From: Philip Yang Philip.Yang@amd.com
[ Upstream commit 6225bb3a88d22594aacea2485dc28ca12d596721 ]
kfd_process_notifier_release flush svm_range_restore_work which calls svm_range_list_lock_and_flush_work to flush deferred_list work, but if deferred_list work mmput release the last user, it will call exit_mmap -> notifier_release, it is deadlock with below backtrace.
Move flush svm_range_restore_work to kfd_process_wq_release to avoid deadlock. Then svm_range_restore_work take task->mm ref to avoid mm is gone while validating and mapping ranges to GPU.
Workqueue: events svm_range_deferred_list_work [amdgpu] Call Trace: wait_for_completion+0x94/0x100 __flush_work+0x12a/0x1e0 __cancel_work_timer+0x10e/0x190 cancel_delayed_work_sync+0x13/0x20 kfd_process_notifier_release+0x98/0x2a0 [amdgpu] __mmu_notifier_release+0x74/0x1f0 exit_mmap+0x170/0x200 mmput+0x5d/0x130 svm_range_deferred_list_work+0x104/0x230 [amdgpu] process_one_work+0x220/0x3c0
Signed-off-by: Philip Yang Philip.Yang@amd.com Reported-by: Ruili Ji ruili.ji@amd.com Tested-by: Ruili Ji ruili.ji@amd.com 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 --- drivers/gpu/drm/amd/amdkfd/kfd_process.c | 1 - drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 15 +++++++++------ 2 files changed, 9 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c b/drivers/gpu/drm/amd/amdkfd/kfd_process.c index d1145da5348f..74f162887d3b 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c @@ -1150,7 +1150,6 @@ static void kfd_process_notifier_release(struct mmu_notifier *mn,
cancel_delayed_work_sync(&p->eviction_work); cancel_delayed_work_sync(&p->restore_work); - cancel_delayed_work_sync(&p->svms.restore_work);
mutex_lock(&p->mutex);
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c index 225affcddbc1..1cf9041c9727 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c @@ -1643,13 +1643,14 @@ static void svm_range_restore_work(struct work_struct *work)
pr_debug("restore svm ranges\n");
- /* kfd_process_notifier_release destroys this worker thread. So during - * the lifetime of this thread, kfd_process and mm will be valid. - */ p = container_of(svms, struct kfd_process, svms); - mm = p->mm; - if (!mm) + + /* Keep mm reference when svm_range_validate_and_map ranges */ + mm = get_task_mm(p->lead_thread); + if (!mm) { + pr_debug("svms 0x%p process mm gone\n", svms); return; + }
svm_range_list_lock_and_flush_work(svms, mm); mutex_lock(&svms->lock); @@ -1703,6 +1704,7 @@ static void svm_range_restore_work(struct work_struct *work) out_reschedule: mutex_unlock(&svms->lock); mmap_write_unlock(mm); + mmput(mm);
/* If validation failed, reschedule another attempt */ if (evicted_ranges) { @@ -2840,6 +2842,8 @@ void svm_range_list_fini(struct kfd_process *p)
pr_debug("pasid 0x%x svms 0x%p\n", p->pasid, &p->svms);
+ cancel_delayed_work_sync(&p->svms.restore_work); + /* Ensure list work is finished before process is destroyed */ flush_work(&p->svms.deferred_list_work);
@@ -2850,7 +2854,6 @@ void svm_range_list_fini(struct kfd_process *p) atomic_inc(&p->svms.drain_pagefaults); svm_range_drain_retry_fault(&p->svms);
- list_for_each_entry_safe(prange, next, &p->svms.list, list) { svm_range_unlink(prange); svm_range_remove_notifier(prange);