From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ej1-f51.google.com (mail-ej1-f51.google.com [209.85.218.51]) (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 2889C2931F1 for ; Wed, 15 Jul 2026 03:02:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.218.51 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784084539; cv=none; b=OEFvXtUVNoFtbfHkuH6mEa5JLVdtKF7sysxVAQCpV4LalVFsVhKrgQD9s4K06TLllUYeR4Agc14vThCvmfjbYnH+OGF4VwtLKVf8nD8PWSz2bOo41kHEjtPvpi5l+TTSPfRnloenicVp248tzj21rZnsUNnKYu35Nm0m2he5qdQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784084539; c=relaxed/simple; bh=Pyp2DnCViCnJgUi88+R0XBfifCiYiXiV56seNpVS6sg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=HkEAZH43l23272B/mbo3ybjq43OuDO9ltEcEfMZqlAGtcjIWuusLTyGVho28RNKMLsyZR51IfvzevbuskjIG041TOcvd27tVCigZJRieW/9S3BWd8qTE6ZBsKZcq7eMylh7YKRcyN23qSdPi3DTbIwTED3Jizf4xCmBgXxxL2/A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com; spf=pass smtp.mailfrom=suse.com; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b=CgJACLJ9; arc=none smtp.client-ip=209.85.218.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b="CgJACLJ9" Received: by mail-ej1-f51.google.com with SMTP id a640c23a62f3a-c15cd3fd760so567932766b.2 for ; Tue, 14 Jul 2026 20:02:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1784084536; x=1784689336; darn=vger.kernel.org; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:from:to:cc:subject :date:message-id:reply-to:content-type; bh=hOjABmuvBW+jCcuokYEE7Gv19LjuO15ZtZi5onZDlks=; b=CgJACLJ98v8bx0a5WjsLkmXa0c45JEdSrekLF6tl5Fk22ghzpLJUvgFKQNzQTq8Ifl /ETsYk5Eo6xIB43MhUwOTHfm6l/60rKnMk3z77HYo3eisYf7NRzZMM+qx11ZKE/B/IiZ vklNHjKz3M8XNO8/Ulp4B/L3Ont5OEf+hb9qmZq7FfrXmYIOgTLvsYr1mcGB8om87koA eNoJog5ZJsjRDPz3ZRg0hRIWoIoPBCEPrG28tjn73CcgQw9BSKK4PCVnl0TowIaMCQJl cKRfYR0ykvJXtO91SW3ILye1CqC2a48Lpg1PjvVqZVEEk6hLo2Llro4s7MO2IjdwzHBW PEJQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1784084536; x=1784689336; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=hOjABmuvBW+jCcuokYEE7Gv19LjuO15ZtZi5onZDlks=; b=JbdXpTRwKLIOAJap3nU6wFM2qBCfi4Qr/mP2VC7QUE7c/HT6fLomQvj2P9fEAe7OIj ZdWWDtJv48PXVgsV0VXHIkKBLYiKbJ51Lm438GfKpF3QjPxPkJAKy2YpR+W8cPmcDZPU Skr6XvCUoUDIMrah8iPf02Oyr8QkWBOEunE2v3F0qtMi0DvRzknYtbew91pkuHBHDNp6 35BRYKc44scuT+VX8P/ICcvzVWjtVGHypS6RtpGY3k6+oAO9K+uhvnYTKWjOVUvVFExX T6i+m8R+94Bf0N+L5cGljEud3Tim/mgyUGysO7wwzNpeKoK2E8FgSukL3c4kGZWsDgQP T1+Q== X-Forwarded-Encrypted: i=1; AHgh+Ro04irtM0qrWTJoKuGic1vaP0I5MDPmA45CXl7kJqOyejYZIjwrKsr6rogtlb1lKHEPzu+Hu1s=@vger.kernel.org X-Gm-Message-State: AOJu0Yxe/8rR6UKPI+tx6DvyR0bguiiijVwZZlbY0ppS3SCmNf87Td2Z 2KNWytQXIEeOnV1eRmF0UQhr1ERhSSL8SqkqobvLOQMMIVrc76DfBDrrKdv/R6yWzYg= X-Gm-Gg: AfdE7cnxiVpOi5k7FjOXZwnHIfbAUWZCI/u0aZPO5iE4PC7Duo9Em0bK+C/yFNre+7Q q/MeHLS4d4X2NUg/xWgDhXLR0bjzG1L0bPKPqcgVqSRLhU/i32ENhAhwqGo6FQKNRnZBas9tZEe