From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id E9F0AC25B08 for ; Mon, 8 Aug 2022 16:38:31 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 7C3478E0001; Mon, 8 Aug 2022 12:38:31 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 799D86B0072; Mon, 8 Aug 2022 12:38:31 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 689348E0001; Mon, 8 Aug 2022 12:38:31 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 5CA6A6B0071 for ; Mon, 8 Aug 2022 12:38:31 -0400 (EDT) Received: from smtpin12.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 2FFFB1C6576 for ; Mon, 8 Aug 2022 16:38:31 +0000 (UTC) X-FDA: 79776983622.12.797935A Received: from mail-yw1-f175.google.com (mail-yw1-f175.google.com [209.85.128.175]) by imf30.hostedemail.com (Postfix) with ESMTP id CD59A8016D for ; Mon, 8 Aug 2022 16:38:30 +0000 (UTC) Received: by mail-yw1-f175.google.com with SMTP id 00721157ae682-328303afa6eso86515247b3.10 for ; Mon, 08 Aug 2022 09:38:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc; bh=XquYmP+vX0zNQXcxrD0gfmPbv/22szoR0PAdjI6c6FQ=; b=RBd6EjHhe971WD13rB9QwkHAT4JUbLr8pEwdWhmPMPYpucCEhUe0Fdxu7UVnbr9qpP hZWuzatpB+IqP6uU510l0sQTdjybSMTSw0lHTUAtbi7VRxP2+VL05RnJSC9tm4F4F9bv 03IZzjd3BMx5tcDns/TvMijdidvLv9/X2frigVbrc5lBTVZIT8xVWMui/Av+CCl2HQ+g QeAwQ4P2RQXrRRxSJ9VYRfWwU8zBUJvN0TSOG9Egg5vBxghw1SEtI2yzQD4i2Egfj5MJ HUwil0l04LL4/UtY+kLAu1nwLKCUhG43pHEAAs+sHgqewUIscMdcTdTZ4xxjKOjwkI6L 2CXQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc; bh=XquYmP+vX0zNQXcxrD0gfmPbv/22szoR0PAdjI6c6FQ=; b=Oq1hiYkJotm52z//36imqAeaIqyuAzg4mcoK0CgDnEVv1TbokDMuE7qJrpkIP/C+V6 he24R5ny+OtcCMwdUfNxjr4I04gKj9E/ZgZmPCoojGitIdJh+ZVpk5J4eqf7I94SmHS0 m1wVhjgsj1ymCMTRiGtlERqgwV4UiglGdsVj2tNAlDPRYr6TIgp9dos6Q7pTW4SM+wQW I6VCV7BWmjfUnk2B5Wema1FJvsH+dZeFK84JP/CINL9lVqXhISXLx0nNvxV4tgnS8Jmm KJsJbmgU9b6qAdRBUzxjVKabWmrQQwBUFTycooWGoGY5f2A/s0TMMsUL8IZfeq0EYxrR MeAw== X-Gm-Message-State: ACgBeo0kBSA+C4r5ETlPKvS6LiqRejVS271SGgYw48q33+bSUytj8BtJ Km9rcswPWYQ6/q1WC6+1cVYWGAoXLrRQH27ZhwDt7Q== X-Google-Smtp-Source: AA6agR7qwVhhNLdxkz/r+4OMSs/UhsdFghsuBlEsQGkMrD95nZ9mCd4coeYCE332Xk5fz/fL87h9vbS2cVX9CTEt9Jg= X-Received: by 2002:a81:7586:0:b0:31f:658e:1ac7 with SMTP id q128-20020a817586000000b0031f658e1ac7mr19730600ywc.295.1659976709754; Mon, 08 Aug 2022 09:38:29 -0700 (PDT) MIME-Version: 1.0 References: <20220701142310.2188015-1-glider@google.com> <20220701142310.2188015-44-glider@google.com> In-Reply-To: <20220701142310.2188015-44-glider@google.com> From: Alexander Potapenko Date: Mon, 8 Aug 2022 18:37:52 +0200 Message-ID: Subject: Re: [PATCH v4 43/45] namei: initialize parameters passed to step_into() To: Alexander Potapenko Cc: Alexander Viro , Alexei Starovoitov , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , kasan-dev , Linux Memory Management List , Linux-Arch , LKML , Evgenii Stepanov , Linus Torvalds , Nathan Chancellor , Nick Desaulniers , Segher Boessenkool , Vitaly Buka , linux-toolchains Content-Type: text/plain; charset="UTF-8" ARC-Authentication-Results: i=1; imf30.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=RBd6EjHh; spf=pass (imf30.hostedemail.com: domain of glider@google.com designates 209.85.128.175 as permitted sender) smtp.mailfrom=glider@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1659976710; a=rsa-sha256; cv=none; b=4IWCC3yTLtbb8SNkoz6belVPmA3DL7qTruzP8KSejFWF34Vnj8oTEm3itCAaRQ0hx5xknZ rMaOJBA1m5es+x/DwjDJuvw58DdhDHPkmMEaTEa/Cu51+Ikqw04qWv2P0W/tATaGbUg9cI e0GOzm7PLYU6l9Iv41B6Z1lEvgk+qlw= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1659976710; h=from:from:sender: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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=XquYmP+vX0zNQXcxrD0gfmPbv/22szoR0PAdjI6c6FQ=; b=sv7YqS4F/hQ9SpIzqhYU6h+9juurUmO5XctRHCe4RiauMYtkMcIeEQlG+clcXb7xtbcL9M y9a162f+rKrZeVoH/rYXkED0CmOX6H0CLCZ9aPXrwnwAjoqPL6/F6AyMzY9bzGlEwq5k1W ZvJzJ6CoF0P2E16RUOzoZ6yWTsxgVPw= X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: CD59A8016D X-Rspam-User: Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=RBd6EjHh; spf=pass (imf30.hostedemail.com: domain of glider@google.com designates 209.85.128.175 as permitted sender) smtp.mailfrom=glider@google.com; dmarc=pass (policy=reject) header.from=google.com X-Stat-Signature: jotikc75uj49hz1z1mx4491gctt7ixoe X-HE-Tag: 1659976710-789999 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Jul 1, 2022 at 4:25 PM Alexander Potapenko wrote: > > Under certain circumstances initialization of `unsigned seq` and > `struct inode *inode` passed into step_into() may be skipped. > In particular, if the call to lookup_fast() in walk_component() > returns NULL, and lookup_slow() returns a valid dentry, then the > `seq` and `inode` will remain uninitialized until the call to > step_into() (see [1] for more info). > > Right now step_into() does not use these uninitialized values, > yet passing uninitialized values to functions is considered undefined > behavior (see [2]). To fix that, we initialize `seq` and `inode` at > definition. Given that Al Viro has a patch series in flight to address the problem, I am going to drop this patch from KMSAN v5 series.