On Fri, Oct 25, 2024 at 08:11:50PM -0400, Kent Overstreet wrote: > On Wed, Oct 23, 2024 at 03:33:22PM +0800, Alan Huang wrote: > > On Oct 23, 2024, at 15:21, Piotr Zalewski <[email protected]> wrote: > > > > > > Add NULL check for key returned from bch2_btree_and_journal_iter_peek in > > > btree_node_iter_and_journal_peek to avoid NULL ptr dereference in > > > bch2_bkey_buf_reassemble. > > > > It would be helpful if the commit message explained why k.k is null in this > > case > > This code is only for iterating over interior btree nodes - k.k is only > null when we have a bad btree topology (gaps). > > Piotr, could you add a comment to that effect?
Actually, not just that - when this happens we should flag the filesystem as having topology repairs, and possibly start topology repair. Calling bch2_topology_error() will do that. We definitely want to log an error message, too; it should reference the btree node we're iterating over and explain that it's missing child nodes.
