[lldb-dev] LLDB got SIGCHLD on hitting the breakpoint

[Pavel Labath via lldb-dev]

When you say "execute binary code", where exactly is this code being
executed? Is it executed by launching another process?

Lldb will not automatically debug all child process spawned by your
process -- they will run freely.

The SIGCHLDs are not coming from lldb -- they are signals which all
processes receive (from the operating system) when one of their children
dies. They just mean that your process has executed some subprocess and
that subprocess has terminated.

pl

On 21/09/2020 11:48, le wang via lldb-dev wrote:
> Hello,everyone:
> I've got a problem, when debugging my process with lldb tool on linux
> OS(CentOS7).While I use lldb command to set breakpoints, and launch my
> process, my process will execute a binary code which contains debug
> information, but when my process launched, all breakpoints can not be
> hit, The debug process and several received informations like below:  
> （lldb）target create  /home/out/lib/linux64/Debug/appEngine 
> Current executable set to '/home/out/lib/linux64/Debug/appEngine'
>  (x86_64)     
> （lldb）br s -f
> /home/out/lib/linux64/Debug/configDB/TestFunctionProcess.cpp -l1
> Breakpoint 1: no locations(pending).
> WARNING :  Unable to resolve breakpoint to any actual locations.
> （lldb）br s -f
> /home/out/lib/linux64/Debug/configDB/TestFunctionProcess.cpp -l2
> Breakpoint 2: no locations(pending).
> WARNING :  Unable to resolve breakpoint to any actual locations.
> （lldb）r
> Process 4256 launched: '/home/out/lib/linux64/Debug/appEngine'  (x86_64)
>     
> Process 4256 stopped and restarted: thread1 received signal:   SIGCHLD
> Process 4256 stopped and restarted: thread1 received signal:   SIGCHLD
> Process 4256 stopped and restarted: thread1 received signal:   SIGCHLD
> Process 4256 stopped and restarted: thread1 received signal:   SIGCHLD
> Process 4256 stopped and restarted: thread1 received signal:   SIGCHLD
> Process 4256 stopped and restarted: thread2 received signal:   SIGCHLD
> 
> Process stopped and restarted: thread 2 received signal: SIGCHLD
> It seems these repeated restart notifications come from lldb, and at
> last although my process is executed,  it is meaningless. I have checked
> that debug information in IR is correct. I have no idea the reason. Can
> anyone tell me the reason and how to fix this problem. My lldb version
> is 5.0.0, which got from http://www.llvm.org/ with llvm5.0.0
> 
> 
> Thanks,
> le wang
> 
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