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Allow interrupting blocking instructions #1930

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3c2f060
fix(wasi-threads): interrupt blocking instructions using signals
eloparco Feb 2, 2023
185cd4d
fix(wasi-threads): fix platform includes
eloparco Feb 3, 2023
f9c0bd1
refactor(wasi-threads): move platform-related code and remove "block …
eloparco Feb 4, 2023
6eecad7
feat(wasi-threads): use blocking operations in thread termination exa…
eloparco Feb 5, 2023
9d6dc29
fix(wasi-threads): handle signal handler being called before os_setjmp
eloparco Feb 7, 2023
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6 changes: 6 additions & 0 deletions build-scripts/config_common.cmake
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Original file line number Diff line number Diff line change
Expand Up @@ -248,6 +248,12 @@ else ()
add_definitions (-DWASM_DISABLE_STACK_HW_BOUND_CHECK=0)
endif ()
endif ()
if (WAMR_DISABLE_BLOCK_INSN_INTERRUPT EQUAL 1)
add_definitions (-DWASM_DISABLE_BLOCK_INSN_INTERRUPT=1)
message (" Interruption of blocking instructions disabled")
else ()
add_definitions (-DWASM_DISABLE_BLOCK_INSN_INTERRUPT=0)
endif ()
if (WAMR_BUILD_SIMD EQUAL 1)
if (NOT WAMR_BUILD_TARGET MATCHES "RISCV64.*")
add_definitions (-DWASM_ENABLE_SIMD=1)
Expand Down
35 changes: 30 additions & 5 deletions core/iwasm/aot/aot_runtime.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1325,6 +1325,9 @@ aot_call_function(WASMExecEnv *exec_env, AOTFunctionInstance *function,
uint32 result_count = func_type->result_count;
uint32 ext_ret_count = result_count > 1 ? result_count - 1 : 0;
bool ret;
#ifdef OS_ENABLE_BLOCK_INSN_INTERRUPT
WASMJmpBuf jmpbuf_node = { 0 }, *jmpbuf_node_pop;
#endif

if (argc < func_type->param_cell_num) {
char buf[108];
Expand Down Expand Up @@ -1385,8 +1388,19 @@ aot_call_function(WASMExecEnv *exec_env, AOTFunctionInstance *function,
}
#endif

ret = invoke_native_internal(exec_env, function->u.func.func_ptr,
func_type, NULL, NULL, argv1, argc, argv);
#ifdef OS_ENABLE_BLOCK_INSN_INTERRUPT
wasm_exec_env_push_jmpbuf(exec_env, &jmpbuf_node);
wasm_runtime_set_exec_env_tls(exec_env);
if (os_setjmp(jmpbuf_node.jmpbuf) == 0)
#endif
ret = invoke_native_internal(exec_env, function->u.func.func_ptr,
func_type, NULL, NULL, argv1, argc,
argv);
#ifdef OS_ENABLE_BLOCK_INSN_INTERRUPT

jmpbuf_node_pop = wasm_exec_env_pop_jmpbuf(exec_env);
bh_assert(&jmpbuf_node == jmpbuf_node_pop);
#endif

#if WASM_ENABLE_DUMP_CALL_STACK != 0
if (!ret) {
Expand Down Expand Up @@ -1444,8 +1458,19 @@ aot_call_function(WASMExecEnv *exec_env, AOTFunctionInstance *function,
}
#endif

ret = invoke_native_internal(exec_env, function->u.func.func_ptr,
func_type, NULL, NULL, argv, argc, argv);
#ifdef OS_ENABLE_BLOCK_INSN_INTERRUPT
wasm_exec_env_push_jmpbuf(exec_env, &jmpbuf_node);
wasm_runtime_set_exec_env_tls(exec_env);
if (os_setjmp(jmpbuf_node.jmpbuf) == 0)
#endif
ret =
invoke_native_internal(exec_env, function->u.func.func_ptr,
func_type, NULL, NULL, argv, argc, argv);
#ifdef OS_ENABLE_BLOCK_INSN_INTERRUPT

jmpbuf_node_pop = wasm_exec_env_pop_jmpbuf(exec_env);
bh_assert(&jmpbuf_node == jmpbuf_node_pop);
#endif

