"Philip Aston" <paston(a)bea.com&gt; writes: Unfortunately that period is both long and contained some quite substantial low-level rewrites by ben. I understand from the backtrace that can run XEmacs under a debugger. Then do the following 1. Make sure you have a full debugging and error checking XEmacs (as is default in the beta builds). 2. Run XEmacs under the debugger. 3. Just before executing the command that triggers the crash break into the debugger and set the global variable always_gc=1. [XEmacs will be come reaaaaaaaally slow at this point. 4. Do the problematic command. XEmacs will hopefull crash more predictably now & closer to the real point. Try to get C & lisp back traces. Jan

Jan Vroonhof writes: I run into gdb on cygwin issues here: (gdb) print always_gc $1 = 229 (gdb) set always_gc=1 (gdb) print always_gc $1 = 229 Hmmm. So I edited eval.c, set int always_gc = 1; and rebuilt. It certainly took longer to dump. :-) The C back trace looks like: (gdb) where 20 #0 0x00406a12 in mark_object (obj=301849280) at alloc.c:2281 #1 0x004037ea in mark_cons (obj=271307272) at alloc.c:850 #2 0x00406ada in mark_object (obj=271307272) at alloc.c:2426 #3 0x005b6f38 in mark_symbol (obj=301843180) at symbols.c:95 #4 0x00406ada in mark_object (obj=301843180) at alloc.c:2426 #5 0x0040b014 in mark_vector (obj=301839360) at alloc.c:1051 #6 0x00406ada in mark_object (obj=301839360) at alloc.c:2426 #7 0x0040b014 in mark_vector (obj=301849088) at alloc.c:1051 #8 0x00406ada in mark_object (obj=301849088) at alloc.c:2426 #9 0x004037ea in mark_cons (obj=270905088) at alloc.c:850 #10 0x00406ada in mark_object (obj=270905088) at alloc.c:2426 #11 0x005b6f38 in mark_symbol (obj=301843252) at symbols.c:95 #12 0x00406ada in mark_object (obj=301843252) at alloc.c:2426 #13 0x0040b014 in mark_vector (obj=301839232) at alloc.c:1051 #14 0x00406ada in mark_object (obj=301839232) at alloc.c:2426 #15 0x0040b014 in mark_vector (obj=301848896) at alloc.c:1051 #16 0x00406ada in mark_object (obj=301848896) at alloc.c:2426 #17 0x004037ea in mark_cons (obj=271307488) at alloc.c:850 #18 0x00406ada in mark_object (obj=271307488) at alloc.c:2426 #19 0x005b6f38 in mark_symbol (obj=301843324) at symbols.c:95 (gdb) where -70 #39901 0x0040b014 in mark_vector (obj=7509792) at alloc.c:1051 #39902 0x00406ada in mark_object (obj=8017952) at alloc.c:2426 #39903 0x005b6f44 in mark_symbol (obj=7342804) at symbols.c:96 #39904 0x00406ada in mark_object (obj=7342804) at alloc.c:2426 #39905 0x0040b014 in mark_vector (obj=6536320) at alloc.c:1051 #39906 0x00406ada in mark_object (obj=6536320) at alloc.c:2426 #39907 0x004037ea in mark_cons (obj=7069512) at alloc.c:850 #39908 0x00406ada in mark_object (obj=7217360) at alloc.c:2426 #39909 0x0040b014 in mark_vector (obj=8081024) at alloc.c:1051 #39910 0x00406ada in mark_object (obj=8013996) at alloc.c:2426 #39911 0x005b6f44 in mark_symbol (obj=6740764) at symbols.c:96 #39912 0x00406ada in mark_object (obj=6740764) at alloc.c:2426 #39913 0x0040b014 in mark_vector (obj=6234112) at alloc.c:1051 #39914 0x00406ada in mark_object (obj=6234112) at alloc.c:2426 #39915 0x0040824c in garbage_collect_1 () at alloc.c:3430 #39916 0x00454d5f in Ffuncall (nargs=2, args=0x22dcf8) at eval.c:3425 #39917 0x00418dcf in execute_optimized_program (program=0x127fed10 "Æ\013®\002\b\034\035\013«\032\013＠ÆHÇHJ«\021È\013＠ÆHÇHJ＠ÆHÉH!T\025\f\n=¬\037\f＠ÆHÉÊ\r!I\210\f＠ÆHÆËÌ\r\"I\210\rT\025\fA\211\024ªß\n¬\aÊ\rS!