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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 26790C2BB3F for ; Sat, 18 Nov 2023 17:35:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229988AbjKRRfJ (ORCPT ); Sat, 18 Nov 2023 12:35:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47128 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229463AbjKRRfI (ORCPT ); Sat, 18 Nov 2023 12:35:08 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2394112B for ; Sat, 18 Nov 2023 09:35:05 -0800 (PST) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EBA61C433C7; Sat, 18 Nov 2023 17:35:03 +0000 (UTC) Date: Sat, 18 Nov 2023 17:35:01 +0000 From: Catalin Marinas To: Jim Cromie Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org Subject: Re: [PATCH 1/2] kmemleak: drop (age ) from leak record Message-ID: References: <20231116224318.124209-1-jim.cromie@gmail.com> <20231116224318.124209-2-jim.cromie@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231116224318.124209-2-jim.cromie@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 16, 2023 at 03:43:17PM -0700, Jim Cromie wrote: > Displaying age is pretty, but counter-productive; it changes with > current-time, so it surrenders idempotency of the output, which breaks > simple hash-based cataloging of the records by the user. > > The trouble: sequential reads, wo new leaks, get new results: > > :#> sum /sys/kernel/debug/kmemleak > 53439 74 /sys/kernel/debug/kmemleak > :#> sum /sys/kernel/debug/kmemleak > 59066 74 /sys/kernel/debug/kmemleak > > and age is why (nothing else changes): > > :#> grep -v age /sys/kernel/debug/kmemleak | sum > 58894 67 > :#> grep -v age /sys/kernel/debug/kmemleak | sum > 58894 67 > > Since jiffies is already printed in the "comm" line, age adds nothing. > > Notably, syzkaller reads kmemleak only for "unreferenced object", and > won't care about this reform of age-ism. A few moribund github repos > mention it, but don't compile. > > Signed-off-by: Jim Cromie Reviewed-by: Catalin Marinas