src/share/vm/utilities/debug.cpp

rev 7424 : improve secondary signal handling

*** 306,333 ****
  }
  
  #ifndef PRODUCT
  #include <signal.h>
  
  void test_error_handler() {
!   uintx test_num = ErrorHandlerTest;
!   if (test_num == 0) return;
  
    // If asserts are disabled, use the corresponding guarantee instead.
!   size_t n = test_num;
!   NOT_DEBUG(if (n <= 2) n += 2);
  
    const char* const str = "hello";
    const size_t      num = (size_t)os::vm_page_size();
  
    const char* const eol = os::line_separator();
    const char* const msg = "this message should be truncated during formatting";
    char * const dataPtr = NULL;  // bad data pointer
    const void (*funcPtr)(void) = (const void(*)()) 0xF;  // bad function pointer
  
    // Keep this in sync with test/runtime/6888954/vmerrors.sh.
!   switch (n) {
      case  1: assert(str == NULL, "expected null");
      case  2: assert(num == 1023 && *str == 'X',
                      err_msg("num=" SIZE_FORMAT " str=\"%s\"", num, str));
      case  3: guarantee(str == NULL, "expected null");
      case  4: guarantee(num == 1023 && *str == 'X',
--- 306,412 ----
  }
  
  #ifndef PRODUCT
  #include <signal.h>
  
+ typedef void (*voidfun_t)();
+ // Crash with an authentic sigill at a known PC.
+ static void crash_with_sigill() {
+   bool rc = false;
+   const size_t size = os::vm_page_size();
+   static void* pc = NULL;
+ 
+   // prepare a "blob" with an illegal instruction sequence which 
+   // we then execute. Have to use os::reserve_memory to be able to
+   // make the memory executable.
+   if (!pc) {
+     void* p = os::reserve_memory(size, NULL, 0);
+     if (p) {
+       bool rc = os::commit_memory((char*)p, size, true);
+       if (rc) {
+         if (get_illegal_instruction_sequence((uint8_t*)p)) {
+           pc = p;
+         }
+       }
+     }
+   }
+  
+   // Fallback: if there is no implementation for get_illegal_instruction_sequence
+   // for the current platform, just do a raise(SIGILL). Raising a signal is 
+   // different from triggering it naturaly (e.g. raised synchronous signals can
+   // be blocked) but for the test purposes it is better than nothing.
+   if (pc == NULL) {
+     tty->print_cr("will raise a SIGILL");
+     tty->flush();
+     raise(SIGILL);
+     ShouldNotReachHere();
+   } 
+ 
+   tty->print_cr("will jump to PC " PTR_FORMAT 
+     ", which should cause a SIGILL.", pc);
+   tty->flush();
+ 
+   volatile voidfun_t g_voidfun = NULL;
+ 
+ #if defined(IA64) || defined(PPC64) 
+   // on ia64 and on ppc we have function descriptors. 
+   struct { void* p1; void* p2; } fundes = 
+     { pc, pc }; 
+   void* p = (void*)(&fundes);
+   g_voidfun = (voidfun_t) (p);
+ #else
+   g_voidfun = (voidfun_t)pc;
+ #endif
+ 
+   g_voidfun(); // boom.
+ 
+ } // end: crash_with_sigill
+ 
+ // crash with sigsegv at non-null address.
+ static void crash_with_segfault() {
+ 
+   char* const crash_addr = (char*) get_segfault_address();
+ 
+   tty->print_cr("will access address " PTR_FORMAT 
+     ", which should cause a SIGSEGV.", crash_addr);
+   tty->flush();
+ 
+   *crash_addr = 'X';
+ 
+ } // end: crash_with_segfault
+ 
+ // returns an address which is guaranteed to generate a SIGSEGV on read,
+ // for test purposes, which is not NULL and contains bits in every word
+ void* get_segfault_address() {
+   return (void*)
+ #ifdef _LP64
+     0xABC0000000000ABCULL;
+ #else
+     0x00000ABC;
+ #endif
+ }
+ 
  void test_error_handler() {
!   controlled_crash(ErrorHandlerTest);
! }
! 
! void controlled_crash(int how) {
!   if (how == 0) return;
  
    // If asserts are disabled, use the corresponding guarantee instead.
!   NOT_DEBUG(if (how <= 2) how += 2);
  
    const char* const str = "hello";
    const size_t      num = (size_t)os::vm_page_size();
  
    const char* const eol = os::line_separator();
    const char* const msg = "this message should be truncated during formatting";
    char * const dataPtr = NULL;  // bad data pointer
    const void (*funcPtr)(void) = (const void(*)()) 0xF;  // bad function pointer
  
    // Keep this in sync with test/runtime/6888954/vmerrors.sh.
!   switch (how) {
      case  1: assert(str == NULL, "expected null");
      case  2: assert(num == 1023 && *str == 'X',
                      err_msg("num=" SIZE_FORMAT " str=\"%s\"", num, str));
      case  3: guarantee(str == NULL, "expected null");
      case  4: guarantee(num == 1023 && *str == 'X',
*** 348,359 ****
      // so "break" out to the ShouldNotReachHere().
      case 12: *dataPtr = '\0'; break;
      // There's no guarantee the bad function pointer will crash us
      // so "break" out to the ShouldNotReachHere().
      case 13: (*funcPtr)(); break;
  
!     default: tty->print_cr("ERROR: %d: unexpected test_num value.", n);
    }
    ShouldNotReachHere();
  }
  #endif // !PRODUCT
  
--- 427,440 ----
      // so "break" out to the ShouldNotReachHere().
      case 12: *dataPtr = '\0'; break;
      // There's no guarantee the bad function pointer will crash us
      // so "break" out to the ShouldNotReachHere().
      case 13: (*funcPtr)(); break;
+     case 14: crash_with_segfault(); break;
+     case 15: crash_with_sigill(); break;
  
!     default: tty->print_cr("ERROR: %d: unexpected test_num value.", how);
    }
    ShouldNotReachHere();
  }
  #endif // !PRODUCT