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From: Merlyn Kline <merlyn.kline@jobsite.co.uk>
To: "modperl@perl.apache.org" <modperl@perl.apache.org>
Date: Tue, 6 Dec 2011 17:40:14 +0000
Subject: [mp2] [BUG] Segfault with Test::More - duping STDOUT?
Thread-Topic: [mp2] [BUG] Segfault with Test::More - duping STDOUT?
Thread-Index: Acy0Pfn/XoWwUASoSRyaPrpBoYFGKg==
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(I have read the bug reporting guides but unfortunately cannot follow all t=
he instructions because I am missing Apache::TestReportPerl and do not have=
 the necessary permissions to install it, nor to rebuild perl with debuggin=
g turned on. Hopefully I have provided enough information.)

I have discovered that simply "use"ing Test::More in a mod_perl script caus=
es my apache to segfault. I originally reported this to the author of Test:=
:More (see https://rt.cpan.org/Public/Bug/Display.html?id=3D69687) but now =
believe the problem to have wider scope. By progressively removing code fro=
m my original example I have reduced it to the trivial example that follows=
.

To REPRODUCE the problem, you need a Broken.pm module like this:

    package Broken;
    my $Testout;
    create(); sub create { # Insert "{#" at the start of this line and the =
segfault goes away
        open( $Testout, ">&STDOUT" ) or die "Can't dup STDOUT:  $!";
    }

and a script like this:

    #!/usr/bin/perl -w

    use Broken;

    print "Content-Type: text/html\r\n\r\nhello ";
    open TEST, "|/bin/cat";
    close TEST;
    print "world\n";

Holding down F5 to generate reloads soon causes a segfault (my server is co=
nfigured for five mod_perl processes).

Note that if the code to dup STDOUT is not in a sub then the fault seems to=
 go away.

Apache, mod_perl and perl version info appended.

I have found a similar(ish) report at http://http://stackoverflow.com/quest=
ions/4413411/ but no resolution. Note that removing from my example the cod=
e that opens the pipe to cat, solves the problem - this is the similarity h=
ere (and I realise that's likely a red herring).

Merlyn Kline


 Apache/2.2.15 (Unix) DAV/2 mod_ssl/2.2.15 OpenSSL/1.0.0-fips mod_perl/2.0.=
4 Perl/v5.10.1 configured -- resuming normal operations
=20
=20
=20
 Summary of my perl5 (revision 5 version 10 subversion 1) configuration:

