Re: emacs 24 randomly hanging

[Chong Yidong <cyd@gnu.org>]

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Andreas Schwab <schwab@linux-m68k.org> writes:

> This is just doctoring the symptoms.  There is an invariant that *every*
> live frame is on Vframe_alist.  If that invariant is violated then this
> is the bug that must be fixed.

That's apparently indeed the problem.  I patched next_frame to abort
when the target frame isn't on Vframe_list (patch attached), and got the
following backtrace with Adam's recipe.

The problem is that x-create-frame calls x_set_menu_bar_lines, which
calls window-configuration-change-hook.  Because that hook is called in
the middle of x-create-frame, the (half-initialized) frame isn't on
Vframe_list yet.

Patch welcome; I don't have time to work on this further right now.



394	  kill (getpid (), SIGABRT);
(gdb) bt
#0  abort () at emacs.c:394
#1  0x00000000004226d7 in next_frame (frame=17277365, minibuf=12761602)
    at frame.c:944
#2  0x000000000042307e in Fnext_frame (frame=17277365, miniframe=12761602)
    at frame.c:1101
#3  0x000000000060637a in eval_sub (form=20840342) at eval.c:2347
#4  0x000000000060271b in Fsetq (args=20840470) at eval.c:455
...
#14 0x0000000000603f3c in Fcatch (args=20841622) at eval.c:1237
...
#21 0x0000000000607c8e in Ffuncall (nargs=1, args=0x7fffffff8d08)
    at eval.c:3057
#22 0x000000000060713a in call0 (fn=21122898) at eval.c:2750
#23 0x000000000048bb27 in run_funs (funs=14101542) at window.c:2872
#24 0x000000000048be39 in run_window_configuration_change_hook (f=0x107a1b0)
    at window.c:2933
#25 0x00000000005100ab in x_set_menu_bar_lines (f=0x107a1b0, value=0, 
    oldval=12761602) at xfns.c:1269
#26 0x000000000042701f in x_set_frame_parameters (f=0x107a1b0, alist=12761602)
    at frame.c:2929
#27 0x000000000042a0dd in x_default_parameter (f=0x107a1b0, alist=19012854, 
    prop=12942274, deflt=0, xprop=0x0, xclass=0x0, type=RES_TYPE_NUMBER)
    at frame.c:3938
#28 0x0000000000513ce8 in Fx_create_frame (parms=19012854) at xfns.c:3327
#29 0x00000000006079cb in Ffuncall (nargs=2, args=0x7fffffff91b0)
    at eval.c:2996
#30 0x0000000000653cc0 in exec_byte_code (bytestr=9928737, vector=9928773, 
    maxdepth=16, args_template=12761602, nargs=0, args=0x0) at bytecode.c:785
#31 0x00000000006083f2 in funcall_lambda (fun=9928669, nargs=1, 
    arg_vector=0x7fffffff9688) at eval.c:3227
#32 0x0000000000607bda in Ffuncall (nargs=2, args=0x7fffffff9680)
    at eval.c:3045
...
#56 0x0000000000607113 in apply1 (fn=21078306, arg=14151190) at eval.c:2739
#57 0x0000000000660a34 in read_process_output_call (fun_and_args=14151174)
    at process.c:5002
#58 0x00000000006047e1 in internal_condition_case_1 (
    bfun=0x660a06 <read_process_output_call>, arg=14151174, handlers=12761602, 
    hfun=0x660a36 <read_process_output_error_handler>) at eval.c:1547
#59 0x000000000066110b in read_process_output (proc=20995733, channel=3123)
    at process.c:5201
#60 0x00000000006603d3 in wait_reading_process_output (time_limit=30, 
    microsecs=0, read_kbd=-1, do_display=1, wait_for_cell=12761602, 
    wait_proc=0x0, just_wait_proc=0) at process.c:4844
#61 0x000000000041f8da in sit_for (timeout=120, reading=1, do_display=1)
    at dispnew.c:6063
#62 0x000000000056977c in read_char (commandflag=1, nmaps=2, 
    maps=0x7fffffffd5a0, prev_event=12761602, used_mouse_menu=0x7fffffffd6e8, 
    end_time=0x0) at keyboard.c:2690
#63 0x0000000000577285 in read_key_sequence (keybuf=0x7fffffffd8b0, 
    bufsize=30, prompt=12761602, dont_downcase_last=0, 
    can_return_switch_frame=1, fix_current_buffer=1) at keyboard.c:9302
#64 0x0000000000566f26 in command_loop_1 () at keyboard.c:1448
#65 0x000000000060467a in internal_condition_case (
    bfun=0x566b41 <command_loop_1>, handlers=12813794, 
    hfun=0x566406 <cmd_error>) at eval.c:1509
#66 0x0000000000566830 in command_loop_2 (ignore=12761602) at keyboard.c:1159
#67 0x0000000000604031 in internal_catch (tag=12809586, 
    func=0x56680a <command_loop_2>, arg=12761602) at eval.c:1266
#68 0x00000000005667e3 in command_loop () at keyboard.c:1138
#69 0x0000000000565f4a in recursive_edit_1 () at keyboard.c:758
#70 0x00000000005660ed in Frecursive_edit () at keyboard.c:822
#71 0x000000000056418e in main (argc=1, argv=0x7fffffffe198) at emacs.c:1715

Lisp Backtrace:
"next-frame" (0xffff7c20)
"setq" (0xffff7ec8)
"while" (0xffff80f8)
"let*" (0xffff8378)
"catch" (0xffff86c8)
"cl-block-wrapper" (0xffff8838)
"block" (0xffff89a8)
"loop" (0xffff8b18)
"walk-frames" (0xffff8d10)
"x-create-frame" (0xffff91b8)
"x-create-frame-with-faces" (0xffff9688)
"make-frame" (0xffff9b68)
"make-frame-on-display" (0xffffa078)
"server-create-window-system-frame" (0xffffa5e0)


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=== modified file 'src/frame.c'
*** src/frame.c	2012-01-19 07:21:25 +0000
--- src/frame.c	2012-02-22 10:43:37 +0000
***************
*** 935,940 ****
--- 935,949 ----
       forever.  Forestall that.  */
    CHECK_LIVE_FRAME (frame);
  
+   passed = 0;
+   for (tail = Vframe_list; CONSP (tail); tail = XCDR (tail))
+     if (EQ (frame, XCAR (tail)))
+       passed++;
+ 
+   if (passed == 0)
+     abort ();
+ 
+   passed = 0;
    while (1)
      for (tail = Vframe_list; CONSP (tail); tail = XCDR (tail))
        {