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=-6.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_GIT autolearn=ham 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 D6C38C43381 for ; Mon, 18 Feb 2019 14:30:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A3B372081B for ; Mon, 18 Feb 2019 14:30:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550500204; bh=tTkwjwq8E1QzwncGkvEvU5JgsPIcxIxyVLAEr2fQ52E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=xqYfSA7stYmxFlihSh4mDoVlqdeuKVfwDL5Uv6Y/k1SrbjebDEFOl2zqDMz5qn4kf eW+HSrZ9AJJcEj55/1OGBrdXAnM238GH6PtygqF/Xj66rybW447cmUttDbt5KWQZFg iwlfTn5EMnCDYLxMBueEb7gFm9JXcBBHjw2rN9fQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388414AbfBROaD (ORCPT ); Mon, 18 Feb 2019 09:30:03 -0500 Received: from mail.kernel.org ([198.145.29.99]:39828 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388475AbfBRN67 (ORCPT ); Mon, 18 Feb 2019 08:58:59 -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 118182070D; Mon, 18 Feb 2019 13:58:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550498338; bh=tTkwjwq8E1QzwncGkvEvU5JgsPIcxIxyVLAEr2fQ52E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2XmQMRgWqK7BGNkTE3sTrBJRPehZktmk39hQA/XbJk53IoAP8bnxfNmMTpgvg7wHt lfOaPnIU9ax/vStEtyQiWFeWOmSWTmvMkaXB70ma9vIJjiwMmbKd7l/H5zKMuHNWQ/ /AhLT0Px6h2IK8bI16eHiJASHTsrZkY0q2mDfNJE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Jin, Yao" , Julien Thierry , Mark Rutland , Alexander Shishkin , Arnaldo Carvalho de Melo , Jiri Olsa , Linus Torvalds , Namhyung Kim , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov Subject: [PATCH 4.9 37/58] perf/core: Fix impossible ring-buffer sizes warning Date: Mon, 18 Feb 2019 14:43:58 +0100 Message-Id: <20190218133511.494490954@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190218133508.567416115@linuxfoundation.org> References: <20190218133508.567416115@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: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ingo Molnar commit 528871b456026e6127d95b1b2bd8e3a003dc1614 upstream. The following commit: 9dff0aa95a32 ("perf/core: Don't WARN() for impossible ring-buffer sizes") results in perf recording failures with larger mmap areas: root@skl:/tmp# perf record -g -a failed to mmap with 12 (Cannot allocate memory) The root cause is that the following condition is buggy: if (order_base_2(size) >= MAX_ORDER) goto fail; The problem is that @size is in bytes and MAX_ORDER is in pages, so the right test is: if (order_base_2(size) >= PAGE_SHIFT+MAX_ORDER) goto fail; Fix it. Reported-by: "Jin, Yao" Bisected-by: Borislav Petkov Analyzed-by: Peter Zijlstra Cc: Julien Thierry Cc: Mark Rutland Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Greg Kroah-Hartman Cc: Fixes: 9dff0aa95a32 ("perf/core: Don't WARN() for impossible ring-buffer sizes") Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- kernel/events/ring_buffer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/kernel/events/ring_buffer.c +++ b/kernel/events/ring_buffer.c @@ -700,7 +700,7 @@ 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) + if (order_base_2(size) >= PAGE_SHIFT+MAX_ORDER) goto fail; rb = kzalloc(size, GFP_KERNEL);