Re: [PATCH] sysfs: upgrade OOB write by buggy .show hook into WARNing

[Alexey Dobriyan <adobriyan@gmail.com>]

On Thu, May 07, 2026 at 11:28:29AM +0200, Danilo Krummrich wrote:
> (Cc: driver-core)
> 
> On Thu May 7, 2026 at 11:01 AM CEST, Alexey Dobriyan wrote:
> > Buggy .show hook will get just 1 line of dmesg:
> >
> > 	fill_read_buffer: ext4_attr_show+0x0/0x600 returned bad count
> >
> > It may or may not oops later in some unrelated process.
> >
> > But buggy .show hook most likely is corrupting random memory past sysfs
> > buffer therefore deserving more. WARN, make it more visible and let
> > QA machines panic earlier.
> >
> > Also, delete useless cast -- "count" is >=0 at this point.
> >
> > Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
> 
> Reviewed-by: Danilo Krummrich <dakr@kernel.org>
> 
> NIT: This patch also cleans up the stale "fill_read_buffer:" prefix, and instead
> points out the actual caller, which could be mentioned in the commit message --
> no need to resend for this though.

Yes. WARN prints enough information to locate the bug, so stale function
name just goes away.