| Message ID | 20210831072501.184211-1-desmondcheongzx@gmail.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | drm: update locking for modesetting | expand |
On 31/8/21 3:24 am, Desmond Cheong Zhi Xi wrote: > Sorry for the noise, rebasing on top of drm-misc-next. Please ignore the > v9 series. > > Hi, > > I updated the patch set with some suggestions by Daniel Vetter, and > dropped the patches after patch 4 so that we can stick the landing for > avoiding races with modesetting rights before dealing with the tricky > spinlock. > > Overall, this series fixes races with modesetting rights, and converts > drm_device.master_mutex into master_rwsem. > > - Patch 1: Fix a potential null ptr dereference in drm_master_release > > - Patch 2: Convert master_mutex into rwsem (avoids creating a new lock) > > - Patch 3: Update global mutex locking in the ioctl handler (avoids > deadlock when grabbing read lock on master_rwsem in drm_ioctl_kernel) > > - Patch 4: Plug races with drm modesetting rights > > v9 -> v10: > - Rebase on top of drm-misc-next, caught by Intel-gfx CI > > v8 -> v9 (suggested by Daniel Vetter): > - Drop patches 5-7 to handle it in another series > - Add the appropriate Fixes: tag for the null ptr dereference fix > (patch 1) > - Create a locked_ioctl bool to clarify locking/unlocking patterns in > the ioctl handler (patch 3) > - Clarify the kernel doc for master_rwsem (patch 4) > > v7 -> v8: > - Avoid calling drm_lease_held in drm_mode_setcrtc and > drm_wait_vblank_ioctl, caught by Intel-gfx CI > > v6 -> v7: > - Export __drm_mode_object_find for loadable modules, caught by the > Intel-gfx CI > > v5 -> v6: > - Fix recursive locking on master_rwsem, caught by the Intel-gfx CI > > v4 -> v5: > - Avoid calling drm_file_get_master while holding on to the modeset > mutex, caught by the Intel-gfx CI > > v3 -> v4 (suggested by Daniel Vetter): > - Drop a patch that added an unnecessary master_lookup_lock in > drm_master_release > - Drop a patch that addressed a non-existent race in > drm_is_current_master_locked > - Remove fixes for non-existent null ptr dereferences > - Protect drm_master.magic_map,unique{_len} with master_rwsem instead of > master_lookup_lock > - Drop the patch that moved master_lookup_lock into struct drm_device > - Drop a patch to export task_work_add > - Revert the check for the global mutex in the ioctl handler to use > drm_core_check_feature instead of drm_dev_needs_global_mutex > - Push down master_rwsem locking for selected ioctls to avoid lock > hierarchy inversions, and to allow us to hold write locks on > master_rwsem instead of flushing readers > - Remove master_lookup_lock by replacing it with master_rwsem > > v2 -> v3: > - Unexport drm_master_flush, as suggested by Daniel Vetter. > - Merge master_mutex and master_rwsem, as suggested by Daniel Vetter. > - Export task_work_add, reported by kernel test robot. > - Make master_flush static, reported by kernel test robot. > - Move master_lookup_lock into struct drm_device. > - Add a missing lock on master_lookup_lock in drm_master_release. > - Fix a potential race in drm_is_current_master_locked. > - Fix potential null ptr dereferences in drm_{auth, ioctl}. > - Protect magic_map,unique{_len} with master_lookup_lock. > - Convert master_mutex into a rwsem. > - Update global mutex locking in the ioctl handler. > > v1 -> v2 (suggested by Daniel Vetter): > - Address an additional race when drm_open runs. > - Switch from SRCU to rwsem to synchronise readers and writers. > - Implement drm_master_flush with task_work so that flushes can be > queued to run before returning to userspace without creating a new > DRM_MASTER_FLUSH ioctl flag. > > Best wishes, > Desmond > > Desmond Cheong Zhi Xi (4): > drm: fix null ptr dereference in drm_master_release > drm: convert drm_device.master_mutex into a rwsem > drm: lock drm_global_mutex earlier in the ioctl handler > drm: avoid races with modesetting rights > > drivers/gpu/drm/drm_auth.c | 39 ++++++++++++++++------------ > drivers/gpu/drm/drm_debugfs.c | 4 +-- > drivers/gpu/drm/drm_drv.c | 3 +-- > drivers/gpu/drm/drm_file.c | 6 ++--- > drivers/gpu/drm/drm_ioctl.c | 49 ++++++++++++++++++++++------------- > drivers/gpu/drm/drm_lease.c | 35 +++++++++++++++++-------- > include/drm/drm_auth.h | 6 ++--- > include/drm/drm_device.h | 16 +++++++++--- > include/drm/drm_file.h | 12 ++++----- > 9 files changed, 104 insertions(+), 66 deletions(-) > Hi Daniel, Just pinging so this doesn't get buried, though I guess it's also a busy merge window. Any thoughts on the series as it is? Tests seemed to have passed with the Intel-gfx CI [1]. Not sure if I can set up the CI to do otherwise, but I think this series has to go in before I can test new patches to remove the drm_file.master_lookup_lock spinlock. As always, thank you for your time. Link: https://patchwork.freedesktop.org/series/93864/ [1] Best wishes, Desmond
