[PATCH v3 00/17] drm/panthor: Fix the unplug logic

[Boris Brezillon]

The current unplug logic is broken in multiple ways. This is an attempt
at addressing the various problems found along the way (some were
reported by Sashiko, others have been found while trying to address
Sashiko's concerns).

Sending a new version even though v2 didn't receive any human review
just to try and address the new stuff pointed out by Sashiko.

Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
---
Changes in v3:
- Fix a race in the reset reschedule logic we added to
  panthor_device_resume() (missing smp_mb__after_atomic())
- Fix a VM leak when reset and suspend are racing with each other
- Add missing drm_dev_enter/exit() sections
- Insert the groups in the user_owned list even if the group creation
  happens during a reset
- Try to document why some of the issues pointed out by Sashiko are
  either not real issues, or are expected (either fixed in a later
  commits, or just expected behavior)
- Fix a race between panthor_device_unplug() and vm_prep_for_cleanup()
  (introduced in v2)
- Link to v2: https://patch.msgid.link/20260811-panthor-unplug-fixes-v2-0-6b583e37f9ae@xxxxxxxxxxxxx

Changes in v2:
- Fix UAFs caused by deferred cleanup works
- Fix UAFs caused by open FDs closed after unplug
- Fix deadlock when device_unplug() is called from the reset work
- Make sure reset requests are not lost in the resume and post_reset
  paths
- Fix a deadlock in the suspend path
- Fix a clk prepare_enable leak in the unplug path
- Don't use a drmm_action to flush the cleanup queue (this could cause
  UAFs)
- Drop the now unused panthor_vm::unusable field
- Keep track of user owned resources to prevent leaks and/or UAFs
- Link to v1: https://patch.msgid.link/20260804-panthor-unplug-fixes-v1-0-abbbd2d41b13@xxxxxxxxxxxxx

---
Boris Brezillon (17):
      drm/panthor: Disable reset work before unplug
      drm/panthor: Further delay reset work enablement
      drm/panthor: Make sure reset requests in the resume path are not lost
      drm/panthor: Make sure reset requests in the post reset path are not lost
      drm/panthor: Flush the cleanup_wq in the unplug path
      drm/panthor: Drop unused vm argument passed to panthor_vm_prepare_sync_only_op_ctx()
      drm/panthor: Move the debugfs initialization to panthor_device.c
      drm/panthor: Split panthor_vm
      drm/panthor: Add fine-grained restrictions on VMs
      drm/panthor: Check AS state before disabling
      drm/panthor: Don't pre-allocate VMAs or page tables when preparing a full VM unmap
      drm/panthor: Make the VM cleanup path more robust against UAF
      drm/panthor: Track user owned VMs
      drm/panthor: Track user owned groups
      drm/panthor: Fix the unplug logic
      drm/panthor: Add a debugfs knob to simulate unplug failures
      drm/panthor: Add a debugfs knobs to simulate reset failures

 drivers/gpu/drm/panthor/panthor_device.c |  189 +++-
 drivers/gpu/drm/panthor/panthor_device.h |   38 +
 drivers/gpu/drm/panthor/panthor_drv.c    |  132 ++-
 drivers/gpu/drm/panthor/panthor_fw.c     |    9 +-
 drivers/gpu/drm/panthor/panthor_mmu.c    | 1493 ++++++++++++++++++------------
 drivers/gpu/drm/panthor/panthor_mmu.h    |    4 +-
 drivers/gpu/drm/panthor/panthor_sched.c  |  132 ++-
 7 files changed, 1344 insertions(+), 653 deletions(-)
---
base-commit: 44e9eb5a762142a4aa46c0b5da7c39bfeb78910e
change-id: 20260804-panthor-unplug-fixes-7927b3ddc2f9

Best regards,
--  
Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>