Re: [syzbot] WARNING in mntput_no_expire (2)

From: Al Viro
Date: Sun Apr 04 2021 - 16:17:40 EST


On Sun, Apr 04, 2021 at 06:50:10PM +0000, Al Viro wrote:

> > Yeah, I have at least namei.o
> >
> > https://drive.google.com/file/d/1AvO1St0YltIrA86DXjp1Xg3ojtS9owGh/view?usp=sharing
>
> *grumble*
>
> Is it reproducible without KASAN? Would be much easier to follow the produced
> asm...

Looks like inode_permission(_, NULL, _) from may_lookup(nd). I.e.
nd->inode == NULL.

Mind slapping BUG_ON(!nd->inode) right before may_lookup() call in
link_path_walk() and trying to reproduce that oops?