zgahb5iY6IISq+QlBmUCFsBEgor1yyAawkKCc72vtTMAKKDMtWilQACgnJQRA3wADPNdlNG8Uya FpirDBolawuzX9NY+JaZFJHIPbe9wmNAzWUKm2KHHeYp4wJvhDhuMXfC2lex/xnb+aBFRqWbLVQ XHXGsLfPlI2wwQfnSxnQqKb7pCVFSzH08jAMD6Vc2vaTeIvyXLmN3F6/lncU4Z7hwU8Tc/EIB4d iJSRIbKs1QzPJqNkoQ1cKZdaqD+1YPFa31uYQ7jX+QE/L2R1OVsCm7lsBNN43QwwcR7ojlqJlgh L+rAInxVGIsO/pUTPBv66wrMf5UYACgcby X-Received: by 2002:a17:907:f815:b0:bb7:eb68:514e with SMTP id a640c23a62f3a-c167940e66bmr67514766b.36.1784084536316; Tue, 14 Jul 2026 20:02:16 -0700 (PDT) Received: from u94a (27-51-89-168.adsl.fetnet.net. [27.51.89.168]) by smtp.gmail.com with ESMTPSA id 006d021491bc7-6a39a4a7797sm7988739eaf.6.2026.07.14.20.02.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 14 Jul 2026 20:02:14 -0700 (PDT) Date: Wed, 15 Jul 2026 11:02:02 +0800 From: Shung-Hsi Yu To: Sun Jian Cc: bpf@vger.kernel.org, Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Eduard Zingerman , Emil Tsalapatis , Jiri Olsa , John Fastabend , Kumar Kartikeya Dwivedi , Martin KaFai Lau , Shuah Khan , Song Liu , Yonghong Song , Matt Mullins , linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH bpf v5 2/2] selftests/bpf: Cover negative buffer pointer offsets Message-ID: References: <20260714093846.18159-1-sun.jian.kdev@gmail.com> <20260714093846.18159-3-sun.jian.kdev@gmail.com> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260714093846.18159-3-sun.jian.kdev@gmail.com> On Tue, Jul 14, 2026 at 02:38:46AM -0700, Sun Jian wrote: > Add verifier coverage for constant negative offsets on PTR_TO_TP_BUFFER > and PTR_TO_BUF pointers. Both programs adjust the buffer pointer by -8 > and access it at offset zero, so the negative effective start must be > rejected at load time. > > Switch the raw tracepoint writable attach checks from nbd_send_request > to bpf_testmod_test_writable_bare_tp, avoiding a dependency on the NBD > tracepoint. Keep the existing past-end case and add a case with a > negative var_off compensated by a positive instruction offset. The > effective start remains non-negative, so the program loads, but its > access end exceeds the writable context size and > bpf_raw_tracepoint_open() must return -EINVAL. > > Reported-by: Shung-Hsi Yu > Link: https://lore.kernel.org/bpf/alRtilWhKw4zzMkI@u94a > Cc: stable@vger.kernel.org # 5.2.0 ... IMO it is slightly better to split this into two. First part would be [1] suggested by Eduard, and the second part would be the addition of negative offset test. That said, I checked that with v5.2 we do have PTR_TO_TP_BUFFER and PTR_TO_BUF support already (latter as PTR_TO_RDONLY_BUF and PTR_TO_RDWR_BUF), so there shouldn't be a problem having these tests back in stable. Acked-by: Shung-Hsi Yu 1: https://lore.kernel.org/bpf/3430dc0a2a141769a596ab21d7abdd86a0a804db.camel@gmail.com/2-tp-test.diff