[PATCH AUTOSEL 5.13 114/189] drm/amdkfd: Fix circular lock in nocpsch path

Sasha Levin
2021-07-06T11:23:38Z

From: Amber Lin <Amber.Lin@amd.com>

[ Upstream commit a7b2451d31cfa2e8aeccf3b35612ce33f02371fc ]

Calling free_mqd inside of destroy_queue_nocpsch_locked can cause a
circular lock. destroy_queue_nocpsch_locked is called under a DQM lock,
which is taken in MMU notifiers, potentially in FS reclaim context.
Taking another lock, which is BO reservation lock from free_mqd, while
causing an FS reclaim inside the DQM lock creates a problematic circular
lock dependency. Therefore move free_mqd out of
destroy_queue_nocpsch_locked and call it after unlocking DQM.

Signed-off-by: Amber Lin <Amber.Lin@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>
---
.../drm/amd/amdkfd/kfd_device_queue_manager.c | 18 +++++++++++++-----
1 file changed, 13 insertions(+), 5 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 ccc9d108caff..e9b3e2e32bf8 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
@@ -486,9 +486,6 @@ static int destroy_queue_nocpsch_locked(struct device_queue_manager *dqm,
if (retval == -ETIME)
qpd->reset_wavefronts = true;

-
- mqd_mgr->free_mqd(mqd_mgr, q->mqd, q->mqd_mem_obj);
-
list_del(&q->list);
if (list_empty(&qpd->queues_list)) {
if (qpd->reset_wavefronts) {
@@ -523,6 +520,8 @@ static int destroy_queue_nocpsch(struct device_queue_manager *dqm,
int retval;
uint64_t sdma_val = 0;
struct kfd_process_device *pdd = qpd_to_pdd(qpd);
+ struct mqd_manager *mqd_mgr =
+ dqm->mqd_mgrs[get_mqd_type_from_queue_type(q->properties.type)];

/* Get the SDMA queue stats */
if ((q->properties.type == KFD_QUEUE_TYPE_SDMA) ||
@@ -540,6 +539,8 @@ static int destroy_queue_nocpsch(struct device_queue_manager *dqm,
pdd->sdma_past_activity_counter += sdma_val;
dqm_unlock(dqm);

+ mqd_mgr->free_mqd(mqd_mgr, q->mqd, q->mqd_mem_obj);
+
return retval;
}

@@ -1629,7 +1630,7 @@ static bool set_cache_memory_policy(struct device_queue_manager *dqm,
static int process_termination_nocpsch(struct device_queue_manager *dqm,
struct qcm_process_device *qpd)
{
- struct queue *q, *next;
+ struct queue *q;
struct device_process_node *cur, *next_dpn;
int retval = 0;
bool found = false;
@@ -1637,12 +1638,19 @@ static int process_termination_nocpsch(struct device_queue_manager *dqm,
dqm_lock(dqm);

/* Clear all user mode queues */
- list_for_each_entry_safe(q, next, &qpd->queues_list, list) {
+ while (!list_empty(&qpd->queues_list)) {
+ struct mqd_manager *mqd_mgr;
int ret;

+ q = list_first_entry(&qpd->queues_list, struct queue, list);
+ mqd_mgr = dqm->mqd_mgrs[get_mqd_type_from_queue_type(
+ q->properties.type)];
ret = destroy_queue_nocpsch_locked(dqm, qpd, q);
if (ret)
retval = ret;
+ dqm_unlock(dqm);
+ mqd_mgr->free_mqd(mqd_mgr, q->mqd, q->mqd_mem_obj);
+ dqm_lock(dqm);
}

/* Unregister process */
--
2.30.2