Re: gdbserver for arm does not support multi-process debugging
Luis Machado <[email protected]>
| Newsgroups | gmane.comp.gdb.devel |
|---|---|
| Message-ID | <[email protected]> |
Hi, I just ran a quick check (foll-fork.exp and follow-vfork.exp tests) on a arm machine and things worked as expected. What version of GDB/kernel are you using? On 10/24/19 2:32 AM, 刘康 wrote: > Hi Luis, > > Yes, I know that gdbserver willcatch PTRACE_EVENT_FORK in > gdb/gdbserver/linux-low.c:handle_extended_wait and get the child > process's pid via PTRACE_GETEVENTMSG. > > I found the way of X86 version gdb to deal with PTRACE_EVENT_FORKwill > set waitstatus toTARGET_WAITKIND_FORKED and add a new inferior .What's > more ,it can trace child/parent process automatically as long as I set > "follow-fork-mode" to "child" or "parent". > > But it seems like gdbserver will not tell PTRACE_EVENT_FORK to thehost > arm-XXX-gdb this event ,as a result , user cannot trace child process or > add a new inferior no matter what value of "detach-on-fork off" and > "follow-fork-mode" I have tried. > > At 2019-10-18 20:27:19, "Luis Machado" <[email protected]> wrote: >>Hi, >> >>On 10/17/19 3:19 AM, 刘康 wrote: >>> Dear [email protected] >>> >>> >>> I am researching the gdbserver's source code for ARM, what confused me is that it does not support multi-process to debug the target's child process, cause it dose not interesting in PTRACE_EVENT_FORK, I don't know whether it's a bug or it's just a feature by design. >> >>The handling of PTRACE_EVENT_FORK, PTRACE_EVENT_VFORK and >>PTRACE_EVENT_CLONE is in generic linux code. See >>gdb/gdbserver/linux-low.c:handle_extended_wait. >> >>As long as the kernel supports reporting such events via ptrace and we >>are debugging using extended remote mode (not regular remote mode), it >>should work. If it doesn't, then we may have a problem that we should fix. >> >>Does that answer your question? >> >>Luis > > >