\026\016\t­\005Í\tÎ\"*\207", stack_depth=6, constants_data=0x10295690) at bytecode.c:744 #39918 0x0041868e in funcall_compiled_function (fun=271056196, nargs=2, args=0x22de74) at bytecode.c:516 #39919 0x0045512b in Ffuncall (nargs=3, args=0x22de70) at eval.c:3512 #39920 0x00418dcf in execute_optimized_program (program=0x128984d0 "\t­\017Â\t:­\002\t\b\"\210Ã\211\021\211\020\207", stack_depth=4, constants_data=0x10287b70) at bytecode.c:744 #39921 0x0041868e in funcall_compiled_function (fun=271056280, nargs=0, args=0x22dff4) at bytecode.c:516 #39922 0x0045512b in Ffuncall (nargs=1, args=0x22dff0) at eval.c:3512 #39923 0x00418dcf in execute_optimized_program (program=0x12898550 "ÃÄ\n!!\211\022­\034\nq\210Å \210\t«\bÆ «\004Ç \210È \210\b«\004É \210Ê \207\214\024\020", stack_depth=4, constants_data=0x10280110) at bytecode.c:744 #39924 0x0041868e in funcall_compiled_function (fun=271056420, nargs=1, args=0x22e180) at bytecode.c:516 #39925 0x0045512b in Ffuncall (nargs=2, args=0x22e17c) at eval.c:3512 #39926 0x004599ae in call1 (fn=271056420, arg0=305495460) at eval.c:4132 #39927 0x005be3e8 in mapatoms_1 (sym=305495460, arg=0x22e23c) at symbols.c:422 #39928 0x005b7afb in map_obarray (obarray=271031296, fn=0x5be3d0 <mapatoms_1>, arg=0x22e23c) at symbols.c:415 #39929 0x005bdf1e in Fmapatoms (function=271056420, obarray=271031296) at symbols.c:439 #39930 0x00454f84 in Ffuncall (nargs=3, args=0x22e2f0) at eval.c:3477 #39931 0x00418dcf in execute_optimized_program (program=0x12898510 "\212ÂÃ\b\"\210Ä\bÅ\"\210)\t«\bÆÇ\t\"\210È\021É \210Ê \207", stack_depth=3, constants_data=0x102800d0) at bytecode.c:744 #39932 0x0041868e in funcall_compiled_function (fun=271056448, nargs=0, args=0x22e464) at bytecode.c:516 #39933 0x0045512b in Ffuncall (nargs=1, args=0x22e460) at eval.c:3512 #39934 0x00418dcf in execute_optimized_program (program=0x22e4ec &quot;Æ\f!?Ç\211\211\211\211\211\211\031\036A\036D\030\036＠\036L\036E\e\016FÈ=«\026É\f!\211\026A¬\006ÊË\f\&quot;\210\f\026DÌ\016A!\024Æ\f!«\004\fªp\f®\aÍ\016M\016G\&quot;\032Î\n!«\aÊÏ\n\&quot;ªZÐ\n!®U\016G«\aÍ\016G!®\003\016NÑÇ\211\211\016O«\004Òª\t\016P«\004Òª\002Ó\036W\036X\036Y\036Z\036[\036NÔÕ\n\&quot;\210Ö\n!\016A®\006\f®\003\016M\211\036Q\016H(a)xn--\232\b\016q\016hb\026h)\n\&quot;\210-wlb76nk6a.xn--\006)\211\026lq\210\016f=\016\016d-zib80tir \232¬\aÙ\016DÑ\"\210\016I«\t\016\\"..., stack_depth=9, constants_data=0x101bcc10) at bytecode.c:744 #39935 0x0041c530 in Fbyte_code (instructions=270284452, constants=270257152, stack_depth=19) at bytecode.c:2392 #39936 0x004544dd in Feval (form=269139820) at eval.c:3279 #39937 0x0045a3a4 in internal_catch (tag=7009436, func=0x453d30 <Feval>, arg=269139820, threw=0x0) at eval.c:1317 #39938 0x004199cd in execute_rare_opcode (stack_ptr=0x22ee84, program_ptr=0x10287df6 "\207\"])\n", opcode=Bcatch) at bytecode.c:1250 #39939 0x00418bc6 in execute_optimized_program (program=0x10287df0 "À \210ÁÂ\215\207\"])\n", stack_depth=2, constants_data=0x101b9b50) at bytecode.c:654 #39940 0x0041868e in funcall_compiled_function (fun=269152372, nargs=3, args=0x22eff4) at bytecode.c:516 #39941 0x0045512b in Ffuncall (nargs=4, args=0x22eff0) at eval.c:3512 #39942 0x00418dcf in execute_optimized_program (program=0x1023c810 "Æ \210Ç \210\n«\004\nq\210È \210\r\026\017É\211\034\e\t;«\024Ê\t\r\"«\016Ë\r!\211\024«\a\f\025Ì\023ª\f\016\020®\002\b\030Í\r!