Re:Re: gdbserver for arm does not support multi-process debugging
刘康 <[email protected]>
| Newsgroups | gmane.comp.gdb.devel |
|---|---|
| Message-ID | <[email protected]> |
Hi, I see, maybe my gdbserver version is too old...I'll compile a latest version and try again. Thank you so much for your help! At 2019-10-24 18:38:46, "Luis Machado" <[email protected]> wrote: >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 >> >> >>