Handling HPD during driver removal is pointless, and can cause different use-after-free/concurrency issues: 1. Setup of deferred fbdev after fbdev unregistration. 2. Access to DP-AUX after DP-AUX removal.
Below stacktraces of both cases observed on CI:
[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]
[283.405824] cpu_latency_qos_update_request called for unknown object [283.405866] WARNING: CPU: 2 PID: 240 at kernel/power/qos.c:296 cpu_latency_qos_update_request+0x2d/0x100 [283.405912] CPU: 2 PID: 240 Comm: kworker/u64:9 Not tainted 5.18.0-rc6-Patchwork_103738v3-g1672d1c43e43+ #1 [283.405915] Hardware name: Intel Corporation Raptor Lake Client Platform/RPL-S ADP-S DDR5 UDIMM CRB, BIOS RPLSFWI1.R00.2397.A01.2109300731 09/30/2021 [283.405916] Workqueue: i915-dp i915_digport_work_func [i915] [283.406020] RIP: 0010:cpu_latency_qos_update_request+0x2d/0x100 ... [283.406040] Call Trace: [283.406041] <TASK> [283.406044] intel_dp_aux_xfer+0x60e/0x8e0 [i915] [283.406131] ? finish_swait+0x80/0x80 [283.406139] intel_dp_aux_transfer+0xc5/0x2b0 [i915] [283.406218] drm_dp_dpcd_access+0x79/0x130 [drm_display_helper] [283.406227] drm_dp_dpcd_read+0xe2/0xf0 [drm_display_helper] [283.406233] intel_dp_hpd_pulse+0x134/0x570 [i915] [283.406308] ? __down_killable+0x70/0x140 [283.406313] i915_digport_work_func+0xba/0x150 [i915]
Signed-off-by: Andrzej Hajda andrzej.hajda@intel.com --- Hi All,
I am not sure about changes in shutdown path, any comments welcome. I suspect suspend path have also some common bits, but I am little bit afraid of touching it.
Changes: v1 - v6: - chasing the bug appearing only on public CI. v7: - shutdown path adjusted (suggested by Jani)
Regards Andrzej --- drivers/gpu/drm/i915/display/intel_display.c | 11 ++++------- drivers/gpu/drm/i915/i915_driver.c | 5 ++--- 2 files changed, 6 insertions(+), 10 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c index 186b37925d23f2..f9952ee8289fb2 100644 --- a/drivers/gpu/drm/i915/display/intel_display.c +++ b/drivers/gpu/drm/i915/display/intel_display.c @@ -10490,13 +10490,6 @@ void intel_modeset_driver_remove_noirq(struct drm_i915_private *i915) */ intel_hpd_poll_fini(i915);
- /* - * MST topology needs to be suspended so we don't have any calls to - * fbdev after it's finalized. MST will be destroyed later as part of - * drm_mode_config_cleanup() - */ - intel_dp_mst_suspend(i915); - /* poll work can call into fbdev, hence clean that up afterwards */ intel_fbdev_fini(i915);
@@ -10588,6 +10581,10 @@ void intel_display_driver_unregister(struct drm_i915_private *i915) if (!HAS_DISPLAY(i915)) return;
+ intel_dp_mst_suspend(i915); + intel_hpd_cancel_work(i915); + drm_kms_helper_poll_disable(&i915->drm); + intel_fbdev_unregister(i915); intel_audio_deinit(i915);
diff --git a/drivers/gpu/drm/i915/i915_driver.c b/drivers/gpu/drm/i915/i915_driver.c index d26dcca7e654aa..82cdccf072e2bc 100644 --- a/drivers/gpu/drm/i915/i915_driver.c +++ b/drivers/gpu/drm/i915/i915_driver.c @@ -1070,15 +1070,14 @@ void i915_driver_shutdown(struct drm_i915_private *i915) i915_gem_suspend(i915);
if (HAS_DISPLAY(i915)) { + intel_dp_mst_suspend(i915); + intel_hpd_cancel_work(i915); drm_kms_helper_poll_disable(&i915->drm);
drm_atomic_helper_shutdown(&i915->drm); }
- intel_dp_mst_suspend(i915); - intel_runtime_pm_disable_interrupts(i915); - intel_hpd_cancel_work(i915);
intel_suspend_encoders(i915); intel_shutdown_encoders(i915);