From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from www62.your-server.de (www62.your-server.de [213.133.104.62]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B593221767D; Thu, 5 Mar 2026 01:34:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.133.104.62 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772674462; cv=none; b=ZoYzQukiO8HU2bRKb4r9m3fsGCVwvIZzkJlwIe1fRzaRy9uRGbcfmUrOd7DsUIj7BkvUBfi4apGbQx/dyyNrTDWRWWiFHv35W7pd6kpOkb/e/oKq+bhqX+M9+mQqNDo6JLEgmmRaMM2yr3XQkv3+1E6e+AyyIMjupVlyuMqiDrk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772674462; c=relaxed/simple; bh=aMYArM3wUrHeJLKp8SWUzOqMDGiQhbwctNABT1AZ9EA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=CeP7ErsgjgoCHVrefpsUKBqcR0Q8jbh2zCLwbwmMp8KyLR1Rrzwc1yDJMR/XeHAmJWKJiOGCyV8Vy/wtMjZme+5/NUIxmV89cKvbbJ+6zw/G4bQi1p9ObZBQwsAO+QrYubFytLCQJSxODC020ALF/scA+Ws0SXA0+YuMyVxwMxQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=iogearbox.net; spf=pass smtp.mailfrom=iogearbox.net; dkim=pass (2048-bit key) header.d=iogearbox.net header.i=@iogearbox.net header.b=CUfFxA6J; arc=none smtp.client-ip=213.133.104.62 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=iogearbox.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=iogearbox.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=iogearbox.net header.i=@iogearbox.net header.b="CUfFxA6J" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=iogearbox.net; s=default2302; h=Content-Transfer-Encoding:Content-Type: In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date:Message-ID:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID; bh=lJnJYDr6bYaboKBefh84q3RkL2P5+oQDO0Dj0RFHaHI=; b=CUfFxA6JYUULdXWfLqMI3SwjlD O6mJ8K21nPXUty5nJdGQuzB7uPwhLngias97vcMbxcgZF02su5TyWn8oHGc+l4jUMxc2XtY/Uhk/g ToITGz7jF8MoANY8kRLz7+QFlNJ5kbV18a3civH8jSxgUWzN0ZST4KPzSWuqrBbLSfmJSuvCeMiwz 7gW0GzpGGG/bpHAb5pATQY+kHqJ4NTodrh+4xTuZi4JUokN/zwsqTdyBcfis9+HJuPxa3/uYVwNCq e4JbI5/7w4MBk98ugsVDAEweuGfyavXVT1sLkBkNyK98Mah0uieWvpNcOj1xX0x5ADqf14+doSTsC E3pC9DoQ==; Received: from sslproxy02.your-server.de ([78.47.166.47]) by www62.your-server.de with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (Exim 4.96.2) (envelope-from ) id 1vxxbR-0003aV-1w; Thu, 05 Mar 2026 02:34:13 +0100 Received: from localhost ([127.0.0.1]) by sslproxy02.your-server.de with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1vxxbP-000DWr-1w; Thu, 05 Mar 2026 02:34:11 +0100 Message-ID: <525dab04-4e64-49cf-94d9-12084e146b80@iogearbox.net> Date: Thu, 5 Mar 2026 02:34:00 +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 1/3] bpf: bpf_out_neigh_v4: Fix nd_tbl NULL dereference when IPv6 is disabled To: Fernando Fernandez Mancera , David Ahern , Jakub Kicinski Cc: =?UTF-8?Q?Ricardo_B=2E_Marli=C3=A8re?