The following occurs on a fully updated Debian 12.9 bookworm.  While
working with firefox on GNOME on XOrg (and some other applications in
the background, such as libreoffice-writer, gedit, uxterm with bash and
a cmp-based script comparing the home directory with its backup on a
thumb drive), the screen and keyboard froze for no known reason: mouse
movements resulted in no cursor movement, and pressing the NumLock key
didn't change the LED on the keyboard. Pressing and holding Alt followed
by pressing and releasing the keys R E I S U B rebooted the computer.

After the boot, I looked up the journal, and the lines before the last
boot are as follows:

Jan 25 18:53:38 AnonymPC rtkit-daemon[1144]: Supervising 0 threads of 0
processes of 0 users.
Jan 25 18:53:39 AnonymPC rtkit-daemon[1144]: Supervising 0 threads of 0
processes of 0 users.
Jan 25 18:53:39 AnonymPC rtkit-daemon[1144]: Supervising 0 threads of 0
processes of 0 users.
Jan 25 18:53:39 AnonymPC rtkit-daemon[1144]: Supervising 0 threads of 0
processes of 0 users.
Jan 25 18:53:39 AnonymPC rtkit-daemon[1144]: Supervising 0 threads of 0
processes of 0 users.
Jan 25 18:53:49 AnonymPC PackageKit[499057]: daemon quit
Jan 25 18:53:49 AnonymPC systemd[1]: packagekit.service: Deactivated
successfully.
Jan 25 18:53:57 AnonymPC dhclient[855]: DHCPDISCOVER on enp6s0 to
255.255.255.255 port 67 interval 4
Jan 25 18:54:01 AnonymPC dhclient[855]: DHCPDISCOVER on enp6s0 to
255.255.255.255 port 67 interval 10
Jan 25 18:54:08 AnonymPC rtkit-daemon[1144]: Supervising 0 threads of 0
processes of 0 users.
Jan 25 18:54:08 AnonymPC rtkit-daemon[1144]: Supervising 0 threads of 0
processes of 0 users.
Jan 25 18:54:09 AnonymPC rtkit-daemon[1144]: Supervising 0 threads of 0
processes of 0 users.
Jan 25 18:54:09 AnonymPC rtkit-daemon[1144]: Supervising 0 threads of 0
processes of 0 users.
Jan 25 18:54:11 AnonymPC dhclient[855]: DHCPDISCOVER on enp6s0 to
255.255.255.255 port 67 interval 12
Jan 25 18:54:11 AnonymPC rtkit-daemon[1144]: Supervising 0 threads of 0
processes of 0 users.
Jan 25 18:54:11 AnonymPC rtkit-daemon[1144]: Supervising 0 threads of 0
processes of 0 users.
Jan 25 18:54:11 AnonymPC rtkit-daemon[1144]: Supervising 0 threads of 0
processes of 0 users.
Jan 25 18:54:11 AnonymPC rtkit-daemon[1144]: Supervising 0 threads of 0
processes of 0 users.
Jan 25 18:54:12 AnonymPC rtkit-daemon[1144]: Supervising 0 threads of 0
processes of 0 users.
Jan 25 18:54:12 AnonymPC rtkit-daemon[1144]: Supervising 0 threads of 0
processes of 0 users.
Jan 25 18:54:12 AnonymPC rtkit-daemon[1144]: Supervising 0 threads of 0
processes of 0 users.
Jan 25 18:54:12 AnonymPC rtkit-daemon[1144]: Supervising 0 threads of 0
processes of 0 users.
