When some client process A call pdr_add_lookup() to add the look up for the service and does schedule locator work, later a process B got a new server packet indicating locator is up and call pdr_locator_new_server() which eventually sets pdr->locator_init_complete to true which process A sees and takes list lock and queries domain list but it will timeout due to deadlock as the response will queued to the same qmi->wq and it is ordered workqueue and process B is not able to complete new server request work due to deadlock on list lock.
Process A Process B
process_scheduled_works() pdr_add_lookup() qmi_data_ready_work() process_scheduled_works() pdr_locator_new_server() pdr->locator_init_complete=true; pdr_locator_work() mutex_lock(&pdr->list_lock);
pdr_locate_service() mutex_lock(&pdr->list_lock);
pdr_get_domain_list() pr_err("PDR: %s get domain list txn wait failed: %d\n", req->service_name, ret);
Fix it by removing the unnecessary list iteration as the list iteration is already being done inside locator work, so avoid it here and just call schedule_work() here.
Fixes: fbe639b44a82 ("soc: qcom: Introduce Protection Domain Restart helpers") CC: stable@vger.kernel.org Signed-off-by: Saranya R quic_sarar@quicinc.com Signed-off-by: Mukesh Ojha mukesh.ojha@oss.qualcomm.com --- Changes in v2: - Added Fixes tag,
drivers/soc/qcom/pdr_interface.c | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-)
diff --git a/drivers/soc/qcom/pdr_interface.c b/drivers/soc/qcom/pdr_interface.c index 328b6153b2be..71be378d2e43 100644 --- a/drivers/soc/qcom/pdr_interface.c +++ b/drivers/soc/qcom/pdr_interface.c @@ -75,7 +75,6 @@ static int pdr_locator_new_server(struct qmi_handle *qmi, { struct pdr_handle *pdr = container_of(qmi, struct pdr_handle, locator_hdl); - struct pdr_service *pds;
mutex_lock(&pdr->lock); /* Create a local client port for QMI communication */ @@ -87,12 +86,7 @@ static int pdr_locator_new_server(struct qmi_handle *qmi, mutex_unlock(&pdr->lock);
/* Service pending lookup requests */ - mutex_lock(&pdr->list_lock); - list_for_each_entry(pds, &pdr->lookups, node) { - if (pds->need_locator_lookup) - schedule_work(&pdr->locator_work); - } - mutex_unlock(&pdr->list_lock); + schedule_work(&pdr->locator_work);
return 0; }