[jdk20] RFR: 8298400: Virtual thread instability when stack overflows

[Fei Yang]

On Thu, 12 Jan 2023 12:12:42 GMT, Ron Pressler <rpressler at openjdk.org> wrote:

> The stack overflow is detected in the native code and a pending exception is set, but it is not thrown.
> 
> Additionally, the stack overflow detection is changed use StackOverflow::shadow_zone_safe_limit rather than StackOverflow::stack_overflow_limit.

Also prepared a small change for RISC-V which has passed sanity test.
Could you please incorporate it while you are on it? Thanks.


diff --git a/src/hotspot/cpu/riscv/sharedRuntime_riscv.cpp b/src/hotspot/cpu/riscv/sharedRuntime_riscv.cpp
index d2992b9012b..56899a3a234 100644
--- a/src/hotspot/cpu/riscv/sharedRuntime_riscv.cpp
+++ b/src/hotspot/cpu/riscv/sharedRuntime_riscv.cpp
@@ -1095,6 +1095,15 @@ static void gen_continuation_yield(MacroAssembler* masm,

   __ bind(pinned); // pinned -- return to caller

+  // handle pending exception thrown by freeze
+  __ ld(t0, Address(xthread, in_bytes(Thread::pending_exception_offset())));
+  Label ok;
+  __ beqz(t0, ok);
+  __ leave();
+  __ la(t0, RuntimeAddress(StubRoutines::forward_exception_entry()));
+  __ jr(t0);
+  __ bind(ok);
+
   __ leave();
   __ ret();

-------------

PR: https://git.openjdk.org/jdk20/pull/101