Re: [PATCH net] netdevsim: Initialize all fields of ip header when building dummy sk_buff

Breno Leitao
2026-04-21T09:12:42Z

On Tue, Apr 21, 2026 at 11:54:19AM +0300, Nikola Z. Ivanov wrote:
> On 4/21/26 11:19 AM, Breno Leitao wrote:
> > On Tue, Apr 21, 2026 at 10:37:38AM +0300, Nikola Z. Ivanov wrote:
> > >
> > > Closes: https://syzkaller.appspot.com/bug?extid=23d7fcd204e3837866ff
> >
> > How do you check in the report above that the missig un-initialized
> > fields are "tos" and "id"?
>
> I don't think it is visible here, my guess would
> be because the checksum calculator walks the
> header in small chunks instead of referencing
> its fields.
>
> The whole "KMSAN: uninit-value in irqentry_exit_to_kernel_mode_preempt"
> doesn't really sound quite right.

That's precisely my question - how does this fix relate to that specific
report?

Were you able to reproduce the KMSAN report?

Thanks for the quick answer,
--breno