From patchwork Tue Sep 1 15:08:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 264636 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=-13.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, 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 734F3C433E6 for ; Tue, 1 Sep 2020 16:08:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4169F204EC for ; Tue, 1 Sep 2020 16:08:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598976493; bh=v9gQOf2yho3wnn66sqsWT+5Vz7QPb2gaJkVZZU4Booc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=aDZXs/XEPZ0IpZzJ0oCzLiIRIivZGXUh1c+cCN+zRWvKQl5aqkg0iBW0f6ZeAkbYY 5Vi1GS6R4V9m06Lh/riovXLlUUkicjCSADdlSACk1yzT9PJnpmPt/MWrNs9XzG/fSc N/CVPVpZZL5MBcoivjQ4qg71PVjwGgNkcWXytn14= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727028AbgIAQIH (ORCPT ); Tue, 1 Sep 2020 12:08:07 -0400 Received: from mail.kernel.org ([198.145.29.99]:49514 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728811AbgIAPj3 (ORCPT ); Tue, 1 Sep 2020 11:39:29 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (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 F3DEF205F4; Tue, 1 Sep 2020 15:39:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598974768; bh=v9gQOf2yho3wnn66sqsWT+5Vz7QPb2gaJkVZZU4Booc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tQm4QJsgYeIRT2cO4XCAgg0Ljk2bCXFqNyCD2d2fMWxo1esIHuTOyytGzoEOQ9bn4 z10JMUKeI6uFmORTSFF8tynLb3cppVXYxAP3jYz1S9gXN8smIc0hHfZ6PIpD44c1uW DZ92S4XqMUOHr/Wpo8h+nwPoPi4RPWuMChsZF9ag= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Chris Wilson , Ingo Molnar , Peter Zijlstra , Sasha Levin Subject: [PATCH 5.8 053/255] locking/lockdep: Fix overflow in presentation of average lock-time Date: Tue, 1 Sep 2020 17:08:29 +0200 Message-Id: <20200901151003.268731935@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200901151000.800754757@linuxfoundation.org> References: <20200901151000.800754757@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@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 5525cd3ba0c83..02ef87f50df29 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)