[Intel-gfx] [PATCH v3 2/3] drm/i915/fbdev: suspend HPD before fbdev unregistration

[Murthy, Arun R]

> -----Original Message-----
> From: Hajda, Andrzej <andrzej.hajda at intel.com>
> Sent: Wednesday, July 13, 2022 8:50 PM
> To: Jani Nikula <jani.nikula at linux.intel.com>; Ville Syrjälä
> <ville.syrjala at linux.intel.com>; Murthy, Arun R <arun.r.murthy at intel.com>
> Cc: Hajda, Andrzej <andrzej.hajda at intel.com>; Joonas Lahtinen
> <joonas.lahtinen at linux.intel.com>; Vivi, Rodrigo <rodrigo.vivi at intel.com>;
> Tvrtko Ursulin <tvrtko.ursulin at linux.intel.com>; Daniel Vetter
> <daniel at ffwll.ch>; intel-gfx at lists.freedesktop.org; dri-
> devel at lists.freedesktop.org
> Subject: [PATCH v3 2/3] drm/i915/fbdev: suspend HPD before fbdev
> unregistration
> 
> HPD event after fbdev unregistration can cause registration of deferred fbdev
> which will not be unregistered later, causing use-after-free.
> To avoid it HPD handling should be suspended before fbdev unregistration.
> 
> It should fix following GPF:
> [272.634530] general protection fault, probably for non-canonical address
> 0x6b6b6b6b6b6b6b6b: 0000 [#1] PREEMPT SMP NOPTI
> [272.634536] CPU: 0 PID: 6030 Comm: i915_selftest Tainted: G     U
> 5.18.0-rc5-CI_DRM_11603-g12dccf4f5eef+ #1
> [272.634541] Hardware name: Intel Corporation Raptor Lake Client
> Platform/RPL-S ADP-S DDR5 UDIMM CRB, BIOS
> RPLSFWI1.R00.2397.A01.2109300731 09/30/2021 [272.634545] RIP:
> 0010:fb_do_apertures_overlap.part.14+0x26/0x60
> ...
> [272.634582] Call Trace:
> [272.634583]  <TASK>
> [272.634585]  do_remove_conflicting_framebuffers+0x59/0xa0
> [272.634589]  remove_conflicting_framebuffers+0x2d/0xc0
> [272.634592]  remove_conflicting_pci_framebuffers+0xc8/0x110
> [272.634595]
> drm_aperture_remove_conflicting_pci_framebuffers+0x52/0x70
> [272.634604]  i915_driver_probe+0x63a/0xdd0 [i915]
> 
> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/5329
> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/5510
> Signed-off-by: Andrzej Hajda <andrzej.hajda at intel.com>
> ---
Reviewed-by: Arun R Murthy <arun.r.murthy at intel.com>

Thanks and Regards,
Arun R Murthy
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