re-enable profiling stack switch test

Removes the warning on platforms where CFI_NORETURN appears likely to be
sufficient alone for this to work (from observation in gdb/lldb) and
re-enables the test on all platforms so we can see if more work here is
needed at all (e.g. similar annotations in jl_setjmp/jl_longjmp).

Refs #43124

src/task.c

@@ -223,14 +223,17 @@ JL_NO_ASAN static void NOINLINE JL_NORETURN restore_stack(jl_ucontext_t *t, jl_p
     }
     void *_y = t->stkbuf;
     assert(_x != NULL && _y != NULL);
+#if defined(_OS_WINDOWS_) // this platform does not implement CFI_NORETURN correctly or at all in libunwind (or equivalent) which requires a workaround
 #if defined(_CPU_X86_) || defined(_CPU_X86_64_)
     void *volatile *return_address = (void *volatile *)__builtin_frame_address(0) + 1;
     assert(*return_address == __builtin_return_address(0));
     *return_address = NULL;
 #else
 #pragma message("warning: CFI_NORETURN not implemented for this platform, so profiling of copy_stacks may segfault in this build")
 #endif
+#else
 CFI_NORETURN
+#endif
     memcpy_stack_a16((uint64_t*)_x, (uint64_t*)_y, nb); // destroys all but the current stackframe
 
 #if defined(_OS_WINDOWS_)
@@ -287,14 +290,15 @@ JL_NO_ASAN static void NOINLINE restore_stack3(jl_ucontext_t *t, jl_ptls_t ptls,
         restore_stack3(t, ptls, p); // pass p to ensure the compiler can't tailcall this or avoid the alloca
     }
 #endif
+#if defined(_OS_WINDOWS_) // this platform does not implement CFI_NORETURN correctly or at all in libunwind (or equivalent) which requires a workaround
 #if defined(_CPU_X86_) || defined(_CPU_X86_64_)
     void *volatile *return_address = (void *volatile *)__builtin_frame_address(0) + 1;
     assert(*return_address == __builtin_return_address(0));
     *return_address = NULL;
-#else
-#pragma message("warning: CFI_NORETURN not implemented for this platform, so profiling of copy_stacks may segfault in this build")
 #endif
+#else
 CFI_NORETURN
+#endif
     tsan_switch_to_ctx(t);
     jl_start_fiber_set(t); // (doesn't return)
     abort();

test/threads.jl

@@ -288,18 +288,16 @@ close(proc.in)
         proc = run(cmd; wait = false)
         done = Threads.Atomic{Bool}(false)
         timeout = false
-        timer = Timer(100) do _
+        timer = Timer(200) do _
             timeout = true
-            for sig in [Base.SIGTERM, Base.SIGHUP, Base.SIGKILL]
-                for _ in 1:1000
+            for sig in (Base.SIGQUIT, Base.SIGKILL)
+                for _ in 1:3
                     kill(proc, sig)
+                    sleep(1)
                     if done[]
-                        if sig != Base.SIGTERM
-                            @warn "Terminating `$script` required signal $sig"
-                        end
+                        @warn "Terminating `$script` required signal $sig"
                         return
                     end
-                    sleep(0.001)
                 end
             end
         end
@@ -309,16 +307,11 @@ close(proc.in)
             done[] = true
             close(timer)
         end
-        if ( !success(proc) ) || ( timeout )
+        if !success(proc) || timeout
             @error "A \"spawn and wait lots of tasks\" test failed" n proc.exitcode proc.termsignal success(proc) timeout
         end
-        if Sys.iswindows() || Sys.isapple()
-            # Known failure: https://github.com/JuliaLang/julia/issues/43124
-            @test_skip success(proc)
-        else
-            @test success(proc)
-            @test !timeout
-        end
+        @test success(proc)
+        @test !timeout
     end
 end