From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 68FC1C3DA7A for ; Wed, 14 Oct 2026 20:06:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:MIME-Version:References:In-Reply-To:Message-ID:Subject:Cc:To: From:Date:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=J74yMVdROHOSqDpQt8vzdEHyhc79HiSag/0ZDT/dVDY=; b=JkFs/KMbdegPc00Ovq/NFd/syk e4gSxJLgbutTgj2WmrneXg88qawkx9DDg3+0Jf20KCbeB3UG0zpJiacku2IScQ988spUgCXqCrgmd EFi+a90kJrFPoHkoKeky8vN1Cf4LIgXI5DLJ1pb+L3fZ1ZuoOmJohAtT3QgEE1EWlISLb0vRbIIKU cXNUm+tYSuoLlWZylAoFyGVfcWzPSHdmPqiQbS52gnvRvs18VnRHNohRssJWPBOxVO/+W/bKcEK2k FgiTWv4O8jKpLixjJjIr/2ajlXBREA/pQdSgXFShu23+XRW0Uon+FYG6BQocxAynwmCTbwTfEuuZ9 Tr2SeBxg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1xH5F2-0000000GFFH-20XD; Wed, 14 Oct 2026 20:06:24 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1xH5Ez-0000000GFF8-2Iaq for linux-arm-kernel@lists.infradead.org; Wed, 14 Oct 2026 20:06:23 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id E1FB060098; Wed, 14 Oct 2026 20:06:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F23E51F000C4; Wed, 14 Oct 2026 20:06:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792008380; bh=J74yMVdROHOSqDpQt8vzdEHyhc79HiSag/0ZDT/dVDY=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=UimVmlXi6yp/94y2kx8+9uB1XS4sKw3as8nM/huU5VvzIfpO6YQj+6B/3woC3x+bo Ia83E6ptRq9nK09Ko/BAX3FEKoa/QyxBRSogLPpNKX4yY8Iipqh/+raj6DPo//etlG nZlFs+4m7TVIRKP9ik9L32WGXvL/2eEPpx5Vsh1vRl5ONRXe7vuWNsVS2BvDA4L9JV xBYyx5X3Y8PBKWfhiJAvBwHNjNsElFDqKrGJnx1tvNrIzlEAFunLD5ackAoLgTholU 8dFVU+1xGaRBSeyt+lV4BN1u2oUpiLZ4LnzQaopEz8AORu2Snv5R9sS/CWhwgIXomt CMX1cbJ/FGrHA== Date: Wed, 14 Oct 2026 13:06:18 -0700 From: Jakub Kicinski To: Nicolai Buchwitz Cc: "David S. Miller" , Eric Dumazet , Paolo Abeni , Simon Horman , Oleksij Rempel , Maxime Chevallier , Andrew Lunn , Maxime Coquelin , Alexandre Torgue , Jose Abreu , Saeed Mahameed , Tariq Toukan , Mark Bloch , Leon Romanovsky , Dragos Tatulea , Alexei Lazar , 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 Message-ID: <20261014130618.4c50f817@kernel.org> In-Reply-To: <20261007-nb-net-selftest-shared-net-v1-0-458369bfa1ba@tipi-net.de> References: <20261007-nb-net-selftest-shared-net-v1-0-458369bfa1ba@tipi-net.de> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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..