Always run fbdev removal first to remove simpledrm via sysfb_disable().
This clears the internal state.
The later call to drm_aperture_detach_drivers() then does nothing.
Otherwise, with drm_aperture_detach_drivers() running first, the call to
sysfb_disable() uses inconsistent state.
Example backtrace show below:
BUG: KASAN: use-after-free in device_del+0x79/0x5f0
Read of size 8 at addr ffff888108185050 by task systemd-udevd/311
CPU: 0 PID: 311 Comm: systemd-udevd Tainted: G E 5.19.0-rc2-1-default+ #1689
Hardware name: HP ProLiant DL120 G7, BIOS J01 04/21/2011
Call Trace:
device_del+0x79/0x5f0
platform_device_del.part.0+0x19/0xe0
platform_device_unregister+0x1c/0x30
sysfb_disable+0x2d/0x70
remove_conflicting_framebuffers+0x1c/0xf0
remove_conflicting_pci_framebuffers+0x130/0x1a0
drm_aperture_remove_conflicting_pci_framebuffers+0x86/0xb0
mgag200_pci_probe+0x2d/0x140 [mgag200]
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: 873eb3b118 ("fbdev: Disable sysfb device registration when removing conflicting FBs")
Cc: Javier Martinez Canillas <javierm@redhat.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Zhen Lei <thunder.leizhen@huawei.com>
Cc: Changcheng Deng <deng.changcheng@zte.com.cn>
Reviewed-by: Zack Rusin <zackr@vmware.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
84499c5d22