Make system_id accesses atomic.

JuliaLang · Aug 1, 2023 · b4acf99 · b4acf99
1 parent 6a356f5
commit b4acf99
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Showing 4 changed files with 14 additions and 13 deletions.
diff --git a/src/julia_threads.h b/src/julia_threads.h
@@ -259,7 +259,7 @@ typedef struct _jl_tls_states_t {
 #else
     void *signal_stack;
 #endif
-    jl_thread_t system_id;
+    _Atomic(jl_thread_t) system_id;
     arraylist_t finalizers;
     struct _jl_gc_pagemeta_t *page_metadata_allocd;
     struct _jl_gc_pagemeta_t *page_metadata_lazily_freed;

diff --git a/src/signals-mach.c b/src/signals-mach.c
@@ -55,7 +55,7 @@ void jl_mach_gc_end(void)
         int8_t gc_state = (int8_t)(item >> 8);
         jl_ptls_t ptls2 = jl_atomic_load_relaxed(&jl_all_tls_states)[tid];
         jl_atomic_store_release(&ptls2->gc_state, gc_state);
-        thread_resume(pthread_mach_thread_np(ptls2->system_id));
+        thread_resume(pthread_mach_thread_np(jl_atomic_load_relaxed(&ptls2->system_id)));
     }
     suspended_threads.len = 0;
 }
@@ -279,7 +279,7 @@ kern_return_t catch_mach_exception_raise(
     int nthreads = jl_atomic_load_acquire(&jl_n_threads);
     for (tid = 0; tid < nthreads; tid++) {
         jl_ptls_t _ptls2 = jl_atomic_load_relaxed(&jl_all_tls_states)[tid];
-        if (pthread_mach_thread_np(_ptls2->system_id) == thread) {
+        if (pthread_mach_thread_np(jl_atomic_load_relaxed(&_ptls2->system_id)) == thread) {
             ptls2 = _ptls2;
             break;
         }
@@ -389,7 +389,7 @@ static int jl_thread_suspend_and_get_state2(int tid, host_thread_state_t *ctx)
     if (ct2 == NULL) // this thread is already dead
         return 0;
 
-    mach_port_t thread = pthread_mach_thread_np(ptls2->system_id);
+    mach_port_t thread = pthread_mach_thread_np(jl_atomic_load_relaxed(&ptls2->system_id));
 
     kern_return_t ret = thread_suspend(thread);
     HANDLE_MACH_ERROR("thread_suspend", ret);
@@ -417,7 +417,7 @@ static void jl_thread_suspend_and_get_state(int tid, int timeout, unw_context_t
 static void jl_thread_resume(int tid, int sig)
 {
     jl_ptls_t ptls2 = jl_atomic_load_relaxed(&jl_all_tls_states)[tid];
-    mach_port_t thread = pthread_mach_thread_np(ptls2->system_id);
+    mach_port_t thread = pthread_mach_thread_np(jl_atomic_load_relaxed(&ptls2->system_id));
     kern_return_t ret = thread_resume(thread);
     HANDLE_MACH_ERROR("thread_resume", ret);
 }
@@ -427,7 +427,7 @@ static void jl_thread_resume(int tid, int sig)
 static void jl_try_deliver_sigint(void)
 {
     jl_ptls_t ptls2 = jl_atomic_load_relaxed(&jl_all_tls_states)[0];
-    mach_port_t thread = pthread_mach_thread_np(ptls2->system_id);
+    mach_port_t thread = pthread_mach_thread_np(jl_atomic_load_relaxed(&ptls2->system_id));
 
     kern_return_t ret = thread_suspend(thread);
     HANDLE_MACH_ERROR("thread_suspend", ret);
@@ -464,7 +464,7 @@ CFI_NORETURN
 static void jl_exit_thread0(int signo, jl_bt_element_t *bt_data, size_t bt_size)
 {
     jl_ptls_t ptls2 = jl_atomic_load_relaxed(&jl_all_tls_states)[0];
-    mach_port_t thread = pthread_mach_thread_np(ptls2->system_id);
+    mach_port_t thread = pthread_mach_thread_np(jl_atomic_load_relaxed(&ptls2->system_id));
 
     host_thread_state_t state;
     if (!jl_thread_suspend_and_get_state2(0, &state)) {

diff --git a/src/signals-unix.c b/src/signals-unix.c
@@ -404,7 +404,7 @@ static void jl_thread_suspend_and_get_state(int tid, int timeout, unw_context_t
         return;
     }
     jl_atomic_store_release(&ptls2->signal_request, 1);
-    pthread_kill(ptls2->system_id, SIGUSR2);
+    pthread_kill(jl_atomic_load_relaxed(&ptls2->system_id), SIGUSR2);
     // wait for thread to acknowledge
     int err = pthread_cond_timedwait(&signal_caught_cond, &in_signal_lock, &ts);
     if (err == ETIMEDOUT) {
@@ -455,7 +455,7 @@ static void jl_try_deliver_sigint(void)
     jl_wake_libuv();
     jl_atomic_store_release(&ptls2->signal_request, 2);
     // This also makes sure `sleep` is aborted.
-    pthread_kill(ptls2->system_id, SIGUSR2);
+    pthread_kill(jl_atomic_load_relaxed(&ptls2->system_id), SIGUSR2);
 }
 
 // Write only by signal handling thread, read only by main thread
@@ -640,7 +640,7 @@ void jl_install_thread_signal_handler(jl_ptls_t ptls)
     }
 
 #ifdef HAVE_MACH
-    attach_exception_port(pthread_mach_thread_np(ptls->system_id), 0);
+    attach_exception_port(pthread_mach_thread_np(jl_atomic_load_relaxed(&ptls->system_id)), 0);
 #endif
 }
 

diff --git a/src/threading.c b/src/threading.c
@@ -347,7 +347,7 @@ jl_ptls_t jl_init_threadtls(int16_t tid)
 #ifndef _OS_WINDOWS_
     pthread_setspecific(jl_task_exit_key, (void*)ptls);
 #endif
-    ptls->system_id = (jl_thread_t)(uintptr_t)uv_thread_self();
+    jl_atomic_store_relaxed(&ptls->system_id, (jl_thread_t)(uintptr_t)uv_thread_self());
     ptls->rngseed = jl_rand();
     if (tid == 0)
         ptls->disable_gc = 1;
@@ -473,8 +473,9 @@ static void jl_delete_thread(void *value) JL_NOTSAFEPOINT_ENTER
         jl_safe_printf("fatal: thread exited from wrong Task.\n");
         abort();
     }
-    jl_atomic_store_relaxed(&ptls->current_task, NULL); // dead
-    ptls->system_id = 0;
+    // mark this thread as dead
+    jl_atomic_store_relaxed(&ptls->current_task, NULL);
+    jl_atomic_store_relaxed(&ptls->system_id, 0);
     // finally, release all of the locks we had grabbed
 #ifdef _OS_WINDOWS_
     jl_unlock_profile_wr();