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=-8.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 36F38C433DB for ; Fri, 26 Mar 2021 18:31:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C224E61A4C for ; Fri, 26 Mar 2021 18:31:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230026AbhCZSaf (ORCPT ); Fri, 26 Mar 2021 14:30:35 -0400 Received: from mail-ua1-f43.google.com ([209.85.222.43]:43834 "EHLO mail-ua1-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230003AbhCZSaH (ORCPT ); Fri, 26 Mar 2021 14:30:07 -0400 Received: by mail-ua1-f43.google.com with SMTP id b7so1844635uam.10; Fri, 26 Mar 2021 11:30:07 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=vZGkD+4E2RmAMLxrWzBsZkwCCLapq9ZQRvLGJF4GNDc=; b=Ng12zlhcQH5p6RIHSBG/HvQCahO/IW1jmW9irIsuJTz/p/TIUDg8IHrOtlDulB5Lf4 SWB6W/F4bvanRi11K3rmYDZHVkakKsnOFJc//pRRum1Hm7N7qqIzU9FMOU5U4oEPo90T lTac3W8p3JPxMGOKEDJByB1wU6uCZSMLSi7h2gapO+CKIZMP2liVVX8F4Up5l3Coz3zf QUtrSUq6e1gdWx7urXAphTI5EGiBD8J9gzQxkuVFoLHrdf/a7M+hHOI0WJxbkh8Ighn+ BWbPCHU0/ARpkogu3ciROCpYz/+omyk2lQR3ycGtymFpK1HW8arJine0zTekrIvLOerT SqTg== X-Gm-Message-State: AOAM531JKz+K7XuRtq/5cnGtjxTheEN+OShArhzDCTa5ctz2Bj+tb/GE ofXCPZzKY3Oh67LxBKlBwHYsfrDtzx2KLjMn83c= X-Google-Smtp-Source: ABdhPJx0IhSE3AkZ3+3lDyKkbS3EoEFfE4627qSgDTDKiNvMtRzb4w4kqJdMTUKAhyc0CMv4LBbwcP4qpaDf7XslJk0= X-Received: by 2002:ab0:30b3:: with SMTP id b19mr9108849uam.58.1616783406884; Fri, 26 Mar 2021 11:30:06 -0700 (PDT) MIME-Version: 1.0 References: <20210205222644.2357303-9-saravanak@google.com> <20210210114435.122242-1-tudor.ambarus@microchip.com> <20210210114435.122242-2-tudor.ambarus@microchip.com> <9b206c4d00dfe8b7f941260f18909914b2b2eecb.camel@suse.de> <161678243444.3012082.5031467952132861429@swboyd.mtv.corp.google.com> In-Reply-To: <161678243444.3012082.5031467952132861429@swboyd.mtv.corp.google.com> From: Geert Uytterhoeven Date: Fri, 26 Mar 2021 19:29:55 +0100 Message-ID: Subject: Re: [PATCH] clk: Mark fwnodes when their clock provider is added To: Stephen Boyd Cc: Marek Szyprowski , Nicolas Saenz Julienne , Tudor Ambarus , Jonathan Corbet , Frank Rowand , Greg KH , Kevin Hilman , Len Brown , Len Brown , Marc Zyngier , Michael Turquette , Pavel Machek , "Rafael J. Wysocki" , Rob Herring , Saravana Kannan , Thomas Gleixner , Ulf Hansson , Nicolas Ferre , Claudiu Beznea , "open list:DOCUMENTATION" , Linux Kernel Mailing List , Linux PM list , linux-clk , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , ACPI Devel Maling List , Android Kernel Team , linux-rpi-kernel Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org Hi Stephen, On Fri, Mar 26, 2021 at 7:13 PM Stephen Boyd wrote: > Quoting Nicolas Saenz Julienne (2021-03-25 11:25:24) > > On Thu, 2021-03-25 at 14:31 +0100, Marek Szyprowski wrote: > > > On 10.02.2021 12:44, Tudor Ambarus wrote: > > > > This is a follow-up for: > > > > commit 3c9ea42802a1 ("clk: Mark fwnodes when their clock provider is added/removed") > > > > > > > > The above commit updated the deprecated of_clk_add_provider(), > > > > but missed to update the preferred of_clk_add_hw_provider(). > > > > Update it now. > > > > > > > > Signed-off-by: Tudor Ambarus > > > > > > This patch, which landed in linux-next as commit 6579c8d97ad7 ("clk: > > > Mark fwnodes when their clock provider is added") causes the following > > > NULL pointer dereference on Raspberry Pi 3b+ boards: > > > > > > --->8--- > > > > > > raspberrypi-firmware soc:firmware: Attached to firmware from > > > 2020-01-06T13:05:25 > > > Unable to handle kernel NULL pointer dereference at virtual address > > > 0000000000000050 > > > Mem abort info: > > > ESR = 0x96000004 > > > EC = 0x25: DABT (current EL), IL = 32 bits > > > SET = 0, FnV = 0 > > > EA = 0, S1PTW = 0 > > > Data abort info: > > > ISV = 0, ISS = 0x00000004 > > > CM = 0, WnR = 0 > > > [0000000000000050] user address but active_mm is swapper > > > Internal error: Oops: 96000004 [#1] PREEMPT SMP > > > Modules linked in: > > > CPU: 0 PID: 10 Comm: kworker/0:1 Not tainted 5.12.0-rc4+ #2764 > > > Hardware name: Raspberry Pi 3 Model B (DT) > > > Workqueue: events deferred_probe_work_func > > > pstate: 00000005 (nzcv daif -PAN -UAO -TCO BTYPE=--) > > > pc : of_clk_add_hw_provider+0xac/0xe8 > > > lr : of_clk_add_hw_provider+0x94/0xe8 > > > sp : ffff8000130936b0 > > > x29: ffff8000130936b0 x28: ffff800012494e04 > > > x27: ffff00003b18cb05 x26: ffff00003aa5c010 > > > x25: 0000000000000000 x24: 0000000000000000 > > > x23: ffff00003aa1e380 x22: ffff8000106830d0 > > > x21: ffff80001233f180 x20: 0000000000000018 > > > x19: 0000000000000000 x18: ffff8000124d38b0 > > > x17: 0000000000000013 x16: 0000000000000014 > > > x15: ffff8000125758b0 x14: 00000000000184e0 > > > x13: 000000000000292e x12: ffff80001258dd98 > > > x11: 0000000000000001 x10: 0101010101010101 > > > x9 : ffff80001233f288 x8 : 7f7f7f7f7f7f7f7f > > > x7 : fefefefeff6c626f x6 : 5d636d8080808080 > > > x5 : 00000000006d635d x4 : 0000000000000000 > > > x3 : 0000000000000000 x2 : 540eb5edae191600 > > > x1 : 0000000000000000 x0 : 0000000000000000 > > > Call trace: > > > of_clk_add_hw_provider+0xac/0xe8 > > > devm_of_clk_add_hw_provider+0x5c/0xb8 > > > raspberrypi_clk_probe+0x110/0x210 > > > platform_probe+0x90/0xd8 > > > really_probe+0x108/0x3c0 > > > driver_probe_device+0x60/0xc0 > > > __device_attach_driver+0x9c/0xd0 > > > bus_for_each_drv+0x70/0xc8 > > > __device_attach+0xec/0x150 > > > device_initial_probe+0x10/0x18 > > > bus_probe_device+0x94/0xa0 > > > device_add+0x47c/0x780 > > > platform_device_add+0x110/0x248 > > > platform_device_register_full+0x120/0x150 > > > rpi_firmware_probe+0x158/0x1f8 > > > platform_probe+0x90/0xd8 > > > really_probe+0x108/0x3c0 > > > driver_probe_device+0x60/0xc0 > > > __device_attach_driver+0x9c/0xd0 > > > bus_for_each_drv+0x70/0xc8 > > > __device_attach+0xec/0x150 > > > device_initial_probe+0x10/0x18 > > > bus_probe_device+0x94/0xa0 > > > deferred_probe_work_func+0x70/0xa8 > > > process_one_work+0x2a8/0x718 > > > worker_thread+0x48/0x460 > > > kthread+0x134/0x160 > > > ret_from_fork+0x10/0x18 > > > Code: b1006294 540000c0 b140069f 54000088 (3940e280) > > > ---[ end trace 7ead5ec2f0c51cfe ]--- > > > > > > This patch mainly revealed that clk/bcm/clk-raspberrypi.c driver calls > > > devm_of_clk_add_hw_provider(), with a device pointer, which has a NULL > > > dev->of_node. I'm not sure if adding a check for a NULL np in > > > of_clk_add_hw_provider() is a right fix, though. > > > > I believe the right fix is not to call 'devm_of_clk_add_hw_provider()' if > > 'pdev->dev.of_node == NULL'. In such case, which is RPi3's, only the CPU clock > > is used, and it's defined and queried later through > > devm_clk_hw_register_clkdev(). > > > > @Marek, I don't mind taking care of it if it's OK with you. > > > > Ah I see this is related to the patch I just reviewed. Can you reference > this in the commit text? And instead of putting the change into the clk > provider let's check for NULL 'np' in of_clk_add_hw_provider() instead > and return 0 if there's nothing to do. That way we don't visit this > problem over and over again. I'm not sure the latter is what we reall want: shouldn't calling *of*_clk_add_hw_provider() with a NULL np be a bug in the provider? Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds