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,URIBL_BLOCKED,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 7ED01C43381 for ; Mon, 18 Feb 2019 14:12:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4E219217D7 for ; Mon, 18 Feb 2019 14:12:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550499170; bh=Lfw8wma/Jjmna9s8yBSaZvvQO0ln0kz69kcLcXe2T6E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=BBvJsqNXobUz0q0eXE+AKG+yWOoDx/v3Yg0eqO6c4LFNPW85qKDqF7Vs3RuYfscN1 TJkuIUViqIE0mGYKSifGTC7kMbg1++wbF0kNCpsdtB2LgX88l1Yvd/Gr5vBBWgGotp HZ4ASqJN+0KvsfS+qiM8JA6DuYEPRbI70OrLV+so= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392162AbfBROMs (ORCPT ); Mon, 18 Feb 2019 09:12:48 -0500 Received: from mail.kernel.org ([198.145.29.99]:57388 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2392055AbfBROMo (ORCPT ); Mon, 18 Feb 2019 09:12:44 -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 04D5921901; Mon, 18 Feb 2019 14:12:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550499163; bh=Lfw8wma/Jjmna9s8yBSaZvvQO0ln0kz69kcLcXe2T6E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FSXvHyaNJINkOgWKOlRdG9kp4VL7jpjYpVu7gaIh3zYGBOMlDmCDweRwDTIZ3AmMs op0VVAvH+LNpsG7nPj1qzwAYmxEOzdVShZ89kTB+k24O9fxVcQqKlLYhr+C9OviWCJ 5MTdTlrKI3n2ULh3Bw2vktTCMpmUh6GScs3cUDeg= 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 3.18 096/108] perf/core: Fix impossible ring-buffer sizes warning Date: Mon, 18 Feb 2019 14:44:32 +0100 Message-Id: <20190218133524.105084135@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190218133519.525507231@linuxfoundation.org> References: <20190218133519.525507231@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 3.18-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 @@ -282,7 +282,7 @@ 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);