src/os_cpu/bsd_x86/vm/os_bsd_x86.cpp

*** 716,726 ****
      //
      // 15 bytes seems to be a (very) safe value for max instruction size.
      bool pc_is_near_addr =
        (pointer_delta((void*) addr, (void*) pc, sizeof(char)) < 15);
      bool instr_spans_page_boundary =
!       (align_size_down((intptr_t) pc ^ (intptr_t) addr,
                         (intptr_t) page_size) > 0);
  
      if (pc == addr || (pc_is_near_addr && instr_spans_page_boundary)) {
        static volatile address last_addr =
          (address) os::non_memory_address_word();
--- 716,726 ----
      //
      // 15 bytes seems to be a (very) safe value for max instruction size.
      bool pc_is_near_addr =
        (pointer_delta((void*) addr, (void*) pc, sizeof(char)) < 15);
      bool instr_spans_page_boundary =
!       (align_down((intptr_t) pc ^ (intptr_t) addr,
                         (intptr_t) page_size) > 0);
  
      if (pc == addr || (pc_is_near_addr && instr_spans_page_boundary)) {
        static volatile address last_addr =
          (address) os::non_memory_address_word();
*** 728,738 ****
        // In conservative mode, don't unguard unless the address is in the VM
        if (addr != last_addr &&
            (UnguardOnExecutionViolation > 1 || os::address_is_in_vm(addr))) {
  
          // Set memory to RWX and retry
!         address page_start = align_ptr_down(addr, page_size);
          bool res = os::protect_memory((char*) page_start, page_size,
                                        os::MEM_PROT_RWX);
  
          log_debug(os)("Execution protection violation "
                        "at " INTPTR_FORMAT
--- 728,738 ----
        // In conservative mode, don't unguard unless the address is in the VM
        if (addr != last_addr &&
            (UnguardOnExecutionViolation > 1 || os::address_is_in_vm(addr))) {
  
          // Set memory to RWX and retry
!         address page_start = align_down(addr, page_size);
          bool res = os::protect_memory((char*) page_start, page_size,
                                        os::MEM_PROT_RWX);
  
          log_debug(os)("Execution protection violation "
                        "at " INTPTR_FORMAT