Re: How to create multiple contexts in different threads?

On Wednesday, March 30, 2016 at 6:24:38 PM UTC+2, Jason Orendorff wrote:
> Buiding SpiderMonkey creates a header, dist/include/js-config.h, that
> defines all these. It is included from jsapi.h (-> jspubtd.h -> jstypes.h
> -> js-config.h). I think the easiest way to mess it up is not by failing to
> -DDEBUG, but by compiling correctly --- and then linking against the wrong
> SM shared library.

I am sure I am using the correct library, the path is everywhere: in the assertion message, in the backtrace, ... And the offsetof warning tell me which header are included.

I rewrote a simple program:
#include <cstdlib>
#include <cstdio>
#include <jsapi.h>
extern "C" {
#include <pthread.h>
}

constexpr uint32_t RT_MAX_BYTES = 8ul*1024ul*1024ul;
JSRuntime *main_rt;

void *worker (void *arg)
{
	JSRuntime *rt = JS_NewRuntime (RT_MAX_BYTES, JS::DefaultNurseryBytes, main_rt);
	if (!rt)
		fprintf (stderr, "JS_NewRuntime failed");
	printf ("in worker\n");
	JS_DestroyRuntime (rt);
}

int main ()
{
	int ret;

	if (!JS_Init ()) {
		fprintf (stderr, "JS_Init failed\n");
		return EXIT_FAILURE;
	}

	main_rt = JS_NewRuntime (RT_MAX_BYTES);
	if (!main_rt)
		fprintf (stderr, "JS_NewRuntime failed");

	pthread_t thread;
	if (0 != (ret = pthread_create (&thread, nullptr, worker, nullptr))) {
		fprintf (stderr, "pthread_create failed: %s\n", strerror (ret));
	}
	pthread_join (thread, nullptr);

	JS_DestroyRuntime (main_rt);

	JS_ShutDown ();
	return EXIT_SUCCESS;
}
This should work, right?

Assertion failure: !isLocked(), at /home/clement/src/mozilla-esr38/js/src/vm/HelperThreads.cpp:515

(gdb) bt
#0  0x00007ffff67abd12 in js::GlobalHelperThreadState::lock (this=0x614ca0) at /home/clement/src/mozilla-esr38/js/src/vm/HelperThreads.cpp:515
#1  0x00007ffff667a422 in js::AutoLockHelperThreadState::AutoLockHelperThreadState (this=0x7ffff4f09dbf, _notifier=...) at /home/clement/src/mozilla-esr38/js/src/vm/HelperThreads.h:415
#2  0x00007ffff67ab78a in js::GlobalHelperThreadState::ensureInitialized (this=0x614ca0) at /home/clement/src/mozilla-esr38/js/src/vm/HelperThreads.cpp:446
#3  0x00007ffff67a9f5a in js::EnsureHelperThreadsInitialized () at /home/clement/src/mozilla-esr38/js/src/vm/HelperThreads.cpp:58
#4  0x00007ffff6862fc4 in JSRuntime::init (this=0x7fffc80008c0, maxbytes=8388608, maxNurseryBytes=16777216) at /home/clement/src/mozilla-esr38/js/src/vm/Runtime.cpp:268
#5  0x00007ffff6cdccaa in JS_NewRuntime (maxbytes=8388608, maxNurseryBytes=16777216, parentRuntime=0x615020) at /home/clement/src/mozilla-esr38/js/src/jsapi.cpp:472
#6  0x0000000000400a5b in worker (arg=0x0) at main.cpp:13
#7  0x00007ffff620d60a in start_thread () from /lib64/libpthread.so.0
#8  0x00007ffff56aca4d in clone () from /lib64/libc.so.6
(gdb) info threads
  Id   Target Id         Frame 
* 10   Thread 0x7ffff4f0a700 (LWP 18925) "a.out" 0x00007ffff67abd12 in js::GlobalHelperThreadState::lock (this=0x614ca0) at /home/clement/src/mozilla-esr38/js/src/vm/HelperThreads.cpp:515
  9    Thread 0x7ffff4f8b700 (LWP 18924) "Analysis Helper" 0x00007ffff6212b10 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
  8    Thread 0x7ffff500c700 (LWP 18923) "Analysis Helper" 0x00007ffff6212b10 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
  7    Thread 0x7ffff508d700 (LWP 18922) "Analysis Helper" 0x00007ffff6212b10 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
  6    Thread 0x7ffff510e700 (LWP 18921) "Analysis Helper" 0x00007ffff6212b10 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
  5    Thread 0x7ffff518f700 (LWP 18920) "Analysis Helper" 0x00007ffff6212b10 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
  4    Thread 0x7ffff7ec6700 (LWP 18919) "Analysis Helper" 0x00007ffff6212b10 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
  3    Thread 0x7ffff7f47700 (LWP 18918) "Analysis Helper" 0x00007ffff6212b10 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
  2    Thread 0x7ffff7fc8700 (LWP 18917) "Analysis Helper" 0x00007ffff6212b10 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
  1    Thread 0x7ffff7fca740 (LWP 18912) "a.out" 0x00007ffff620e6ad in pthread_join () from /lib64/libpthread.so.0

Compiled with:
g++ -g -std=c++11 main.cpp -include /home/clement/opt/mozjs-38.hg-debug/include/mozjs-38/js/RequiredDefines.h -I/home/clement/opt/mozjs-38.hg-debug/include/mozjs-38 -I/usr/include/nspr4 -L/home/clement/opt/mozjs-38.hg-debug/lib -lmozjs-38 -lpthread
and LD_LIBRARY_PATH=/home/clement/opt/mozjs-38.hg-debug/lib/

I don't know enough about SM internals to know the relevant places to test that but when the assertion fails lockOwner is null. PR_GetCurrentThread () also returns 0.