From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-188.mta0.migadu.com (out-188.mta0.migadu.com [91.218.175.188]) (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 D46581CAA7D for ; Wed, 1 Jul 2026 06:21:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.188 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782886882; cv=none; b=p6XY4Y1gR2yGG+Bis85hM2SmN0HMN/cRg+P49+IFQ2b/aS8E+KlkOCJGrHkwuyhAxFmwZjy3sj711WfcNBDiTZFmBKuuiYnICgAzGPUEuyv6pSkl+FPKdr8z/2FXdjAJh9DGkjpMkC53lbfTvXbM9oL5VFrr8l0N46f1Jx4oXuw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782886882; c=relaxed/simple; bh=T6VVV/sZwKH2UqabUKP3L89K2WchKWmMle57esVdtyM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=s3KBaXIdSCX2f3jZPwqL8U5l2ZhUffpJpV9esFLYkbliT05S7F0m/gEmd2Rxlj/xlTbJ6TGx9jaIrySK/ls4YlDCA6gp8GRSDcPvSaVEQ1MmrxENieDywepwi9oc5xXUHLN4u3MtOy8PYZCDx5XjtpNO13++1KQeD17T91PuZyE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=hqhY1jAB; arc=none smtp.client-ip=91.218.175.188 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="hqhY1jAB" Message-ID: <945b57b1-c2ed-44d2-8fa7-07300930783c@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1782886869; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=T6VVV/sZwKH2UqabUKP3L89K2WchKWmMle57esVdtyM=; b=hqhY1jABygfGs3qJ4+bHhAwOBA3a0eSaaDMrYfEat8rIkzElEg1iXPu5WsneIzWRyIype+ +E1mm5yk3AOrTdw28j3EHl+WnHj8uosW136zpVjjCXpiEqJsh5A/2TTiKHrTGipD5S15Lw xweA96yn808zBEJ0mfRl7k4OfX9SNJk= Date: Wed, 1 Jul 2026 14:20:57 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [RFC PATCH bpf 0/6] bpf: Disallow interpreter fallback for interpreter-unsupported insns Content-Language: en-US To: Alexei Starovoitov , bpf@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , John Fastabend , Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi , Martin KaFai Lau , Song Liu , Yonghong Song , Jiri Olsa , Emil Tsalapatis , Andrew Morton , Shuah Khan , Puranjay Mohan , Anton Protopopov , linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org References: <20260626154330.33619-1-leon.hwang@linux.dev> <18678d0c-f878-4d7b-bf7e-ffca4967dec5@linux.dev> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Leon Hwang In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT On 1/7/26 13:50, Alexei Starovoitov wrote: > On Tue Jun 30, 2026 at 7:59 PM PDT, Leon Hwang wrote: >> On 1/7/26 07:12, Alexei Starovoitov wrote: >>> On Fri Jun 26, 2026 at 8:43 AM PDT, Leon Hwang wrote: >> [...] >>> >>> I don't think we need such fallback in patch [3]. >> >> Do you mean we can add the internal BPF_ADDR_PERCPU insn support to the >> interpreter? > > No. See why CONFIG_BPF_JIT_ALWAYS_ON was introduced. > The interpreter is a security hole. Got it. The commit message of 290af86629b2 ("bpf: introduce BPF_JIT_ALWAYS_ON config") has explained the security concern. > It has to be _compiled out_ of the kernel. > Hence all patches that improve fallback to interpreter are misguided. > The interpreter has to be removed completely... sooner or later. Will disallow interpreter fallback for the internal BPF_ADDR_PERCPU insn. Thanks, Leon