Re: [PATCH 1/2] mm/huge_memory: skip invalid debugfs file entry for folio split

[Luis Chamberlain]

On Mon, Apr 29, 2024 at 09:23:07AM -0700, Andrew Morton wrote:
> On Sun, 28 Apr 2024 21:04:50 -0700 Luis Chamberlain <mcgrof@xxxxxxxxxx> wrote:
> 
> > On Thu, Apr 25, 2024 at 02:01:26PM -0700, Andrew Morton wrote:
> > > On Wed, 24 Apr 2024 15:54:48 -0700 Luis Chamberlain <mcgrof@xxxxxxxxxx> wrote:
> > > 
> > > > If the file entry is too long we may easily end up going out of bounds
> > > > and crash after strsep() on sscanf(). 
> > > > 
> > > 
> > > Can you explain why?  I'm not seeing it.
> > 
> > I couldn't see it either but I just looked at the crash below and
> > its the only thing I could think of. So I think its when userspace
> > somehow abuses MAX_INPUT_BUF_SZ a lot somehow.
> 
> This isn't a good basis for making kernel changes :(
> 
> Can you investigate a little further please?

Sure, this will require some more time, feel free to ignore these two
patches for now then.

  Luis