src/hotspot/share/utilities/debug.cpp

rev 55480 : [mq]: 8227275-native-oom-hanging-assertions

*** 732,741 ****
--- 732,745 ----
        g_assert_poison = page;
      }
    }
  }
  
+ void disarm_assert_poison() {
+   g_assert_poison = &g_dummy;
+ }
+ 
  static void store_context(const void* context) {
    memcpy(&g_stored_assertion_context, context, sizeof(ucontext_t));
  #if defined(__linux) && defined(PPC64)
    // on Linux ppc64, ucontext_t contains pointers into itself which have to be patched up
    //  after copying the context (see comment in sys/ucontext.h):
*** 744,754 ****
  }
  
  bool handle_assert_poison_fault(const void* ucVoid, const void* faulting_address) {
    if (faulting_address == g_assert_poison) {
      // Disarm poison page.
!     os::protect_memory((char*)g_assert_poison, os::vm_page_size(), os::MEM_PROT_RWX);
      // Store Context away.
      if (ucVoid) {
        const intx my_tid = os::current_thread_id();
        if (Atomic::cmpxchg(my_tid, &g_asserting_thread, (intx)0) == 0) {
          store_context(ucVoid);
--- 748,765 ----
  }
  
  bool handle_assert_poison_fault(const void* ucVoid, const void* faulting_address) {
    if (faulting_address == g_assert_poison) {
      // Disarm poison page.
!     if (os::protect_memory((char*)g_assert_poison, os::vm_page_size(), os::MEM_PROT_RWX) == false) {
! #ifdef ASSERT
!       fprintf(stderr, "Assertion poison page cannot be unprotected - mprotect failed with %d (%s)",
!               errno, os::strerror(errno));
!       fflush(stderr);
! #endif
!       return false; // unprotecting memory may fail in OOM situations, as surprising as this sounds.
!     }
      // Store Context away.
      if (ucVoid) {
        const intx my_tid = os::current_thread_id();
        if (Atomic::cmpxchg(my_tid, &g_asserting_thread, (intx)0) == 0) {
          store_context(ucVoid);