In Android, How can I get the stacktrace according to the sigcontext

I'm trying to collect the stacktrace of the target thread. For this purpose, I start a new thread and signal to the target thread in JNI:

 //this is in a new thread
 while (true) {
        usleep(100000);
        syscall(__NR_tgkill, pid, targetThread, SIGPROF);
    }

And then, every time the signal comes, this function is called:

void signalHandler(int signal, siginfo *info, void *context_) {
    ucontext_t *context = reinterpret_cast<ucontext_t *>(context_);
    mcontext_t mcontext = context->uc_mcontext;
    //get the stacktrace from mcontext_t

};

I can get the mcontext_t of the target thread, and I see the struct is:

struct sigcontext {
  __u64 fault_address;
  __u64 regs[31];
  __u64 sp;
  __u64 pc;
  __u64 pstate;
  __u8 __reserved[4096] __attribute__((__aligned__(16)));
};

However, I don't know how to get the stacktrace from the sigcontext and even what means of these fields. I searched for lots of blogs, they always use fp and pc or backtrace(), but I can't find it.