Jan 25 18:54:14 AnonymPC rtkit-daemon[1144]: Supervising 0 threads of 0
processes of 0 users.
Jan 25 18:54:14 AnonymPC rtkit-daemon[1144]: Supervising 0 threads of 0
processes of 0 users.
Jan 25 18:54:14 AnonymPC rtkit-daemon[1144]: Supervising 0 threads of 0
processes of 0 users.
Jan 25 18:54:14 AnonymPC rtkit-daemon[1144]: Supervising 0 threads of 0
processes of 0 users.
Jan 25 18:54:22 AnonymPC rtkit-daemon[1144]: Supervising 0 threads of 0
processes of 0 users.
Jan 25 18:54:22 AnonymPC rtkit-daemon[1144]: Supervising 0 threads of 0
processes of 0 users.
Jan 25 18:54:23 AnonymPC dhclient[855]: DHCPDISCOVER on enp6s0 to
255.255.255.255 port 67 interval 13
Jan 25 18:54:25 AnonymPC rtkit-daemon[1144]: Supervising 0 threads of 0
processes of 0 users.
Jan 25 18:54:25 AnonymPC rtkit-daemon[1144]: Supervising 0 threads of 0
processes of 0 users.
Jan 25 18:54:25 AnonymPC rtkit-daemon[1144]: Supervising 0 threads of 0
processes of 0 users.
Jan 25 18:54:25 AnonymPC rtkit-daemon[1144]: Supervising 0 threads of 0
processes of 0 users.
Jan 25 18:54:36 AnonymPC dhclient[855]: DHCPDISCOVER on enp6s0 to
255.255.255.255 port 67 interval 19
Jan 25 18:54:55 AnonymPC dhclient[855]: DHCPDISCOVER on enp6s0 to
255.255.255.255 port 67 interval 3
Jan 25 18:54:58 AnonymPC dhclient[855]: No DHCPOFFERS received.
Jan 25 18:54:58 AnonymPC dhclient[855]: No working leases in persistent
database - sleeping.
Jan 25 18:54:58 AnonymPC root[501438]:
/etc/dhcp/dhclient-exit-hooks.d/zzz_avahi-autoipd returned non-zero exit
status 1
Jan 25 18:55:17 AnonymPC kernel: nouveau 0000:65:00.0: gr: TRAP ch 5
[017ea38000 Xorg[2631]]
Jan 25 18:55:17 AnonymPC kernel: nouveau 0000:65:00.0: gr: GPC0/TPC0/SM0
trap: global 00000004 [MULTIPLE_WARP_ERRORS] warp b060020 []
Jan 25 18:55:17 AnonymPC kernel: nouveau 0000:65:00.0: gr: GPC0/TPC0/SM1
trap: global 00000004 [MULTIPLE_WARP_ERRORS] warp b020020 []
Jan 25 18:55:17 AnonymPC kernel: nouveau 0000:65:00.0: gr: GPC0/TPC1/SM0
trap: global 00000004 [MULTIPLE_WARP_ERRORS] warp b060020 []
Jan 25 18:55:17 AnonymPC kernel: nouveau 0000:65:00.0: gr: GPC0/TPC1/SM1
trap: global 00000004 [MULTIPLE_WARP_ERRORS] warp b050020 []
Jan 25 18:55:17 AnonymPC kernel: nouveau 0000:65:00.0: gr: GPC0/TPC2/SM0
trap: global 00000004 [MULTIPLE_WARP_ERRORS] warp b010020 []
Jan 25 18:55:17 AnonymPC kernel: nouveau 0000:65:00.0: gr: GPC0/TPC2/SM1
trap: global 00000004 [MULTIPLE_WARP_ERRORS] warp b050020 []
Jan 25 18:55:17 AnonymPC kernel: nouveau 0000:65:00.0: gr: GPC1/TPC0/SM0
trap: global 00000004 [MULTIPLE_WARP_ERRORS] warp b020020 []
Jan 25 18:55:17 AnonymPC kernel: nouveau 0000:65:00.0: gr: GPC1/TPC0/SM1
trap: global 00000004 [MULTIPLE_WARP_ERRORS] warp b070020 []
Jan 25 18:55:17 AnonymPC kernel: nouveau 0000:65:00.0: gr: GPC1/TPC1/SM0
