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 9B1D8C52D7D for ; Sat, 17 Aug 2024 16:26:45 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 928EF8D00D4; Sat, 17 Aug 2024 12:26:44 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8B44C8D00B8; Sat, 17 Aug 2024 12:26:44 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6DA508D00D4; Sat, 17 Aug 2024 12:26:44 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 4C4128D00B8 for ; Sat, 17 Aug 2024 12:26:44 -0400 (EDT) Received: from smtpin29.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id C7FAFA0820 for ; Sat, 17 Aug 2024 16:26:43 +0000 (UTC) X-FDA: 82462265886.29.0255852 Received: from mail-ed1-f45.google.com (mail-ed1-f45.google.com [209.85.208.45]) by imf18.hostedemail.com (Postfix) with ESMTP id 7FC2F1C001B for ; Sat, 17 Aug 2024 16:26:41 +0000 (UTC) Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=google header.b=CFKBiRXl; spf=pass (imf18.hostedemail.com: domain of torvalds@linuxfoundation.org designates 209.85.208.45 as permitted sender) smtp.mailfrom=torvalds@linuxfoundation.org; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1723911901; 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=bJUpF+ZilJ5tJUWYdG1B4XodSC5itu+LywsKXdFMvvc=; b=IsqWh6BIFD4iU1yBVtl2Z1KGT9o3DpaeR7RtxICQ7ZTvX6ZJSvzPq+mmTliiHg92AEJcPE eKP1LDXdUj9Itzuoscwz+lKrOp62tEZFW0heZccd50AAYpR4cR8grHD+eH9q5tvBrjqDaP c+9vlI+mmJq8CAihX5GOcc89H934MHA= ARC-Authentication-Results: i=1; imf18.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=google header.b=CFKBiRXl; spf=pass (imf18.hostedemail.com: domain of torvalds@linuxfoundation.org designates 209.85.208.45 as permitted sender) smtp.mailfrom=torvalds@linuxfoundation.org; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1723911901; a=rsa-sha256; cv=none; b=l5MBVVXNrAfKtDChrnk2gVRwpygRXk0Dx7msHlg+i6oleFjJI2V4CM0SYpbgtVoS6djURs uZm9ZDNA1Fjbi1g3kydoP2FSPbdbAyhy9QY8NHAVV7OuyXA99TtF7fsIUHXBcmdQhTFxEc OhZ9KpQutv1IqUU9BdbNHwNX8sfqYAY= Received: by mail-ed1-f45.google.com with SMTP id 4fb4d7f45d1cf-5bed0a2b1e1so435343a12.3 for ; Sat, 17 Aug 2024 09:26:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=google; t=1723912000; x=1724516800; darn=kvack.org; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=bJUpF+ZilJ5tJUWYdG1B4XodSC5itu+LywsKXdFMvvc=; b=CFKBiRXl6xmFq+g8gkrvl6KV5Vk5WSpJFcOThPR+RmqgaVjlOU6PCp5rFf9rWxuVid EFcKwPbYB0aS1jZM8whDq9wnfyM8/POEBljHQlP1/DD+ECNzcLJMhnQs8oFBxGfUtRum IAUJrmLazcZjAr42S8uVX602P9vHrR3GMFjFs= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1723912000; x=1724516800; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=bJUpF+ZilJ5tJUWYdG1B4XodSC5itu+LywsKXdFMvvc=; b=lR1rLmjA9giU2M+25siUPAIBZGJ4ObpQxcavyT0/zLscAlumr1qmEwoqj+jXdwMZ7x 33ZIa2OdPzFaHJQ9qSsHxg0DCW4jCKYOIIHYgfB+aK7qzStWLored12cxPwZp3xv5OEa J4BkvD0owyNi6SxjP5CSXbICoROGKKTQrYFMNs+EkMLs1AP6jtExEoWhQs7CY1sFWZxC og6T3wVRYWpjPlTWxarNN11NMpRDAXHOMukEuOlzi1VGzH3nIPmhTK5RWwB6OhwKST79 