bug#12832: 24.3.50; Emacs lockup when idle

[Andy Moreton]

Windows Emacs (built from r110828) was idle for a few minutes while I made a
coffee. On returning, emacs was completely unresponsive and redisplay
was not drawing anything.

Windows XP SP3
MinGW gcc 4.7.2

Backtrace from "thread apply all bt full":

Thread 6 (Thread 8744.0x2080):
#0  0x7c90120f in ntdll!DbgUiConnectToDbg () from C:\WINDOWS\system32\ntdll.dll
No symbol table info available.
#1  0x7c952119 in ntdll!KiIntSystemCall () from C:\WINDOWS\system32\ntdll.dll
No symbol table info available.
#2  0x00000005 in ?? ()
No symbol table info available.
#3  0x00000004 in ?? ()
No symbol table info available.
#4  0x00000001 in ?? ()
No symbol table info available.
#5  0x5ad3ffd0 in ?? ()
No symbol table info available.
#6  0x00000000 in ?? ()
No symbol table info available.

Lisp Backtrace:
"redisplay_internal (C function)" (0x167235c)

Thread 5 (Thread 8744.0x5ec):
#0  0x7c90e514 in ntdll!LdrAccessResource () from C:\WINDOWS\system32\ntdll.dll
No symbol table info available.
#1  0x7c90d9da in ntdll!ZwReadFile () from C:\WINDOWS\system32\ntdll.dll
No symbol table info available.
#2  0x7c801879 in ReadFile () from C:\WINDOWS\system32\kernel32.dll
No symbol table info available.
#3  0x00000610 in ?? ()
No symbol table info available.
#4  0x00000000 in ?? ()
No symbol table info available.

Lisp Backtrace:
"redisplay_internal (C function)" (0x167235c)

Thread 4 (Thread 8744.0x241c):
#0  0x7c90e514 in ntdll!LdrAccessResource () from C:\WINDOWS\system32\ntdll.dll
No symbol table info available.
#1  0x7c90df5a in ntdll!ZwWaitForSingleObject () from 
C:\WINDOWS\system32\ntdll.dll
No symbol table info available.
#2  0x7c8025db in WaitForSingleObjectEx () from C:\WINDOWS\system32\kernel32.dll
No symbol table info available.
#3  0x000005d0 in ?? ()
No symbol table info available.
#4  0x00000000 in ?? ()
No symbol table info available.

Lisp Backtrace:
"redisplay_internal (C function)" (0x167235c)

Thread 3 (Thread 8744.0x21d4):
#0  0x7c90e514 in ntdll!LdrAccessResource () from C:\WINDOWS\system32\ntdll.dll
No symbol table info available.
#1  0x7e4191be in USER32!GetProcessWindowStation () from 
C:\WINDOWS\system32\user32.dll
No symbol table info available.
#2  0x7e4191f1 in USER32!GetMessageW () from C:\WINDOWS\system32\user32.dll
No symbol table info available.
#3  0x0114875d in w32_msg_pump (msg_buf=0x5b5aff54) at w32fns.c:2386
        msg = {
          hwnd = 0x3f9500bc,
          message = 0xf,
          wParam = 0x0,
          lParam = 0x0,
          time = 0x6cc97f02,
          pt = {
            x = 0xdd,
            y = 0x2f
          }
        }
        result = 0x0
        focus_window = 0x403
#4  0x0114899b in w32_msg_worker@4 (arg=0x0) at w32fns.c:2612
        msg = {
          hwnd = 0x86af0b20,
          message = 0x80502fc0,
          wParam = 0x0,
          lParam = 0x0,
          time = 0x0,
          pt = {
            x = 0x80502fc8,
            y = 0x8dedcca0
          }
        }
        dummy_buf = {
          next = 0x0,
          w32msg = {
            msg = {
              hwnd = 0x0,
              message = 0x0,
              wParam = 0x0,
              lParam = 0x0,
              time = 0x0,
              pt = {
                x = 0x0,
                y = 0x0
              }
            },
            dwModifiers = 0x0,
            rect = {
              left = 0x0,
              top = 0x0,
              right = 0x0,
              bottom = 0x0
            }
          },
          result = 0x0,
          completed = 0x0
        }
#5  0x7c80b729 in KERNEL32!GetModuleFileNameA () from 
C:\WINDOWS\system32\kernel32.dll
No symbol table info available.
#6  0x00000000 in ?? ()
No symbol table info available.

Lisp Backtrace:
"redisplay_internal (C function)" (0x167235c)

Thread 2 (Thread 8744.0x1840):
#0  0x7c90e514 in ntdll!LdrAccessResource () from C:\WINDOWS\system32\ntdll.dll
No symbol table info available.
#1  0x7c90d21a in ntdll!ZwDelayExecution () from C:\WINDOWS\system32\ntdll.dll
No symbol table info available.
#2  0x7c8023f1 in SleepEx () from C:\WINDOWS\system32\kernel32.dll
No symbol table info available.
#3  0x00000000 in ?? ()
No symbol table info available.

Lisp Backtrace:
"redisplay_internal (C function)" (0x167235c)

Thread 1 (Thread 8744.0xf50):
#0  0x7c90e514 in ntdll!LdrAccessResource () from C:\WINDOWS\system32\ntdll.dll
No symbol table info available.
#1  0x7c90d2aa in ntdll!ZwDuplicateObject () from C:\WINDOWS\system32\ntdll.dll
No symbol table info available.
#2  0x7c80df03 in KERNEL32!DuplicateHandle () from 
C:\WINDOWS\system32\kernel32.dll
No symbol table info available.
#3  0xffffffff in ?? ()
No symbol table info available.
#4  0xfffffffe in ?? ()
No symbol table info available.
#5  0xffffffff in ?? ()
No symbol table info available.
#6  0x0162acb8 in real_itimer ()
No symbol table info available.
#7  0x00000000 in ?? ()
No symbol table info available.

Lisp Backtrace:
"redisplay_internal (C function)" (0x167235c)