#if WASM_ENABLE_DUMP_CALL_STACK != 0
if (aot_get_exception(module_inst)) {
Expand All @@ -1471,7 +1496,7 @@ aot_create_exec_env_and_call_function(AOTModuleInstance *module_inst,
WASMExecEnv *exec_env = NULL, *existing_exec_env = NULL;
bool ret;

#if defined(OS_ENABLE_HW_BOUND_CHECK)
#if defined(OS_ENABLE_HW_BOUND_CHECK) || defined(OS_ENABLE_BLOCK_INSN_INTERRUPT)
existing_exec_env = exec_env = wasm_runtime_get_exec_env_tls();
#elif WASM_ENABLE_THREAD_MGR != 0
existing_exec_env = exec_env =
Expand Down
2 changes: 1 addition & 1 deletion core/iwasm/common/wasm_exec_env.c
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Expand Up @@ -227,7 +227,7 @@ wasm_exec_env_set_thread_arg(WASMExecEnv *exec_env, void *thread_arg)
}
#endif

#ifdef OS_ENABLE_HW_BOUND_CHECK
#if defined(OS_ENABLE_HW_BOUND_CHECK) || defined(OS_ENABLE_BLOCK_INSN_INTERRUPT)
void
wasm_exec_env_push_jmpbuf(WASMExecEnv *exec_env, WASMJmpBuf *jmpbuf)
{
Expand Down
8 changes: 5 additions & 3 deletions core/iwasm/common/wasm_exec_env.h
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Expand Up @@ -25,7 +25,7 @@ typedef struct WASMCurrentEnvStatus WASMCurrentEnvStatus;
#endif
#endif

#ifdef OS_ENABLE_HW_BOUND_CHECK
#if defined(OS_ENABLE_HW_BOUND_CHECK) || defined(OS_ENABLE_BLOCK_INSN_INTERRUPT)
typedef struct WASMJmpBuf {
struct WASMJmpBuf *prev;
korp_jmpbuf jmpbuf;
Expand Down Expand Up @@ -135,8 +135,10 @@ typedef struct WASMExecEnv {
BlockAddr block_addr_cache[BLOCK_ADDR_CACHE_SIZE][BLOCK_ADDR_CONFLICT_SIZE];
#endif

#ifdef OS_ENABLE_HW_BOUND_CHECK
#if defined(OS_ENABLE_HW_BOUND_CHECK) || defined(OS_ENABLE_BLOCK_INSN_INTERRUPT)
WASMJmpBuf *jmpbuf_stack_top;
#endif
#ifdef OS_ENABLE_HW_BOUND_CHECK
/* One guard page for the exception check */
uint8 *exce_check_guard_page;
#endif
Expand Down Expand Up @@ -291,7 +293,7 @@ void
wasm_exec_env_set_thread_arg(WASMExecEnv *exec_env, void *thread_arg);
#endif

#ifdef OS_ENABLE_HW_BOUND_CHECK
#if defined(OS_ENABLE_HW_BOUND_CHECK) || defined(OS_ENABLE_BLOCK_INSN_INTERRUPT)
void
wasm_exec_env_push_jmpbuf(WASMExecEnv *exec_env, WASMJmpBuf *jmpbuf);

Expand Down
42 changes: 39 additions & 3 deletions core/iwasm/common/wasm_runtime_common.c
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Expand Up @@ -128,12 +128,14 @@ runtime_malloc(uint64 size, WASMModuleInstanceCommon *module_inst,
static JitCompOptions jit_options = { 0 };
#endif

#ifdef OS_ENABLE_HW_BOUND_CHECK
#if defined(OS_ENABLE_HW_BOUND_CHECK) || defined(OS_ENABLE_BLOCK_INSN_INTERRUPT)
/* The exec_env of thread local storage, set before calling function
and used in signal handler, as we cannot get it from the argument
of signal handler */
static os_thread_local_attribute WASMExecEnv *exec_env_tls = NULL;
#endif

#ifdef OS_ENABLE_HW_BOUND_CHECK
#ifndef BH_PLATFORM_WINDOWS
static void
runtime_signal_handler(void *sig_addr)
Expand Down Expand Up @@ -303,7 +305,9 @@ runtime_signal_destroy()
#endif
os_thread_signal_destroy();
}
#endif /* end of OS_ENABLE_HW_BOUND_CHECK */

