Re: [PATCH v3 1/4] ext4: fix bug_on in __es_tree_search caused by bad quota inode

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On 2022/10/26 12:23, 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 the inode is
bad_inode in vfs_setup_quota_inode().

Signed-off-by: Baokun Li<libaokun1@xxxxxxxxxx>
---
  fs/quota/dquot.c | 2 ++
  1 file changed, 2 insertions(+)

Looks good,
Reviewed-by: Jason Yan <yanaijie@xxxxxxxxxx>



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