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 635BCC4332F for ; Fri, 2 Dec 2022 19:43:18 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id BBD996B0073; Fri, 2 Dec 2022 14:43:17 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B6DAC6B0074; Fri, 2 Dec 2022 14:43:17 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A36216B0075; Fri, 2 Dec 2022 14:43:17 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 909C06B0073 for ; Fri, 2 Dec 2022 14:43:17 -0500 (EST) Received: from smtpin22.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 5E973A057C for ; Fri, 2 Dec 2022 19:43:17 +0000 (UTC) X-FDA: 80198390034.22.5207422 Received: from mail-il1-f175.google.com (mail-il1-f175.google.com [209.85.166.175]) by imf02.hostedemail.com (Postfix) with ESMTP id 0FDAB80014 for ; Fri, 2 Dec 2022 19:43:16 +0000 (UTC) Authentication-Results: imf02.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=Hjyg7ElN; spf=pass (imf02.hostedemail.com: domain of jannh@google.com designates 209.85.166.175 as permitted sender) smtp.mailfrom=jannh@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1670010197; 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=of7uVX1tXYOzviZXLnVMaGfqQG4lADtgdnHuJ5eU4J8=; b=fgJlqLshIyAzri2AVj2kkk4qKcO78hd16ViGHkoIzsZ/LqR+IlEy9pmW9bUuj8QV4Ultei xFNUZWpbCCTf+9wq7dVpfqKkXG0YdZMS6OBmNEK/7QbpYHBVkT1Y2FRChgQHwlus5j8WIF vj4IkcUTCexvO6lxh7lWQJXDKos7/5I= ARC-Authentication-Results: i=1; imf02.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=Hjyg7ElN; spf=pass (imf02.hostedemail.com: domain of jannh@google.com designates 209.85.166.175 as permitted sender) smtp.mailfrom=jannh@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1670010197; a=rsa-sha256; cv=none; b=kv1QXhqNIW0HwTaFIV/qY8uSp1vhYH3hTV9WA39W6v0kA22taZmS32ONi2WqcTqunn25HI tbQdtnQE7q9BvQCJzHLKX83qryMdU7NwQ73wJWSwOgxptfn4ONsSa7oyRMElCZ8T8KpXAk hgd+TiuVijMCDr/6dWJxKKPX/RrztRg= Received: by mail-il1-f175.google.com with SMTP id s16so2498165iln.4 for ; Fri, 02 Dec 2022 11:43:16 -0800 (PST) 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:subject:date:message-id:reply-to; bh=of7uVX1tXYOzviZXLnVMaGfqQG4lADtgdnHuJ5eU4J8=; b=Hjyg7ElN0qzCGB7na9HaUNn7ciQAT0b5qOatwgrfMuVI8j/sV5jXT0FFQY/GI1o1qC AcczKv1OlDCC2eJzSdLDvg/tSJdISvhiRx2JUnskBQ54VvwOov89yEj+4Pjm4vCMD57Y ehzOk8IOa4UMEVIOZeyyYOx766NiGzY+WI0MPE4EZW2+9KmOlRuoWKFhIm/EzklGuJDK eVo/w9wt/Axw9kLT1MkqxEFIlc30vO989++RzYyvu4zlErOjlCFeJNGWtm1eJWP/DXQa t7yf3zo3aKJx/8lIZk0zMYfs1bpH+FBS4NklapQa6OxLyamj+a8GB9Tuf6quubMFgtbZ kHaA== 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:subject:date:message-id :reply-to; bh=of7uVX1tXYOzviZXLnVMaGfqQG4lADtgdnHuJ5eU4J8=; b=Rh6F1PmGSfZPQGzRKJ/niAo7aJn2bY7Yrizq9Pn/n/6O4LUlajjWYYXpUqQgOnVaNG a2bK9FGAUe6DrEy+28db+HQz2iydRQd5DzUOd1lki6OabruAf9ycPOpmqVbuGiZiu/kc 5v49YZvGnp+m1zTIBFCxfNj8qFU+ETbcZD4YqqbCOKMC7i/1Nz4niyLr30g85xDdVt5v 7GpYPcn1G+AQUgjGDiNB5jmKvl3HAHWGyK/WacH0mwiTaWl1ZYYZT9SMCjrF2MbQfG2O Q5pBYpxSSxWAslEegQVqklpoUpHiXEMv2PT0VqKuboYfGGQbgvNLr6Rpry3e2WsH9zDv pdMQ== X-Gm-Message-State: ANoB5pnSJz8Ji7+kbOQLFcm2sp4BXuR9GBTcCk+2akfGjhSNdfwKLYj8 PwnjhCdgryca1oD6BdZmEFL7hAO7BVvIDl5ZBY9PVDks3QbFLdvE X-Google-Smtp-Source: AA0mqf5vOr9B1OU2Kl1NzZ7MyNVHUUPr7ggM2JuciN0rkZ2xGqqig1ovb82pzSOmo204S05lutg74iv4GrrL5Q065ec= X-Received: by 2002:a92:6809:0:b0:2f9:4d92:5b2a with SMTP id d9-20020a926809000000b002f94d925b2amr24412987ilc.177.1670010196130; Fri, 02 Dec 2022 11:43:16 -0800 (PST) MIME-Version: 1.0 References: In-Reply-To: From: Jann Horn Date: Fri, 2 Dec 2022 20:42:39 +0100 Message-ID: Subject: Re: brk() in v6.1-rc1 can expand file mappings, seemingly without taking file locks To: Linux-MM , "Liam R. Howlett" , Andrew Morton Cc: kernel list , Jason Donenfeld , Yu Zhao , "Matthew Wilcox (Oracle)" , SeongJae Park , Vlastimil Babka Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 0FDAB80014 X-Rspam-User: X-Stat-Signature: cjwuqw8wfwjkmi4ny1z35w43rbx3ajs8 X-Spamd-Result: default: False [3.09 / 9.00]; SORBS_IRL_BL(3.00)[209.85.166.175:from]; BAD_REP_POLICIES(0.10)[]; MIME_GOOD(-0.10)[text/plain]; RCVD_NO_TLS_LAST(0.10)[]; BAYES_HAM(-0.01)[45.94%]; DMARC_POLICY_ALLOW(0.00)[google.com,reject]; MIME_TRACE(0.00)[0:+]; FROM_EQ_ENVFROM(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; RCPT_COUNT_SEVEN(0.00)[9]; DKIM_TRACE(0.00)[google.com:+]; TO_DN_ALL(0.00)[]; ARC_SIGNED(0.00)[hostedemail.com:s=arc-20220608:i=1]; R_DKIM_ALLOW(0.00)[google.com:s=20210112]; TO_MATCH_ENVRCPT_SOME(0.00)[]; FROM_HAS_DN(0.00)[]; PREVIOUSLY_DELIVERED(0.00)[linux-mm@kvack.org]; R_SPF_ALLOW(0.00)[+ip4:209.85.128.0/17]; ARC_NA(0.00)[] X-HE-Tag: 1670010196-5132 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, Dec 2, 2022 at 7:53 PM Jann Horn wrote: > As of commit ca57f02295f, brk() can expand ordinary file mappings (but Sorry, that was worded confusingly - I meant "ca57f02295f is the commit from Linus' tree on top of which I was testing". The broken code seems to have been introduced in commit 2e7ce7d354f2 ("mm/mmap: change do_brk_flags() to expand existing VMA and add do_brk_munmap()").