On Wed, Sep 16, 2020 at 08:29:42PM -0700, Darrick J. Wong wrote: > From: Darrick J. Wong <darrick.wong@xxxxxxxxxx> > > In xfs_bui_item_recover, there exists a use-after-free bug with regards > to the inode that is involved in the bmap replay operation. If the > mapping operation does not complete, we call xfs_bmap_unmap_extent to > create a deferred op to finish the unmapping work, and we retain a > pointer to the incore inode. > > Unfortunately, the very next thing we do is commit the transaction and > drop the inode. If reclaim tears down the inode before we try to finish > the defer ops, we dereference garbage and blow up. Therefore, create a > way to join inodes to the defer ops freezer so that we can maintain the > xfs_inode reference until we're done with the inode. > > Note: This imposes the requirement that there be enough memory to keep > every incore inode in memory throughout recovery. As in every inode that gets recovered, not every inode in the system. I think the commit log could use a very slight tweak here. Didn't we think of just storing the inode number for recovery, or did this turn out too complicated? (I'm pretty sure we dicussed this in detail before, but my memory gets foggy).
