[PATCH AUTOSEL 5.13 111/189] drm/amdkfd: fix circular locking on get_wave_state
From: Sasha Levin <sashal@kernel.org>
Date: 2021-07-06 11:22:46
Also in:
amd-gfx, dri-devel, lkml
Subsystem:
amd kfd, drm drivers, radeon and amdgpu drm drivers, the rest · Maintainers:
Felix Kuehling, David Airlie, Simona Vetter, Alex Deucher, Christian König, Linus Torvalds
From: Jonathan Kim <redacted> [ Upstream commit 63f6e01237257e7226efc5087f3f0b525d320f54 ] get_wave_state acquires the mmap_lock on copy_to_user but so do mmu_notifiers. mmu_notifiers allows dqm locking so do get_wave_state outside the dqm_lock to prevent circular locking. v2: squash in unused variable removal. Signed-off-by: Jonathan Kim <redacted> Reviewed-by: Felix Kuehling <felix.kuehling@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> Signed-off-by: Sasha Levin <sashal@kernel.org> --- .../drm/amd/amdkfd/kfd_device_queue_manager.c | 28 +++++++++---------- 1 file changed, 13 insertions(+), 15 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
index d3eaa1549bd7..ccc9d108caff 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c@@ -1674,29 +1674,27 @@ static int get_wave_state(struct device_queue_manager *dqm, u32 *save_area_used_size) { struct mqd_manager *mqd_mgr; - int r; dqm_lock(dqm); - if (q->properties.type != KFD_QUEUE_TYPE_COMPUTE || - q->properties.is_active || !q->device->cwsr_enabled) { - r = -EINVAL; - goto dqm_unlock; - } - mqd_mgr = dqm->mqd_mgrs[KFD_MQD_TYPE_CP]; - if (!mqd_mgr->get_wave_state) { - r = -EINVAL; - goto dqm_unlock; + if (q->properties.type != KFD_QUEUE_TYPE_COMPUTE || + q->properties.is_active || !q->device->cwsr_enabled || + !mqd_mgr->get_wave_state) { + dqm_unlock(dqm); + return -EINVAL; } - r = mqd_mgr->get_wave_state(mqd_mgr, q->mqd, ctl_stack, - ctl_stack_used_size, save_area_used_size); - -dqm_unlock: dqm_unlock(dqm); - return r; + + /* + * get_wave_state is outside the dqm lock to prevent circular locking + * and the queue should be protected against destruction by the process + * lock. + */ + return mqd_mgr->get_wave_state(mqd_mgr, q->mqd, ctl_stack, + ctl_stack_used_size, save_area_used_size); } static int process_termination_cpsch(struct device_queue_manager *dqm,
--
2.30.2