In the Linux kernel, the following vulnerability has been resolved: soc: qcom: pdr: Fix the potential deadlock 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. 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. 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); Timeout error log due to deadlock: " PDR: tms/servreg get domain list txn wait failed: -110 PDR: service lookup for msm/adsp/sensor_pd:tms/servreg failed: -110 " Thanks to Bjorn and Johan for letting me know that this commit also fixes an audio regression when using the in-kernel pd-mapper as that makes it easier to hit this race. [1]
https://git.kernel.org/stable/c/f4489260f5713c94e1966e5f20445bff262876f4
https://git.kernel.org/stable/c/f2bbfd50e95bc117360f0f59e629aa03d821ebd6
https://git.kernel.org/stable/c/daba84612236de3ab39083e62c9e326a654ebd20
https://git.kernel.org/stable/c/72a222b6af10c2a05a5fad0029246229ed8912c2
https://git.kernel.org/stable/c/2eeb03ad9f42dfece63051be2400af487ddb96d2
https://git.kernel.org/stable/c/0a566a79aca9851fae140536e0fc5b0853c90a90
https://git.kernel.org/stable/c/02612f1e4c34d94d6c8ee75bf7d254ed697e22d4