Code 7 halts occur using 3.6.0-beta.3 and beta.3

[dc42]

At least one use has reported Code 7 halts using beta.2 and another user has reported one using beta.3. The one in beta.3 had this message and M122 report:

2024-11-13T02:54:48: : Error: Movement halted because a step timing error occurred on drive 0 (code 7). Please reset the controller.
2024-11-13T02:54:48: : Error: Extra info=-6.175608e+11
2024-11-13T18:10:21: : M122: === Diagnostics ===
RepRapFirmware for Duet 3 Mini 5+ version 3.6.0-beta.3 (2025-01-16 19:08:29) running on Duet 3 Mini5plus Ethernet (SBC mode)
Board ID: XW5F6-GU8LU-F65J0-409N2-4603Z-7J7VS
Used output buffers: 1 of 40 (18 max)
=== RTOS ===
Static ram: 94252
Dynamic ram: 88412 of which 12 recycled
Never used RAM 45016, free system stack 124 words
Tasks: SBC(2,ready,2.4%,767) HEAT(3,nWait 6,0.0%,325) Move(4,invalid,0.7%,247) TMC(4,nWait 6,0.8%,65) CanReceiv(6,nWait 1,0.1%,771) CanSender(5,nWait 7,0.0%,327) CanClock(7,delaying,0.0%,348) MAIN(2,running,95.1%,579) IDLE(0,ready,0.0%,29) USBD(3,blocked,0.0%,147) AIN(4,delaying,0.8%,255), total 100.0%
Owned mutexes: HTTP(MAIN)
=== Platform ===
Last reset 43:53:32 ago, cause: power up
Last software reset at 2024-11-10 23:28, reason: User, Gcodes spinning, available RAM 40288, slot 0
Software reset code 0x2003 HFSR 0x00000000 CFSR 0x00000000 ICSR 0x00000000 BFAR 0xe000ed38 SP 0x00000000 Task SBC Freestk 0 n/a
Error status: 0x00
MCU temperature: min 25.8, current 39.6, max 57.8
Supply voltage: min 23.8, current 24.0, max 24.1, under voltage events: 0, over voltage events: 0, power good: yes
Heap OK, handles allocated/used 99/57, heap memory allocated/used/recyclable 2048/1232/432, gc cycles 4049
Events: 0 queued, 0 completed
Date/time: 2024-11-13 18:10:20
Slowest loop: 71.05ms; fastest: 0.09ms
USB interrupts 0
=== Storage ===
Free file entries: 20
SD card 0 not detected, interface speed: 0.0MBytes/sec
SD card longest read time 0.0ms, write time 0.0ms, max retries 0
=== Move ===
Segments created 574, maxWait 56781322ms, bed comp in use: mesh, height map offset 0.000, hiccups added 0/0 (0.00/0.00ms), max steps late 1, ebfmin 0.00, ebfmax 0.00
Pos req/act/dcf: 18773.00/18372/-1.00 5880.00/5500/-0.22 21904.00/21907/-0.06 0.00/0/0.00
no step interrupt scheduled
Driver 0: standstill, SG min 0, read errors 2, write errors 0, ifcnt 53, reads 48265, writes 53, timeouts 0, DMA errors 0, CC errors 0
Driver 1: standstill, SG min 0, read errors 0, write errors 0, ifcnt 54, reads 48265, writes 54, timeouts 1, DMA errors 0, CC errors 0, failedOp 0x71
Driver 2: standstill, SG min 0, read errors 1, write errors 0, ifcnt 35, reads 48284, writes 35, timeouts 0, DMA errors 0, CC errors 0
Driver 3: standstill, SG min 0, read errors 2, write errors 0, ifcnt 27, reads 48034, writes 283, timeouts 0, DMA errors 0, CC errors 0
Driver 4: standstill, SG min 0, read errors 2, write errors 0, ifcnt 10, reads 48308, writes 10, timeouts 0, DMA errors 0, CC errors 0
Driver 5: not present
Driver 6: not present
=== DDARing 0 ===
Scheduled moves 1725105, completed 1725066, LaErrors 0, Underruns [477, 0, 0]
Segments left 1, axes/extruders owned 0x0000080f, drives owned 0x0000080f
=== DDARing 1 ===
Scheduled moves 0, completed 0, LaErrors 0, Underruns [0, 0, 0]
Segments left 0, axes/extruders owned 0x00000000, drives owned 0x00000000
Code queue is empty
=== Heat ===
Bed heaters 0 -1 -1 -1, chamber heaters -1 -1 -1 -1, ordering errs 0
=== GCodes ===
Movement locks held by null, null
HTTP* is doing "M122" in state(s) 0
Telnet is idle in state(s) 0
File* is doing "G1 F11257.339844" in state(s) 0
USB is idle in state(s) 0
Aux is idle in state(s) 0
Trigger* is idle in state(s) 0
Queue* is idle in state(s) 0
LCD is idle in state(s) 0
SBC* is idle in state(s) 0
Daemon* is doing "M42 P10 S1" in state(s) 0 0, running macro
Aux2 is idle in state(s) 0
Autopause is idle in state(s) 0
File2 is idle in state(s) 0
Queue2 is idle in state(s) 0
=== Filament sensors ===
check 0 clear 0
Extruder 0: no data received, errs: frame 0 parity 0 ovrun 0 pol 0 ovdue 0
=== CAN ===
Messages queued 3841254, received 3673674, lost 0, ignored 0, errs 0, boc 0
Longest wait 8ms for reply type 6029, peak Tx sync delay 507, free buffers 26 (min 24), ts 748873/748872/0
Tx timeouts 0,0,0,0,0,0
=== SBC interface ===
Transfer state: 5, failed transfers: 0, checksum errors: 0
RX/TX seq numbers: 19837/19837
SPI underruns 0, overruns 0
State: 5, disconnects: 0, timeouts: 0 total, 0 by SBC, IAP RAM available 0x14fe0
Buffer RX/TX: 536/24-1464, open files: 0
=== Duet Control Server ===
Duet Control Server version 3.5.3 (2024-09-21 10:20:47, 32-bit)
HTTP+Executed:

[dc42]

The "extra info" in the above report appears to indicate a very large value of distanceCarriedForwards. In firmware 3.5.0-beta.3+2 the information provided when one f these halts occurs has been extended to include the whole of the segment being processed.