trap: global 00000000 [] warp b050020 []
Jan 25 18:55:17 AnonymPC kernel: nouveau 0000:65:00.0: gr: GPC1/TPC1/SM1
trap: global 00000000 [] warp b020020 []
Jan 25 18:55:17 AnonymPC kernel: nouveau 0000:65:00.0: gr: GPC1/TPC2/SM0
trap: global 00000000 [] warp b050020 []
Jan 25 18:55:17 AnonymPC kernel: nouveau 0000:65:00.0: gr: GPC1/TPC2/SM1
trap: global 00000000 [] warp b030020 []
Jan 25 18:55:17 AnonymPC kernel: nouveau 0000:65:00.0: gr: GPC1/TPC3/SM0
trap: global 00000004 [MULTIPLE_WARP_ERRORS] warp b040020 []
Jan 25 18:55:17 AnonymPC kernel: nouveau 0000:65:00.0: gr: GPC1/TPC3/SM1
trap: global 00000004 [MULTIPLE_WARP_ERRORS] warp b020020 []
Jan 25 18:55:17 AnonymPC kernel: nouveau 0000:65:00.0: gr: GPC2/TPC0/SM0
trap: global 00000004 [MULTIPLE_WARP_ERRORS] warp b070020 []
Jan 25 18:55:17 AnonymPC kernel: nouveau 0000:65:00.0: gr: GPC2/TPC0/SM1
trap: global 00000004 [MULTIPLE_WARP_ERRORS] warp b070020 []
Jan 25 18:55:17 AnonymPC kernel: nouveau 0000:65:00.0: gr: GPC2/TPC1/SM0
trap: global 00000004 [MULTIPLE_WARP_ERRORS] warp b060020 []
Jan 25 18:55:17 AnonymPC kernel: nouveau 0000:65:00.0: gr: GPC2/TPC1/SM1
trap: global 00000004 [MULTIPLE_WARP_ERRORS] warp b050020 []
Jan 25 18:55:17 AnonymPC kernel: nouveau 0000:65:00.0: gr: GPC2/TPC2/SM0
trap: global 00000004 [MULTIPLE_WARP_ERRORS] warp b010020 []
Jan 25 18:55:17 AnonymPC kernel: nouveau 0000:65:00.0: gr: GPC2/TPC2/SM1
trap: global 00000004 [MULTIPLE_WARP_ERRORS] warp b050020 []
Jan 25 18:55:17 AnonymPC kernel: nouveau 0000:65:00.0: gr: GPC2/TPC3/SM0
trap: global 00000004 [MULTIPLE_WARP_ERRORS] warp b040020 []
Jan 25 18:55:17 AnonymPC kernel: nouveau 0000:65:00.0: gr: GPC2/TPC3/SM1
trap: global 00000000 [] warp b000020 []
Jan 25 18:55:17 AnonymPC kernel: nouveau 0000:65:00.0: fifo: fault 00
[VIRT_READ] at 000000000aab5000 engine 40 [gr] client 00 [GPC2/T1_0]
reason 00 [PDE] on channel 5 [017ea38000 Xorg[2631]]
Jan 25 18:55:17 AnonymPC kernel: nouveau 0000:65:00.0: fifo: channel 5:
killed
Jan 25 18:55:17 AnonymPC kernel: nouveau 0000:65:00.0: fifo: runlist 0:
scheduled for recovery
Jan 25 18:55:17 AnonymPC kernel: nouveau 0000:65:00.0: fifo: engine 0:
scheduled for recovery
Jan 25 18:55:24 AnonymPC rtkit-daemon[1144]: Supervising 0 threads of 0
processes of 0 users.
Jan 25 18:55:24 AnonymPC rtkit-daemon[1144]: Supervising 0 threads of 0
processes of 0 users.
Jan 25 18:55:44 AnonymPC kernel: sysrq: Keyboard mode set to system default
Jan 25 18:55:44 AnonymPC kernel: sysrq: This sysrq operation is disabled.
Jan 25 18:55:45 AnonymPC kernel: sysrq: This sysrq operation is disabled.
Jan 25 18:55:45 AnonymPC kernel: sysrq: Emergency Sync
Jan 25 18:55:45 AnonymPC kernel: Emergency Sync complete
Jan 25 18:55:45 AnonymPC kernel: sysrq: Emergency Remount R/O