= , Martin KaFai Lau , John Fastabend , Stanislav Fomichev , Alexei Starovoitov , Andrii Nakryiko , Eduard Zingerman , Song Liu , Yonghong Song , KP Singh , Hao Luo , Jiri Olsa , "David S. Miller" , Eric Dumazet , Paolo Abeni , Simon Horman , =?UTF-8?Q?Toke_H=C3=B8iland-J=C3=B8rgensen?= , Jay Vosburgh , Andrew Lunn , Hangbin Liu , bpf@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260228-net-nd_tbl_fixes-v1-0-2b2a274df9bb@suse.com> <20260228-net-nd_tbl_fixes-v1-1-2b2a274df9bb@suse.com> <0b52257d-d557-4f26-9931-34c81ab621bc@iogearbox.net> <20260302171131.28373ccb@kernel.org> <0d7bb5c5-4122-4dc9-b52b-c305591207d1@suse.de> Content-Language: en-US From: Daniel Borkmann Autocrypt: addr=daniel@iogearbox.net; keydata= xsFNBGNAkI0BEADiPFmKwpD3+vG5nsOznvJgrxUPJhFE46hARXWYbCxLxpbf2nehmtgnYpAN 2HY+OJmdspBntWzGX8lnXF6eFUYLOoQpugoJHbehn9c0Dcictj8tc28MGMzxh4aK02H99KA8 VaRBIDhmR7NJxLWAg9PgneTFzl2lRnycv8vSzj35L+W6XT7wDKoV4KtMr3Szu3g68OBbp1TV HbJH8qe2rl2QKOkysTFRXgpu/haWGs1BPpzKH/ua59+lVQt3ZupePpmzBEkevJK3iwR95TYF 06Ltpw9ArW/g3KF0kFUQkGXYXe/icyzHrH1Yxqar/hsJhYImqoGRSKs1VLA5WkRI6KebfpJ+ RK7Jxrt02AxZkivjAdIifFvarPPu0ydxxDAmgCq5mYJ5I/+BY0DdCAaZezKQvKw+RUEvXmbL 94IfAwTFA1RAAuZw3Rz5SNVz7p4FzD54G4pWr3mUv7l6dV7W5DnnuohG1x6qCp+/3O619R26 1a7Zh2HlrcNZfUmUUcpaRPP7sPkBBLhJfqjUzc2oHRNpK/1mQ/+mD9CjVFNz9OAGD0xFzNUo yOFu/N8EQfYD9lwntxM0dl+QPjYsH81H6zw6ofq+jVKcEMI/JAgFMU0EnxrtQKH7WXxhO4hx 3DFM7Ui90hbExlFrXELyl/ahlll8gfrXY2cevtQsoJDvQLbv7QARAQABzSZEYW5pZWwgQm9y a21hbm4gPGRhbmllbEBpb2dlYXJib3gubmV0PsLBkQQTAQoAOxYhBCrUdtCTcZyapV2h+93z cY/jfzlXBQJjQJCNAhsDBQkHhM4ACAsJCAcNDAsKBRUKCQgLAh4BAheAAAoJEN3zcY/jfzlX dkUQAIFayRgjML1jnwKs7kvfbRxf11VI57EAG8a0IvxDlNKDcz74mH66HMyhMhPqCPBqphB5 ZUjN4N5I7iMYB/oWUeohbuudH4+v6ebzzmgx/EO+jWksP3gBPmBeeaPv7xOvN/pPDSe/0Ywp dHpl3Np2dS6uVOMnyIsvmUGyclqWpJgPoVaXrVGgyuer5RpE/a3HJWlCBvFUnk19pwDMMZ8t 0fk9O47HmGh9Ts3O8pGibfdREcPYeGGqRKRbaXvcRO1g5n5x8cmTm0sQYr2xhB01RJqWrgcj ve1TxcBG/eVMmBJefgCCkSs1suriihfjjLmJDCp9XI/FpXGiVoDS54TTQiKQinqtzP0jv+TH 1Ku+6x7EjLoLH24ISGyHRmtXJrR/1Ou22t0qhCbtcT1gKmDbTj5TcqbnNMGWhRRTxgOCYvG0 0P2U6+wNj3HFZ7DePRNQ08bM38t8MUpQw4Z2SkM+jdqrPC4f/5S8JzodCu4x80YHfcYSt+Jj ipu1Ve5/ftGlrSECvy80ZTKinwxj6lC3tei1bkI8RgWZClRnr06pirlvimJ4R0IghnvifGQb M1HwVbht8oyUEkOtUR0i0DMjk3M2NoZ0A3tTWAlAH8Y3y2H8yzRrKOsIuiyKye9pWZQbCDu4 ZDKELR2+8LUh+ja1RVLMvtFxfh07w9Ha46LmRhpCzsFNBGNAkI0BEADJh65bNBGNPLM7cFVS nYG8tqT+hIxtR4Z8HQEGseAbqNDjCpKA8wsxQIp0dpaLyvrx4TAb/vWIlLCxNu8Wv4W1JOST wI+PIUCbO/UFxRy3hTNlb3zzmeKpd0detH49bP/Ag6F7iHTwQQRwEOECKKaOH52tiJeNvvyJ pPKSKRhmUuFKMhyRVK57ryUDgowlG/SPgxK9/Jto1SHS1VfQYKhzMn4pWFu0ILEQ5x8a0RoX