从 Ubuntu 18.04 升级到 20.04（网络管理器版本 1.22.10-1ubuntu2.1）后，我的 WiFi 网络连接时好时坏。我使用的是 rtl88x2bu-dkms 软件包中的 r88x2bu 网络驱动程序。我浏览网页时，连接突然断开一两分钟，然后最终重新连接。这个问题持续存在，以至于浏览网页等简单任务几乎不可能完成。我尝试探索不同的方法来调试这个问题。
我不认为这个问题与 DDos 有关，因为网络中我所有其他设备都接收大约相同数量的传入流量。
探索 NetworkManager 和 wpa-supplicant 调试日志，我发现当问题出现时，日志如下所示。网络管理器启动 wifi 扫描，并且网络请求被阻止，直到 wifi 扫描成功完成。
Jun 03 16:45:35 pipemon-desktop NetworkManager[1140]: <debug> [1591217135.3233] device[2daeef8128d7ad35] (wlx74ee2af4348b): wifi-scan: scanning requested but not allowed at this time
Jun 03 16:45:35 pipemon-desktop NetworkManager[1140]: <debug> [1591217135.3233] device[2daeef8128d7ad35] (wlx74ee2af4348b): wifi-scan: scheduled in 120 seconds (interval now 120 seconds)
Jun 03 16:45:41 pipemon-desktop kernel: [UFW BLOCK] IN=wlx74ee2af4348b OUT= MAC=74:ee:2a:f4:34:8b:40:ce:24:74:a9:b2:08:00 SRC=18.20.245.218 DST=18.20.198.88 LEN=40 TOS=0x00 PREC=0x00 TTL=63 ID=0 DF PROTO=TCP SPT=631 DPT=34756 WINDOW=0 RES=0x00 RST URGP=0
Jun 03 16:45:59 pipemon-desktop kernel: [UFW BLOCK] IN=wlx74ee2af4348b OUT= MAC=74:ee:2a:f4:34:8b:40:ce:24:74:a9:b2:08:00 SRC=5.188.210.109 DST=18.20.198.88 LEN=40 TOS=0x00 PREC=0x00 TTL=241 ID=58332 PROTO=TCP SPT=56836 DPT=8080 WINDOW=1024 RES=0x00 SYN URGP=0
Jun 03 16:46:07 pipemon-desktop kernel: [UFW BLOCK] IN=wlx74ee2af4348b OUT= MAC=74:ee:2a:f4:34:8b:40:ce:24:74:a9:b2:08:00 SRC=52.114.128.10 DST=18.20.198.88 LEN=40 TOS=0x00 PREC=0x00 TTL=112 ID=18141 DF PROTO=TCP SPT=443 DPT=47960 WINDOW=0 RES=0x00 ACK RST URGP=0
Jun 03 16:46:12 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: BSS: Remove id 89198 BSSID c4:6e:1f:2c:89:42 SSID 'PRG-IRCP2.4' due to wpa_bss_flush_by_age
Jun 03 16:46:12 pipemon-desktop wpa_supplicant[1173]: dbus: Unregister BSS object '/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89198'
Jun 03 16:46:12 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: BSS: Remove id 89199 BSSID 58:f3:9c:f0:e7:eb SSID 'eduroam' due to wpa_bss_flush_by_age
Jun 03 16:46:12 pipemon-desktop wpa_supplicant[1173]: dbus: Unregister BSS object '/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89199'
Jun 03 16:46:12 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: BSS: Remove id 89200 BSSID 58:f3:9c:af:d2:12 SSID 'MIT SECURE' due to wpa_bss_flush_by_age
Jun 03 16:46:12 pipemon-desktop wpa_supplicant[1173]: dbus: Unregister BSS object '/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89200'
Jun 03 16:46:12 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: BSS: Remove id 89201 BSSID 58:f3:9c:af:d2:13 SSID '\x00' due to wpa_bss_flush_by_age
Jun 03 16:46:12 pipemon-desktop wpa_supplicant[1173]: dbus: Unregister BSS object '/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89201'
Jun 03 16:46:12 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: BSS: Remove id 89202 BSSID 58:f3:9c:f0:e7:e2 SSID 'MIT SECURE' due to wpa_bss_flush_by_age
...
