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=-13.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 50168C433E1 for ; Fri, 21 Aug 2020 16:32:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 224ED20724 for ; Fri, 21 Aug 2020 16:32:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598027558; bh=FresQJ+8YrzQahGXKniizpkZbx4mcAjvUTHqjSRmheQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=pqwGebK5JlPnzhTlu+nFUa2matDHtjxWr9w0gQP8g+GprXMXQIN+I5x4BvKigmsDQ F9XVz40ypLfkBZpKyjT9EZzvjbvOH7Z6Xoohx4QHgHaUgiL55orOgG+jyc5U7FMdcJ SOH9yttBPfmv2j70XehSOxaTYvvHX8D1GolXQXV0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728516AbgHUQce (ORCPT ); Fri, 21 Aug 2020 12:32:34 -0400 Received: from mail.kernel.org ([198.145.29.99]:50002 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728451AbgHUQVe (ORCPT ); Fri, 21 Aug 2020 12:21:34 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0F4A022D75; Fri, 21 Aug 2020 16:20:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598026837; bh=FresQJ+8YrzQahGXKniizpkZbx4mcAjvUTHqjSRmheQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bRYa7XV6D+HRAUzu5oELpY0QFg75IKNawAx6Y8vLEHrwHKFHg3sIvYsAIBHa8NSg8 1+O08ChVhxwpPizYicNwvqnQjEX7uiJwb9frNbv8SfIntVQc/LpnCAUkB5qSNDdeun Yj3XRibcmUIKfKT0j4Yd9TmBckh36pSLbbXtYTgM= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Chris Wilson , Ingo Molnar , Peter Zijlstra , Sasha Levin Subject: [PATCH AUTOSEL 4.4 18/22] locking/lockdep: Fix overflow in presentation of average lock-time Date: Fri, 21 Aug 2020 12:20:10 -0400 Message-Id: <20200821162014.349506-18-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200821162014.349506-1-sashal@kernel.org> References: <20200821162014.349506-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Chris Wilson [ Upstream commit a7ef9b28aa8d72a1656fa6f0a01bbd1493886317 ] Though the number of lock-acquisitions is tracked as unsigned long, this is passed as the divisor to div_s64() which interprets it as a s32, giving nonsense values with more than 2 billion acquisitons. E.g. acquisitions holdtime-min holdtime-max holdtime-total holdtime-avg ------------------------------------------------------------------------- 2350439395 0.07 353.38 649647067.36 0.-32 Signed-off-by: Chris Wilson Signed-off-by: Ingo Molnar Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20200725185110.11588-1-chris@chris-wilson.co.uk Signed-off-by: Sasha Levin --- kernel/locking/lockdep_proc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/locking/lockdep_proc.c b/kernel/locking/lockdep_proc.c index 35b34eccdd109..9484f934aa349 100644 --- a/kernel/locking/lockdep_proc.c +++ b/kernel/locking/lockdep_proc.c @@ -423,7 +423,7 @@ static void seq_lock_time(struct seq_file *m, struct lock_time *lt) seq_time(m, lt->min); seq_time(m, lt->max); seq_time(m, lt->total); - seq_time(m, lt->nr ? div_s64(lt->total, lt->nr) : 0); + seq_time(m, lt->nr ? div64_u64(lt->total, lt->nr) : 0); } static void seq_stats(struct seq_file *m, struct lock_stat_data *data) -- 2.25.1