  Platform:
    osname=3Dlinux, osvers=3D2.6.18-194.26.1.el5, archname=3Dx86_64-linux-t=
hread-multi
    uname=3D'linux x86-003.build.bos.redhat.com 2.6.18-194.26.1.el5 #1 smp =
fri oct 29 14:21:16 edt 2010 x86_64 x86_64 x86_64 gnulinux '
    config_args=3D'-des -Doptimize=3D-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOUR=
CE=3D2 -fexceptions -fstack-protector --param=3Dssp-buffer-size=3D4 -m64 -m=
tune=3Dgeneric -DDEBUGGING=3D-g -Dversion=3D5.10.1 -Dmyhostname=3Dlocalhost=
 -Dperladmin=3Droot@localhost -Dcc=3Dgcc -Dcf_by=3DRed Hat, Inc. -Dprefix=
=3D/usr -Dvendorprefix=3D/usr -Dsiteprefix=3D/usr/local -Dsitelib=3D/usr/lo=
cal/share/perl5 -Dsitearch=3D/usr/local/lib64/perl5 -Dprivlib=3D/usr/share/=
perl5 -Darchlib=3D/usr/lib64/perl5 -Dvendorlib=3D/usr/share/perl5/vendor_pe=
rl -Dvendorarch=3D/usr/lib64/perl5/vendor_perl -Dinc_version_list=3D5.10.0 =
-Darchname=3Dx86_64-linux-thread-multi -Dlibpth=3D/usr/local/lib64 /lib64 /=
usr/lib64 -Duseshrplib -Dusethreads -Duseithreads -Duselargefiles -Dd_dosui=
d -Dd_semctl_semun -Di_db -Ui_ndbm -Di_gdbm -Di_shadow -Di_syslog -Dman3ext=
=3D3pm -Duseperlio -Dinstallusrbinperl=3Dn -Ubincompat5005 -Uversiononly -D=
pager=3D/usr/bin/less -isr -Dd_gethostent_r_proto -Ud_endhostent_r_proto -U=
d_sethostent_r_proto -Ud_endprotoent_r_proto -Ud_setprotoent_r_proto -Ud_en=
dservent_r_proto -Ud_setservent_r_proto -Dscriptdir=3D/usr/bin'
    hint=3Drecommended, useposix=3Dtrue, d_sigaction=3Ddefine
    useithreads=3Ddefine, usemultiplicity=3Ddefine
    useperlio=3Ddefine, d_sfio=3Dundef, uselargefiles=3Ddefine, usesocks=3D=
undef
    use64bitint=3Ddefine, use64bitall=3Ddefine, uselongdouble=3Dundef
    usemymalloc=3Dn, bincompat5005=3Dundef
  Compiler:
    cc=3D'gcc', ccflags =3D'-D_REENTRANT -D_GNU_SOURCE -fno-strict-aliasing=
 -pipe -fstack-protector -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_O=
FFSET_BITS=3D64',
    optimize=3D'-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=3D2 -fexceptions -=
fstack-protector --param=3Dssp-buffer-size=3D4 -m64 -mtune=3Dgeneric',
    cppflags=3D'-D_REENTRANT -D_GNU_SOURCE -fno-strict-aliasing -pipe -fsta=
ck-protector -I/usr/local/include'
    ccversion=3D'', gccversion=3D'4.4.4 20100726 (Red Hat 4.4.4-13)', gccos=
andvers=3D''
    intsize=3D4, longsize=3D8, ptrsize=3D8, doublesize=3D8, byteorder=3D123=
45678
    d_longlong=3Ddefine, longlongsize=3D8, d_longdbl=3Ddefine, longdblsize=
=3D16
    ivtype=3D'long', ivsize=3D8, nvtype=3D'double', nvsize=3D8, Off_t=3D'of=
f_t', lseeksize=3D8
    alignbytes=3D8, prototype=3Ddefine
  Linker and Libraries:
    ld=3D'gcc', ldflags =3D' -fstack-protector'
    libpth=3D/usr/local/lib64 /lib64 /usr/lib64
    libs=3D-lresolv -lnsl -lgdbm -ldb -ldl -lm -lcrypt -lutil -lpthread -lc
    perllibs=3D-lresolv -lnsl -ldl -lm -lcrypt -lutil -lpthread -lc
    libc=3D, so=3Dso, useshrplib=3Dtrue, libperl=3Dlibperl.so
    gnulibc_version=3D'2.12'
  Dynamic Linking:
    dlsrc=3Ddl_dlopen.xs, dlext=3Dso, d_dlsymun=3Dundef, ccdlflags=3D'-Wl,-=
E -Wl,-rpath,/usr/lib64/perl5/CORE'
    cccdlflags=3D'-fPIC', lddlflags=3D'-shared -O2 -g -pipe -Wall -Wp,-D_FO=
RTIFY_SOURCE=3D2 -fexceptions -fstack-protector --param=3Dssp-buffer-size=
=3D4 -m64 -mtune=3Dgeneric'


Characteristics of this binary (from libperl):
  Compile-time options: MULTIPLICITY PERL_DONT_CREATE_GVSV
                        PERL_IMPLICIT_CONTEXT PERL_MALLOC_WRAP USE_64_BIT_A=
LL
                        USE_64_BIT_INT USE_ITHREADS USE_LARGE_FILES
                        USE_PERLIO USE_REENTRANT_API
  Built under linux
  Compiled at Apr 19 2011 15:27:31