On Sun 16-06-24 10:39:51, Hillf Danton wrote:
> 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
OK, so based on syzbot results this seems to be a bug in
nilfs_evict_inode() (likely caused by corrupted filesystem so that root
inode's link count was 0 and hence was getting deleted on iput()). I guess
nilfs maintainers need to address these with more consistency checks of
metadata when loading them...
Honza
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
