Re: [PATCHv2 bpf] bpf: Check the helper function is valid in get_helper_proto

[Jiri Olsa <olsajiri@gmail.com>]

On Thu, Aug 14, 2025 at 03:53:14PM +0200, Paul Chaignon wrote:
> On Wed, Aug 13, 2025 at 03:38:32PM +0200, Jiri Olsa wrote:
> > From: Jiri Olsa <olsajiri@gmail.com>
> > 
> > syzbot reported an verifier bug [1] where the helper func pointer
> > could be NULL due to disabled config option.
> > 
> > As Alexei suggested we could check on that in get_helper_proto
> > directly. Excluding tail_call helper from the check, because it
> > is NULL by design and valid in all configs.
> > 
> > [1] https://lore.kernel.org/bpf/68904050.050a0220.7f033.0001.GAE@google.com/
> > Reported-by: syzbot+a9ed3d9132939852d0df@syzkaller.appspotmail.com
> 
> The same bug was reported before by the kernel test robot at
> https://lore.kernel.org/oe-lkp/202507160818.68358831-lkp@intel.com, so
> I guess we'll need:
> 
> Reported-by: kernel test robot <oliver.sang@intel.com>
> Closes: https://lore.kernel.org/oe-lkp/202507160818.68358831-lkp@intel.com
> 
> With that,
> 
> Acked-by: Paul Chaignon <paul.chaignon@gmail.com>

thanks, will fix

jirka