• Filipe Manana's avatar
    Btrfs: fix selftests failure due to uninitialized i_mode in test inodes · 9f7fec0b
    Filipe Manana authored
    Some of the self tests create a test inode, setup some extents and then do
    calls to btrfs_get_extent() to test that the corresponding extent maps
    exist and are correct. However btrfs_get_extent(), since the 5.2 merge
    window, now errors out when it finds a regular or prealloc extent for an
    inode that does not correspond to a regular file (its ->i_mode is not
    S_IFREG). This causes the self tests to fail sometimes, specially when
    KASAN, slub_debug and page poisoning are enabled:
    
      $ modprobe btrfs
      modprobe: ERROR: could not insert 'btrfs': Invalid argument
    
      $ dmesg
      [ 9414.691648] Btrfs loaded, crc32c=crc32c-intel, debug=on, assert=on, integrity-checker=on, ref-verify=on
      [ 9414.692655] BTRFS: selftest: sectorsize: 4096  nodesize: 4096
      [ 9414.692658] BTRFS: selftest: running btrfs free space cache tests
      [ 9414.692918] BTRFS: selftest: running extent only tests
      [ 9414.693061] BTRFS: selftest: running bitmap only tests
      [ 9414.693366] BTRFS: selftest: running bitmap and extent tests
      [ 9414.696455] BTRFS: selftest: running space stealing from bitmap to extent tests
      [ 9414.697131] BTRFS: selftest: running extent buffer operation tests
      [ 9414.697133] BTRFS: selftest: running btrfs_split_item tests
      [ 9414.697564] BTRFS: selftest: running extent I/O tests
      [ 9414.697583] BTRFS: selftest: running find delalloc tests
      [ 9415.081125] BTRFS: selftest: running find_first_clear_extent_bit test
      [ 9415.081278] BTRFS: selftest: running extent buffer bitmap tests
      [ 9415.124192] BTRFS: selftest: running inode tests
      [ 9415.124195] BTRFS: selftest: running btrfs_get_extent tests
      [ 9415.127909] BTRFS: selftest: running hole first btrfs_get_extent test
      [ 9415.128343] BTRFS critical (device (efault)): regular/prealloc extent found for non-regular inode 256
      [ 9415.131428] BTRFS: selftest: fs/btrfs/tests/inode-tests.c:904 expected a real extent, got 0
    
    This happens because the test inodes are created without ever initializing
    the i_mode field of the inode, and neither VFS's new_inode() nor the btrfs
    callback btrfs_alloc_inode() initialize the i_mode. Initialization of the
    i_mode is done through the various callbacks used by the VFS to create
    new inodes (regular files, directories, symlinks, tmpfiles, etc), which
    all call btrfs_new_inode() which in turn calls inode_init_owner(), which
    sets the inode's i_mode. Since the tests only uses new_inode() to create
    the test inodes, the i_mode was never initialized.
    
    This always happens on a VM I used with kasan, slub_debug and many other
    debug facilities enabled. It also happened to someone who reported this
    on bugzilla (on a 5.3-rc).
    
    Fix this by setting i_mode to S_IFREG at btrfs_new_test_inode().
    
    Fixes: 6bf9e4bd ("btrfs: inode: Verify inode mode to avoid NULL pointer dereference")
    Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=204397Signed-off-by: default avatarFilipe Manana <fdmanana@suse.com>
    Reviewed-by: default avatarQu Wenruo <wqu@suse.com>
    Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
    9f7fec0b
btrfs-tests.c 7.36 KB