From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="XgmEJ98z" Received: from mail-ej1-x630.google.com (mail-ej1-x630.google.com [IPv6:2a00:1450:4864:20::630]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7A9CCCA for ; Mon, 4 Dec 2023 10:43:44 -0800 (PST) Received: by mail-ej1-x630.google.com with SMTP id a640c23a62f3a-a1b68ae4104so193490366b.3 for ; Mon, 04 Dec 2023 10:43:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1701715423; x=1702320223; darn=vger.kernel.org; h=mime-version:user-agent:content-transfer-encoding:autocrypt :references:in-reply-to:date:cc:to:from:subject:message-id:from:to :cc:subject:date:message-id:reply-to; bh=4++Z2sNBabjPV0Q4Q9J34w4K444dMXDCFRsRIrazGs4=; b=XgmEJ98zFdgE29FuJWzFLJd7nMFJsHRqQ2qDkJT2dGq+kdENxqpgmdDfI28R+GmaA0 UojzCtLfYbBiqJ7o4n3LmbRooVrYTp4mIkl7GrUJzqS3+6koEqAhamdg+ogdyxnC/Dii wbB0yI2/8zP/ZS4QWTVSqPQkpTg5z32o+Dy+iNhyN6KK3t0YLBx1nDrAPL3WjONwv/LL VmSKV6jDfIwvGcV6HD3X+GXgmvbwjHVpnvDYPkX8kxdEzlcIZ9rVnfWIOhmLmIDF19cu jtLH9FLBPBVpTSodWgjnNNAT1GcLEU87AC3RC9+TPurh5ShiVAlTEL/9oa3VibD6FWzt Zp4A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1701715423; x=1702320223; h=mime-version:user-agent:content-transfer-encoding:autocrypt :references:in-reply-to:date:cc:to:from:subject:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=4++Z2sNBabjPV0Q4Q9J34w4K444dMXDCFRsRIrazGs4=; b=YWkX50v5cD+RP40eYvNXReYQt1qyxgq2LrpptstPRYoXoqPjml04eq+w5ffpiE/3JC CGBFfzs1hnbkHA1caf1xvFl+JSHM2O46A3nFG2Pnt6FRWlQcIzPOMuUch8y5zxh04lGp hB/2hjL2FSzuqmP/137u4WN6sEz0AkNKuBuR3g7n5xwBwe3VswAftQ2e5u7+EA2byHds C87B4u1SeBGuEFEP+wA4UVY8m4nMnUVubB1fJIAO9qWm6KAoDhzhIsuBAeO3fu+3eBdC nHEsrLUW8k7BtUxqSsJ/QHkDGTVq6HvoRD5RhTytCw5Pt5TPtB3xwHAQpHg/b3Jm6nHe xRgA== X-Gm-Message-State: AOJu0YzZ+Odm+PGSrbnY38ETFLUAV9XRqW4lWQe1TakCwjE09nYp9TyQ pdC5U3uf5UHHr20RXgOE0/A= X-Google-Smtp-Source: AGHT+IErqR6+Y2btI0AcVMiSdKFHkGViy88H/XagM0fFOzQJNleYwsA+z8CwsdjxrrDfLwcFPGC7zQ== X-Received: by 2002:a17:906:2207:b0:a16:9a60:1bdb with SMTP id s7-20020a170906220700b00a169a601bdbmr4178869ejs.39.1701715422872; Mon, 04 Dec 2023 10:43:42 -0800 (PST) Received: from [192.168.1.95] (host-176-36-0-241.b024.la.net.ua. [176.36.0.241]) by smtp.gmail.com with ESMTPSA id qc14-20020a170906d8ae00b009a9fbeb15f2sm5560306ejb.62.2023.12.04.10.43.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 04 Dec 2023 10:43:42 -0800 (PST) Message-ID: Subject: Re: [PATCH bpf v3 3/3] bpf: minor cleanup around stack bounds From: Eduard Zingerman To: Andrii Nakryiko , Andrei Matei Cc: bpf@vger.kernel.org, sunhao.th@gmail.com, kernel-team@dataexmachina.dev Date: Mon, 04 Dec 2023 20:43:41 +0200 In-Reply-To: References: <20231202230558.1648708-1-andreimatei1@gmail.com> <20231202230558.1648708-4-andreimatei1@gmail.com> Autocrypt: addr=eddyz87@gmail.com; prefer-encrypt=mutual; keydata=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 nYzhLWGcczc6J71q1Dje0l5vIPaSFOgwmWD4DA+WvuxM/shH4rtWeodbv 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 t1iq+gsfnXbPz5AnS598ScZI1oP7OrPSFJkt/z4acEbOQDQs8aUqrd46PV jsdqGvKnXZxzylux29UTNby4jTlz9pNJM+wPrDRmGfchLDUmf6CffaUYCbu4FiId+9+dcTCDvxbABRy1C3OJ8QY7cxfJ+pEZW18fRJ0XCl/fiV/ecAOfB3HsqgTzAn555h0rkFgay0hAvMU/mAW/CFNSIxV397zm749ZNLA0L2dMy1AKuOqH+/B+/ImBfJMDjmdyJQ8WU/OFRuGLdqOd2oZrA1iuPIa+yUYyZkaZfz/emQwpIL1+Q4p1R/OplA4yc301AqruXXUcVDbEB+joHW3hy5FwK5t5OwTKatrSJBkydSF9zdXy98fYzGniRyRA65P0Ix/8J3BYB4edY2/w0Ip/mdYsYQljBY0A== Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.50.1 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Mon, 2023-12-04 at 10:19 -0800, Andrii Nakryiko wrote: [...] > > @@ -6828,7 +6831,10 @@ static int check_stack_access_within_bounds( > > return err; > > } > >=20 > > - return grow_stack_state(env, state, round_up(-min_off, BPF_REG_= SIZE)); > > + /* Note that there is no stack access with offset zero, so the = needed stack > > + * size is -min_off, not -min_off+1. > > + */ > > + return grow_stack_state(env, state, -min_off /* size */); >=20 > hmm.. there is still a grow_stack_state() call in > check_stack_write_fixed_off(), right? Which is not necessary because > we do check_stack_access_within_bounds() before that one. Can you drop > it as part of patch #2? I'm not sure I understand what you mean. Patch #2 (v3) drops grow_stack_state() from check_stack_write_fixed_off() so all seems good?