Re: fuse: kernel BUG at mm/truncate.c:763!

[Matthew Wilcox]

On Mon, Mar 15, 2021 at 09:47:45AM +0000, Luis Henriques wrote:
> On Fri, Mar 12, 2021 at 01:11:23PM +0000, Matthew Wilcox wrote:
> > On Fri, Mar 12, 2021 at 12:21:59PM +0000, Luis Henriques wrote:
> > > > > I've seen a bug report (5.10.16 kernel splat below) that seems to be
> > > > > reproducible in kernels as early as 5.4.
> > 
> > If this is reproducible, can you turn this BUG_ON into a VM_BUG_ON_PAGE()
> > so we know what kind of problem we're dealing with?  Assuming the SUSE
> > tumbleweed kernels enable CONFIG_DEBUG_VM, which I'm sure they do.
> 
> Just to make sure I got this right, you want to test something like this:
> 
>  				}
>  			}
> -			BUG_ON(page_mapped(page));
> +			VM_BUG_ON_PAGE(page_mapped(page), page);
>  			ret2 = do_launder_page(mapping, page);
>  			if (ret2 == 0) {
>  				if (!invalidate_complete_page2(mapping, page))

Yes, exactly.