APPROVE COMMIT NOTE: This patch has been committed. # HG changeset patch # User Aidan Kehoe <kehoea(a)parhasard.net&gt; # Date 1514544619 0 # Fri Dec 29 10:50:19 2017 +0000 # Node ID 27b87c12a3aba5014f70dcb1b0ebb884c302f6fe # Parent 24f04bada33d560caea25b9f26471e885d17c1a9 Avoid begin_gc_forbidden(), end_gc_forbidden(), doprnt.c src/ChangeLog addition: 2017-12-29 Aidan Kehoe <kehoea(a)parhasard.net&gt; * doprnt.c (emacs_vsprintf_string): * doprnt.c (emacs_vasprintf): There is no need to forbid GC in these functions, the resizing buffer output stream cannot GC and continue, nor can write_fmt_string_lisp_va(). Jerry James just showed a backtrace where forbidding GC here actually caused XEmacs to crash, early in startup when specpdl_size was unitialised and begin_gc_forbidden() did an infinite loop. diff -r 24f04bada33d -r 27b87c12a3ab src/ChangeLog --- a/src/ChangeLog Fri Dec 29 10:25:26 2017 +0000 +++ b/src/ChangeLog Fri Dec 29 10:50:19 2017 +0000 ＠＠ -1,3 +1,15 ＠＠ +2017-12-29 Aidan Kehoe <kehoea(a)parhasard.net&gt; + + * doprnt.c (emacs_vsprintf_string): + * doprnt.c (emacs_vasprintf): + There is no need to forbid GC in these functions, the resizing + buffer output stream cannot GC and continue, nor can + write_fmt_string_lisp_va(). + Jerry James just showed a backtrace where forbidding GC here + actually caused XEmacs to crash, early in startup when + specpdl_size was unitialised and begin_gc_forbidden() did an + infinite loop. + 2017-12-29 Aidan Kehoe <kehoea(a)parhasard.net&gt; * print.c (output_string): diff -r 24f04bada33d -r 27b87c12a3ab src/doprnt.c --- a/src/doprnt.c Fri Dec 29 10:25:26 2017 +0000 +++ b/src/doprnt.c Fri Dec 29 10:50:19 2017 +0000 ＠＠ -3125,17 +3125,15 ＠＠ /* vsprintf()-like replacement. Arguments are interpreted as C objects--doubles, char *s, EMACS_INTs, etc. Returns a Lisp string. Data - from Lisp strings is OK because we explicitly inhibit GC. */ + from Lisp strings is OK because we cannot GC. */ Lisp_Object emacs_vsprintf_string (const CIbyte *format, va_list vargs) { Lisp_Object stream = make_resizing_buffer_output_stream (), obj; - int count = begin_gc_forbidden (); write_fmt_string_va (stream, format, vargs); obj = resizing_buffer_to_lisp_string (XLSTREAM (stream)); Lstream_delete (XLSTREAM (stream)); - end_gc_forbidden (count); return obj; } ＠＠ -3157,14 +3155,13 ＠＠ /* vasprintf() implementation. Arguments are interpreted as C objects--doubles, char *s, EMACS_INTs, etc. Data from Lisp strings is OK - because we explicitly inhibit GC. Returns length (not including the + because we cannot GC. Returns length (not including the terminating zero). Stores a pointer to be freed with free() into *RETVAL_OUT. */ Bytecount emacs_vasprintf (Ibyte **retval_out, const CIbyte *format, va_list vargs) { Lisp_Object stream = make_resizing_buffer_output_stream (); - int count = begin_gc_forbidden (); Bytecount len; write_fmt_string_va (stream, format, vargs); ＠＠ -3176,8 +3173,6 ＠＠ (*retval_out)[len] = '\0'; Lstream_delete (XLSTREAM (stream)); - end_gc_forbidden (count); - return len; } -- ‘As I sat looking up at the Guinness ad, I could never figure out / How your man stayed up on the surfboard after forty pints of stout’ (C. Moore)