bin/140309: bad syntax cause yacc segfault
Philippe Pepiot
ksh at philpep.org
Thu Nov 5 12:50:03 UTC 2009
>Number: 140309
>Category: bin
>Synopsis: bad syntax cause yacc segfault
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Thu Nov 05 12:50:02 UTC 2009
>Closed-Date:
>Last-Modified:
>Originator: Philippe Pepiot
>Release: 9.0 CURRENT
>Organization:
>Environment:
FreeBSD shen.philpep.org 9.0-CURRENT FreeBSD 9.0-CURRENT #0: Wed Nov 4 19:56:02 CET 2009 root at shen.philpep.org:/usr/src/sys/i386/compile/SHEN i386
>Description:
Sometimes yacc segfault when declare typed rule and you don't set a value to $$ in the grammar rule.
The expected behavior of yacc in this case is to print an error message like
"the value of typed rule hasn't been set".
Here's backtrace :
#0 0x08053811 in end_rule () at /usr/src/usr.bin/yacc/reader.c:1260
1260 if (pitem[i+1] == 0 || pitem[i+1]->tag != plhs[nrules]->tag)
#0 0x08053811 in end_rule () at /usr/src/usr.bin/yacc/reader.c:1260
#1 0x0805486d in read_grammar () at /usr/src/usr.bin/yacc/reader.c:1632
#2 0x08055591 in reader () at /usr/src/usr.bin/yacc/reader.c:1926
#3 0x0804c4b4 in main (argc=2, argv=0xbfbfeb48) at /usr/src/usr.bin/yacc/main.c:434
>How-To-Repeat:
Just yacc this file :
%type <int> rule
%%
rule:
;
%%
$ yacc file.y
segmentation fault (core dumped) /usr/bin/yacc
>Fix:
>Release-Note:
>Audit-Trail:
>Unformatted:
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