From: Jakub Kicinski <kuba@kernel.org>
To: Nicolai Buchwitz <nb@tipi-net.de>
Cc: "David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@kernel.org>,
Paolo Abeni <pabeni@redhat.com>, Simon Horman <horms@kernel.org>,
Oleksij Rempel <o.rempel@pengutronix.de>,
Maxime Chevallier <maxime.chevallier@bootlin.com>,
Andrew Lunn <andrew+netdev@lunn.ch>,
Maxime Coquelin <mcoquelin.stm32@gmail.com>,
Alexandre Torgue <alexandre.torgue@foss.st.com>,
Jose Abreu <Jose.Abreu@synopsys.com>,
Saeed Mahameed <saeedm@nvidia.com>,
Tariq Toukan <tariqt@nvidia.com>, Mark Bloch <mbloch@nvidia.com>,
Leon Romanovsky <leon@kernel.org>,
Dragos Tatulea <dtatulea@nvidia.com>,
Alexei Lazar <alazar@nvidia.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-stm32@st-md-mailman.stormreply.com,
linux-arm-kernel@lists.infradead.org, linux-rdma@vger.kernel.org
Subject: Re: [PATCH net-next 0/3] net: use skb_share_check() in loopback selftest hooks
Date: Wed, 14 Oct 2026 13:06:18 -0700 [thread overview]
Message-ID: <20261014130618.4c50f817@kernel.org> (raw)
In-Reply-To: <20261007-nb-net-selftest-shared-net-v1-0-458369bfa1ba@tipi-net.de>
On Wed, 07 Oct 2026 20:29:21 +0200 Nicolai Buchwitz wrote:
> The loopback selftest hooks can get a shared skb when another handler
> is bound to the device. Linearizing a non-linear frame then hits
> BUG_ON(skb_shared()) in pskb_expand_head().
>
> Stumbled over this on RPi CM4 (bcmgenet, with jumbo series applied +
> WIP selftest patches) with a packet socket open at the same time as
> running ethtool -t.
>
> stmmac and mlx5 seem to have the same pattern, xgbe already handles
> shared skbs. Patches 2 and 3 are compile tested only.
>
> As the impact is pretty limited and doesn't seem to bother anyone in
> the wild, I've chosen net-next, but kept the Fixes tags. That matches
> what Paolo suggested during the LPC track.
Wonder if we should follow up and rename skb_unshare to skb_unclone_full
or some such? The "share" in the name is quite confusing for people who
haven't been around for 10+ years..
next prev parent reply other threads:[~2026-10-14 20:06 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-07 18:29 [PATCH net-next 0/3] net: use skb_share_check() in loopback selftest hooks Nicolai Buchwitz
2026-10-07 18:29 ` [PATCH net-next 1/3] net: selftests: use skb_share_check() in the loopback receive hook Nicolai Buchwitz
2026-10-08 21:31 ` netdev-bot+sashiko
2026-10-09 6:49 ` Nicolai Buchwitz
2026-10-09 16:59 ` Simon Horman
2026-10-07 18:29 ` [PATCH net-next 2/3] net: stmmac: " Nicolai Buchwitz
2026-10-09 16:59 ` Simon Horman
2026-10-07 18:29 ` [PATCH net-next 3/3] net/mlx5e: use skb_share_check() in the loopback selftest hook Nicolai Buchwitz
2026-10-08 21:31 ` netdev-bot+sashiko
2026-10-09 8:37 ` Nicolai Buchwitz
2026-10-09 17:00 ` Simon Horman
2026-10-12 19:07 ` Tariq Toukan
2026-10-14 20:06 ` Jakub Kicinski [this message]
2026-10-14 21:02 ` [PATCH net-next 0/3] net: use skb_share_check() in loopback selftest hooks Nicolai Buchwitz
2026-10-14 21:40 ` patchwork-bot+netdevbpf
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