#if defined(OS_ENABLE_HW_BOUND_CHECK) || defined(OS_ENABLE_BLOCK_INSN_INTERRUPT)
void
wasm_runtime_set_exec_env_tls(WASMExecEnv *exec_env)
{
Expand All @@ -315,7 +319,35 @@ wasm_runtime_get_exec_env_tls()
{
return exec_env_tls;
}
#endif /* end of OS_ENABLE_HW_BOUND_CHECK */
#endif

#ifdef OS_ENABLE_BLOCK_INSN_INTERRUPT
static void
os_interrupt_block_insn_sig_handler(int sig)
{
bh_assert(sig == SIGUSR1);

WASMJmpBuf *jmpbuf_node = exec_env_tls->jmpbuf_stack_top;
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jmpbuf_stack_top here can be for another handler.

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Yes, if HW bound check is enabled, it will get a "HW bound" jmpbuf #1930 (comment), but that should not be a problem unless I'm missing something

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you can even get a signal between wasm_exec_env_push_jmpbuf and os_setjmp.

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@eloparco eloparco Feb 6, 2023 •
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you can even get a signal between wasm_exec_env_push_jmpbuf and os_setjmp.

In that case, the jmpbuf would be invalid, as it is in general before being set up by os_setjmp. Isn't that the same for the HW bound check before my PR?

I wonder if we have to mask/un-mask signals to avoid the signal handler being called in the middle. We want to avoid signal handlers being called between wasm_exec_env_push_jmpbuf and os_setjmp as they would use a non-initialized jmpbuf iiuc.

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it isn't a problem for hw bound check because the signal for it is basically synchronous to the thread execution. ie. the thread itself can control where it can happen.

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@eloparco eloparco Feb 7, 2023 •
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Can we maybe invert the order of wasm_exec_env_push_jmpbuf and os_setjmp? So that the jmpbuf is only pushed after being initialized by os_setjmp.

But there are probably other cases that are not covered, like an exception before os_setjmp. [EDIT] These cases shouldn't be a problem since they're already handled by the normal exception spreading mechanism.

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@eloparco eloparco Feb 7, 2023 •
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Can we maybe invert the order of wasm_exec_env_push_jmpbuf and os_setjmp? So that the jmpbuf is only pushed after being initialized by os_setjmp.

I tried that in the latest commit, but maybe it's safer to use something like static volatile sig_atomic_t canjump; (but with tls) as explained here https://notes.shichao.io/apue/ch10/?

you can even get a signal between wasm_exec_env_push_jmpbuf and os_setjmp.

Apart from this, do you think there are other cases that are not covered? If we get the signal before os_setjmp, the signal handler (for instruction interruption) will return and the thread will stop when starting to execute instructions, using the normal exception propagation mechanism.

bh_assert(jmpbuf_node);

os_longjmp(jmpbuf_node->jmpbuf, 1);
}

bool
os_interrupt_block_insn_init()
{
struct sigaction act;
memset(&act, 0, sizeof(act));
act.sa_handler = os_interrupt_block_insn_sig_handler;
sigfillset(&act.sa_mask);
if (sigaction(SIGUSR1, &act, NULL) < 0) {
LOG_ERROR("failed to set signal handler");
return false;
}

return true;
}
#endif

static bool
wasm_runtime_env_init()
Expand Down Expand Up @@ -348,7 +380,11 @@ wasm_runtime_env_init()
goto fail5;
}
#endif

#ifdef OS_ENABLE_BLOCK_INSN_INTERRUPT
if (!os_interrupt_block_insn_init()) {
goto fail5;
}
#endif
#ifdef OS_ENABLE_HW_BOUND_CHECK
if (!runtime_signal_init()) {
goto fail6;
Expand Down
2 changes: 2 additions & 0 deletions core/iwasm/common/wasm_runtime_common.h
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Expand Up @@ -423,7 +423,9 @@ typedef struct WASMSignalInfo {
EXCEPTION_POINTERS *exce_info;
#endif
} WASMSignalInfo;
#endif

