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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 7D6F1C6369E for ; Thu, 19 Nov 2020 13:45:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3993322264 for ; Thu, 19 Nov 2020 13:45:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727268AbgKSNpb (ORCPT ); Thu, 19 Nov 2020 08:45:31 -0500 Received: from www262.sakura.ne.jp ([202.181.97.72]:53871 "EHLO www262.sakura.ne.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726480AbgKSNpb (ORCPT ); Thu, 19 Nov 2020 08:45:31 -0500 Received: from fsav402.sakura.ne.jp (fsav402.sakura.ne.jp [133.242.250.101]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id 0AJDjTc9008098; Thu, 19 Nov 2020 22:45:29 +0900 (JST) (envelope-from penguin-kernel@i-love.sakura.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav402.sakura.ne.jp (F-Secure/fsigk_smtp/550/fsav402.sakura.ne.jp); Thu, 19 Nov 2020 22:45:29 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/fsav402.sakura.ne.jp) Received: from [192.168.1.9] (M106072142033.v4.enabler.ne.jp [106.72.142.33]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id 0AJDjS0O008048 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NO); Thu, 19 Nov 2020 22:45:29 +0900 (JST) (envelope-from penguin-kernel@i-love.sakura.ne.jp) Subject: Re: [PATCH v3] lockdep: Allow tuning tracing capacity constants. To: Dmitry Vyukov Cc: syzkaller , Ingo Molnar , Will Deacon , Andrew Morton , LKML , Linus Torvalds , Peter Zijlstra References: <1595640639-9310-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp> <384ce711-25c5-553b-8d22-965847132fbd@i-love.sakura.ne.jp> <0eb519fa-e77b-b655-724a-4e9eecc64626@i-love.sakura.ne.jp> <6933e938-f219-5e13-aee6-fe4de87eb43e@i-love.sakura.ne.jp> <81ab0ffd-6e80-c96c-053a-b1b4fe8694c1@i-love.sakura.ne.jp> <20201118142357.GW3121392@hirez.programming.kicks-ass.net> <1778f2e5-0a0c-2c6e-2c83-fe51d938e8a2@i-love.sakura.ne.jp> <20201118151038.GX3121392@hirez.programming.kicks-ass.net> <9bc4e07d-2a58-077b-b4c7-ab056ba33cf1@i-love.sakura.ne.jp> From: Tetsuo Handa Message-ID: <5e8342c4-702f-80a9-e669-8a7386ce0da1@i-love.sakura.ne.jp> Date: Thu, 19 Nov 2020 22:45:25 +0900 User-Agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.4.3 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020/11/19 22:06, Dmitry Vyukov wrote: >>>> >>>> I am trying to reproduce this locally first. syzbot caims it can >>>> reproduce it with a number of very simpler reproducers (like spawn >>>> process, unshare, create socket): >>>> https://syzkaller.appspot.com/bug?id=8a18efe79140782a88dcd098808d6ab20ed740cc >>>> >>>> I see a very slow drift, but it's very slow, so get only to: >>>> direct dependencies: 22072 [max: 32768] >>>> >>>> But that's running a very uniform workload. >>>> >>>> However when I tried to cat /proc/lockdep to see if there is anything >>>> fishy already, >>>> I got this (on c2e7554e1b85935d962127efa3c2a76483b0b3b6). >>>> >>>> Some missing locks? Not a TOMOYO's bug. Maybe a lockdep's bug. > > But I don't know if it's enough to explain the overflow or not... > Since you can't hit the limit locally, I guess we need to ask syzbot to run massive testcases.