linux-kernel - Re: a bochs-drm (?) oops on head

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Message-ID: <b2e2a217-dced-472f-9084-9822f7e6803c@suse.de>
Date: Mon, 16 Dec 2024 09:41:52 +0100
From: Thomas Zimmermann <tzimmermann@...e.de>
To: "Dr. David Alan Gilbert" <dave@...blig.org>, kraxel@...hat.com
Cc: virtualization@...ts.linux.dev, linux-kernel@...r.kernel.org,
 dri-devel <dri-devel@...ts.freedesktop.org>
Subject: Re: a bochs-drm (?) oops on head

Hi

Am 15.12.24 um 19:18 schrieb Dr. David Alan Gilbert:
> Hey Gerd, Thomas,
>    I've got the following oops that looks bochs-drm related on the current
> HEAD ( 4800575d8c0b2f354ab05ab1c4749e45e213bf73 ) and it's been there
> for at least a few days; this is
[...]
>
> The oops has :
> [   78.463760][    T1]  bochs_pci_driver_init+0x8a/0xc0
>
> in it, hence why I'm blaming that.
> (Other odd observation, the Tuxen flicker heavily during booting!)
>
> [   72.756014][    T1] bochs-drm 0000:00:02.0: vgaarb: deactivate vga console
> [   72.758258][    T1] [drm] Found bochs VGA, ID 0xb0c5.
> [   72.758793][    T1] [drm] Framebuffer size 16384 kB @ 0xfd000000, mmio @ 0xfebf0000.
> [   72.767777][    T1] [drm] Initialized bochs-drm 1.0.0 for 0000:00:02.0 on minor 2
> [   72.839222][    T1] fbcon: bochs-drmdrmfb (fb1) is primary device
> [   72.839311][    T1] fbcon: Remapping primary device, fb1, to tty 1-63
> [   78.402163][    T1] bochs-drm 0000:00:02.0: [drm] fb1: bochs-drmdrmfb frame buffer device
> [   78.459984][    T1] BUG: unable to handle page fault for address: ffff8dd345604004
> [   78.463246][    T1] #PF: supervisor write access in kernel mode
> [   78.463760][    T1] #PF: error_code(0x0002) - not-present page
> [   78.463760][    T1] PGD 72001067 P4D 72001067 PUD 72002067 PMD 7fbe1067 PTE 800ffffffa9fb060
> [   78.463760][    T1] Oops: Oops: 0002 [#1] PREEMPT SMP DEBUG_PAGEALLOC NOPTI
> [   78.463760][    T1] CPU: 2 UID: 0 PID: 1 Comm: swapper/0 Tainted: G        W        N 6.13.0-rc2+ #363 6c653a430ed30aae3dac648429c492a2726da3d7
> [   78.463760][    T1] Tainted: [W]=WARN, [N]=TEST
> [   78.463760][    T1] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-3.fc41 04/01/2014
> [   78.463760][    T1] RIP: 0010:devm_drm_dev_init_release+0x4e/0x140
[...]
>
> [   78.463760][    T1] ---[ end Kernel panic - not syncing: Fatal exception ]---
>
>
> The config is a fairly full yes-config ish; see attached.

Thanks for reporting. I've been able to reproduce the problem by setting 
CONFIG_DEBUG_TEST_DRIVER_REMOVE 
<https://elixir.bootlin.com/linux/v6.13-rc2/K/ident/CONFIG_DEBUG_TEST_DRIVER_REMOVE>=y. 
The attached patch fixes the problem for me. Could you please test and 
report back the results.

Best regards
Thomas


>
> Dave
>

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)

View attachment "0001-drm-bochs-Do-not-put-DRM-device-in-PCI-remove-callba.patch" of type "text/x-patch" (3388 bytes)