On Fri, Jan 12, 2024 at 02:21:55PM +0000, David Howells wrote: > Jitindar Singh, Suraj <surajjs@xxxxxxxxxx> wrote: > > > When testing the v6.1.69 kernel I bisected an issue to the below commit > > which was added in v6.1.68. When running the xfstests[1] on cifs I > > observe a null pointer dereference in cifs_flush_folio() because folio > > is null and dereferenced in size = folio_size(folio). > > Yeah. __filemap_get_folio() works differently in v6.1.y. There it returns a Let's cc hch so he's aware of how much pain this change caused. Never change function semantics without changing its name or arguments. > folio or NULL. In 6.7 it returns a folio or a negative error code. The error > check in cifs_flush_folio() needs to change to something like: > > folio = filemap_get_folio(inode->i_mapping, index); > if (!folio) > return -ENOMEM; > > David >
