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=-3.0 required=3.0 tests=BAYES_00,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 60CFEC4361B for ; Mon, 14 Dec 2020 10:02:29 +0000 (UTC) Received: by mail.kernel.org (Postfix) id 1D81322AAD; Mon, 14 Dec 2020 10:02:29 +0000 (UTC) Received: by smtp.codeaurora.org (Postfix, from userid 1001) id CDCD4C43464; Mon, 14 Dec 2020 10:02:28 +0000 (UTC) Received: from potku.adurom.net (88-114-240-156.elisa-laajakaista.fi [88.114.240.156]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: kvalo) by smtp.codeaurora.org (Postfix) with ESMTPSA id D6097C433C6; Mon, 14 Dec 2020 10:02:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org D6097C433C6 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=fail smtp.mailfrom=kvalo@codeaurora.org From: Kalle Valo To: Linus Walleij List-Id: Cc: David Hildenbrand , arm-soc , SoC Team , Linux ARM , stable , Pavel Procopiuc , Vlastimil Babka , wi nk Subject: Re: [PATCH] ARM: dts: ux500: Reserve memory carveouts References: <20201213225517.3838501-1-linus.walleij@linaro.org> Date: Mon, 14 Dec 2020 12:02:23 +0200 In-Reply-To: (Linus Walleij's message of "Mon, 14 Dec 2020 10:27:28 +0100") Message-ID: <877dpk3du8.fsf@codeaurora.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.5 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Linus Walleij writes: > On Mon, Dec 14, 2020 at 10:21 AM David Hildenbrand wrote: > >> > ARM SoC folks: please apply this directly for fixes. >> >> Can we come up with a Fixes: tag or has this been broken forever? >> (assuming modern boot loaders) > > It's been broken forever :/ > >> > David: just FYI if you run into more of these type of >> > regressions. Actually the patch is unintentionally good >> > at smoking out other bugs :D >> >> Thanks for CCing - I'm adding some people that ran into similar issues, >> but not sure if the other bugreports are related (or have similar root >> causes). > > Yeah we first were convinced there was something wrong with > the patch you made but I read it over and over again and there > is nothing wrong with it at all. It just alters the behaviour pattern of > memory management in some apparently drastic ways. > > After a lot of silent crashes I finally got an external abort with > a reasonable backtrace showing the PTE pointing to this > modem memory and then we figured it out. We had similar experiences with ath11k (Wi-Fi 6) and QCA6390 firmware. So indeed commit 7fef431be9c9 ("mm/page_alloc: place pages to tail in __free_pages_core()") is a great way to catch odd firmware or hardware problems, which most likely would have gone unnoticed otherwise and users would have end up experiencing random crashes. -- https://patchwork.kernel.org/project/linux-wireless/list/ https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches