Debugging from VSCode with nRF Connect Extension

[diogodias]

Hello, I'm having problems to debug my application when I check the "Enable debug options" in the build configuration. If I don't check this box, I can debug, however, most of the break points are ignored and most of the variables are optimized, making the process much harder.

I'm using Linux, SDK v.1.8.0 and I have the following output when I press the Debug button of the nRF Connect extension:

Waiting for gdb server to start...[2022-05-04T12:46:11.237Z] SERVER CONSOLE DEBUG: onBackendConnect: gdb-server session connected. You can switch to "DEBUG CONSOLE" to see GDB interactions.
/opt/SEGGER/JLink/JLinkGDBServerCLExe -singlerun -nogui -if swd -port 50000 -swoport 50001 -telnetport 50002 -device nRF9160_xxAA -select usb=960091702 -rtos /opt/SEGGER/JLink/GDBServer/RTOSPlugin_Zephyr.so
SEGGER J-Link GDB Server V7.60g Command Line Version

JLinkARM.dll V7.60g (DLL compiled Feb  2 2022 10:33:24)

Command line: -singlerun -nogui -if swd -port 50000 -swoport 50001 -telnetport 50002 -device nRF9160_xxAA -select usb=960091702 -rtos /opt/SEGGER/JLink/GDBServer/RTOSPlugin_Zephyr.so
-----GDB Server start settings-----
GDBInit file:                  none
GDB Server Listening port:     50000
SWO raw output listening port: 50001
Terminal I/O port:             50002
Accept remote connection:      yes
Generate logfile:              off
Verify download:               off
Init regs on start:            off
Silent mode:                   off
Single run mode:               on
Target connection timeout:     0 ms
------J-Link related settings------
J-Link Host interface:         USB
J-Link script:                 none
J-Link settings file:          none
------Target related settings------
Target device:                 nRF9160_xxAA
Target interface:              SWD
Target interface speed:        4000kHz
Target endian:                 little

