ext4: Avoid freeing inodes on dirty list
When we are evicting inode with journalled data, we may race with
transaction commit in the following way:
CPU0 CPU1
jbd2_journal_commit_transaction() evict(inode)
inode_io_list_del()
inode_wait_for_writeback()
process BJ_Forget list
__jbd2_journal_insert_checkpoint()
__jbd2_journal_refile_buffer()
__jbd2_journal_unfile_buffer()
if (test_clear_buffer_jbddirty(bh))
mark_buffer_dirty(bh)
__mark_inode_dirty(inode)
ext4_evict_inode(inode)
frees the inode
This results in use-after-free issues in the writeback code (or
the assertion added in the previous commit triggering).
Fix the problem by removing inode from writeback lists once all the page
cache is evicted and so inode cannot be added to writeback lists again.
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20200421085445.5731-4-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
1 file changed