The entries

Jan 25 18:54:58 AnonymPC root[501438]:
/etc/dhcp/dhclient-exit-hooks.d/zzz_avahi-autoipd returned non-zero exit
status 1

through

Jan 25 18:55:17 AnonymPC kernel: nouveau 0000:65:00.0: fifo: fault 00
[VIRT_READ] at 000000000aab5000 engine 40 [gr] client 00 [GPC2/T1_0]
reason 00 [PDE] on channel 5 [017ea38000 Xorg[2631]]

are marked red.


$ sudo lspci -vvvvvv | grep -A81 GeForce
65:00.0 VGA compatible controller: NVIDIA Corporation TU116 [GeForce GTX
1660] (rev a1) (prog-if 00 [VGA controller])
     Subsystem: NVIDIA Corporation TU116 [GeForce GTX 1660]
     Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr-
Stepping- SERR+ FastB2B- DisINTx+
     Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort-
<TAbort- <MAbort- >SERR- <PERR- INTx-
     Latency: 0, Cache Line Size: 32 bytes
     Interrupt: pin A routed to IRQ 84
     NUMA node: 0
     IOMMU group: 3
     Region 0: Memory at d7000000 (32-bit, non-prefetchable) [size=16M]
     Region 1: Memory at c0000000 (64-bit, prefetchable) [size=256M]
     Region 3: Memory at d0000000 (64-bit, prefetchable) [size=32M]
     Region 5: I/O ports at b000 [size=128]
     Expansion ROM at 000c0000 [disabled] [size=128K]
     Capabilities: [60] Power Management version 3
         Flags: PMEClk- DSI- D1- D2- AuxCurrent=375mA
PME(D0+,D1-,D2-,D3hot+,D3cold+)
         Status: D0 NoSoftRst+ PME-Enable- DSel=0 DScale=0 PME-
     Capabilities: [68] MSI: Enable+ Count=1/1 Maskable- 64bit+
         Address: 00000000fee000b8  Data: 0000
     Capabilities: [78] Express (v2) Legacy Endpoint, MSI 00
         DevCap:    MaxPayload 256 bytes, PhantFunc 0, Latency L0s
unlimited, L1 <64us
             ExtTag+ AttnBtn- AttnInd- PwrInd- RBE+ FLReset+
         DevCtl:    CorrErr- NonFatalErr- FatalErr- UnsupReq-
             RlxdOrd+ ExtTag+ PhantFunc- AuxPwr- NoSnoop+ FLReset-
             MaxPayload 128 bytes, MaxReadReq 512 bytes
         DevSta:    CorrErr+ NonFatalErr- FatalErr- UnsupReq+ AuxPwr+
TransPend-
         LnkCap:    Port #0, Speed 8GT/s, Width x16, ASPM L0s L1, Exit
Latency L0s <512ns, L1 <4us
             ClockPM+ Surprise- LLActRep- BwNot- ASPMOptComp+
         LnkCtl:    ASPM Disabled; RCB 64 bytes, Disabled- CommClk+
             ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
         LnkSta:    Speed 2.5GT/s (downgraded), Width x16
             TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
         DevCap2: Completion Timeout: Range AB, TimeoutDis+ NROPrPrP- LTR+
              10BitTagComp- 10BitTagReq- OBFF Via message, ExtFmt-
EETLPPrefix-
              EmergencyPowerReduction Not Supported,
EmergencyPowerReductionInit-
              FRS-
              AtomicOpsCap: 32bit- 64bit- 128bitCAS-
         DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis+ LTR-
10BitTagReq- OBFF Disabled,
              AtomicOpsCtl: ReqEn-
