From: Kuniyuki Iwashima <kuniyu@google.com>
To: Jiayuan Chen <jiayuan.chen@linux.dev>
Cc: netdev@vger.kernel.org, stable@vger.kernel.org,
Fernando Fernandez Mancera <fmancera@suse.de>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@kernel.org>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Simon Horman <horms@kernel.org>,
Jonathan Corbet <corbet@lwn.net>,
Shuah Khan <skhan@linuxfoundation.org>,
Randy Dunlap <rdunlap@infradead.org>,
David Ahern <dsahern@kernel.org>,
Ido Schimmel <idosch@nvidia.com>,
Joel Granados <joel.granados@kernel.org>,
Thomas Gleixner <tglx@kernel.org>,
Petr Pavlu <petr.pavlu@suse.com>,
Maoyi Xie <maoyi.xie@ntu.edu.sg>,
Jiri Wiesner <jwiesner@suse.de>, Oleg Nesterov <oleg@redhat.com>,
Gerd Rausch <gerd.rausch@oracle.com>,
Neal Cardwell <ncardwell@google.com>,
Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com>,
Yung Chih Su <yuuchihsu@gmail.com>,
Wyatt Feng <bronzed_45_vested@icloud.com>,
Hannes Frederic Sowa <hannes@stressinduktion.org>,
Flavio Leitner <fbl@redhat.com>,
"Paul E. McKenney" <paulmck@kernel.org>,
Petr Mladek <pmladek@suse.com>,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH net v3 4/5] ipv4: restrict igmp_qrv to 255
Date: Tue, 3 Nov 2026 05:29:31 +0000 [thread overview]
Message-ID: <aulxMqNrVTWFRuv3@google.com> (raw)
In-Reply-To: <20261101061331.286404-5-jiayuan.chen@linux.dev>
On Sun, 01 Nov 2026 14:12:02 +0800, Jiayuan Chen wrote:
> net.ipv4.igmp_qrv only has a lower bound, but ip_mc_reset() stores it
> into the u8 in_device::mr_qrv, and the IGMPv3 retransmit counters filled
> from it (crcount, sf_crcount) are u8 as well. Anything above 255
> silently wraps. With 256, mr_qrv becomes 0, every
> "in_dev->mr_qrv ?: sysctl_igmp_qrv" falls back to 256, which truncates
> to 0 again in crcount, and igmpv3_send_cr() never puts the state change
> records for the group into a report. The older version querier present
> timeout (mr_qrv * mr_qi + mr_qri) also collapses to just mr_qri.
>
> Make the sysctl a u8 like mr_qrv and switch to proc_dou8vec_minmax(),
> which rejects anything above 255, and document it.
>
> Fixes: a9fe8e29945d ("ipv4: implement igmp_qrv sysctl to tune igmp robustness variable")
> Cc: stable@vger.kernel.org
> Reviewed-by: Fernando Fernandez Mancera <fmancera@suse.de>
> Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
next prev parent reply other threads:[~2026-11-03 5:29 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-01 6:11 [PATCH net v3 0/5] net: fix misc signed overflows caused by bad sysctl values Jiayuan Chen
2026-11-01 6:11 ` [PATCH net v3 1/5] ipv6: restrict gc_elasticity to 31 Jiayuan Chen
2026-11-02 1:25 ` Hangbin Liu
2026-11-01 6:12 ` [PATCH net v3 2/5] ipv4: fix shift-out-of-bounds in ip_rt_send_redirect() Jiayuan Chen
2026-11-03 5:28 ` Kuniyuki Iwashima
2026-11-01 6:12 ` [PATCH net v3 3/5] ipv6: restrict mld_qrv to 255 Jiayuan Chen
2026-11-01 10:23 ` Nikolay Aleksandrov
2026-11-02 1:31 ` Hangbin Liu
2026-11-03 5:29 ` Kuniyuki Iwashima
2026-11-01 6:12 ` [PATCH net v3 4/5] ipv4: restrict igmp_qrv " Jiayuan Chen
2026-11-02 1:29 ` Hangbin Liu
2026-11-03 5:29 ` Kuniyuki Iwashima [this message]
2026-11-01 6:12 ` [PATCH net v3 5/5] net: restrict message_cost and message_burst to non-negative values Jiayuan Chen
2026-11-02 1:55 ` Hangbin Liu
2026-11-02 2:23 ` Jiayuan Chen
2026-11-02 3:32 ` Hangbin Liu
2026-11-03 5:30 ` Kuniyuki Iwashima
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