fs: do not update freeing inode i_io_list
[ Upstream commit 4e3c51f4e805291b057d12f5dda5aeb50a538dc4 ]
After commit cbfecb927f42 ("fs: record I_DIRTY_TIME even if inode
already has I_DIRTY_INODE") writeback_single_inode can push inode with
I_DIRTY_TIME set to b_dirty_time list. In case of freeing inode with
I_DIRTY_TIME set this can happen after deletion of inode from i_io_list
at evict. Stack trace is following.
evict
fat_evict_inode
fat_truncate_blocks
fat_flush_inodes
writeback_inode
sync_inode_metadata(inode, sync=0)
writeback_single_inode(inode, wbc) <- wbc->sync_mode == WB_SYNC_NONE
This will lead to use after free in flusher thread.
Similar issue can be triggered if writeback_single_inode in the
stack trace update inode->i_io_list. Add explicit check to avoid it.
Fixes: cbfecb927f42 ("fs: record I_DIRTY_TIME even if inode already has I_DIRTY_INODE")
Reported-by: syzbot+6ba92bd00d5093f7e371@syzkaller.appspotmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Svyatoslav Feldsherov <feldsherov@google.com>
Link: https://lore.kernel.org/r/20221115202001.324188-1-feldsherov@google.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 2a27f02..f4a5a0c 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -1739,18 +1739,26 @@
wb = inode_to_wb_and_lock_list(inode);
spin_lock(&inode->i_lock);
/*
- * If the inode is now fully clean, then it can be safely removed from
- * its writeback list (if any). Otherwise the flusher threads are
- * responsible for the writeback lists.
+ * If the inode is freeing, its i_io_list shoudn't be updated
+ * as it can be finally deleted at this moment.
*/
- if (!(inode->i_state & I_DIRTY_ALL))
- inode_cgwb_move_to_attached(inode, wb);
- else if (!(inode->i_state & I_SYNC_QUEUED)) {
- if ((inode->i_state & I_DIRTY))
- redirty_tail_locked(inode, wb);
- else if (inode->i_state & I_DIRTY_TIME) {
- inode->dirtied_when = jiffies;
- inode_io_list_move_locked(inode, wb, &wb->b_dirty_time);
+ if (!(inode->i_state & I_FREEING)) {
+ /*
+ * If the inode is now fully clean, then it can be safely
+ * removed from its writeback list (if any). Otherwise the
+ * flusher threads are responsible for the writeback lists.
+ */
+ if (!(inode->i_state & I_DIRTY_ALL))
+ inode_cgwb_move_to_attached(inode, wb);
+ else if (!(inode->i_state & I_SYNC_QUEUED)) {
+ if ((inode->i_state & I_DIRTY))
+ redirty_tail_locked(inode, wb);
+ else if (inode->i_state & I_DIRTY_TIME) {
+ inode->dirtied_when = jiffies;
+ inode_io_list_move_locked(inode,
+ wb,
+ &wb->b_dirty_time);
+ }
}
}
