LLDB: Unexpected scripting behaviour

Question

LLDB: Unexpected scripting behaviour

fritzlb opened this issue 9 months ago · 11 comments

While executing debug commands in a file works fine from interactive lldb mode (command source -s 0 "myfile.txt"), trying to start lldb with "lldb -s "myfile.txt" doesn't work correctly. It seems like lldb executes the first command and then somehow stops.

The used file contains the following debug commands:

process connect --plugin gdb-remote connect://[fde0:5d53:fb4d::1]:52213
settings set target.memory-module-load-level minimal
attach -p 1881
detach

(the script seems useless but actually by connecting a debugger to an iOS app for a short period of time the app gets privileges that are needed for JIT compiling)

This happens on both 17.06 as well as on 18.1.0 RC2.

output with lldb -s "myfile.txt":

(lldb) command source -s 0 C:\Users\User\Desktop\myfile.txt
Executing commands in 'C:\Users\User\Desktop\myfile.txt'.
(lldb) process connect --plugin gdb-remote connect://[fde0:5d53:fb4d::1]:52213

(then hangs there forever)

trying to solve the issue by using lldb -o "command source -s 0 C:\Users\User\Desktop\batch-file.txt" doesn't work either.

also, by adding "quit" to the bottom of myfile.txt lldb doesn't quit but instead crashes (sometimes) when typing another command with the following errors:

PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.      Program arguments: C:\\Users\\Frederik\\Downloads\\llvm-mingw-20240207-msvcrt-x86_64\\llvm-mingw-20240207-msvcrt-x86_64\\bin\\lldb.exe
1.      HandleCommand(command = "command source -s 0 C:/Users/Frederik/Desktop/batch-file.txt")
2.      HandleCommand(command = "attach -p 1881")
3.      HandleCommand(command = "process attach -p 1881")
LLDB diagnostics will be written to C:\Users\Frederik\AppData\Local\Temp\diagnostics-8625d3
Please include the directory content when filing a bug report
Exception Code: 0xC0000005
 #0 0x00007ffd866166d6 PyInit__lldb (C:\Users\Frederik\Downloads\llvm-mingw-20240207-msvcrt-x86_64\llvm-mingw-20240207-msvcrt-x86_64\bin\liblldb.dll+0x3166d6)
 #1 0x00007ffd867c1c3e PyInit__lldb (C:\Users\Frederik\Downloads\llvm-mingw-20240207-msvcrt-x86_64\llvm-mingw-20240207-msvcrt-x86_64\bin\liblldb.dll+0x4c1c3e)
 #2 0x00007ffd8665a81c PyInit__lldb (C:\Users\Frederik\Downloads\llvm-mingw-20240207-msvcrt-x86_64\llvm-mingw-20240207-msvcrt-x86_64\bin\liblldb.dll+0x35a81c)
 #3 0x00007ffd8692ef82 PyInit__lldb (C:\Users\Frederik\Downloads\llvm-mingw-20240207-msvcrt-x86_64\llvm-mingw-20240207-msvcrt-x86_64\bin\liblldb.dll+0x62ef82)
 #4 0x00007ffd865c501a PyInit__lldb (C:\Users\Frederik\Downloads\llvm-mingw-20240207-msvcrt-x86_64\llvm-mingw-20240207-msvcrt-x86_64\bin\liblldb.dll+0x2c501a)
 #5 0x00007ffd865b9cac PyInit__lldb (C:\Users\Frederik\Downloads\llvm-mingw-20240207-msvcrt-x86_64\llvm-mingw-20240207-msvcrt-x86_64\bin\liblldb.dll+0x2b9cac)
 #6 0x00007ffd8698b17a PyInit__lldb (C:\Users\Frederik\Downloads\llvm-mingw-20240207-msvcrt-x86_64\llvm-mingw-20240207-msvcrt-x86_64\bin\liblldb.dll+0x68b17a)
 #7 0x00007ffd865c53c1 PyInit__lldb (C:\Users\Frederik\Downloads\llvm-mingw-20240207-msvcrt-x86_64\llvm-mingw-20240207-msvcrt-x86_64\bin\liblldb.dll+0x2c53c1)
 #8 0x00007ffd865b9cac PyInit__lldb (C:\Users\Frederik\Downloads\llvm-mingw-20240207-msvcrt-x86_64\llvm-mingw-20240207-msvcrt-x86_64\bin\liblldb.dll+0x2b9cac)
 #9 0x00007ffd865bd96f PyInit__lldb (C:\Users\Frederik\Downloads\llvm-mingw-20240207-msvcrt-x86_64\llvm-mingw-20240207-msvcrt-x86_64\bin\liblldb.dll+0x2bd96f)
#10 0x00007ffd868a35e2 PyInit__lldb (C:\Users\Frederik\Downloads\llvm-mingw-20240207-msvcrt-x86_64\llvm-mingw-20240207-msvcrt-x86_64\bin\liblldb.dll+0x5a35e2)
#11 0x00007ffd865436bc PyInit__lldb (C:\Users\Frederik\Downloads\llvm-mingw-20240207-msvcrt-x86_64\llvm-mingw-20240207-msvcrt-x86_64\bin\liblldb.dll+0x2436bc)
#12 0x00007ffd865bb10a PyInit__lldb (C:\Users\Frederik\Downloads\llvm-mingw-20240207-msvcrt-x86_64\llvm-mingw-20240207-msvcrt-x86_64\bin\liblldb.dll+0x2bb10a)
#13 0x00007ffd868f4303 PyInit__lldb (C:\Users\Frederik\Downloads\llvm-mingw-20240207-msvcrt-x86_64\llvm-mingw-20240207-msvcrt-x86_64\bin\liblldb.dll+0x5f4303)
#14 0x00007ffd865c501a PyInit__lldb (C:\Users\Frederik\Downloads\llvm-mingw-20240207-msvcrt-x86_64\llvm-mingw-20240207-msvcrt-x86_64\bin\liblldb.dll+0x2c501a)
#15 0x00007ffd865b9cac PyInit__lldb (C:\Users\Frederik\Downloads\llvm-mingw-20240207-msvcrt-x86_64\llvm-mingw-20240207-msvcrt-x86_64\bin\liblldb.dll+0x2b9cac)
#16 0x00007ffd865bd96f PyInit__lldb (C:\Users\Frederik\Downloads\llvm-mingw-20240207-msvcrt-x86_64\llvm-mingw-20240207-msvcrt-x86_64\bin\liblldb.dll+0x2bd96f)
#17 0x00007ffd868a35e2 PyInit__lldb (C:\Users\Frederik\Downloads\llvm-mingw-20240207-msvcrt-x86_64\llvm-mingw-20240207-msvcrt-x86_64\bin\liblldb.dll+0x5a35e2)
#18 0x00007ffd8654348e PyInit__lldb (C:\Users\Frederik\Downloads\llvm-mingw-20240207-msvcrt-x86_64\llvm-mingw-20240207-msvcrt-x86_64\bin\liblldb.dll+0x24348e)
#19 0x00007ffd865bf4a0 PyInit__lldb (C:\Users\Frederik\Downloads\llvm-mingw-20240207-msvcrt-x86_64\llvm-mingw-20240207-msvcrt-x86_64\bin\liblldb.dll+0x2bf4a0)
#20 0x00007ffd86346259 lldb::SBDebugger::RunCommandInterpreter(bool, bool) (C:\Users\Frederik\Downloads\llvm-mingw-20240207-msvcrt-x86_64\llvm-mingw-20240207-msvcrt-x86_64\bin\liblldb.dll+0x46259)
#21 0x00007ff635b23f3b (C:\Users\Frederik\Downloads\llvm-mingw-20240207-msvcrt-x86_64\llvm-mingw-20240207-msvcrt-x86_64\bin\lldb.exe+0x3f3b)
#22 0x00007ff635b24a41 (C:\Users\Frederik\Downloads\llvm-mingw-20240207-msvcrt-x86_64\llvm-mingw-20240207-msvcrt-x86_64\bin\lldb.exe+0x4a41)
#23 0x00007ff635b21311 (C:\Users\Frederik\Downloads\llvm-mingw-20240207-msvcrt-x86_64\llvm-mingw-20240207-msvcrt-x86_64\bin\lldb.exe+0x1311)
#24 0x00007ff635b21366 (C:\Users\Frederik\Downloads\llvm-mingw-20240207-msvcrt-x86_64\llvm-mingw-20240207-msvcrt-x86_64\bin\lldb.exe+0x1366)
#25 0x00007ffdd910257d (C:\Windows\System32\KERNEL32.DLL+0x1257d)
#26 0x00007ffddad0aa58 (C:\Windows\SYSTEM32\ntdll.dll+0x5aa58)