         LnkCap2: Supported Link Speeds: 2.5-8GT/s, Crosslink- Retimer-
2Retimers- DRS-
         LnkCtl2: Target Link Speed: 8GT/s, EnterCompliance- SpeedDis-
              Transmit Margin: Normal Operating Range,
EnterModifiedCompliance- ComplianceSOS-
              Compliance Preset/De-emphasis: -6dB de-emphasis, 0dB preshoot
         LnkSta2: Current De-emphasis Level: -3.5dB,
EqualizationComplete+ EqualizationPhase1+
              EqualizationPhase2+ EqualizationPhase3+
LinkEqualizationRequest-
              Retimer- 2Retimers- CrosslinkRes: unsupported
     Capabilities: [100 v1] Virtual Channel
         Caps:    LPEVC=0 RefClk=100ns PATEntryBits=1
         Arb:    Fixed- WRR32- WRR64- WRR128-
         Ctrl:    ArbSelect=Fixed
         Status:    InProgress-
         VC0:    Caps:    PATOffset=00 MaxTimeSlots=1 RejSnoopTrans-
             Arb:    Fixed- WRR32- WRR64- WRR128- TWRR128- WRR256-
             Ctrl:    Enable+ ID=0 ArbSelect=Fixed TC/VC=01
             Status:    NegoPending- InProgress-
     Capabilities: [250 v1] Latency Tolerance Reporting
         Max snoop latency: 0ns
         Max no snoop latency: 0ns
     Capabilities: [258 v1] L1 PM Substates
         L1SubCap: PCI-PM_L1.2+ PCI-PM_L1.1+ ASPM_L1.2+ ASPM_L1.1+
L1_PM_Substates+
               PortCommonModeRestoreTime=255us PortTPowerOnTime=10us
         L1SubCtl1: PCI-PM_L1.2- PCI-PM_L1.1- ASPM_L1.2- ASPM_L1.1-
                T_CommonMode=0us LTR1.2_Threshold=0ns
         L1SubCtl2: T_PwrOn=10us
     Capabilities: [128 v1] Power Budgeting <?>
     Capabilities: [420 v2] Advanced Error Reporting
         UESta:    DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt-
RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
         UEMsk:    DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt-
RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
         UESvrt:    DLP+ SDES+ TLP- FCP+ CmpltTO- CmpltAbrt- UnxCmplt-
RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol-
         CESta:    RxErr- BadTLP- BadDLLP- Rollover- Timeout-
AdvNonFatalErr+
         CEMsk:    RxErr- BadTLP- BadDLLP- Rollover- Timeout-
AdvNonFatalErr+
         AERCap:    First Error Pointer: 00, ECRCGenCap- ECRCGenEn-
ECRCChkCap- ECRCChkEn-
             MultHdrRecCap- MultHdrRecEn- TLPPfxPres- HdrLogCap-
         HeaderLog: 00000000 00000000 00000000 00000000
     Capabilities: [600 v1] Vendor Specific Information: ID=0001 Rev=1
Len=024 <?>
     Capabilities: [900 v1] Secondary PCI Express
         LnkCtl3: LnkEquIntrruptEn- PerformEqu-
         LaneErrStat: 0
     Capabilities: [bb0 v1] Physical Resizable BAR
         BAR 0: current size: 16MB, supported: 16MB
         BAR 1: current size: 256MB, supported: 64MB 128MB 256MB
         BAR 3: current size: 32MB, supported: 32MB
     Kernel driver in use: nouveau
     Kernel modules: nouveau


