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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 67F51C433B4 for ; Tue, 20 Apr 2021 08:12:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 22FF1611C9 for ; Tue, 20 Apr 2021 08:12:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229559AbhDTINL (ORCPT ); Tue, 20 Apr 2021 04:13:11 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:33202 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229521AbhDTINL (ORCPT ); Tue, 20 Apr 2021 04:13:11 -0400 Received: from mail-lj1-f199.google.com ([209.85.208.199]) by youngberry.canonical.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1lYlUs-0001f3-Ub for linux-fbdev@vger.kernel.org; Tue, 20 Apr 2021 08:12:39 +0000 Received: by mail-lj1-f199.google.com with SMTP id u24-20020a2e14180000b02900bf2bea127dso350919ljd.16 for ; Tue, 20 Apr 2021 01:12:38 -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=IV9Eebskso7YyD0zMzspoNTbhY3LJpAmQOuTJ1c9y40=; b=FmJJ26zxq//onnIrDrj3ClEYNRhr5We8lbQWOu3M8+4jhngW+9ERYQGBkqq4tb/HTN 1u9j7VY57MQ20wJqivre+BXZfKrsyaxrBxC48YsHMwamL1bc6s+wm9g/wth//oJ6hch+ pkFLf1z03ouzer0FRFErI9G3J5qs9ERSOMuuL06AGWZ0GX2XCAKfK63ECaex3JZheeFa jo31y7fYUDroZFslc+Fgio0z4MOizzjbX2FWwPnnebeBwujt2l12sclY3qVjQ32iymS0 Pojsxn+TLZFTZylIbRgRQ1dM6wjL9caHpvb866oDS6/q/NG22qJwigRFB1U+FoRLlrTr 3m7w== X-Gm-Message-State: AOAM533EyqAH/Rhj+kZWimZQc5CzEvlcb6rlyKa48s5p8KlCLDdViiZv rHYqi+an1WBcoMncHdG0px59ffHL2gY4Nr2YA1F3iG9wsvbOSFuoGRHIwFNT+NhO8eVty0xxJQu H5Ef+LCXp4fWuqRPGosl4M0lmXbdBsD5hafrmBoIVhYcdyZZUnyZiZ6/N X-Received: by 2002:ac2:5f1b:: with SMTP id 27mr14782464lfq.425.1618906358349; Tue, 20 Apr 2021 01:12:38 -0700 (PDT) X-Google-Smtp-Source: ABdhPJxGj+Hlh1J4/cwN5jCaEklO5slca58XNB7qVuci1XVRA8XrEJfTHTIictY7IK+d0qKQHdTKXplsFsdyezE44Ec= X-Received: by 2002:ac2:5f1b:: with SMTP id 27mr14782427lfq.425.1618906357768; Tue, 20 Apr 2021 01:12:37 -0700 (PDT) MIME-Version: 1.0 References: <20210415102224.2764054-1-sudeep.holla@arm.com> <20210420075332.t56dlpppb6bnpjzd@bogus> In-Reply-To: <20210420075332.t56dlpppb6bnpjzd@bogus> From: Kai-Heng Feng Date: Tue, 20 Apr 2021 16:12:26 +0800 Message-ID: Subject: Re: [PATCH] efifb: Fix runtime pm calls for non PCI efifb device To: Sudeep Holla Cc: Alex Deucher , Thomas Zimmermann , Peter Jones , "open list:EFIFB FRAMEBUFFER DRIVER" , "open list:DRM DRIVERS" , LKML Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org Hi Sudeep, On Tue, Apr 20, 2021 at 3:53 PM Sudeep Holla wrote: > > Gentle Ping! There is boot failure because of this issue with linux-next > on few arm platforms with non PCIe efifb. Please review and get the fix > merged ASAP so the testing on these platforms can continue with linux-next. It was merged in drm-tip as d510c88cfbb2 ("efifb: Check efifb_pci_dev before using it"). Kai-Heng > > On Thu, Apr 15, 2021 at 11:22:24AM +0100, Sudeep Holla wrote: > > Commit a6c0fd3d5a8b ("efifb: Ensure graphics device for efifb stays at PCI D0") > > added runtime pm calls to probe and remove