System:
latest version of Win11

Answer 1 · 2024-02-12T12:28:43.000Z

Is this issue specific to connecting to remote targets somehow? Because I do use script files successfully in some cases - see e.g. https://github.com/mstorsjo/llvm-mingw/blob/master/run-lldb-tests.sh. This does run successfully as part of each build. However I don't do quit at the end of the script file there, I invoke lldb with the option -b, to make it quit when done.

Can you provide instructions for a way to reproduce this issue that doesn't involve connecting to exotic remote targets; is it possible to test by starting up a separate process with lldb-server locally, then connecting to it with LLDB?

Answer 2 · 2024-02-18T14:33:01.000Z

yes, it seems like that. Running lldb-server g localhost:9090 and then attaching using interactive lldb (even by loading commands from a file) works, using a file directly by launching lldb with -s doesn't.

Terminal 1:
.\lldb-server.exe g localhost:9090

Terminal 2:
.\lldb.exe -b -s "C:\Users\User\bugfile.txt"

doesn't work while starting lldb in interactive mode and then typing command source -s 0 C:\Users\User\bugfile.txt does.

bugfile.txt contains the following:
process connect --plugin gdb-remote connect://localhost:9090
attach error

ofc error isn't a valid process name, but it throws an error so that I can see if the line is reached at all.

Answer 3 · 2024-02-19T12:13:01.000Z

yes, it seems like that. Running lldb-server g localhost:9090 and then attaching using interactive lldb (even by loading commands from a file) works, using a file directly by launching lldb with -s doesn't.

Terminal 1: .\lldb-server.exe g localhost:9090

Terminal 2: .\lldb.exe -b -s "C:\Users\User\bugfile.txt"

doesn't work while starting lldb in interactive mode and then typing command source -s 0 C:\Users\User\bugfile.txt does.

bugfile.txt contains the following: process connect --plugin gdb-remote connect://localhost:9090 attach error

ofc error isn't a valid process name, but it throws an error so that I can see if the line is reached at all.

Thanks for the reproducer steps. Unfortunately, I didn't manage to reproduce this. I tried with the latest 18.1.0 RC2 builds, and whenever I try to execute the process connect ... command, I get this error:

(lldb) process connect --plugin gdb-remote connect://localhost:9090 attach error
error: 'process connect' takes exactly one argument:
Usage: process connect <remote-url>

Answer 4 · 2024-02-19T13:11:48.000Z

Sorry, my bad. I did not format the text correctly.attach error has to be in a new line of the file

Answer 5 · 2024-02-19T13:25:17.000Z

Thanks, now I've managed to reproduce it, somewhat, I think. When doing this, it looks like the lldb-server process hangs, consuming 100% cpu.

Answer 6 · 2024-02-19T14:18:36.000Z

@alvinhochun As you've poked LLDB a bit, do you have time to look into this? Otherwise I can try to look at it at some later point when I have time.

FWIW, this sounds like an issue which is a clear upstream bug, so if you wanted to, you could file it as a bug at https://github.com/llvm/llvm-project/issues, especially if it is reproducible with the LLDB builds from their official builds. (LLDB is a bit tricky to use there, though, since it requires you to have the same version of Python installed as was used for building it.)