On Sat, 15 Jun 2024 21:44:54 +0100 Matthew Wilcox wrote:
>
> I suspect this would trigger:
>
> +++ b/fs/inode.c
> @@ -282,6 +282,7 @@ static struct inode *alloc_inode(struct super_block *sb)
> void __destroy_inode(struct inode *inode)
> {
> BUG_ON(inode_has_buffers(inode));
> + BUG_ON(inode->i_data.nrpages);
> inode_detach_wb(inode);
> security_inode_free(inode);
> fsnotify_inode_delete(inode);
>
Yes, it was triggered [1]
[1] https://lore.kernel.org/lkml/00000000000084b401061af6ab80@xxxxxxxxxx/
and given trigger after nrpages is checked in clear_inode(),
iput(inode)
evict(inode)
truncate_inode_pages_final(&inode->i_data);
clear_inode(inode);
destroy_inode(inode);
why is folio added to exiting mapping?
#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 83a7eefedc9b
--- x/mm/filemap.c
+++ y/mm/filemap.c
@@ -870,6 +870,7 @@ noinline int __filemap_add_folio(struct
folio_ref_add(folio, nr);
folio->mapping = mapping;
folio->index = xas.xa_index;
+ BUG_ON(mapping_exiting(mapping));
for (;;) {
int order = -1, split_order = 0;
--
