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([2620:10d:c092:600::1:b123]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-84edbd3a4b6sm2475959b3a.4.2026.08.02.05.33.01 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 02 Aug 2026 05:33:11 -0700 (PDT) Message-ID: <11a640b6-46b1-44d6-aee6-872107f7f570@gmail.com> Date: Sun, 2 Aug 2026 13:33:02 +0100 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net v1 1/3] net: core: propagate unreadable flag in skb_zerocopy To: Mina Almasry Cc: Stanislav Fomichev , Bobby Eshleman , Florian Westphal , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Jason Xing , Kuniyuki Iwashima , =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= , Jiayuan Chen , Willem de Bruijn , Kaiyuan Zhang , "open list:NETWORKING [GENERAL]" , open list References: <20260801125308.1342897-1-almasrymina@google.com> Content-Language: en-US From: Pavel Begunkov In-Reply-To: <20260801125308.1342897-1-almasrymina@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 8/1/26 13:52, Mina Almasry wrote: > When skb_zerocopy() copies devmem payload fragments, it fails to update > the target skb's unreadable flag. This causes the target to appear as > readable memory. > > Propagate the unreadable flag if any devmem fragments were copied from > the source. From a quick look, it doesn't seem like the function would work reliably with netmems even with this patch, but that's a different kind of issue we can return to later. Curious, did you hit this in prod? Reviewed-by: Pavel Begunkov > Fixes: 65249feb6b3d ("net: add support for skbs with unreadable frags") > Cc: Pavel Begunkov > Cc: Stanislav Fomichev > Cc: Bobby Eshleman > Cc: Florian Westphal > Signed-off-by: Mina Almasry > --- > net/core/skbuff.c | 3 +++ > 1 file changed, 3 insertions(+) -- Pavel Begunkov