mono_thread_platform_create_thread crashing with pthread_attr_setstacksize invalid argument error

[stephentoub]

Mono does not round up the argument to pthread_attr_setstacksize to the platform virtual page size which results in an EINVAL which will cause new Thread(ThreadStart, Int32) to fail

---

#105445 (comment)

The osx-x64 Debug Mono_MiniJIT_LibrariesTests leg crashed with:

mono_thread_platform_create_thread: pthread_attr_setstacksize failed, error: "Invalid argument" (22)

when trying to set a maxStackSize on a new thread to 100_000.

[lambdageek]

I think this is because we're not aligning the requested stakc size to a multiple of the page size

compare Mono

runtime/src/mono/mono/utils/mono-threads-posix.c

Lines 60 to 80 in 1d27457

	if (stack_size)
	set_stack_size = *stack_size;
	else
	set_stack_size = 0;
	#ifdef HAVE_PTHREAD_ATTR_SETSTACKSIZE
	if (set_stack_size == 0) {
	#if HAVE_VALGRIND_MEMCHECK_H
	if (RUNNING_ON_VALGRIND)
	set_stack_size = 1 << 20;
	else
	set_stack_size = (SIZEOF_VOID_P / 4) * 1024 * 1024;
	#else
	set_stack_size = (SIZEOF_VOID_P / 4) * 1024 * 1024;
	#endif
	}
	#ifdef PTHREAD_STACK_MIN
	if (set_stack_size < PTHREAD_STACK_MIN)
	set_stack_size = PTHREAD_STACK_MIN;
	#endif

to coreCLR PAL

runtime/src/coreclr/pal/src/thread/thread.cpp

Lines 550 to 565 in 1d27457

	alignedStackSize = dwStackSize;
	if (alignedStackSize != 0)
	{
	// Some systems require the stack size to be aligned to the page size
	if (sizeof(alignedStackSize) <= sizeof(dwStackSize) && alignedStackSize + (GetVirtualPageSize() - 1) < alignedStackSize)
	{
	// When coming here from the public API surface, the incoming value is originally a nonnegative signed int32, so
	// this shouldn't happen
	ASSERT(
	"Couldn't align the requested stack size (%zu) to the page size because the stack size was too large\n",
	alignedStackSize);
	palError = ERROR_INVALID_PARAMETER;
	goto EXIT;
	}
	alignedStackSize = ALIGN_UP(alignedStackSize, GetVirtualPageSize());
	}

[lambdageek]

/cc @steveisok

[EgorBo]

@lambdageek I am not sure if that is related, but we also bumped default thread stack size on macOS for CoreCLR, from 512kb (which is fairly low) to 1 or 2 mb.

Since mac has 8mb for mainthread and 512kb for all secondary threads by default (on system level)

[lambdageek]

limits.h in the MacOSX.sdk has

#if defined(__arm__) || defined(__arm64__)
#define PTHREAD_STACK_MIN 		16384
#else
#define PTHREAD_STACK_MIN 		8192
#endif

So requesting something smaller than the default ought to work. Mono does have a check that we ask for at least PTHREAD_STACK_MIN even if the user specified something smaller.

[lambdageek]

Not a recent regression, btw. The following fails on mono going back to net6.0 at least (and probably older)

using System.Threading;

public class Program
{
    public static void Main()
    {
        var t = new Thread(() => {
            Console.WriteLine ("from a new thread");
            }, 16384 + 1);
        t.Start();
        t.Join();
    }
}

[lambdageek]

DeepEquals_TooDeepJsonDocument_ThrowsInsufficientExecutionStackException was updated to use a multiple of 64k for the stack size. So there's no disabled test anymore; it's just about aligning behavior now