From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-lj1-f171.google.com (mail-lj1-f171.google.com [209.85.208.171]) (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 28F033BB24 for ; Tue, 9 Jan 2024 18:02:45 +0000 (UTC) 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="PWzY5dej" Received: by mail-lj1-f171.google.com with SMTP id 38308e7fff4ca-2cd0f4f306fso38562521fa.0 for ; Tue, 09 Jan 2024 10:02:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1704823364; x=1705428164; 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=qdkJC+ujzcdAYnRBhIl4ExzHPcdimqPKuukxz/IQcv4=; b=PWzY5dej/Rs/uMlzgp3ybGdmbBmjJvAcYTAhPZ8eoIAg/JYrUCf1hNRYVaNNWjn/01 JZ5EX91befSXwbPSI1SSnhMiXS51Ar9CJUlfaHvuPv/Kms1mJM53lOiWmzq8h0oWWx99 EyVtbT+fqyiQrY2Xnmg2U+UcwVXAIkQMtj7sL6+egTVcoMbwTIEDSkgW89+30HPcgUpB aShEw2Tl8tULsTS0CDfylneu5BgNq3cNPRz8ex4x/a5cX8r46FuoNomr8kryPgYmOXKP ORjWBx47jndzhyRJ5WSHKDasQyDHL0sI3wXqYyS1R1+M8xIh4AoXe1t8bgK9vsOst1ft phqQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1704823364; x=1705428164; 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=qdkJC+ujzcdAYnRBhIl4ExzHPcdimqPKuukxz/IQcv4=; b=glZkQDh5s9PGsUpCUABYurIxpg7362j4ek342Uz9IHSpXMmEOi5pe7ZzzeWLuH8ErF uT5dmQ1ny9fqTcrnAKlCa6P9hEDhUq6Q9d5vcPNbgWw4GQcbZPfpfcjMIu7DborI2V9K SZC8br92j96Zg0m3uwpStI376rAuui9oHe+isUNCigyyjQZDB5w3ZjS3A9UmuwQFk7Gb gfioBV5RXnzPI/Ij7SPJU2O6FhFopjgnmSQymeW5OvwJzV8YI2v4Bp2hnnmQcjmojbuE pZb4aMScEOp7ZO4kKQculLdV8nOw0chO/kxre+kHxMDYN5YlGMZ2zWggYjbMVSvrSw4i sHKQ== X-Gm-Message-State: AOJu0YxJLByDREaatkSwn/baRSjO1VjqxT5EN2Y8DDlwZ87Wm9icPsYO 5Ae89oXSPmF0VgBFx8PlR2I= X-Google-Smtp-Source: AGHT+IElW3zYu4XEtkB/6yD9RKqrEWWEJj1PTamCWYSzRrOX71bLUaMogowkkHvu6DFNkCU9TR0tZg== X-Received: by 2002:a05:651c:200c:b0:2cc:eefc:20af with SMTP id s12-20020a05651c200c00b002cceefc20afmr2117958ljo.52.1704823363904; Tue, 09 Jan 2024 10:02:43 -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 z7-20020a2ebcc7000000b002cd632cea48sm426086ljp.106.2024.01.09.10.02.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 09 Jan 2024 10:02:43 -0800 (PST) Message-ID: Subject: Re: [PATCH bpf-next v3 1/2] bpf: Track aligned st store as imprecise spilled registers From: Eduard Zingerman To: Yonghong Song , bpf@vger.kernel.org Cc: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , kernel-team@fb.com, Martin KaFai Lau , Kuniyuki Iwashima , Martin KaFai Lau Date: Tue, 09 Jan 2024 20:02:41 +0200 In-Reply-To: <20240109040524.2313448-1-yonghong.song@linux.dev> References: <20240109040524.2313448-1-yonghong.song@linux.dev> 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 3.50.2 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Mon, 2024-01-08 at 20:05 -0800, Yonghong Song wrote: [...] > @@ -4640,7 +4641,18 @@ static int check_stack_write_var_off(struct bpf_ve= rifier_env *env, > return -EINVAL; > } > =20 > - /* Erase all spilled pointers. */ > + /* If writing_zero and the the spi slot contains a spill of value 0, > + * maintain the spill type. > + */ > + if (writing_zero && is_spilled_scalar_reg(&state->stack[spi])) { As discussed on offlist today, this should probably look as follows: - if (writing_zero && is_spilled_scalar_reg(&state->stack[spi= ])) { + if (writing_zero && *stype =3D=3D STACK_SPILL && is_spilled= _scalar_reg(&state->stack[spi])) { In order to handle cases like "mmmmSSSS" for slot types. > + spill_reg =3D &state->stack[spi].spilled_ptr; > + if (tnum_is_const(spill_reg->var_off) && spill_reg->var_off.value =3D= =3D 0) { > + zero_used =3D true; > + continue; > + } > + } > + > + /* Erase all other spilled pointers. */ > state->stack[spi].spilled_ptr.type =3D NOT_INIT; > =20 > /* Update the slot type. */ [...]