From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-lj1-f180.google.com (mail-lj1-f180.google.com [209.85.208.180]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D50F718DF60; Wed, 2 Oct 2024 13:36:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.180 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727876202; cv=none; b=svT64e/au2gQUTGB6lUkAItQGgMHyhef1b/9Fla9HVGEvdYIBYFpi4iVAPhF5XiZIajVU5sHO8zn2x09FPNkyxooMcRCKudlUrOezmCpRifqsukvyCYAi11PIlD6gOW4a64zONIsiD7cF1nOe9sXlxUzbOuILpFpb+XHq2FqvrA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727876202; c=relaxed/simple; bh=q5ZkCgADhBZHl7oDwalsHIstFb7FyHGt5fNF8Px/R0E=; h=Subject:To:Cc:References:From:Message-ID:Date:MIME-Version: In-Reply-To:Content-Type; b=kNBP5dyEX38JQw121M+unZRRGaZNA7rqRNuU0it+xlddig0FCHI0LdKVEh/cLvIfHwlt+TRMJ0Ts8ogS2bgdl6iDduTWqFJw8vgFfN+7WZiUyA4zx0GXsWqyMkYNk2pVVpHKhTVwO4uazpacBibBAL8A5ZX0piEtqG8AjMTIAUI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=ItAsTeOf; arc=none smtp.client-ip=209.85.208.180 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="ItAsTeOf" Received: by mail-lj1-f180.google.com with SMTP id 38308e7fff4ca-2faccccbca7so31411291fa.2; Wed, 02 Oct 2024 06:36:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1727876199; x=1728480999; darn=vger.kernel.org; h=content-transfer-encoding:content-language:in-reply-to:mime-version :user-agent:date:message-id:from:references:cc:to:subject:from:to:cc :subject:date:message-id:reply-to; bh=wMUkkI59XlnjFeOEzlmttnyMpJecab4sH6mMElSC+Oo=; b=ItAsTeOfwjx1WVdWQ+Q++Lp+FCmJADQsrpqp2lQvMxA4QCvA8Fl1q9RW0NZGSa1yu0 xtZJXIJxxggqeULKESaRyAYWgX2tgEKrYh7PLAoxfyCWaIiaR4aDPjnDYVL2BVin7HXT GLuRdAAu47Q1XpI5Yq4VmAeWJvB4HOn5GHjFpKnS2Q5Pp4j5b92nqGJUMyrds/75WG8M ZUGbq1V6VnyDOaG6R0bGSFPwREdFaA6ENZzsIYzJnj8q0S7ZxV3/VLHyJQvyCg+AI1uh NKhizjWd5/RVlrXdzHculpka0f/I35KQvGEIFweq/+4svrZklgRF0KIvL5Lv9y8qA2nW N6Bw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1727876199; x=1728480999; h=content-transfer-encoding:content-language:in-reply-to:mime-version :user-agent:date:message-id:from:references:cc:to:subject :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=wMUkkI59XlnjFeOEzlmttnyMpJecab4sH6mMElSC+Oo=; b=gzNZ0rMnqpdNAEOK9SfyMGLkUTvFmvRjgzHsndrBZoB+7gDis6LOGHaynUWX6pjMr4 +qvi4wwM82hZAxgPkoDnUpctJ/nt/a+0JCo4tgWrvDxWQuO1/y5JmFqsXdgf4Y9DBUXG id7KbFB1VsOCZXeVbcbymlKYIFMAwWXFrsaPJAh9/fCeUe9BQT2eQOyM0mfcocZogGK4 aLc+h+CwU6a0y0W/EJEMC1lr6n7iV90L5DaHvLB96V5si9Ikz4iUZMjIYy82ASilrmFF Ooha5xQmlUg9s1U5xZkjZQPKCMKAJ8fQl/QW1/fwEhM1cEy2UwHWO3cDBqGFbBqlvxiV W/5w== X-Forwarded-Encrypted: i=1; AJvYcCVkNphg90ZXy+zTgD0XGCT/aVDRarmLmfwh3N7uKYz8xwnLwNhimkyCUW1JVYBBCNepIko=@vger.kernel.org, AJvYcCW5B1Y8WX+yrbjimW2xMbdZ6rFUuygW73hmXnRXsxfKxiwUmFl9GRSQOvLjRyerefFsN778HRQz@vger.kernel.org X-Gm-Message-State: AOJu0YzpFON37UgfuLXJU/OfRUrNbbJKV6vP0KOQvz74YmiAOJ1x+spS ciaWiQT9NBVSlfc/tcKSg5jSXb1lAwRv/JTPpLYx4JQhTByWB3BQ X-Google-Smtp-Source: AGHT+IHHkz5Ebi30JV7ibbxjE4ZedXGtGwgY4Rri5mgNFizv+ZYBDL8OqlSEe8L+5FmGQ4DnRoTm1g== X-Received: by 2002:a2e:751:0:b0:2fa:dce8:7387 with SMTP id 38308e7fff4ca-2fae107f75bmr16016341fa.32.1727876198578; Wed, 02 Oct 2024 06:36:38 -0700 (PDT) Received: from [192.168.1.122] (cpc159313-cmbg20-2-0-cust161.5-4.cable.virginm.net. [82.0.78.162]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-5c882493e54sm7664465a12.80.2024.10.02.06.36.37 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 02 Oct 2024 06:36:37 -0700 (PDT) Subject: Re: [PATCH net] sfc: Don't invoke xdp_do_flush() from netpoll. To: Sebastian Andrzej Siewior , netdev@vger.kernel.org, linux-net-drivers@amd.com, bpf@vger.kernel.org Cc: "David S. Miller" , =?UTF-8?Q?Toke_H=c3=b8iland-J=c3=b8rgensen?= , Alexei Starovoitov , Daniel Borkmann , Eric Dumazet , Jakub Kicinski , Jesper Dangaard Brouer , John Fastabend , Martin Habets , Paolo Abeni , Thomas Gleixner , Yury Vostrikov References: <20241002125837.utOcRo6Y@linutronix.de> From: Edward Cree Message-ID: <48bb0155-cc1a-b72c-2d04-98d28adb467b@gmail.com> Date: Wed, 2 Oct 2024 14:36:36 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.14.0 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: <20241002125837.utOcRo6Y@linutronix.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit On 02/10/2024 13:58, Sebastian Andrzej Siewior wrote: > Yury reported a crash in the sfc driver originated from > netpoll_send_udp(). The netconsole sends a message and then netpoll > invokes the driver's NAPI function with a budget of zero. It is > dedicated to allow driver to free TX resources, that it may have used > while sending the packet. > > In the netpoll case the driver invokes xdp_do_flush() unconditionally, > leading to crash because bpf_net_context was never assigned. > > Invoke xdp_do_flush() only if budget is not zero. > > Fixes: 401cb7dae8130 ("net: Reference bpf_redirect_info via task_struct on PREEMPT_RT.") > Reported-by: Yury Vostrikov > Closes: https://lore.kernel.org/5627f6d1-5491-4462-9d75-bc0612c26a22@app.fastmail.com > Signed-off-by: Sebastian Andrzej Siewior Reviewed-by: Edward Cree