UC7UmQ6YUsQ2yVCvXwYJe7pgUwjLj8Ox7VF/3QVAFVbR3y7T/54XzwRlmNtvJwwJRBeO o6GQ== X-Forwarded-Encrypted: i=1; AJvYcCVROKV2aCPcEkYo06JP48OtW+hUNow1RVghKsQE8SWaG6u9TYGhHmYOts/W/6psQKc34N6jrZz0Bm7di+n85Op7ubI= X-Gm-Message-State: AOJu0YyrwVNbUkIxIqfDI8TBG87JJM/jIxFIxeLrGgjuauzirsY8mmKA 6is5bQAby9SDtz2XmkMVfTh/SwwcWUeHtnQFNiHfqUiNMwQsVbGQCFmuHy/HG1eKpJH00AdThGe lQNO+fQ== X-Google-Smtp-Source: AGHT+IHdCzWa93IbnsxHS2SYrKACD1std19jPQF/ZQ1GblH406s5bk+SF3b/E/rzc7m0l9AXNf1QZA== X-Received: by 2002:a05:6402:27d4:b0:5b9:1067:61e9 with SMTP id 4fb4d7f45d1cf-5beca594365mr5660071a12.18.1723911999217; Sat, 17 Aug 2024 09:26:39 -0700 (PDT) Received: from mail-ed1-f42.google.com (mail-ed1-f42.google.com. [209.85.208.42]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-5bebbe7f191sm3567431a12.61.2024.08.17.09.26.38 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 17 Aug 2024 09:26:39 -0700 (PDT) Received: by mail-ed1-f42.google.com with SMTP id 4fb4d7f45d1cf-5b8c2a6117aso1263123a12.0 for ; Sat, 17 Aug 2024 09:26:38 -0700 (PDT) X-Forwarded-Encrypted: i=1; AJvYcCWMaZE9O0oAqrryOf0LqzHKSm54dwPi6GRY5N4JzSsJNgPTKxZsPJuPBYkRFywsmwn1DRA1sgkJ4gNdP8Ii9+0pE7o= X-Received: by 2002:a05:6402:278b:b0:5a1:b6d8:b561 with SMTP id 4fb4d7f45d1cf-5beca527ec4mr6027442a12.9.1723911998605; Sat, 17 Aug 2024 09:26:38 -0700 (PDT) MIME-Version: 1.0 References: <20240817025624.13157-1-laoar.shao@gmail.com> <20240817025624.13157-6-laoar.shao@gmail.com> In-Reply-To: From: Linus Torvalds Date: Sat, 17 Aug 2024 09:26:21 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v7 5/8] mm/util: Fix possible race condition in kstrdup() To: Alejandro Colomar Cc: Yafang Shao , akpm@linux-foundation.org, justinstitt@google.com, ebiederm@xmission.com, alexei.starovoitov@gmail.com, rostedt@goodmis.org, catalin.marinas@arm.com, penguin-kernel@i-love.sakura.ne.jp, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, audit@vger.kernel.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org, bpf@vger.kernel.org, netdev@vger.kernel.org, dri-devel@lists.freedesktop.org Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 7FC2F1C001B X-Stat-Signature: jrhket5zrm5iynq6gkktkhmwdx6jizpx X-Rspam-User: X-HE-Tag: 1723912001-227390 X-HE-Meta: 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 +Ce48++C 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 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: List-Subscribe: List-Unsubscribe: On Sat, 17 Aug 2024 at 01:48, Alejandro Colomar wrote: > > I would compact the above to: > > len = strlen(s); > buf = kmalloc_track_caller(len + 1, gfp); > if (buf) > strcpy(mempcpy(buf, s, len), ""); No, we're not doing this kind of horror. If _FORTIFY_SOURCE has problems with a simple "memcpy and add NUL", then _FORTIFY_SOURCE needs to be fixed. We don't replace a "buf[len] = 0" with strcpy(,""). Yes, compilers may simplify it, but dammit, it's an unreadable incomprehensible mess to humans, and humans still matter a LOT more. Linus