\025)Î\r\016\021\013#*\207o", stack_depth=4, constants_data=0x101ada10) at bytecode.c:744 #39943 0x0041868e in funcall_compiled_function (fun=269152484, nargs=2, args=0x22f170) at bytecode.c:516 #39944 0x0045512b in Ffuncall (nargs=3, args=0x22f16c) at eval.c:3512 #39945 0x00455950 in Fapply (nargs=2, args=0x22f1dc) at eval.c:3753 #39946 0x00459920 in apply1 (fn=269152484, arg=269282616) at eval.c:4106 #39947 0x0041db54 in Fcall_interactively (function=269381900, record_flag=6232092, keys=6232068) at callint.c:465 #39948 0x004537ff in Fcommand_execute (cmd=269381900, record_flag=6232092, keys=6232068) at eval.c:2918 #39949 0x00454f9c in Ffuncall (nargs=3, args=0x22f4c0) at eval.c:3477 #39950 0x00418dcf in execute_optimized_program (program=0x10192810 "\r\035Æ\rÇa«\004Ȫ$\rÉk«\004ʪ\034\r¨«\aËÌ\r\"ª\022\r:«\r\r＠¨«\bËÌ\r＠\"ª\002Í!\024)\t«Kt«HÎ\f!\f\032\eÏ\fÐ\"\210\013­8\b¬\023Ñ Ò a«\aÓ pa«\006Ô \210ª\004Õ \210Ö×!­\eØÙË\013A«\004Úª\002Û\nÜ\013!#\"\210Ö\016\036!\210ÝÙ!*\207Ï\fÐ\"\207", stack_depth=7, constants_data=0x6c7510) at bytecode.c:744 #39951 0x0041868e in funcall_compiled_function (fun=7066080, nargs=1, args=0x22f650) at bytecode.c:516 #39952 0x0045512b in Ffuncall (nargs=2, args=0x22f64c) at eval.c:3512 #39953 0x0041f6d4 in Fcall_interactively (function=7174676, record_flag=6232068, keys=6232068) at callint.c:1008 #39954 0x004537ff in Fcommand_execute (cmd=7174676, record_flag=6232068, keys=6232068) at eval.c:2918 #39955 0x004ce359 in execute_command_event (command_builder=0x100e25c0, event=269758732) at event-stream.c:3902 #39956 0x004cf1f6 in Fdispatch_event (event=269758732) at event-stream.c:4234 #39957 0x0042888e in Fcommand_loop_1 () at cmdloop.c:583 #39958 0x00428c2e in command_loop_1 (dummy=6232068) at cmdloop.c:494 #39959 0x004515c1 in condition_case_1 (handlers=6232164, bfun=0x428bf0 <command_loop_1>, barg=6232068, hfun=0x428cc8 <cmd_error>, harg=6232068) at eval.c:1692 #39960 0x00428da7 in command_loop_2 (dummy=6232068) at cmdloop.c:256 #39961 0x0045a3a4 in internal_catch (tag=6312372, func=0x428d80 <command_loop_2>, arg=6232068, threw=0x0) at eval.c:1317 #39962 0x004280ce in initial_command_loop (load_me=6232068) at cmdloop.c:305 #39963 0x0044b4d5 in xemacs_21_5_b4_i686_pc_cygwin () at emacs.c:2358 #39964 0x0044ebc5 in main () at emacs.c:2787 #39965 0x61003fa2 in _bss_end__ () #39966 0x610041b9 in _bss_end__ () #39967 0x610041f8 in _bss_end__ () #39968 0x005dd3c3 in cygwin_crt0 () #39969 0x0040103d in mainCRTStartup () #39970 0x77e97d08 in _bss_end__ () How do you recommend getting a Lisp trace? - Phil

I took another look at this GC crash. Didn't get far at all, but I found a work around that I thought I'd log for the record. I can repeat the problem under the latest CVS source. Jan Vroonhof writes on 30 January: Due to a cygwin gdb issue I never managed to set always_gc=1 so, to mix metaphors, this recipe didn't bear fruit. I'm also not sure that always_gc would help. Looking at the stack trace, its huge (>30K frames). My simple thinking is that some temporary structure that VM creates when loading a folder causes the GC loop in such away that the stack exceeds the space available or some processor limit. I've discovered that I can work around the crash by setting gc-cons-threshold real high. Since I have 512M on my machine, I'm happy with this as a work around. BTW I have a _huge_ (44M) VM folder which is a dump from a public newsgroup, so if anyone with more brains and bandwidth than me is interested looking into this, get in touch. - Phil