[PATCH 0/2] Fix crash due to open pmu events during unbind

[Umesh Nerlige Ramappa]

Resending to include patch 2/2. Please ignore this series.

On Mon, Feb 12, 2024 at 10:46:48PM -0800, Umesh Nerlige Ramappa wrote:
>Once a user opens an fd for a perf event, if the driver undergoes a
>function level reset (FLR), the resources are not cleaned up as
>expected. For this discussion FLR is defined as a PCI unbind followed by
>a bind. perf_pmu_unregister() would cleanup everything, but when the
>user closes the perf fd much later, perf_release() is called and we
>encounter null pointer dereferences and/or list corruption in that path
>which require a reboot to recover.
>
>The only approach that worked to resolve this was to close the file
>associated with the event such that the relevant cleanup happens w.r.t.
>the open file. To do so, use the event->owner task and find the file
>relevant to the event and close it. This relies on the
>file->private_data matching the event object.
>
>Test-with: 20240213062948.32735-1-umesh.nerlige.ramappa at intel.com
>Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa at intel.com>
>
>Umesh Nerlige Ramappa (2):
>  i915/pmu: Add pmu_teardown helper
>  INTEL_DII: i915/pmu: Cleanup pending events on unbind
>
> drivers/gpu/drm/i915/i915_pmu.c | 192 ++++++++++++++++++++++++--------
> drivers/gpu/drm/i915/i915_pmu.h |  15 +++
> 2 files changed, 161 insertions(+), 46 deletions(-)
>
>-- 
>2.34.1
>