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 34A73C433DF for ; Fri, 21 Aug 2020 16:47:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 07A72206DA for ; Fri, 21 Aug 2020 16:47:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598028476; bh=VASL87ppPiboOQq6qJXQxxe2/VsGTwKQP8c1PE8NMyg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=BEjuJ+Q6P1rtRSDltyctlyfK2wbAzjC2EJk0eA9dHWZt/5AxsT/xWATYqyi3rkhsw IJyDbmRATq9IxBb+wqZS5CGz6FVi0OhsQDjBu9eBzYlY5++OYzcXAST4MYEnOybkSy yVi5t98eji3Vugu10J2r6KqvDXaF4s9j2By1oF+0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728497AbgHUQrw (ORCPT ); Fri, 21 Aug 2020 12:47:52 -0400 Received: from mail.kernel.org ([198.145.29.99]:49728 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728371AbgHUQU3 (ORCPT ); Fri, 21 Aug 2020 12:20:29 -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 F251F22BF5; Fri, 21 Aug 2020 16:19:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598026771; bh=VASL87ppPiboOQq6qJXQxxe2/VsGTwKQP8c1PE8NMyg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dEiqnIGwwCDfaSR2PjjdCv/DuHzJVklBk8z0yQQsM9X7ieysA0KVkFVXZBNRlqqpy rcf74NexVBirVuagAdznJ9I36E1QbYFS/emZ8FjT0Ma0pve0oN5zZATp0hU+XF7F+T tAelgFDLhmVB8I6HKBK/01p0xlundj1m99JWKFAI= 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 4.14 26/30] locking/lockdep: Fix overflow in presentation of average lock-time Date: Fri, 21 Aug 2020 12:18:53 -0400 Message-Id: <20200821161857.348955-26-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200821161857.348955-1-sashal@kernel.org> References: <20200821161857.348955-1-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 8b2ef15e35524..06c02cd0ff577 100644 --- a/kernel/locking/lockdep_proc.c +++ b/kernel/locking/lockdep_proc.c @@ -430,7 +430,7 @@ 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