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=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 0190AC282D7 for ; Mon, 11 Feb 2019 15:51:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C81A821855 for ; Mon, 11 Feb 2019 15:51:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1549900283; bh=buwIrzeTtNxuDndP9yFI8r5S4TeNuCDP2K/6GxA0j70=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=It4rSqg/GfCmyoEZ9XMezB0b/vc6rVeLrU9eYp6YZYXuelGiaWcUEQaMFM2kaTGan 0wkWGI7+NQ2v+amETf/dJ61/totglwjt4hX/2eStyXqLWEpi98/GIHT5zRYPj4ELhm /lQnVbIutJRaKrHjXY2L0HP76/KND9As1iAXUpFQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731174AbfBKOiM (ORCPT ); Mon, 11 Feb 2019 09:38:12 -0500 Received: from mail.kernel.org ([198.145.29.99]:47874 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731614AbfBKOiM (ORCPT ); Mon, 11 Feb 2019 09:38:12 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1EC03222A1; Mon, 11 Feb 2019 14:38:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1549895891; bh=buwIrzeTtNxuDndP9yFI8r5S4TeNuCDP2K/6GxA0j70=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=X2zU8Lc5QoOFR4RKEpv0UTdd0Yb5iHKtfjelnF+6p2Sx3P+YgEMqWk+oYF/ZoIYCL 3+cbZaU1LWkmcyMkcoJNSvzoGU0nkjBb7VtlbMRnC4+boh2kUvW/iArcB54sa+F33N /KKPXgGEZdel9PFbpH5gCgy4KRkJREzgGQK9gYeI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Julien Thierry , Mark Rutland , "Peter Zijlstra (Intel)" , Alexander Shishkin , Arnaldo Carvalho de Melo , Jiri Olsa , Linus Torvalds , Namhyung Kim , Thomas Gleixner , Ingo Molnar Subject: [PATCH 4.20 346/352] perf/core: Dont WARN() for impossible ring-buffer sizes Date: Mon, 11 Feb 2019 15:19:33 +0100 Message-Id: <20190211141909.196297884@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190211141846.543045703@linuxfoundation.org> References: <20190211141846.543045703@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 4.20-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mark Rutland commit 9dff0aa95a324e262ffb03f425d00e4751f3294e upstream. The perf tool uses /proc/sys/kernel/perf_event_mlock_kb to determine how large its ringbuffer mmap should be. This can be configured to arbitrary values, which can be larger than the maximum possible allocation from kmalloc. When this is configured to a suitably large value (e.g. thanks to the perf fuzzer), attempting to use perf record triggers a WARN_ON_ONCE() in __alloc_pages_nodemask(): WARNING: CPU: 2 PID: 5666 at mm/page_alloc.c:4511 __alloc_pages_nodemask+0x3f8/0xbc8 Let's avoid this by checking that the requested allocation is possible before calling kzalloc. Reported-by: Julien Thierry Signed-off-by: Mark Rutland Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Julien Thierry Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Link: https://lkml.kernel.org/r/20190110142745.25495-1-mark.rutland@arm.com Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- kernel/events/ring_buffer.c | 3 +++ 1 file changed, 3 insertions(+) --- a/kernel/events/ring_buffer.c +++ b/kernel/events/ring_buffer.c @@ -734,6 +734,9 @@ struct ring_buffer *rb_alloc(int nr_page size = sizeof(struct ring_buffer); size += nr_pages * sizeof(void *); + if (order_base_2(size) >= MAX_ORDER) + goto fail; + rb = kzalloc(size, GFP_KERNEL); if (!rb) goto fail;