#if defined(OS_ENABLE_HW_BOUND_CHECK) || defined(OS_ENABLE_BLOCK_INSN_INTERRUPT)
/* Set exec_env of thread local storage */
void
wasm_runtime_set_exec_env_tls(WASMExecEnv *exec_env);
Expand Down
18 changes: 16 additions & 2 deletions core/iwasm/interpreter/wasm_runtime.c
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Expand Up @@ -2137,11 +2137,25 @@ wasm_call_function(WASMExecEnv *exec_env, WASMFunctionInstance *function,
{
WASMModuleInstance *module_inst =
(WASMModuleInstance *)exec_env->module_inst;
#ifdef OS_ENABLE_BLOCK_INSN_INTERRUPT
WASMJmpBuf jmpbuf_node = { 0 }, *jmpbuf_node_pop;
#endif

/* set thread handle and stack boundary */
wasm_exec_env_set_thread_info(exec_env);

interp_call_wasm(module_inst, exec_env, function, argc, argv);
#ifdef OS_ENABLE_BLOCK_INSN_INTERRUPT
wasm_exec_env_push_jmpbuf(exec_env, &jmpbuf_node);
wasm_runtime_set_exec_env_tls(exec_env);
if (os_setjmp(jmpbuf_node.jmpbuf) == 0)
#endif
interp_call_wasm(module_inst, exec_env, function, argc, argv);
#ifdef OS_ENABLE_BLOCK_INSN_INTERRUPT

jmpbuf_node_pop = wasm_exec_env_pop_jmpbuf(exec_env);
bh_assert(&jmpbuf_node == jmpbuf_node_pop);
#endif

return !wasm_get_exception(module_inst) ? true : false;
}

Expand All @@ -2153,7 +2167,7 @@ wasm_create_exec_env_and_call_function(WASMModuleInstance *module_inst,
WASMExecEnv *exec_env = NULL, *existing_exec_env = NULL;
bool ret;

#if defined(OS_ENABLE_HW_BOUND_CHECK)
#if defined(OS_ENABLE_HW_BOUND_CHECK) || defined(OS_ENABLE_BLOCK_INSN_INTERRUPT)
existing_exec_env = exec_env = wasm_runtime_get_exec_env_tls();
#elif WASM_ENABLE_THREAD_MGR != 0
existing_exec_env = exec_env =
Expand Down
4 changes: 4 additions & 0 deletions core/iwasm/libraries/thread-mgr/thread_manager.c
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Expand Up @@ -1064,6 +1064,10 @@ set_exception_visitor(void *node, void *user_data)
bh_memcpy_s(curr_wasm_inst->cur_exception,
sizeof(curr_wasm_inst->cur_exception),
wasm_inst->cur_exception, sizeof(wasm_inst->cur_exception));

bh_assert(curr_exec_env->handle);
os_thread_signal(curr_exec_env->handle, SIGUSR1);

/* Terminate the thread so it can exit from dead loops */
set_thread_cancel_flags(curr_exec_env);
}
Expand Down
17 changes: 11 additions & 6 deletions core/shared/platform/android/platform_internal.h
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Expand Up @@ -63,19 +63,17 @@ typedef sem_t korp_sem;

#define bh_socket_t int

#if WASM_DISABLE_BLOCK_INSN_INTERRUPT == 0
#define OS_ENABLE_BLOCK_INSN_INTERRUPT
#endif

#if WASM_DISABLE_HW_BOUND_CHECK == 0
#if defined(BUILD_TARGET_X86_64) || defined(BUILD_TARGET_AMD_64) \
|| defined(BUILD_TARGET_AARCH64) || defined(BUILD_TARGET_RISCV64_LP64D) \
|| defined(BUILD_TARGET_RISCV64_LP64)

#include <setjmp.h>

#define OS_ENABLE_HW_BOUND_CHECK

typedef jmp_buf korp_jmpbuf;

#define os_setjmp setjmp
#define os_longjmp longjmp
#define os_alloca alloca

#define os_getpagesize getpagesize
Expand All @@ -99,6 +97,13 @@ os_sigreturn();
#endif /* end of BUILD_TARGET_X86_64/AMD_64/AARCH64/RISCV64 */
#endif /* end of WASM_DISABLE_HW_BOUND_CHECK */

#if defined(OS_ENABLE_BLOCK_INSN_INTERRUPT) || defined(OS_ENABLE_HW_BOUND_CHECK)
#include <setjmp.h>
typedef jmp_buf korp_jmpbuf;
#define os_setjmp setjmp
#define os_longjmp longjmp
#endif

typedef long int __syscall_slong_t;

