FYI, we noticed the following commit (built with gcc-7): commit: c470bdc1aaf36669e04ba65faf1092b2d1c6cabe ("mac80211: don't WARN on bad WMM parameters from buggy APs") https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master in testcase: hwsim with following parameters: group: hwsim-01 on test machine: 8 threads Intel(R) Core(TM) i7-2600K CPU @ 3.40GHz with 8G memory caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): 2018-04-20 03:46:16 ./run-tests.py ap_qosmap_default_acm DEV: wlan0: 02:00:00:00:00:00 DEV: wlan1: 02:00:00:00:01:00 DEV: wlan2: 02:00:00:00:02:00 APDEV: wlan3 APDEV: wlan4 START ap_qosmap_default_acm 1/1 Test: QoS mapping with default values and ACM=1 for VO/VI Starting AP wlan3 Connect STA wlan0 to AP Expected TX DSCP 32 with TID 3 but counters: {0: 0, 1: 0, 2: 0, 3: 0, 4: 2, 5: 0, 6: 0, 7: 0, 8: 0, 9: 0, 10: 0, 11: 0, 12: 0, 13: 0, 14: 0, 15: 0, 16: 0} No STA->AP data frame using the expected TID Traceback (most recent call last): File "./run-tests.py", line 453, in main t(dev, apdev) File "/lkp/benchmarks/hwsim/tests/hwsim/test_ap_qosmap.py", line 131, in test_ap_qosmap_default_acm check_qos_map(apdev[0], hapd, dev[0], addr, dscp, tid, ap_tid) File "/lkp/benchmarks/hwsim/tests/hwsim/test_ap_qosmap.py", line 30, in check_qos_map raise Exception("No STA->AP data frame using the expected TID") Exception: No STA->AP data frame using the expected TID FAIL ap_qosmap_default_acm 0.7513 2018-04-20 03:46:17.399828 passed 0 test case(s) skipped 0 test case(s) failed tests: ap_qosmap_default_acm Thanks, Xiaolong