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@xxxxxxxxx> Reviewed-by: Arun R Murthy <arun.r.murthy@xxxxxxxxx> --- drivers/gpu/drm/i915/display/intel_fbdev.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/display/intel_fbdev.c b/drivers/gpu/drm/i915/display/intel_fbdev.c index 221336178991f0..94ddc0f34fde64 100644 --- a/drivers/gpu/drm/i915/display/intel_fbdev.c +++ b/drivers/gpu/drm/i915/display/intel_fbdev.c @@ -573,7 +573,8 @@ void intel_fbdev_unregister(struct drm_i915_private *dev_priv) if (!ifbdev) return; - cancel_work_sync(&dev_priv->fbdev_suspend_work); + intel_fbdev_set_suspend(&dev_priv->drm, FBINFO_STATE_SUSPENDED, true); + if (!current_is_async()) intel_fbdev_sync(ifbdev); @@ -618,7 +619,7 @@ void intel_fbdev_set_suspend(struct drm_device *dev, int state, bool synchronous struct fb_info *info; if (!ifbdev || !ifbdev->vma) - return; + goto unlock; info = ifbdev->helper.fbdev; @@ -661,6 +662,7 @@ void intel_fbdev_set_suspend(struct drm_device *dev, int state, bool synchronous drm_fb_helper_set_suspend(&ifbdev->helper, state); console_unlock(); +unlock: intel_fbdev_hpd_set_suspend(dev_priv, state); } -- 2.25.1