Jun 03 16:46:12 pipemon-desktop wpa_supplicant[1173]: dbus: Unregister BSS object '/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89258'
Jun 03 16:46:12 pipemon-desktop wpa_supplicant[1173]: dbus: flush_object_timeout_handler: Timeout - sending changed properties of object /fi/w1/wpa_supplicant1/Interfaces/0
Jun 03 16:46:24 pipemon-desktop kernel: [UFW BLOCK] IN=wlx74ee2af4348b OUT= MAC=01:00:5e:00:00:01:b4:de:31:be:26:b7:08:00 SRC=18.4.115.12 DST=224.0.0.1 LEN=28 TOS=0x00 PREC=0xC0 TTL=1 ID=27935 PROTO=2
Jun 03 16:46:26 pipemon-desktop kernel: [UFW BLOCK] IN=wlx74ee2af4348b OUT= MAC=01:00:5e:7f:ff:fa:7c:b2:7d:6f:b3:23:08:00 SRC=18.20.212.77 DST=239.255.255.250 LEN=71 TOS=0x00 PREC=0x00 TTL=1 ID=41164 PROTO=UDP SPT=5050 DPT=5050 LEN=51
Jun 03 16:46:37 pipemon-desktop kernel: [UFW BLOCK] IN=wlx74ee2af4348b OUT= MAC=01:00:5e:7f:ff:fa:50:1a:c5:f0:31:b3:08:00 SRC=18.20.210.73 DST=239.255.255.250 LEN=680 TOS=0x00 PREC=0x00 TTL=1 ID=20222 PROTO=UDP SPT=62748 DPT=3702 LEN=660
Jun 03 16:46:42 pipemon-desktop colord[1291]: failed to get session [pid 262019]: No data available
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: bgscan simple: Request a background scan
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: Add radio work 'scan'@0x564aa014b180
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: First radio work item in the queue - schedule start immediately
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: Starting radio work 'scan'@0x564aa014b180 after 0.000006 second wait
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: nl80211: scan request
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: nl80211: Scan SSID MIT SECURE
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: Scan requested (ret=0) - scan timeout 30 seconds
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: nl80211: Event message available
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: nl80211: Drv Event 33 (NL80211_CMD_TRIGGER_SCAN) received for wlx74ee2af4348b
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: nl80211: Scan trigger
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: Event SCAN_STARTED (47) received
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: Own scan request started a scan in 0.000015 seconds
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: nl80211: Event message available
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: nl80211: Drv Event 34 (NL80211_CMD_NEW_SCAN_RESULTS) received for wlx74ee2af4348b
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: nl80211: New scan results available
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: nl80211: Scan probed for SSID 'MIT SECURE'
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: nl80211: Scan included frequencies: 2412 2417 2422 2427 2432 2437 2442 2447 2452 2457 2462 2467 2472 5180 5200 5220 5240 5260 5280 5300 5320 5500 5520 5540 5560 5580 5600 5620 5640 5660 5680 5700 5745 5765 5785 5805 5825
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: Event SCAN_RESULTS (3) received
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: Scan completed in 0.000029 seconds
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: nl80211: Received scan results (62 BSSes)
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: nl80211: Scan results indicate BSS status with 58:f3:9c:f0:e7:ed as associated
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: BSS: Start scan result update 8833
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: BSS: Add new id 89259 BSSID c4:6e:1f:2c:89:42 SSID 'PRG-IRCP2.4' freq 2462
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: Register BSS object '/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89259'
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: WPS: Unknown Vendor Extension (Vendor ID 9442)
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: WPS: Unknown Vendor Extension (Vendor ID 9442)
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: BSS: Add new id 89260 BSSID 58:f3:9c:f0:e7:eb SSID 'eduroam' freq 5805
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: Register BSS object '/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89260'
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: BSS: Add new id 89261 BSSID 58:f3:9c:af:d2:12 SSID 'MIT SECURE' freq 2412
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: Register BSS object '/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89261'
...
