Hi folks, I've run into a nasty segfault that I suspect is related to deeply recursive regular expressions. The odd thing is that just a deeply recursive regex won't trigger this bug by itself, it must be run in combination with another regex. Please see the test case below.
Cheers, -J -- test.pl -- #!/usr/bin/perl use strict; use warnings; use Regexp::Common qw( balanced ); open(my $file, shift) or die "can't open file: $!"; my $text = do {local $/; <$file> }; close($file) or die "can't close file: $!"; # possible bug in the regex engine? When combined, these two regexes # cause segfaults on Linux/x86 w/ perl 5.8.5, 5.8.6, & 5.8.7 & on # Linux/amd64 w/ perl 5.8.5. There seems to be some dependance on the # size of text file being parsed. It appears that the minimuze number # of lines is ~11K on my systems. # strip C++ style comments $text =~ s| // [^\n]* ||gx; # leave the \n # strip C block style comments # this regex has quoting issues inside a s/// or qr// my $block_remover = $RE{balanced}{-begin => "/*"}{-end => "*/"}; $text =~ s/$block_remover//sg; -- howto reproduce the segfault: -- find /usr/include/ -name "*.h" -exec cat {} \; > include.txt ./test.pl include.txt Segmentation fault -- gdb backtrace -- (gdb) run test.pl include.txt Starting program: /usr/bin/perl test.pl include.txt [Thread debugging using libthread_db enabled] [New Thread -1208052032 (LWP 14674)] Program received signal SIGSEGV, Segmentation fault. [Switching to Thread -1208052032 (LWP 14674)] 0x0812e38f in Perl_regexec_flags () (gdb) bt #0 0x0812e38f in Perl_regexec_flags () #1 0x0813390e in Perl_regexec_flags () #2 0x08133151 in Perl_regexec_flags () #3 0x08133151 in Perl_regexec_flags () #4 0x081327cb in Perl_regexec_flags () #5 0x08133fc8 in Perl_regexec_flags () #6 0x08133151 in Perl_regexec_flags () #7 0x08133151 in Perl_regexec_flags () #8 0x0812e91a in Perl_regexec_flags () #9 0x08132f73 in Perl_regexec_flags () #10 0x08133151 in Perl_regexec_flags () . . (and so on into the thousands) -- perlbug -d -- Flags: category= severity= --- Site configuration information for perl v5.8.7: Configured by Gentoo at Fri Jul 1 11:56:11 HST 2005. Summary of my perl5 (revision 5 version 8 subversion 7) configuration: Platform: osname=linux, osvers=2.6.11-gentoo-r9, archname=i686-linux-thread-multi uname='linux moanui 2.6.11-gentoo-r9 #1 thu jun 9 14:59:30 hst 2005 i686 intel(r) pentium(r) m processor 2.00ghz genuineintel gnulinux ' config_args='-des -Darchname=i686-linux-thread -Dcccdlflags=-fPIC -Dccdlflags=-rdynamic -Dcc=i686-pc-linux-gnu-gcc -Dprefix=/usr -Dvendorprefix=/usr -Dsiteprefix=/usr -Dlocincpth= -Doptimize=-O2 -mcpu=pentium3 -pipe -g -Duselargefiles -Dd_semctl_semun -Dscriptdir=/usr/bin -Dman1dir=/usr/share/man/man1 -Dman3dir=/usr/share/man/man3 -Dinstallman1dir=/var/tmp/portage/perl-5.8.7/image//usr/share/man/man1 -Dinstallman3dir=/var/tmp/portage/perl-5.8.7/image//usr/share/man/man3 -Dman1ext=1 -Dman3ext=3pm -Dinc_version_list=5.8.0 5.8.0/i686-linux-thread-multi 5.8.2 5.8.2/i686-linux-thread-multi 5.8.4 5.8.4/i686-linux-thread-multi 5.8.5 5.8.5/i686-linux-thread-multi 5.8.6 5.8.6/i686-linux-thread-multi -Dcf_by=Gentoo -Ud_csh -Dusethreads -Di_ndbm -Di_gdbm -Di_db' hint=recommended, useposix=true, d_sigaction=define usethreads=define use5005threads=undef useithreads=define usemultiplicity=define useperlio=define d_sfio=undef uselargefiles=define usesocks=undef use64bitint=undef use64bitall=undef uselongdouble=undef usemymalloc=n, bincompat5005=undef Compiler: cc='i686-pc-linux-gnu-gcc', ccflags ='-D_REENTRANT -D_GNU_SOURCE -DTHREADS_HAVE_PIDS -DDEBUGGING -fno-strict-aliasing -pipe -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64', optimize='-O2 -mcpu=pentium3 -pipe -g', cppflags='-D_REENTRANT -D_GNU_SOURCE -DTHREADS_HAVE_PIDS -DDEBUGGING -fno-strict-aliasing -pipe' ccversion='', gccversion='3.3.5-20050130 (Gentoo 3.3.5.20050130-r1, ssp-3.3.5.20050130-1, pie-8.7.7.1)', gccosandvers='' intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234 d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12 ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8 alignbytes=4, prototype=define Linker and Libraries: ld='i686-pc-linux-gnu-gcc', ldflags =' -L/usr/local/lib' libpth=/usr/local/lib /lib /usr/lib libs=-lpthread -lnsl -lndbm -lgdbm -ldb -ldl -lm -lcrypt -lutil -lc perllibs=-lpthread -lnsl -ldl -lm -lcrypt -lutil -lc libc=/lib/libc-2.3.4.so, so=so, useshrplib=false, libperl=libperl.a gnulibc_version='2.3.4' Dynamic Linking: dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-rdynamic' cccdlflags='-fPIC', lddlflags='-shared -L/usr/local/lib' Locally applied patches: --- @INC for perl v5.8.7: /etc/perl /usr/lib/perl5/site_perl/5.8.7/i686-linux-thread-multi /usr/lib/perl5/site_perl/5.8.7 /usr/lib/perl5/site_perl/5.8.5 /usr/lib/perl5/site_perl/5.8.6 /usr/lib/perl5/site_perl/5.8.6/i686-linux-thread-multi /usr/lib/perl5/site_perl /usr/lib/perl5/vendor_perl/5.8.7/i686-linux-thread-multi /usr/lib/perl5/vendor_perl/5.8.7 /usr/lib/perl5/vendor_perl/5.8.5 /usr/lib/perl5/vendor_perl /usr/lib/perl5/5.8.7/i686-linux-thread-multi /usr/lib/perl5/5.8.7 /usr/local/lib/site_perl /usr/lib/perl5/site_perl/5.8.5 /usr/lib/perl5/site_perl/5.8.6 /usr/lib/perl5/site_perl/5.8.6/i686-linux-thread-multi . --- Environment for perl v5.8.7: HOME=/home/moanui/jhoblitt LANG (unset) LANGUAGE (unset) LD_LIBRARY_PATH (unset) LOGDIR (unset) PATH=/bin:/usr/bin:/usr/local/bin:/opt/bin:/usr/i686-pc-linux-gnu/gcc-bin/3.3.5-20050130:/usr/i386-pc-linux-gnu/gcc-bin/3.3:/usr/qt/3/bin:/usr/kde/3.3/bin:/usr/games/bin:/home/moanui/jhoblitt/bin PERL_BADLANG (unset) SHELL=/bin/bash
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