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 X-Spam-Level: X-Spam-Status: No, score=-8.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5BB66C33CAC for ; Mon, 3 Feb 2020 11:10:28 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 1A2F820721 for ; Mon, 3 Feb 2020 11:10:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="AXsQGMeb" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1A2F820721 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id AAD726B0638; Mon, 3 Feb 2020 06:10:27 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id A37F86B0639; Mon, 3 Feb 2020 06:10:27 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8D7AF6B063A; Mon, 3 Feb 2020 06:10:27 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0005.hostedemail.com [216.40.44.5]) by kanga.kvack.org (Postfix) with ESMTP id 70C476B0638 for ; Mon, 3 Feb 2020 06:10:27 -0500 (EST) Received: from smtpin28.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 1D8F72492 for ; Mon, 3 Feb 2020 11:10:27 +0000 (UTC) X-FDA: 76448547294.28.sail59_20fd30dc0d922 X-HE-Tag: sail59_20fd30dc0d922 X-Filterd-Recvd-Size: 3861 Received: from mail-wr1-f66.google.com (mail-wr1-f66.google.com [209.85.221.66]) by imf49.hostedemail.com (Postfix) with ESMTP for ; Mon, 3 Feb 2020 11:10:26 +0000 (UTC) Received: by mail-wr1-f66.google.com with SMTP id c9so17455685wrw.8 for ; Mon, 03 Feb 2020 03:10:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=eXyME1mq17rm0IImOgWuGxF6wFut+db0luoN5CMuBlE=; b=AXsQGMebOkcbIw7nCNQE9z1LItm+E8r7+NMUuNoJAbtLIuCvm1TcvNPVX5pykD/ai9 ESpfomC/TWLLdhRF0kGVRlzCno1vT9MaNtlfvq+VyvUhCd2PxU8gm+5+omBDhRLfCUrI m4up1FWn2+TFJb1SgRkEbSCXhPVy/1HR8OPPavOroCBwatC83V8auiQW7+fW4t99QJ/n bi3mcC/7sVgazS7z50jLDyOlUMrZeb9Dyo2lmNfbvYyiTsbmDUIfmfXhmp1j0MmY2D4R LdcVFnwStKiMlZKgsEY7rZCDGdPc4FkngpLuK5zgdKtUAU9YeoQUf7Pq1HWuWN0K49W4 NAYg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=eXyME1mq17rm0IImOgWuGxF6wFut+db0luoN5CMuBlE=; b=aYNO9aGYHEjFkgEBOnVQe4e0F7nsR7HALmgL/fB1Gj91/M4MpWVawUz9TwbvmwUd4y b/6POuS2NCMTZ/vgkGroF0xoGqIQC0BUst3n6p2n7t09pVn7gwxJ7THFLEuWIRT4Dsh6 8yqIaxquxZTCH66AH5R+9jR+HWKJX1Vt0ajvNOMr1mNGn4E/zJ8JBwn52axJE8DJy2EO mtSf792B0mOtQrWyqYNGvXEpu2NnHLd+gs3f/g099VwcwNrS09t9qgQBm/tECxicOiR8 2EKpQiey9tTZURb9CEa032eMsQzxIuCEN/3x2zbQL3GeNcr9d/yEBih75PEkOMdWkhXJ qhSg== X-Gm-Message-State: APjAAAUMGq0zAGBVtLjBRURARAMJTxSBqHWX2cItvM+SH2EtTkMDoqiC rE6qF5wFPR3Ry+peAW9gEUngx8KWe/YrKU8HymwCYA== X-Google-Smtp-Source: APXvYqwsyRCmHsIrSXNcBVzTgOw3Cgul4TmEBpA9ogoxeKKCFTXUlQr5ZuBR0mBmfzB7wVrN2Z+xIzKX6eUo8ZAcow4= X-Received: by 2002:a5d:6692:: with SMTP id l18mr14299669wru.382.1580728225159; Mon, 03 Feb 2020 03:10:25 -0800 (PST) MIME-Version: 1.0 References: <20200203102953.17349-1-glider@google.com> In-Reply-To: From: Alexander Potapenko Date: Mon, 3 Feb 2020 12:10:13 +0100 Message-ID: Subject: Re: [PATCH] lib/stackdepot: fix global out-of-bounds in stack_slabs To: Tetsuo Handa Cc: Walter Wu , Dmitriy Vyukov , Greg Kroah-Hartman , Andrew Morton , Matthias Brugger , Thomas Gleixner , Josh Poimboeuf , Kate Stewart , Linux Memory Management List Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable 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: > > - stack_slabs[depot_index + 1] =3D *prealloc; > > + /* If this is the last depot slab, do not touch the next = one. */ > > + if (depot_index + 1 < STACK_ALLOC_MAX_SLABS) > > + stack_slabs[depot_index + 1] =3D *prealloc; > > What prevents memory leak (caused by "*prealloc =3D NULL;") > when we hit depot_index + 1 >=3D STACK_ALLOC_MAX_SLABS condition? > Nice catch! We must return from this function instead of setting *prealloc to NULL. --=20 Alexander Potapenko Software Engineer Google Germany GmbH Erika-Mann-Stra=C3=9Fe, 33 80636 M=C3=BCnchen Gesch=C3=A4ftsf=C3=BChrer: Paul Manicle, Halimah DeLaine Prado Registergericht und -nummer: Hamburg, HRB 86891 Sitz der Gesellschaft: Hamburg