k9p9XkwmXRYcENhC1P3nW4q1xHHlCkiqvrjmWSbSVFYRHHkbeUbh6GYuCuhqLe6SEJtqJW2l EVhf5AOp7eguba23h82M8PC4cYFl5moLAaNcPHsdBaQZznZ6NndTtmUENPiQc2EHjHrrZI5l kRx9hvDcV3Xnk7ie0eAZDmDEbMLvI13AvjqoabONZxra5YcPqxV2Biv0OYp+OiqavBwmk48Z P63kTxLddd7qSWbAArBoOd0wxZGZ6mV8Ci/ob8tV4rLSR/UOUi+9QnkxnJor14OfYkJKxot5 hWdJ3MYXjmcHjImBWplOyRiB81JbVf567MQlanforHd1r0ITzMHYONmRghrQvzlaMQrs0V0H 5/sIufaiDh7rLeZSimeVyoFvwvQPx5sXhjViaHa+zHZExP9jhS/WWfFE881fNK9qqV8pi+li 2uov8g5yD6hh+EPH6wARAQABwsF8BBgBCgAmFiEEKtR20JNxnJqlXaH73fNxj+N/OVcFAmNA kI0CGwwFCQeEzgAACgkQ3fNxj+N/OVfFMhAA2zXBUzMLWgTm6iHKAPfz3xEmjtwCF2Qv/TT3 KqNUfU3/0VN2HjMABNZR+q3apm+jq76y0iWroTun8Lxo7g89/VDPLSCT0Nb7+VSuVR/nXfk8 R+OoXQgXFRimYMqtP+LmyYM5V0VsuSsJTSnLbJTyCJVu8lvk3T9B0BywVmSFddumv3/pLZGn 17EoKEWg4lraXjPXnV/zaaLdV5c3Olmnj8vh+14HnU5Cnw/dLS8/e8DHozkhcEftOf+puCIl Awo8txxtLq3H7KtA0c9kbSDpS+z/oT2S+WtRfucI+WN9XhvKmHkDV6+zNSH1FrZbP9FbLtoE T8qBdyk//d0GrGnOrPA3Yyka8epd/bXA0js9EuNknyNsHwaFrW4jpGAaIl62iYgb0jCtmoK/ rCsv2dqS6Hi8w0s23IGjz51cdhdHzkFwuc8/WxI1ewacNNtfGnorXMh6N0g7E/r21pPeMDFs rUD9YI1Je/WifL/HbIubHCCdK8/N7rblgUrZJMG3W+7vAvZsOh/6VTZeP4wCe7Gs/cJhE2gI DmGcR+7rQvbFQC4zQxEjo8fNaTwjpzLM9NIp4vG9SDIqAm20MXzLBAeVkofixCsosUWUODxP owLbpg7pFRJGL9YyEHpS7MGPb3jSLzucMAFXgoI8rVqoq6si2sxr2l0VsNH5o3NgoAgJNIg= In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: Clear (ClamAV 1.4.3/27930/Wed Mar 4 08:24:08 2026) On 3/4/26 5:13 PM, Fernando Fernandez Mancera wrote: > On 3/4/26 4:49 PM, David Ahern wrote: >> On 3/3/26 9:49 PM, Daniel Borkmann wrote: >>> Maybe the "fix" could be to just switch IPV6 from tristate to bool in >>> the Kconfig, and then once net merges into net-next we could deconstruct >>> all the helper cruft which makes the late on-demand module loading of >>> IPv6 work. >> >> +1 > > Maybe I am missing something here, but I believe this won't solve the problem. Even if ipv6 is built-in, it should be possible to pass ipv6.disable=1 during boot and therefore nd_tbl would still be uninitialized, not NULL tho. I presume you mean disable_ipv6_mod which then bails out during the module load process without error, right? It could be deprecated with a warning so that it turns into a no-op: diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c index 31ba677d0442..fdb8648647fd 100644 --- a/net/ipv6/af_inet6.c +++ b/net/ipv6/af_inet6.c @@ -1082,8 +1082,8 @@ static int __init inet6_init(void) raw_hashinfo_init(&raw_v6_hashinfo); if (disable_ipv6_mod) { - pr_info("Loaded, but administratively disabled, reboot required to enable\n"); - goto out; + pr_warn("The ipv6.disable module parameter has been deprecated and will be removed in future kernels.\n"); + disable_ipv6_mod = 0; } err = proto_register(&tcpv6_prot, 1);