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=-9.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS 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 4E24DC433DB for ; Wed, 17 Mar 2021 18:47:16 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D027564F04 for ; Wed, 17 Mar 2021 18:47:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D027564F04 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=3juwnosQwJdRcTVsFNhVCEwC8IfNC76h59zeNphdOqE=; b=ZQ2q/jm5OJWO4hw/luN+WnG8I WwkPbBh3RF1zQVWwUhB/qC6UY3SToTf5KS2waTUdp2MfPPFA7Rea9bCN4cUecAAKC7w6DEY/JRxKP DKLSw3QN4ku5n3L7oUuacQWDrZaQnbO9I8K8S9VM854EQKL9jYBExG1imTjxiPFh64osS+nVXdGnq UDIKsIasNPqzXdrqXSy8ptUbxWnL8XsWLjQ6uIR/1HhObwdHNsEbeamt+tzS2gcYLocCbi7nL0DNk M6mPTwzzaq/8nklYmdr12sE8r2rpOEzrkQz/K4eAF496U1Reh400S/JIRivLloXF7jtYJicy0Rf12 d5GUo5Hfw==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lMbB3-003lP9-Jm; Wed, 17 Mar 2021 18:45:53 +0000 Received: from foss.arm.com ([217.140.110.172]) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lMbAz-003lO7-MI for linux-arm-kernel@lists.infradead.org; Wed, 17 Mar 2021 18:45:51 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 3501ED6E; Wed, 17 Mar 2021 11:45:47 -0700 (PDT) Received: from C02TD0UTHF1T.local (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1F6F53F70D; Wed, 17 Mar 2021 11:45:44 -0700 (PDT) Date: Wed, 17 Mar 2021 18:45:38 +0000 From: Mark Rutland To: Dmitry Vyukov Cc: maz@kernel.org, Will Deacon , Ard Biesheuvel , Linux ARM , Arnd Bergmann , syzkaller , LKML Subject: Re: arm64 syzbot instances Message-ID: <20210317184538.GB2508@C02TD0UTHF1T.local> References: <20210311123315.GF37303@C02TD0UTHF1T.local> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210317_184549_920959_78BE27F1 X-CRM114-Status: GOOD ( 14.82 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Mar 11, 2021 at 05:56:46PM +0100, Dmitry Vyukov wrote: > On Thu, Mar 11, 2021 at 1:33 PM Mark Rutland wrote: > > FWIW, I keep my fuzzing config fragment in my fuzzing/* branches on > > git.kernel.org, and for comparison my fragment for v5.12-rc1 is: > > > > https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git/commit/?h=fuzzing/5.12-rc1&id=6d9f7f8a2514fe882823fadbe7478228f71d7ab1 > > > > ... I'm not sure whether there's anything in that which is novel to you. > > Hi Mark, > > I've learned about DEBUG_TIMEKEEPING which we had disabled. I am enabling it. > We also have CONTEXT_TRACKING_FORCE disabled. I don't completely > understand what it's doing. Is it also "more debug checks" type of > config? Context tracking tracks user<->kernel transitions, and tries to disable RCU when it is not needed (e.g. while a CPU is in usersspace), to avoid the need to perturb that CPU with IPIs and so on. Normally this is not enabled unless CPUs are set aside for NOHZ usage, as there's some expense in doing this tracking. I haven't measured how expensive it is in practice. CONTEXT_TRACKING_FORCE enables that tracking regardless of whether any CPUs are set aside for NOHZ usage, and makes it easier to find bugs in that tracking code, or where it is not being used correctly (e.g. missed calls, or called in the wrong places). I added it to my debug fragment back when I fixed the arm64 entry code accounting for lockdep, and I keep it around to make sure that we don't accidentally regress any of that. Thanks, Mark. > FWIW we have more debug configs: > https://github.com/google/syzkaller/blob/master/dashboard/config/linux/bits/debug.yml > https://github.com/google/syzkaller/blob/master/dashboard/config/linux/bits/base.yml > https://github.com/google/syzkaller/blob/master/dashboard/config/linux/bits/kasan.yml > https://github.com/google/syzkaller/blob/master/dashboard/config/linux/bits/kmemleak.yml _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel