[Rd] valgrind complains about regex.c (PR#8043)

[murdoch@stats.uwo.ca]

Prof Brian Ripley wrote:
> Did you compile R without optimization?  Such reads are often the result 
> of read-aheads produced by the optimizer in an attempt to keep 
> pipelines full (and are harmless).

There were both a read and a write.  I can see the read being harmless, 
but is the write harmless?  I suspect this may be the bug I fixed on 
July 16, since it had to do with character classes including ranges 
(like Charlie's "[a-pr-z]").

Charlie, have you tried a recent version of R-patched?

Duncan Murdoch

> 
> On an un-optimized build of R I am unable to reproduce this.  (I also was 
> unable to reproduce it on my optimized build of 2.1.1 using gcc 3.4.4, 
> although I did get a report on other read-aheads.)
> 
> On Mon, 1 Aug 2005 charlie at stat.umn.edu wrote:
> 
> 
>>I think I am using objects according to the man page.
>>This seems to be a valid regular expression.  But whether
>>I know what I'm doing or no, it still shouldn't be doing
>>what valgrind seems to be saying it's doing.  (IMHO)
> 
> 
> I think you need to take that up with compiler designers: it is common 
> practice.
> 
> 
>>---------- start of script ----------
>>Script started on Mon 01 Aug 2005 02:09:00 PM PDT
>>linux$ printenv VALGRIND_OPTS
>>--tool=3Dmemcheck
>>linux$ cat bar.R
>>
>>foo <- 1
>>bar <- 2:3
>>baz <- 4:6
>>qux <- matrix(7:10, 2)
>>
>>ls()
>>rm(list =3D objects(pattern =3D "^[a-pr-z]"))
>>ls()
>>
>>linux$ R --version
>>R 2.1.1 (2005-06-20).
>>Copyright (C) 2005 R Development Core Team
>>
>>R is free software and comes with ABSOLUTELY NO WARRANTY.
>>You are welcome to redistribute it under the terms of the GNU
>>General Public License.  For more information about these matters,
>>see http://www.gnu.org/copyleft/gpl.html.
>>linux$ gcc --version
>>=1B[0mgcc (GCC) 3.3.5 20050117 (prerelease) (SUSE Linux)
>>=1B[0mCopyright (C) 2003 Free Software Foundation, Inc.
>>=1B[0mThis is free software; see the source for copying conditions.  There =
>>is NO
>>=1B[0mwarranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PU=
>>RPOSE.
>>=1B[0m
>>linux$ cat /etc/SuSE-release=20
>>SuSE Linux 9.3 (i586)
>>VERSION =3D 9.3
>>linux$ R --vanilla --debugger=3Dvalgrind < bar.R >| bar.Rout
>>=3D=3D22324=3D=3D Memcheck, a memory error detector for x86-linux.
>>=3D=3D22324=3D=3D Copyright (C) 2002-2004, and GNU GPL'd, by Julian Seward =
>>et al.
>>=3D=3D22324=3D=3D Using valgrind-2.2.0, a program supervision framework for=
>>x86-linux.
>>=3D=3D22324=3D=3D Copyright (C) 2000-2004, and GNU GPL'd, by Julian Seward =
>>et al.
>>=3D=3D22324=3D=3D For more details, rerun with: -v
>>=3D=3D22324=3D=3D=20
>>=3D=3D22324=3D=3D Invalid read of size 4
>>=3D=3D22324=3D=3D    at 0x81255AD: parse_expression (regex.c:5045)
>>=3D=3D22324=3D=3D    by 0x8125868: parse_branch (regex.c:4475)
>>=3D=3D22324=3D=3D    by 0x8125913: parse_reg_exp (regex.c:4420)
>>=3D=3D22324=3D=3D    by 0x81261B3: Rf_regcomp (regex.c:4384)
>>=3D=3D22324=3D=3D  Address 0x1C1E23A8 is 0 bytes after a block of size 32 a=
>>lloc'd
>>=3D=3D22324=3D=3D    at 0x1B90650D: calloc (in /usr/lib/valgrind/vgpreload_=
>>memcheck.so)
>>=3D=3D22324=3D=3D    by 0x81247B5: parse_expression (regex.c:5406)
>>=3D=3D22324=3D=3D    by 0x8125868: parse_branch (regex.c:4475)
>>=3D=3D22324=3D=3D    by 0x8125913: parse_reg_exp (regex.c:4420)
>>=3D=3D22324=3D=3D=20
>>=3D=3D22324=3D=3D Invalid write of size 4
>>=3D=3D22324=3D=3D    at 0x81255B2: parse_expression (regex.c:5045)
>>=3D=3D22324=3D=3D    by 0x8125868: parse_branch (regex.c:4475)
>>=3D=3D22324=3D=3D    by 0x8125913: parse_reg_exp (regex.c:4420)
>>=3D=3D22324=3D=3D    by 0x81261B3: Rf_regcomp (regex.c:4384)
>>=3D=3D22324=3D=3D  Address 0x1C1E23A8 is 0 bytes after a block of size 32 a=
>>lloc'd
>>=3D=3D22324=3D=3D    at 0x1B90650D: calloc (in /usr/lib/valgrind/vgpreload_=
>>memcheck.so)
>>=3D=3D22324=3D=3D    by 0x81247B5: parse_expression (regex.c:5406)
>>=3D=3D22324=3D=3D    by 0x8125868: parse_branch (regex.c:4475)
>>=3D=3D22324=3D=3D    by 0x8125913: parse_reg_exp (regex.c:4420)
>>=3D=3D22324=3D=3D=20
>>=3D=3D22324=3D=3D ERROR SUMMARY: 2 errors from 2 contexts (suppressed: 39 f=
>>rom 2)
>>=3D=3D22324=3D=3D malloc/free: in use at exit: 12691882 bytes in 6426 block=
>>s.
>>=3D=3D22324=3D=3D malloc/free: 32534 allocs, 26108 frees, 33105500 bytes al=
>>located.
>>=3D=3D22324=3D=3D For a detailed leak analysis,  rerun with: --leak-check=
>>=3Dyes
>>=3D=3D22324=3D=3D For counts of detected errors, rerun with: -v
>>linux$ exit
>>
>>Script done on Mon 01 Aug 2005 02:10:42 PM PDT
>>---------- end of script ----------
>>--=20
>>Charles Geyer
>>Professor, School of Statistics
>>University of Minnesota
>>charlie at stat.umn.edu
>>
>>______________________________________________
>>R-devel at r-project.org mailing list
>>https://stat.ethz.ch/mailman/listinfo/r-devel
>>
>>
> 
>