#if __ANDROID_API__ < 19
Expand Down
6 changes: 6 additions & 0 deletions core/shared/platform/common/posix/posix_thread.c
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Expand Up @@ -346,6 +346,12 @@ os_thread_exit(void *retval)
return pthread_exit(retval);
}

int
os_thread_signal(korp_tid tid, int sig)
{
return pthread_kill(tid, sig);
}

#if defined(os_thread_local_attribute)
static os_thread_local_attribute uint8 *thread_stack_boundary = NULL;
#endif
Expand Down
17 changes: 11 additions & 6 deletions core/shared/platform/darwin/platform_internal.h
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Expand Up @@ -66,19 +66,17 @@ typedef sem_t korp_sem;

#define bh_socket_t int

#if WASM_DISABLE_BLOCK_INSN_INTERRUPT == 0
#define OS_ENABLE_BLOCK_INSN_INTERRUPT
#endif

#if WASM_DISABLE_HW_BOUND_CHECK == 0
#if defined(BUILD_TARGET_X86_64) || defined(BUILD_TARGET_AMD_64) \
|| defined(BUILD_TARGET_AARCH64) || defined(BUILD_TARGET_RISCV64_LP64D) \
|| defined(BUILD_TARGET_RISCV64_LP64)

#include <setjmp.h>

#define OS_ENABLE_HW_BOUND_CHECK

typedef jmp_buf korp_jmpbuf;

#define os_setjmp setjmp
#define os_longjmp longjmp
#define os_alloca alloca

#define os_getpagesize getpagesize
Expand All @@ -102,6 +100,13 @@ os_sigreturn();
#endif /* end of BUILD_TARGET_X86_64/AMD_64/AARCH64/RISCV64 */
#endif /* end of WASM_DISABLE_HW_BOUND_CHECK */

#if defined(OS_ENABLE_BLOCK_INSN_INTERRUPT) || defined(OS_ENABLE_HW_BOUND_CHECK)
#include <setjmp.h>
typedef jmp_buf korp_jmpbuf;
#define os_setjmp setjmp
#define os_longjmp longjmp
#endif

#ifdef __cplusplus
}
#endif
Expand Down
17 changes: 11 additions & 6 deletions core/shared/platform/freebsd/platform_internal.h
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Expand Up @@ -65,19 +65,17 @@ typedef sem_t korp_sem;

#define bh_socket_t int

#if WASM_DISABLE_BLOCK_INSN_INTERRUPT == 0
#define OS_ENABLE_BLOCK_INSN_INTERRUPT
#endif

#if WASM_DISABLE_HW_BOUND_CHECK == 0
#if defined(BUILD_TARGET_X86_64) || defined(BUILD_TARGET_AMD_64) \
|| defined(BUILD_TARGET_AARCH64) || defined(BUILD_TARGET_RISCV64_LP64D) \
|| defined(BUILD_TARGET_RISCV64_LP64)

#include <setjmp.h>

#define OS_ENABLE_HW_BOUND_CHECK

typedef jmp_buf korp_jmpbuf;

#define os_setjmp setjmp
#define os_longjmp longjmp
#define os_alloca alloca

#define os_getpagesize getpagesize
Expand All @@ -101,6 +99,13 @@ os_sigreturn();
#endif /* end of BUILD_TARGET_X86_64/AMD_64/AARCH64/RISCV64 */
#endif /* end of WASM_DISABLE_HW_BOUND_CHECK */

#if defined(OS_ENABLE_BLOCK_INSN_INTERRUPT) || defined(OS_ENABLE_HW_BOUND_CHECK)
#include <setjmp.h>
typedef jmp_buf korp_jmpbuf;
#define os_setjmp setjmp
#define os_longjmp longjmp
#endif

#ifdef __cplusplus
}
#endif
Expand Down
3 changes: 3 additions & 0 deletions core/shared/platform/include/platform_api_extension.h
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Expand Up @@ -92,6 +92,9 @@ int os_thread_detach(korp_tid);
void
os_thread_exit(void *retval);

int
os_thread_signal(korp_tid tid, int sig);

/**
* Initialize current thread environment if current thread
* is created by developer but not runtime
Expand Down
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