Connecting to J-Link...
J-Link is connected.
Firmware: J-Link OB-K22-NordicSemi compiled Dec  3 2021 15:46:55
Hardware: V1.00
S/N: 960091702
Feature(s): RDI, FlashBP, FlashDL, JFlash, GDB
Checking target voltage...
Target voltage: 3.30 V
Listening on TCP/IP port 50000
Connecting to target...
Connected to target
Waiting for GDB connection...Connected to 127.0.0.1
Reading all registers
Read 4 bytes @ address 0x0003668A (Data = 0xF3BFB662)
Read 2 bytes @ address 0x0003668A (Data = 0xB662)
Loading RTOS plugin: //opt/SEGGER/JLink/GDBServer/RTOSPlugin_Zephyr.so...
RTOS plugin (API v1.1) loaded successfully
RTOS_Init() core = 235012351
RTOS plugin: Loaded
RTOS_GetSymbols()
Received symbol: _kernel (0x2001B8D0)
Received symbol: _kernel_openocd_offsets (0x0005F864)
Received symbol: z_sys_post_kernel (0x2001BA75)
All mandatory symbols successfully loaded.
Read 4 bytes @ address 0x0003668A (Data = 0xF3BFB662)
All mandatory symbols successfully loaded.
Read 4 bytes @ address 0x0003668A (Data = 0xF3BFB662)
All mandatory symbols successfully loaded.
Received monitor command: halt
Halting target CPU...
...Target halted (PC = 0x0003668A)
Received monitor command: reset
Resetting target
Downloading 16048 bytes @ address 0x00000000
Downloading 15832 bytes @ address 0x00003EB0
Downloading 16080 bytes @ address 0x00010000
Downloading 16128 bytes @ address 0x00013ED0
Downloading 16224 bytes @ address 0x00017DD0
Downloading 16368 bytes @ address 0x0001BD30
Downloading 736 bytes @ address 0x0001FD20
Downloading 15984 bytes @ address 0x00020000
Downloading 16112 bytes @ address 0x00023E70
Downloading 15984 bytes @ address 0x00027D60
Downloading 16000 bytes @ address 0x0002BBD0
Downloading 1456 bytes @ address 0x0002FA50
Downloading 15920 bytes @ address 0x00030000
Downloading 16016 bytes @ address 0x00033E30
Downloading 15968 bytes @ address 0x00037CC0
Downloading 15952 bytes @ address 0x0003BB20
Downloading 1680 bytes @ address 0x0003F970
Downloading 16048 bytes @ address 0x00040000
Downloading 15984 bytes @ address 0x00043EB0
Downloading 16112 bytes @ address 0x00047D20
Downloading 15968 bytes @ address 0x0004BC10
Downloading 1424 bytes @ address 0x0004FA70
Downloading 15984 bytes @ address 0x00050000
Downloading 15968 bytes @ address 0x00053E70
Downloading 15968 bytes @ address 0x00057CD0
Downloading 16016 bytes @ address 0x0005BB30
Downloading 1600 bytes @ address 0x0005F9C0
Downloading 16272 bytes @ address 0x00060000
Downloading 16208 bytes @ address 0x00063F90
Downloading 2079 bytes @ address 0x00067EE0
Comparing flash   [....................] Done.
Erasing flash     [....................] Done.
Programming flash [....................] Done.
Writing register (PC = 0x       0)
Received monitor command: reset
Resetting target
Read 4 bytes @ address 0x00000000 (Data = 0x20017D68)
Read 2 bytes @ address 0x00000000 (Data = 0x7D68)
Reading 64 bytes @ address 0x00031C80
Read 2 bytes @ address 0x00031C9C (Data = 0x4B80)
Read 2 bytes @ address 0x00031CA0 (Data = 0x2300)
Read 2 bytes @ address 0x00031CB2 (Data = 0x461A)
Read 2 bytes @ address 0x00031CDE (Data = 0xF001)
Read 2 bytes @ address 0x00031CE2 (Data = 0xF001)
Reading 64 bytes @ address 0x00053FC0
Read 2 bytes @ address 0x00053FE6 (Data = 0xF8C0)
Reading 64 bytes @ address 0x000187C0
Read 2 bytes @ address 0x00031C8C (Data = 0xE92D)
Read 2 bytes @ address 0x000187CE (Data = 0xB508)
Read 2 bytes @ address 0x00000438 (Data = 0xB57F)
Setting breakpoint @ address 0x00000438, Size = 2, BPHandle = 0x0001
Setting breakpoint @ address 0x000187CE, Size = 2, BPHandle = 0x0002
Setting breakpoint @ address 0x00031C8C, Size = 2, BPHandle = 0x0003
Setting breakpoint @ address 0x00031C9C, Size = 2, BPHandle = 0x0004
Setting breakpoint @ address 0x00031CA0, Size = 2, BPHandle = 0x0005
Setting breakpoint @ address 0x00031CB2, Size = 2, BPHandle = 0x0006
Setting breakpoint @ address 0x00031CDE, Size = 2, BPHandle = 0x0007
Setting breakpoint @ address 0x00031CE2, Size = 2, BPHandle = 0x0008
Setting breakpoint @ address 0x00053FE6, Size = 2, BPHandle = 0x0009
Starting target CPU...
Erasing flash     [....................] Done.
Programming flash [....................] Done.
...Breakpoint reached @ address 0x00000438
RTOS_UpdateThreads()
Parsed thread -1046179653, next=0
RTOS_GetNumThreads() --> 1
RTOS_GetCurrentThreadId()
Reading all registers
RTOS_GetThreadRegList(, -583729001)
RTOS_GetThreadReg(, 0, -583729001)
Read register 0 (4 bytes) from DLL: 04000000
RTOS_GetThreadReg(, 1, -583729001)
Read register 1 (4 bytes) from DLL: 00000000
RTOS_GetThreadReg(, 2, -583729001)
Read register 2 (4 bytes) from DLL: 01000000
RTOS_GetThreadReg(, 3, -583729001)
Read register 3 (4 bytes) from DLL: 746D0000
RTOS_GetThreadReg(, 4, -583729001)
Read register 4 (4 bytes) from DLL: 193C0000
RTOS_GetThreadReg(, 5, -583729001)
Read register 5 (4 bytes) from DLL: 20000000
RTOS_GetThreadReg(, 6, -583729001)
Read register 6 (4 bytes) from DLL: 68550120
RTOS_GetThreadReg(, 7, -583729001)
Read register 7 (4 bytes) from DLL: 00000000
RTOS_GetThreadReg(, 8, -583729001)
Read register 8 (4 bytes) from DLL: 00000000
RTOS_GetThreadReg(, 9, -583729001)
Read register 9 (4 bytes) from DLL: 00000000
RTOS_GetThreadReg(, 10, -583729001)
Read register 10 (4 bytes) from DLL: 00000000
RTOS_GetThreadReg(, 11, -583729001)
Read register 11 (4 bytes) from DLL: 00000000
RTOS_GetThreadReg(, 12, -583729001)
Read register 12 (4 bytes) from DLL: 00000000
RTOS_GetThreadReg(, 13, -583729001)
Read register 13 (4 bytes) from DLL: 607D0120
RTOS_GetThreadReg(, 14, -583729001)
Read register 14 (4 bytes) from DLL: 353C0000
RTOS_GetThreadReg(, 15, -583729001)
Read register 15 (4 bytes) from DLL: 38040000
RTOS_GetThreadReg(, 16, -583729001)
Read register 16 (4 bytes) from DLL: 00000069
RTOS_GetNumThreads() --> 1
RTOS_GetThreadId(0)
Removing breakpoint @ address 0x00000438, Size = 2
Removing breakpoint @ address 0x000187CE, Size = 2
Removing breakpoint @ address 0x00031C8C, Size = 2
Removing breakpoint @ address 0x00031C9C, Size = 2
Removing breakpoint @ address 0x00031CA0, Size = 2
Removing breakpoint @ address 0x00031CB2, Size = 2
Removing breakpoint @ address 0x00031CDE, Size = 2
Removing breakpoint @ address 0x00031CE2, Size = 2
Removing breakpoint @ address 0x00053FE6, Size = 2
Debugger requested to halt target...

Any idea how to fix this? 

Thank you!

[Einar Thorsrud]

Hi,

It is a general concept that compilers will do code optimization if configured to do so, and for release builds you typically always enable optimization. This can of course on speed, code size, etc. This changes the machine code so that it does not exactly map the C code, so it makes debugging harder. Therefor you often want to disable optimization when you debug. The "Enable debug options" in nRF Connect for VS Code causes optimization to be disabled, and also sets a few other options to further aid debugging VS code. If you want to permanently disable optimization you can do that, for instance by adding CONFIG_DEBUG_OPTIMIZATIONS=y to your prj.conf. See this post for more.

[diogodias]

Hi,

Thank you for your response. 

Yes, I'm aware of code optimization and that it makes debug harder.  With the CONFIG_DEBUG_OPTIMIZATIONS=y I was able to properly debug and my "problem" is solved. However, just out of curiosity, do you know why I cant debug the board if I check the "Enable debug options" in the build configuration? As you can see in the code that I posted, I get stuck in "Debugger requested to halt target...".

[Einar Thorsrud]

Ah, sorry. I misread your question. No, you should be able to debug with the checkbox checked. I do not see anything obviously wrogn when browsing through the log in your original post. What happens when you try to debug with the "Enable debug options" box checked? And which VS Code version and version of the nRF plugins do you use?

[diogodias]

No problem. 
Nothing happens, it just gets stuck in  "Debugger requested to halt target..." and the debugger doesn't start.

My vscode version is 1.66.2 and nRF Connect Exntension Pack is v2021.9.1.

[Einar Thorsrud]

I see. Which version is nRF Connect for VS Code?

[diogodias]

2022.4.219

[Einar Thorsrud]

I see, that is the latest. I have not been able to reproduce myself and have not found any other reports of this. Are there other factors that are need to reproduce this? Also, which Linux distribution (and version of it) are you using?

For now, enabling debug options in the project configuration file or just adding "-DCONFIG_DEBUG_OPTIMIZATIONS=y" as an extra CMake argument when you make a build configuration in VS Code should be a good workaround.