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: BSS: last_scan_res_used=62/64
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: New scan results available (own=1 ext=0)
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: bgscan simple: scan result notification
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: WPS: Unknown Vendor Extension (Vendor ID 9442)
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: WPS: Unknown Vendor Extension (Vendor ID 9442)
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: WPS: Unknown Vendor Extension (Vendor ID 9442)
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: WPS: AP[0] c4:6e:1f:2c:89:42 type=0 tries=0 last_attempt=-1 sec ago blacklist=0
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: WPS: AP[1] 04:4e:5a:fc:2f:9a type=0 tries=0 last_attempt=-1 sec ago blacklist=0
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: WPS: AP[2] 78:d2:94:9a:0a:f7 type=0 tries=0 last_attempt=-1 sec ago blacklist=0
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: Radio work 'scan'@0x564aa014b180 done in 0.002779 seconds
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: radio_work_free('scan'@0x564aa014b180): num_active_works --> 0
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: Scan results matching the currently selected network
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: 1: 58:f3:9c:f0:e7:ed freq=5805 level=-58 snr=34 est_throughput=65001
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: 3: 58:f3:9c:af:d2:12 freq=2412 level=-53 snr=36 est_throughput=65000
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: 5: 58:f3:9c:f0:e7:e2 freq=2412 level=-57 snr=32 est_throughput=65000
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: 9: 58:f3:9c:af:d2:1d freq=5220 level=-72 snr=20 est_throughput=54000
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: 11: 58:f3:9c:a0:9d:72 freq=2412 level=-70 snr=19 est_throughput=54000
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: 12: 10:05:ca:73:7c:42 freq=2412 level=-70 snr=19 est_throughput=54000
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: 20: b0:26:80:8b:12:0d freq=5745 level=-83 snr=9 est_throughput=40501
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: 23: 58:f3:9c:e5:c4:3d freq=5320 level=-80 snr=12 est_throughput=36000
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: Selecting BSS from priority group 0
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: 0: c4:6e:1f:2c:89:42 ssid='PRG-IRCP2.4' wpa_ie_len=0 rsn_ie_len=20 caps=0x431 level=-57 freq=2462 wps
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: skip - SSID mismatch
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: 1: 58:f3:9c:f0:e7:ed ssid='MIT SECURE' wpa_ie_len=0 rsn_ie_len=20 caps=0x1111 level=-58 freq=5805
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: selected based on RSN IE
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: selected BSS 58:f3:9c:f0:e7:ed ssid='MIT SECURE'
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: RTM_NEWLINK: ifi_index=5 ifname=wlx74ee2af4348b wext ifi_family=0 ifi_flags=0x11043 ([UP][RUNNING][LOWER_UP])
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: flush_object_timeout_handler: Timeout - sending changed properties of object /fi/w1/wpa_supplicant1/Interfaces/0
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: flush_object_timeout_handler: Timeout - sending changed properties of object /fi/w1/wpa_supplicant1/Interfaces/0/BSSs/125
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89259) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: WPS: Unknown Vendor Extension (Vendor ID 9442)
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: WPS: Unknown Vendor Extension (Vendor ID 9442)
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89260) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89261) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89262) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89263) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89264) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89265) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89266) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89267) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89268) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89269) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89270) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89271) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89272) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89273) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89274) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89275) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89276) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89277) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89278) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89279) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89280) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89281) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89282) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89283) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89284) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89285) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89286) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89287) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89288) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89289) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89290) [s]
