From: Breno Leitao <leitao@debian.org>
To: "Nikola Z. Ivanov" <zlatistiv@gmail.com>
Cc: kuba@kernel.org, andrew+netdev@lunn.ch, davem@davemloft.net,
edumazet@google.com, pabeni@redhat.com, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH net] netdevsim: Initialize all fields of ip header when building dummy sk_buff
Date: Tue, 21 Apr 2026 01:19:25 -0700 [thread overview]
Message-ID: <aecyEArzjx8KRp8-@gmail.com> (raw)
In-Reply-To: <20260421073738.22110-1-zlatistiv@gmail.com>
On Tue, Apr 21, 2026 at 10:37:38AM +0300, Nikola Z. Ivanov wrote:
> Syzbot reports a KMSAN uninit-value originating from
> nsim_dev_trap_skb_build, with the allocation also
> being performed in the same function.
>
> The cause of the KMSAN warning is a missing assignment of
> the tos and id fields of the ip header.
>
> Fix this by calling skb_put_zero instead of skb_put to
> guarantee null initialization.
> Additionally remove the now redundant zero assignments
> and reorder the remaining ones so that they more closely
> match the order of the fields as they appear in the ip header.
>
> 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"?
Thanks for the fix,
--breno
next prev parent reply other threads:[~2026-04-21 8:19 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-21 7:37 [PATCH net] netdevsim: Initialize all fields of ip header when building dummy sk_buff Nikola Z. Ivanov
2026-04-21 8:19 ` Breno Leitao [this message]
2026-04-21 8:54 ` Nikola Z. Ivanov
2026-04-21 9:12 ` Breno Leitao
2026-04-21 11:44 ` Nikola Z. Ivanov
2026-04-21 15:20 ` Jakub Kicinski
2026-04-23 2:48 ` Jakub Kicinski
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