[crash] GC-bug in Fcall-interactive

try this with "Benadir": - xemacs -vanilla - C-h k - click on the Options/Fonts menu entry (generating the list of fonts) and wait for the submenu to pop up - click somewhere in the window outside the menus - watch XEmacs dump core. You can replace the options/fonts menu with any operation that generates enough garbage to trigger a GC (e.g. selecting Options/Customize/Emacs). The backtrace is pretty uninformative -- xemacs tries to print "wrong type argument: stringp" but the object is corrupted and a segfault in print_internal occurs. Setting a breakpoint at Fthrow reveals that the string 'prompt' in Fnext_event has been collected (see backtrace below). This string had been created by callint_prompt (callint.c:202) but not gcpro'd sufficiently. One possible fix would be to replace the calls to callint_prompt (through the macro PROMPT()) by a local variable in Fcall_interactively which can be gcpro'd. I can cook up a patch for this if all of you agree that this is The Right Thing. Any comments? ---------------------------------------------------------------------- (gdb) break Fthrow Breakpoint 1 at 0x80b5393: file /local/srcdisk/gunnar/src/XEmacs/xemacs-20/src/eval.c, line 1479. (gdb) c Continuing. Breakpoint 1, Fthrow (tag=137658496, val=137680396) at /local/srcdisk/gunnar/src/XEmacs/xemacs-20/src/eval.c:1479 1479 throw_or_bomb_out (tag, val, 0, Qnil, Qnil); /* Doesn't return */ (gdb) where #0 Fthrow (tag=137658496, val=137680396) at /local/srcdisk/gunnar/src/XEmacs/xemacs-20/src/eval.c:1479 #1 0x80b5eb2 in signal_1 (sig=137490828, data=137680420) at /local/srcdisk/gunnar/src/XEmacs/xemacs-20/src/eval.c:1956 #2 0x80b612d in Fsignal (error_symbol=137490828, data=137680420) at /local/srcdisk/gunnar/src/XEmacs/xemacs-20/src/eval.c:2044 #3 0x80b6191 in signal_error (sig=137490828, data=137680420) at /local/srcdisk/gunnar/src/XEmacs/xemacs-20/src/eval.c:2053 #4 0x8099161 in dead_wrong_type_argument (predicate=137566696, value=137947804) at /local/srcdisk/gunnar/src/XEmacs/xemacs-20/src/data.c:115 #5 0x80e55ff in Fnext_event (event=139133164, prompt=137947804) at /local/srcdisk/gunnar/src/XEmacs/xemacs-20/src/event-stream.c:2156 #6 0x80e9d24 in Fread_key_sequence (prompt=137947804, continue_echo=137490660, dont_downcase_last=137490660) at /local/srcdisk/gunnar/src/XEmacs/xemacs-20/src/event-stream.c:4761 #7 0x808e91f in Fcall_interactively (function=138183092, record_flag=137490660, keys=137490660) at /local/srcdisk/gunnar/src/XEmacs/xemacs-20/src/callint.c:718 ---------------------------------------------------------------------- -- Gunnar Evermann Natural Language Systems Group, University of Hamburg EMail: Gunnar.Evermann(a)nats.informatik.uni-hamburg.de