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 4B310C433FE for ; Fri, 11 Nov 2022 08:45:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233385AbiKKIpt (ORCPT ); Fri, 11 Nov 2022 03:45:49 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35106 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233352AbiKKIpb (ORCPT ); Fri, 11 Nov 2022 03:45:31 -0500 Received: from out1-smtp.messagingengine.com (out1-smtp.messagingengine.com [66.111.4.25]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 96AA382C5F; Fri, 11 Nov 2022 00:45:19 -0800 (PST) Received: from compute3.internal (compute3.nyi.internal [10.202.2.43]) by mailout.nyi.internal (Postfix) with ESMTP id 5D8965C026A; Fri, 11 Nov 2022 03:45:16 -0500 (EST) Received: from imap51 ([10.202.2.101]) by compute3.internal (MEProxy); Fri, 11 Nov 2022 03:45:16 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arndb.de; h=cc :cc:content-type:date:date:from:from:in-reply-to:in-reply-to :message-id:mime-version:references:reply-to:sender:subject :subject:to:to; s=fm3; t=1668156316; x=1668242716; bh=lImIfGrlwD JCi6Gs7wYZwHzBayogHUUB/nuYnjmfvnc=; b=HSWytxZdec4Cg3qZTidPfFN7h4 dKWUFG6IQTt67q0WxeegvQqdFmEkyq+ZOWMs1EbcZD1SKI59RfmXhOKAU0SfSJ2X vZz3bijWI1rKSEI68YPE9tX03R9A1msYYBRZekrTSrmJ4ezWM4GMJHlfbQgkZFnp NgNN6rxzbCv069qVV1knx1s+mSktv5WpNZJ3r9HTNLliIaXwRG1MwnT3GUvgC8Cb RgDCTfM05EIyspHj0dOf+m3HARlkTvuO1+g4wqviGbH9RZMdtePAReqXkcfQuT8y 4G2uh6rD36wghcRkXkitB0TF1ksN21tdFQ968FmMHDmhwACrl9re5U6YhugQ== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-type:date:date:feedback-id :feedback-id:from:from:in-reply-to:in-reply-to:message-id :mime-version:references:reply-to:sender:subject:subject:to:to :x-me-proxy:x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s= fm1; t=1668156316; x=1668242716; bh=lImIfGrlwDJCi6Gs7wYZwHzBayog HUUB/nuYnjmfvnc=; b=kXjrFlM85DqYuO+vn6R/8oP6WYWqd8Py/ODBLPOYnwMb 2WKRwkFnWW9GeVBYhMLA36TvLGktCUbVTcokrrDBSrSvu5PUUK39H9JMt3XS/1Xg tVCtugOUpi2eipXDTAzBUJXtEVUIbDT9QHlzQLTK/ScjO0lK4J/0+0Iyx9IIjjtO caIVC+gfZywncr+CdxT4vTO2U+kIb5usQOdxeou0ecGX6APDFwUaALsKgO48ilev Ym73gRUoMTignVDEmHdDdyBQ5WDEbKuQvtsxVjLfSBoDMAkvyIJEN3LbIP8N5ihZ dAX5Ayvg9CqX7kA+uBhNHiy4P85iEZbKazh6/Nt1Pg== X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvgedrfeehgdduvdeiucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne cujfgurhepofgfggfkjghffffhvfevufgtsehttdertderredtnecuhfhrohhmpedftehr nhguuceuvghrghhmrghnnhdfuceorghrnhgusegrrhhnuggsrdguvgeqnecuggftrfgrth htvghrnhephfdtlefhtedttedvtedvueeugedvueelueduvefhuefhuefgvddtveevvdff hfdunecuffhomhgrihhnpehlihhnrghrohdrohhrghenucevlhhushhtvghrufhiiigvpe dtnecurfgrrhgrmhepmhgrihhlfhhrohhmpegrrhhnugesrghrnhgusgdruggv X-ME-Proxy: Feedback-ID: i56a14606:Fastmail Received: by mailuser.nyi.internal (Postfix, from userid 501) id 22B53B60086; Fri, 11 Nov 2022 03:45:16 -0500 (EST) X-Mailer: MessagingEngine.com Webmail Interface User-Agent: Cyrus-JMAP/3.7.0-alpha0-1115-g8b801eadce-fm-20221102.001-g8b801ead Mime-Version: 1.0 Message-Id: <89a8e93c-f667-4de1-972f-3d2d051bd789@app.fastmail.com> In-Reply-To: References: <29824864-f076-401f-bfb4-bc105bb2d38f@app.fastmail.com> <96a99291-7caa-429c-9bbd-29721a2b5637@app.fastmail.com> Date: Fri, 11 Nov 2022 09:44:55 +0100 From: "Arnd Bergmann" To: "Naresh Kamboju" Cc: linux-stable , "open list" , "Linux ARM" , lkft-triage@lists.linaro.org, "Greg Kroah-Hartman" , "Sasha Levin" , "Linus Walleij" , "Mark Brown" , "Liam Girdwood" , "Ard Biesheuvel" Subject: Re: arm: TI BeagleBoard X15 : Unable to handle kernel NULL pointer dereference at virtual address 00000369 - Internal error: Oops: 5 [#1] SMP ARM Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Nov 11, 2022, at 07:28, Naresh Kamboju wrote: > On Thu, 10 Nov 2022 at 03:33, Arnd Bergmann wrote: >> >> One more idea I had is the unwinder: since this kernel is built >> with the frame-pointer unwinder, I think the stack usage per >> function is going to be slightly larger than with the arm unwinder. >> >> Naresh, how hard is it to reproduce this bug intentionally? >> Can you try if it still happens if you change the .config to >> use these:? >> >> # CONFIG_FUNCTION_GRAPH_TRACER is not set >> # CONFIG_UNWINDER_FRAME_POINTER is not set >> CONFIG_UNWINDER_ARM=y > > I have done this experiment and reported crash not reproduced > after eight rounds of testing [1]. > > https://lkft.validation.linaro.org/scheduler/job/5835922#L1993 Ok, good to hear. In this case, I see three possible ways forward to prevent this from coming back on your system: a) use asynchronous probing for one or more of the drivers as Dmitry suggested. This means fixing it upstream first and then backporting the fix to all stable kernels. We should probably do this anyway, but this will need more testing on your side. b) Change your kernel config permanently with the options above, if LKFT does not actually rely on CONFIG_FUNCTION_GRAPH_TRACER. I don't know if it does. c) backport commit 41918ec82eb6 ("ARM: ftrace: enable the graph tracer with the EABI unwinder") from 5.17. This was part of a longer series from Ard, and while the patch itself looks simple enough to be backported, I suspect we'd have to backport the entire series, which is probably not going to be realistic. Ard, any comments on this? Arnd