I observed such a freeze for the second time since the recent update of
the kernel to 6.1.0-30 (some other packages I don't recall were updated,
too). During the first such freeze, I took no journal log, so I can't
tell with certainty whether the cause was the same or at least similar.
In my recollection, no such freezes occurred for many months with prior
versions till and including 6.1.0-28 (and, probably, 6.1.0-29, though it
was used only for a short duration).

As of the kernel 6.1.0-32-amd64 on bookworm, such freezes continue to occur.  The last one happened when I browsed the Web in Firefox 128.9.0esr-1~deb12u1; the cursor froze when it was on a tab ruler.

Here's the log of the last seconds prior to the freeze:

Apr 11 20:30:09 AnonymPC dhclient[882]: DHCPDISCOVER on enp6s0 to 255.255.255.255 port 67 interval 12
Apr 11 20:30:21 AnonymPC dhclient[882]: DHCPDISCOVER on enp6s0 to 255.255.255.255 port 67 interval 14
Apr 11 20:30:35 AnonymPC dhclient[882]: DHCPDISCOVER on enp6s0 to 255.255.255.255 port 67 interval 9
Apr 11 20:30:44 AnonymPC dhclient[882]: DHCPDISCOVER on enp6s0 to 255.255.255.255 port 67 interval 8
Apr 11 20:30:45 AnonymPC dbus-daemon[2765]: [session uid=1000 pid=2765] Activating service name='org.gnome.Settings.SearchProvider' requested by ':1.35' (uid=1000 pid=3032 comm="/usr/bin/gnome-shell")
Apr 11 20:30:45 AnonymPC dbus-daemon[2765]: [session uid=1000 pid=2765] Activating service name='org.gnome.Contacts.SearchProvider' requested by ':1.35' (uid=1000 pid=3032 comm="/usr/bin/gnome-shell")
Apr 11 20:30:45 AnonymPC dbus-daemon[2765]: [session uid=1000 pid=2765] Activating service name='org.gnome.seahorse.Application' requested by ':1.35' (uid=1000 pid=3032 comm="/usr/bin/gnome-shell")
Apr 11 20:30:45 AnonymPC dbus-daemon[2765]: [session uid=1000 pid=2765] Activating service name='org.gnome.Calculator.SearchProvider' requested by ':1.35' (uid=1000 pid=3032 comm="/usr/bin/gnome-shell")
Apr 11 20:30:45 AnonymPC dbus-daemon[2765]: [session uid=1000 pid=2765] Activating via systemd: service name='org.gnome.Terminal' unit='gnome-terminal-server.service' requested by ':1.35' (uid=1000 pid=3032 comm="/usr/bin/gnome-shell")
Apr 11 20:30:45 AnonymPC dbus-daemon[2765]: [session uid=1000 pid=2765] Activating service name='org.gnome.clocks' requested by ':1.35' (uid=1000 pid=3032 comm="/usr/bin/gnome-shell")
Apr 11 20:30:45 AnonymPC dbus-daemon[2765]: [session uid=1000 pid=2765] Activating service name='org.gnome.Epiphany.SearchProvider' requested by ':1.35' (uid=1000 pid=3032 comm="/usr/bin/gnome-shell")
Apr 11 20:30:45 AnonymPC dbus-daemon[2765]: [session uid=1000 pid=2765] Activating service name='org.gnome.Characters' requested by ':1.35' (uid=1000 pid=3032 comm="/usr/bin/gnome-shell")
Apr 11 20:30:45 AnonymPC systemd[2728]: Starting gnome-terminal-server.service - GNOME Terminal Server...
░░ Subject: A start job for unit UNIT has begun execution
░░ Defined-By: systemd
░░ Support: https://www.debian.org/support
░░
░░ A start job for unit UNIT has begun execution.
░░
░░ The job identifier is 1665.
Apr 11 20:30:45 AnonymPC dbus-daemon[2765]: [session uid=1000 pid=2765] Successfully activated service 'org.gnome.Settings.SearchProvider'
Apr 11 20:30:45 AnonymPC dbus-daemon[2765]: [session uid=1000 pid=2765] Successfully activated service 'org.gnome.clocks'
Apr 11 20:30:45 AnonymPC dbus-daemon[2765]: [session uid=1000 pid=2765] Successfully activated service 'org.gnome.seahorse.Application'
Apr 11 20:30:45 AnonymPC dbus-daemon[2765]: [session uid=1000 pid=2765] Successfully activated service 'org.gnome.Contacts.SearchProvider'
Apr 11 20:30:45 AnonymPC dbus-daemon[2765]: [session uid=1000 pid=2765] Successfully activated service 'org.gnome.Characters'
Apr 11 20:30:45 AnonymPC dbus-daemon[2765]: [session uid=1000 pid=2765] Successfully activated service 'org.gnome.Terminal'
Apr 11 20:30:45 AnonymPC systemd[2728]: Started gnome-terminal-server.service - GNOME Terminal Server.
░░ Subject: A start job for unit UNIT has finished successfully
░░ Defined-By: systemd
░░ Support: https://www.debian.org/support
░░
░░ A start job for unit UNIT has finished successfully.
░░
░░ The job identifier is 1665.
