diff options
| author | Brian Foster <bfoster@redhat.com> | 2025-05-16 13:38:00 -0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2025-05-20 10:31:13 -0400 |
| commit | e26268ff1dcae5662c1b96c35f18cfa6ab73d9de (patch) | |
| tree | 0f29f14f8818e01de277bd94bd917537ae40f53c | |
| parent | 0bf1f51e34c4e260095fc7306c564c7fe01503e3 (diff) | |
ext4: only dirty folios when data journaling regular files
fstest generic/388 occasionally reproduces a crash that looks as
follows:
BUG: kernel NULL pointer dereference, address: 0000000000000000
...
Call Trace:
<TASK>
ext4_block_zero_page_range+0x30c/0x380 [ext4]
ext4_truncate+0x436/0x440 [ext4]
ext4_process_orphan+0x5d/0x110 [ext4]
ext4_orphan_cleanup+0x124/0x4f0 [ext4]
ext4_fill_super+0x262d/0x3110 [ext4]
get_tree_bdev_flags+0x132/0x1d0
vfs_get_tree+0x26/0xd0
vfs_cmd_create+0x59/0xe0
__do_sys_fsconfig+0x4ed/0x6b0
do_syscall_64+0x82/0x170
...
This occurs when processing a symlink inode from the orphan list. The
partial block zeroing code in the truncate path calls
ext4_dirty_journalled_data() -> folio_mark_dirty(). The latter calls
mapping->a_ops->dirty_folio(), but symlink inodes are not assigned an
a_ops vector in ext4, hence the crash.
To avoid this problem, update the ext4_dirty_journalled_data() helper to
only mark the folio dirty on regular files (for which a_ops is
assigned). This also matches the journaling logic in the ext4_symlink()
creation path, where ext4_handle_dirty_metadata() is called directly.
Fixes: d84c9ebdac1e ("ext4: Mark pages with journalled data dirty")
Signed-off-by: Brian Foster <bfoster@redhat.com>
Link: https://patch.msgid.link/20250516173800.175577-1-bfoster@redhat.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: stable@kernel.org
| -rw-r--r-- | fs/ext4/inode.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 2f59036df800..ce0632094c50 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -1119,7 +1119,12 @@ int ext4_walk_page_buffers(handle_t *handle, struct inode *inode, */ static int ext4_dirty_journalled_data(handle_t *handle, struct buffer_head *bh) { - folio_mark_dirty(bh->b_folio); + struct folio *folio = bh->b_folio; + struct inode *inode = folio->mapping->host; + + /* only regular files have a_ops */ + if (S_ISREG(inode->i_mode)) + folio_mark_dirty(folio); return ext4_handle_dirty_metadata(handle, NULL, bh); } |