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Date: Tue, 25 Oct 2022 10:48:33 +0800 From: Baokun Li <libaokun1@...wei.com> To: Jan Kara <jack@...e.cz> CC: <linux-ext4@...r.kernel.org>, <tytso@....edu>, <adilger.kernel@...ger.ca>, <ritesh.list@...il.com>, <linux-kernel@...r.kernel.org>, <yi.zhang@...wei.com>, <yukuai3@...wei.com>, Baokun Li <libaokun1@...wei.com> Subject: Re: [PATCH v2 1/2] ext4: fix bug_on in __es_tree_search caused by wrong s_usr_quota_inum On 2022/10/24 22:16, Jan Kara wrote: > On Mon 24-10-22 16:10:53, Jan Kara wrote: >> On Fri 21-10-22 12:07:30, Baokun Li wrote: >>> We got a issue as fllows: >>> ================================================================== >>> kernel BUG at fs/ext4/extents_status.c:202! >>> invalid opcode: 0000 [#1] PREEMPT SMP >>> CPU: 1 PID: 810 Comm: mount Not tainted 6.1.0-rc1-next-g9631525255e3 #352 >>> RIP: 0010:__es_tree_search.isra.0+0xb8/0xe0 >>> RSP: 0018:ffffc90001227900 EFLAGS: 00010202 >>> RAX: 0000000000000000 RBX: 0000000077512a0f RCX: 0000000000000000 >>> RDX: 0000000000000002 RSI: 0000000000002a10 RDI: ffff8881004cd0c8 >>> RBP: ffff888177512ac8 R08: 47ffffffffffffff R09: 0000000000000001 >>> R10: 0000000000000001 R11: 00000000000679af R12: 0000000000002a10 >>> R13: ffff888177512d88 R14: 0000000077512a10 R15: 0000000000000000 >>> FS: 00007f4bd76dbc40(0000)GS:ffff88842fd00000(0000)knlGS:0000000000000000 >>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >>> CR2: 00005653bf993cf8 CR3: 000000017bfdf000 CR4: 00000000000006e0 >>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >>> Call Trace: >>> <TASK> >>> ext4_es_cache_extent+0xe2/0x210 >>> ext4_cache_extents+0xd2/0x110 >>> ext4_find_extent+0x5d5/0x8c0 >>> ext4_ext_map_blocks+0x9c/0x1d30 >>> ext4_map_blocks+0x431/0xa50 >>> ext4_getblk+0x82/0x340 >>> ext4_bread+0x14/0x110 >>> ext4_quota_read+0xf0/0x180 >>> v2_read_header+0x24/0x90 >>> v2_check_quota_file+0x2f/0xa0 >>> dquot_load_quota_sb+0x26c/0x760 >>> dquot_load_quota_inode+0xa5/0x190 >>> ext4_enable_quotas+0x14c/0x300 >>> __ext4_fill_super+0x31cc/0x32c0 >>> ext4_fill_super+0x115/0x2d0 >>> get_tree_bdev+0x1d2/0x360 >>> ext4_get_tree+0x19/0x30 >>> vfs_get_tree+0x26/0xe0 >>> path_mount+0x81d/0xfc0 >>> do_mount+0x8d/0xc0 >>> __x64_sys_mount+0xc0/0x160 >>> do_syscall_64+0x35/0x80 >>> entry_SYSCALL_64_after_hwframe+0x63/0xcd >>> </TASK> >>> ================================================================== >>> >>> Above issue may happen as follows: >>> ------------------------------------- >>> ext4_fill_super >>> ext4_orphan_cleanup >>> ext4_enable_quotas >>> ext4_quota_enable >>> ext4_iget --> get error inode <5> >>> ext4_ext_check_inode --> Wrong imode makes it escape inspection >>> make_bad_inode(inode) --> EXT4_BOOT_LOADER_INO set imode >>> dquot_load_quota_inode >>> vfs_setup_quota_inode --> check pass >>> dquot_load_quota_sb >>> v2_check_quota_file >>> v2_read_header >>> ext4_quota_read >>> ext4_bread >>> ext4_getblk >>> ext4_map_blocks >>> ext4_ext_map_blocks >>> ext4_find_extent >>> ext4_cache_extents >>> ext4_es_cache_extent >>> __es_tree_search.isra.0 >>> ext4_es_end --> Wrong extents trigger BUG_ON >>> >>> In the above issue, s_usr_quota_inum is set to 5, but inode<5> contains >>> incorrect imode and disordered extents. Because 5 is EXT4_BOOT_LOADER_INO, >>> the ext4_ext_check_inode check in the ext4_iget function can be bypassed, >>> finally, the extents that are not checked trigger the BUG_ON in the >>> __es_tree_search function. To solve this issue, check whether qf_inode >>> obtained by ext4_iget is bad_inode. >>> >>> Signed-off-by: Baokun Li <libaokun1@...wei.com> >> Looks good to me. Feel free to add: >> >> Reviewed-by: Jan Kara <jack@...e.cz> > Hum, on a second thought: Would not it be better if vfs_setup_quota_inode() > actually checked for bad inode and refused it with EUCLEAN? That would > sound like a more generic approach (covers all filesystems) to this > problem. > > Honza Hello Honza, Totally agree with you! We initially added the check to vfs_setup_quota_inode(), because the check for imode is here. However, in ext4_quota_enable, if qf_inode is abnormal, "Bad quota inode..." is printed. Therefore, we feel that adding a check here can help us quickly find out where the problem occurs. Perhaps we should still add the check to vfs_setup_quota_inode() and also add the print ino when ext4_enable_quotas fails. Thank you for your review! -- With Best Regards, Baokun Li
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