Sorry for the noise, rebasing on top of drm-misc-next. Please ignore the v9 series. Hi, I updated the patch set with some suggestions by Daniel Vetter, and dropped the patches after patch 4 so that we can stick the landing for avoiding races with modesetting rights before dealing with the tricky spinlock. Overall, this series fixes races with modesetting rights, and converts drm_device.master_mutex into master_rwsem. - Patch 1: Fix a potential null ptr dereference in drm_master_release - Patch 2: Convert master_mutex into rwsem (avoids creating a new lock) - Patch 3: Update global mutex locking in the ioctl handler (avoids deadlock when grabbing read lock on master_rwsem in drm_ioctl_kernel) - Patch 4: Plug races with drm modesetting rights v9 -> v10: - Rebase on top of drm-misc-next, caught by Intel-gfx CI v8 -> v9 (suggested by Daniel Vetter): - Drop patches 5-7 to handle it in another series - Add the appropriate Fixes: tag for the null ptr dereference fix (patch 1) - Create a locked_ioctl bool to clarify locking/unlocking patterns in the ioctl handler (patch 3) - Clarify the kernel doc for master_rwsem (patch 4) v7 -> v8: - Avoid calling drm_lease_held in drm_mode_setcrtc and drm_wait_vblank_ioctl, caught by Intel-gfx CI v6 -> v7: - Export __drm_mode_object_find for loadable modules, caught by the Intel-gfx CI v5 -> v6: - Fix recursive locking on master_rwsem, caught by the Intel-gfx CI v4 -> v5: - Avoid calling drm_file_get_master while holding on to the modeset mutex, caught by the Intel-gfx CI v3 -> v4 (suggested by Daniel Vetter): - Drop a patch that added an unnecessary master_lookup_lock in drm_master_release - Drop a patch that addressed a non-existent race in drm_is_current_master_locked - Remove fixes for non-existent null ptr dereferences - Protect drm_master.magic_map,unique{_len} with master_rwsem instead of master_lookup_lock - Drop the patch that moved master_lookup_lock into struct drm_device - Drop a patch to export task_work_add - Revert the check for the global mutex in the ioctl handler to use drm_core_check_feature instead of drm_dev_needs_global_mutex - Push down master_rwsem locking for selected ioctls to avoid lock hierarchy inversions, and to allow us to hold write locks on master_rwsem instead of flushing readers - Remove master_lookup_lock by replacing it with master_rwsem v2 -> v3: - Unexport drm_master_flush, as suggested by Daniel Vetter. - Merge master_mutex and master_rwsem, as suggested by Daniel Vetter. - Export task_work_add, reported by kernel test robot. - Make master_flush static, reported by kernel test robot. - Move master_lookup_lock into struct drm_device. - Add a missing lock on master_lookup_lock in drm_master_release. - Fix a potential race in drm_is_current_master_locked. - Fix potential null ptr dereferences in drm_{auth, ioctl}. - Protect magic_map,unique{_len} with master_lookup_lock. - Convert master_mutex into a rwsem. - Update global mutex locking in the ioctl handler. v1 -> v2 (suggested by Daniel Vetter): - Address an additional race when drm_open runs. - Switch from SRCU to rwsem to synchronise readers and writers. - Implement drm_master_flush with task_work so that flushes can be queued to run before returning to userspace without creating a new DRM_MASTER_FLUSH ioctl flag. Best wishes, Desmond Desmond Cheong Zhi Xi (4): drm: fix null ptr dereference in drm_master_release drm: convert drm_device.master_mutex into a rwsem drm: lock drm_global_mutex earlier in the ioctl handler drm: avoid races with modesetting rights drivers/gpu/drm/drm_auth.c | 39 ++++++++++++++++------------ drivers/gpu/drm/drm_debugfs.c | 4 +-- drivers/gpu/drm/drm_drv.c | 3 +-- drivers/gpu/drm/drm_file.c | 6 ++--- drivers/gpu/drm/drm_ioctl.c | 49 ++++++++++++++++++++++------------- drivers/gpu/drm/drm_lease.c | 35 +++++++++++++++++-------- include/drm/drm_auth.h | 6 ++--- include/drm/drm_device.h | 16 +++++++++--- include/drm/drm_file.h | 12 ++++----- 9 files changed, 104 insertions(+), 66 deletions(-)