drm/amdkfd: Fix NULL deref during sysfs teardown

Move kfd_process_remove_sysfs() earlier in kfd_process_wq_release() so
that all sysfs/procfs entries are removed before tearing down PDDs and
dropping lead_thread. The per-process sysfs attributes are backed by
struct kfd_process_device, and their show/store callbacks dereference
PDD fields. Since sysfs removal waits for active callbacks to complete,
removing these entries first closes a race where userspace reads sdma_*
and stats_* files after PDD teardown.

Previously this cleanup ran after kfd_process_destroy_pdds(), which
resets p->n_pdds to 0. This meant kfd_process_remove_sysfs() could no
longer walk the PDD array, so the per-PDD sysfs cleanup did not run as
intended.

This race caused NULL pointer dereferences observed in
kfd_sdma_activity_worker and kfd_procfs_stats_show.

Also harden kfd_process_remove_sysfs() against partially
initialized or already-freed objects:
- Check kobj_queues before removing PASID and deleting it
- Guard kobj_stats and kobj_counters before use

These checks prevent invalid dereferences during cleanup.

Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Geoffrey McRae <geoffrey.mcrae@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 674c692702341fed321720b4b92036c5934fb485)

0 files changed, 0 insertions, 0 deletions