Jun 03 16:46:56 pipemon-desktop NetworkManager[1140]: <debug> [1591217216.1498] device[2daeef8128d7ad35] (wlx74ee2af4348b): failed to match hidden AP 58:F3:9C:AF:D2:13
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89291) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89292) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89293) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89294) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89295) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89296) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89297) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89298) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89299) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89300) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89301) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89302) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89303) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89304) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89305) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89306) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89307) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89308) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89309) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89310) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89311) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89312) [s]
Jun 03 16:46:56 pipemon-desktop NetworkManager[1140]: <debug> [1591217216.1536] device[2daeef8128d7ad35] (wlx74ee2af4348b): failed to match hidden AP 58:F3:9C:A0:9D:73
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89313) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89314) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89315) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89316) [s]
Jun 03 16:46:56 pipemon-desktop NetworkManager[1140]: <debug> [1591217216.1543] device[2daeef8128d7ad35] (wlx74ee2af4348b): failed to match hidden AP 58:F3:9C:E5:C4:33
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89317) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89318) [s]
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: dbus: org.freedesktop.DBus.Properties.GetAll (/fi/w1/wpa_supplicant1/Interfaces/0/BSSs/89319) [s]
Jun 03 16:46:56 pipemon-desktop NetworkManager[1140]: <debug> [1591217216.1592] device[2daeef8128d7ad35] (wlx74ee2af4348b): failed to match hidden AP 62:45:B1:BA:00:4A
Jun 03 16:46:56 pipemon-desktop NetworkManager[1140]: <debug> [1591217216.1712] device[2daeef8128d7ad35] (wlx74ee2af4348b): wifi-scan: scan-done callback: successful
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: 24: 58:f3:9c:d0:19:7d freq=5560 level=-80 snr=12 est_throughput=36000
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: 27: 58:f3:9c:a0:9d:7d freq=5180 level=-82 snr=10 est_throughput=24000
Jun 03 16:46:56 pipemon-desktop wpa_supplicant[1173]: wlx74ee2af4348b: 28: b0:26:80:8b:12:02 freq=2412 level=-79 snr=10 est_throughput=24000
我猜测这个问题是新 NetworkManager 的一个错误，可能是网络管理器执行常规 wifi 扫描时阻塞线程。我很乐意提供任何有助于解决此问题的其他信息。
答案1
日志表明（大学）漫游环境，您所连接的无线网络“MIT Secure”是所谓的扩展服务集（ESS），包含许多单独的接入点/基本服务集（BSS-ID）。
您看到的是 NetworkManager 安排的、由 wpa_supplicant 执行的定期后台扫描，用于查找可用的 BSSID。我推测，根据扫描结果中的信号质量，NM 希望选择 ESS 中信号最好的 AP。
在日志中，它看起来像是58:f3:9c:f0:e7:ed在扫描后重新选择了 BSS，但我对调试输出不太熟悉。
我推测 NM 选择 AP 的方式可能存在错误，没有跳过重新选择或驱动程序不够快。如果您不住在漫游环境中，则禁用 bgscans 并因此避免在接入点之间切换是一种选择。如果您大部分时间都坐在同一个角落，您可以忍受不漫游，如果它可以避免破坏性行为，直到更好地理解它为止。
有关背景扫描的解释，请参阅 Dan Williams博客文章来自 2016 年的 Dave Täht参考第一段包含了大量有关扫描所造成的挫折的信息。
关于 nm 如何安排 bgscans 或者根本不安排，我将自由nm_supplicant_config_add_bgscan引用nm-请求者-配置.c版本 1.22.10 来自 20.04：
当以下情况时，扫描将被禁用
（1）共享连接（AP 或 Ad-Hoc）处于活动状态
（2）连接被锁定到特定的AP [...]（#513820）
相反，
（3）当信号正常时，默认使用非常长的 bgscan 间隔 [...]
（4）如果使用 WPA Enterprise、动态 WEP 或我们已经看到了多个 AP
因此，在 gnome-settings 中或使用nmcli dev wifi connect <bssid>一个 BSSID 明确选择将使用 (2) 并禁用 bgscans。
对于双频 AP，这也会选择一个频段（2.4Ghz/5Ghz）而不是另一个频段。
请注意，在企业网络 (4) 中 bgscans 间隔较短，这适用于您所连接的漫游网络。
Ubuntu 20.04 Focal 也是第一个使用 NetworkManager 的版本犯罪导致家庭网络环境中 bgscans 更频繁地发生（双频 AP 具有不同的 BSSID）。 值表示simple:30:-65:300当信号弱于 -65 dBm 时每 30 秒扫描一次，否则每 300 秒扫描一次。 该值可以在 wpa_supplicant 中自定义，请参阅维基百科。
如上所述，明确选择 BSSID 以避免 bgscans 是一种解决方法，直到发现错误为止。另一种选择是将 NM 后端从 wpa_supplicant 更改为iwdCanonical试以获得早期反馈。