routines to ensure the PCI > > device for efifb stays in D0 state. However not ever efifb is based on > > PCI device and efifb_pci_dev can be NULL if that is the case. > > > > In such cases, we will get a boot splat like below due to NULL dereference: > > -->8 > > Console: switching to colour frame buffer device 240x67 > > fb0: EFI VGA frame buffer device > > Unable to handle kernel NULL pointer dereference at virtual address 0000000000000270 > > 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 > > [0000000000000270] user address but active_mm is swapper > > Internal error: Oops: 96000004 [#1] PREEMPT SMP > > Modules linked in: > > CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.12.0-rc7-next-20210413 #1 > > Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform > > pstate: 60000005 (nZCv daif -PAN -UAO -TCO BTYPE=--) > > pc : pm_runtime_drop_link+0x12c/0x338 > > lr : efifb_probe+0x7bc/0x7f0 > > Call trace: > > pm_runtime_drop_link+0x12c/0x338 > > efifb_probe+0x7bc/0x7f0 > > platform_probe+0x68/0xd8 > > really_probe+0xe4/0x3a8 > > driver_probe_device+0x64/0xc8 > > device_driver_attach+0x74/0x80 > > __driver_attach+0x64/0xf0 > > bus_for_each_dev+0x70/0xc0 > > driver_attach+0x24/0x30 > > bus_add_driver+0x150/0x1f8 > > driver_register+0x64/0x120 > > __platform_driver_register+0x28/0x38 > > efifb_driver_init+0x1c/0x28 > > do_one_initcall+0x48/0x2b0 > > kernel_init_freeable+0x1e8/0x258 > > kernel_init+0x14/0x118 > > ret_from_fork+0x10/0x30 > > Code: 88027c01 35ffffa2 17fff706 f9800051 (885f7c40) > > ---[ end trace 17d8da630bf8ff77 ]--- > > Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b > > -->8 > > > > Fix the issue by checking for non-NULL efifb_pci_dev before dereferencing > > for runtime pm calls in probe and remove routines. > > > > Fixes: a6c0fd3d5a8b ("efifb: Ensure graphics device for efifb stays at PCI D0") > > Cc: Kai-Heng Feng > > Cc: Alex Deucher > > Cc: Thomas Zimmermann > > Cc: Peter Jones > > Signed-off-by: Sudeep Holla > > --- > > drivers/video/fbdev/efifb.c | 6 ++++-- > > 1 file changed, 4 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/video/fbdev/efifb.c b/drivers/video/fbdev/efifb.c > > index f58a545b3bf3..8ea8f079cde2 100644 > > --- a/drivers/video/fbdev/efifb.c > > +++ b/drivers/video/fbdev/efifb.c > > @@ -575,7 +575,8 @@ static int efifb_probe(struct platform_device *dev) > > goto err_fb_dealoc; > > } > > fb_info(info, "%s frame buffer device\n", info->fix.id); > > - pm_runtime_get_sync(&efifb_pci_dev->dev); > > + if (efifb_pci_dev) > > + pm_runtime_get_sync(&efifb_pci_dev->dev); > > return 0; > > > > err_fb_dealoc: > > @@ -602,7 +603,8 @@ static int efifb_remove(struct platform_device *pdev) > > unregister_framebuffer(info); > > sysfs_remove_groups(&pdev->dev.kobj, efifb_groups); > > framebuffer_release(info); > > - pm_runtime_put(&efifb_pci_dev->dev); > > + if (efifb_pci_dev) > > + pm_runtime_put(&efifb_pci_dev->dev); > > > > return 0; > > } > > -- > > 2.25.1 > > > > -- > Regards, > Sudeep