Apr 11 20:30:45 AnonymPC dbus-daemon[2765]: [session uid=1000 pid=2765] Successfully activated service 'org.gnome.Calculator.SearchProvider'
Apr 11 20:30:45 AnonymPC dbus-daemon[2765]: [session uid=1000 pid=2765] Successfully activated service 'org.gnome.Epiphany.SearchProvider'
Apr 11 20:30:45 AnonymPC rtkit-daemon[1189]: Supervising 4 threads of 4 processes of 1 users.
Apr 11 20:30:45 AnonymPC rtkit-daemon[1189]: Failed to look up client: No such file or directory
Apr 11 20:30:45 AnonymPC dbus-daemon[2765]: [session uid=1000 pid=2765] Activating service name='org.gnome.seahorse.Application' requested by ':1.35' (uid=1000 pid=3032 comm="/usr/bin/gnome-shell")
Apr 11 20:30:45 AnonymPC gnome-shell[3032]: Unhandled promise rejection. To suppress this warning, add an error handler to your promise chain with .catch() or a try-catch block around your await expression. Stack trace of the failed promise:
                                              _doProviderSearch@resource:///org/gnome/shell/ui/search.js:655:28
                                              _doSearch/<@resource:///org/gnome/shell/ui/search.js:682:18
                                              _doSearch@resource:///org/gnome/shell/ui/search.js:680:25
                                              _onSearchTimeout@resource:///org/gnome/shell/ui/search.js:692:14
Apr 11 20:30:45 AnonymPC gnome-shell[3032]: Unhandled promise rejection. To suppress this warning, add an error handler to your promise chain with .catch() or a try-catch block around your await expression. Stack trace of the failed promise:
                                              _doProviderSearch@resource:///org/gnome/shell/ui/search.js:655:28
                                              _doSearch/<@resource:///org/gnome/shell/ui/search.js:682:18
                                              _doSearch@resource:///org/gnome/shell/ui/search.js:680:25
                                              _onSearchTimeout@resource:///org/gnome/shell/ui/search.js:692:14
Apr 11 20:30:45 AnonymPC gnome-shell[3032]: Received error from D-Bus search provider org.gnome.Terminal.desktop: Gio.DBusError: GDBus.Error:org.freedesktop.DBus.Error.UnknownMethod: Das Objekt existiert nicht am Pfad »/org/gnome/Terminal/SearchProvider«
Apr 11 20:30:45 AnonymPC gnome-character[826639]: JS LOG: Characters Application started
Apr 11 20:30:45 AnonymPC dbus-daemon[2765]: [session uid=1000 pid=2765] Successfully activated service 'org.gnome.seahorse.Application'
Apr 11 20:30:45 AnonymPC dbus-daemon[2765]: [session uid=1000 pid=2765] Activating service name='org.gnome.seahorse.Application' requested by ':1.35' (uid=1000 pid=3032 comm="/usr/bin/gnome-shell")
Apr 11 20:30:45 AnonymPC gnome-shell[3032]: Received error from D-Bus search provider org.gnome.Terminal.desktop: Gio.DBusError: GDBus.Error:org.freedesktop.DBus.Error.UnknownMethod: Das Objekt existiert nicht am Pfad »/org/gnome/Terminal/SearchProvider«
Apr 11 20:30:45 AnonymPC dbus-daemon[2765]: [session uid=1000 pid=2765] Successfully activated service 'org.gnome.seahorse.Application'
Apr 11 20:30:45 AnonymPC dbus-daemon[2765]: [session uid=1000 pid=2765] Activating service name='org.gnome.seahorse.Application' requested by ':1.35' (uid=1000 pid=3032 comm="/usr/bin/gnome-shell")
Apr 11 20:30:45 AnonymPC gnome-shell[3032]: Unhandled promise rejection. To suppress this warning, add an error handler to your promise chain with .catch() or a try-catch block around your await expression. Stack trace of the failed promise:
                                              _doProviderSearch@resource:///org/gnome/shell/ui/search.js:655:28
                                              _doSearch/<@resource:///org/gnome/shell/ui/search.js:682:18
                                              _doSearch@resource:///org/gnome/shell/ui/search.js:680:25
                                              _onSearchTimeout@resource:///org/gnome/shell/ui/search.js:692:14
Apr 11 20:30:45 AnonymPC gnome-shell[3032]: Unhandled promise rejection. To suppress this warning, add an error handler to your promise chain with .catch() or a try-catch block around your await expression. Stack trace of the failed promise:
                                              _doProviderSearch@resource:///org/gnome/shell/ui/search.js:655:28
                                              _doSearch/<@resource:///org/gnome/shell/ui/search.js:682:18
                                              _doSearch@resource:///org/gnome/shell/ui/search.js:680:25
                                              _onSearchTimeout@resource:///org/gnome/shell/ui/search.js:692:14
Apr 11 20:30:45 AnonymPC gnome-shell[3032]: Received error from D-Bus search provider org.gnome.Terminal.desktop: Gio.DBusError: GDBus.Error:org.freedesktop.DBus.Error.UnknownMethod: Das Objekt existiert nicht am Pfad »/org/gnome/Terminal/SearchProvider«
Apr 11 20:30:45 AnonymPC dbus-daemon[2765]: [session uid=1000 pid=2765] Successfully activated service 'org.gnome.seahorse.Application'
Apr 11 20:30:46 AnonymPC dbus-daemon[2765]: [session uid=1000 pid=2765] Activating service name='org.gnome.seahorse.Application' requested by ':1.35' (uid=1000 pid=3032 comm="/usr/bin/gnome-shell")
Apr 11 20:30:46 AnonymPC gnome-shell[3032]: Received error from D-Bus search provider org.gnome.Terminal.desktop: Gio.DBusError: GDBus.Error:org.freedesktop.DBus.Error.UnknownMethod: Das Objekt existiert nicht am Pfad »/org/gnome/Terminal/SearchProvider«
Apr 11 20:30:46 AnonymPC dbus-daemon[2765]: [session uid=1000 pid=2765] Successfully activated service 'org.gnome.seahorse.Application'
Apr 11 20:30:46 AnonymPC dbus-daemon[979]: [system] Activating via systemd: service name='org.freedesktop.PackageKit' unit='packagekit.service' requested by ':1.118' (uid=1000 pid=3253 comm="/usr/bin/gnome-software --gapplication-service")
Apr 11 20:30:46 AnonymPC systemd[1]: Starting packagekit.service - PackageKit Daemon...
░░ Subject: A start job for unit packagekit.service has begun execution
░░ Defined-By: systemd
░░ Support: https://www.debian.org/support
░░
░░ A start job for unit packagekit.service has begun execution.
░░
░░ The job identifier is 27304.
Apr 11 20:30:46 AnonymPC PackageKit[826873]: daemon start
Apr 11 20:30:46 AnonymPC dbus-daemon[979]: [system] Successfully activated service 'org.freedesktop.PackageKit'
Apr 11 20:30:46 AnonymPC systemd[1]: Started packagekit.service - PackageKit Daemon.
░░ Subject: A start job for unit packagekit.service has finished successfully
░░ Defined-By: systemd
░░ Support: https://www.debian.org/support
░░
░░ A start job for unit packagekit.service has finished successfully.
░░
░░ The job identifier is 27304.
Apr 11 20:30:47 AnonymPC PackageKit[826873]: resolve transaction /30863_dbdddded from uid 1000 finished with success after 765ms
Apr 11 20:30:52 AnonymPC dhclient[882]: No DHCPOFFERS received.
Apr 11 20:30:52 AnonymPC dhclient[882]: No working leases in persistent database - sleeping.
Apr 11 20:30:52 AnonymPC root[826899]: /etc/dhcp/dhclient-exit-hooks.d/zzz_avahi-autoipd returned non-zero exit status 1
Apr 11 20:30:55 AnonymPC gnome-character[826639]: JS LOG: Characters Application exiting
Apr 11 20:31:04 AnonymPC kernel: nouveau 0000:65:00.0: fifo: fault 01 [VIRT_WRITE] at 0000000004600000 engine 40 [gr] client 13 [GPC1/PROP_0] reason 00 [PDE] on channel 4 [017eff5000 systemd-logind[995]]
Apr 11 20:31:04 AnonymPC kernel: nouveau 0000:65:00.0: fifo: channel 4: killed
Apr 11 20:31:04 AnonymPC kernel: nouveau 0000:65:00.0: fifo: runlist 0: scheduled for recovery
Apr 11 20:31:04 AnonymPC kernel: nouveau 0000:65:00.0: fifo: engine 0: scheduled for recovery

The message in the fourth line from below, namely, “nouveau 0000:65:00.0: fifo: fault 01 [VIRT_WRITE] at 0000000004600000 engine 40 [gr] client 13 [GPC1/PROP_0] reason 00 [PDE] on channel 4 [017eff5000 systemd-logind[995]]” is marked red.  Also, all messages “/etc/dhcp/dhclient-exit-hooks.d/zzz_avahi-autoipd returned non-zero exit status 1” (e.g., in the sixth line from below) are marked red.

Some recovery was possible when I logged in via ssh from another machine; I made myself root and issued `kill -9 -1`.  After a minute or so, lots of stuff apparently restarted itself until I saw a GDM3 log in screen. I could log in into my user account and write this very message.

On an earlier attempt of recovering from an earlier freeze a few days ago, killing gdm3 and removing and modprobing the nouveau driver with dependencies via ssh helped.