Closed
Description
Description
Setting a breakpoint on an AUTOLOAD under certain circumstances causes a segmentation fault. It's unclear what is the minimum amount of code required to reproduce the issue, but at the very least it seems to require:
- Two or more stack frames
- An eval block
- use vars for $AUTOLOAD
- Assigning $AUTOLOAD to another variable
I was able to reproduce this on both 5.32 and 5.34.
Steps to Reproduce
I was able to get this code to segfault, but it didn't happen every time.
package Test;
sub AUTOLOAD {
use vars '$AUTOLOAD';
my $sub = $AUTOLOAD;
return 1;
}
package main;
sub test
{
Test::test();
}
sub test_test
{
eval { test() };
}
test_test();Start the perl debugger with this code, then set a breakpoint on Test::AUTOLOAD, and continue. You should get this error message:
Signal SEGV at autoload_segv.pl line 14.
main::test() called at autoload_segv.pl line 19
eval {...} called at autoload_segv.pl line 19
main::test_test() called at autoload_segv.pl line 22
Aborted (core dumped)
Expected behavior
It should break on the first line of the AUTOLOAD subroutine and not segfault.
Perl configuration
Summary of my perl5 (revision 5 version 34 subversion 0) configuration:
Platform:
osname=linux
osvers=4.18.0-305.el8.x86_64
archname=x86_64-linux
uname='linux vm-mreisner.epic.com 4.18.0-305.el8.x86_64 #1 smp thu may 27 16:46:28 utc 2021 x86_64 x86_64 x86_64 gnulinux '
config_args='-de -Dprefix=/home/mreisner/perl5/perlbrew/perls/perl-5.34.0 -Aeval:scriptdir=/home/mreisner/perl5/perlbrew/perls/perl-5.34.0/bin'
hint=recommended
useposix=true
d_sigaction=define
useithreads=undef
usemultiplicity=undef
use64bitint=define
use64bitall=define
uselongdouble=undef
usemymalloc=n
default_inc_excludes_dot=define
Compiler:
cc='cc'
ccflags ='-fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -D_FORTIFY_SOURCE=2'
optimize='-O2'
cppflags='-fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include'
ccversion=''
gccversion='8.4.1 20200928 (Red Hat 8.4.1-1)'
gccosandvers=''
intsize=4
longsize=8
ptrsize=8
doublesize=8
byteorder=12345678
doublekind=3
d_longlong=define
longlongsize=8
d_longdbl=define
longdblsize=16
longdblkind=3
ivtype='long'
ivsize=8
nvtype='double'
nvsize=8
Off_t='off_t'
lseeksize=8
alignbytes=8
prototype=define
Linker and Libraries:
ld='cc'
ldflags =' -fstack-protector-strong -L/usr/local/lib'
libpth=/usr/local/lib /usr/lib /usr/lib64 /usr/local/lib64
libs=-lpthread -ldl -lm -lcrypt -lutil -lc
perllibs=-lpthread -ldl -lm -lcrypt -lutil -lc
libc=libc-2.28.so
so=so
useshrplib=false
libperl=libperl.a
gnulibc_version='2.28'
Dynamic Linking:
dlsrc=dl_dlopen.xs
dlext=so
d_dlsymun=undef
ccdlflags='-Wl,-E'
cccdlflags='-fPIC'
lddlflags='-shared -O2 -L/usr/local/lib -fstack-protector-strong'
Characteristics of this binary (from libperl):
Compile-time options:
HAS_TIMES
PERLIO_LAYERS
PERL_COPY_ON_WRITE
PERL_DONT_CREATE_GVSV
PERL_MALLOC_WRAP
PERL_OP_PARENT
PERL_PRESERVE_IVUV
USE_64_BIT_ALL
USE_64_BIT_INT
USE_LARGE_FILES
USE_LOCALE
USE_LOCALE_COLLATE
USE_LOCALE_CTYPE
USE_LOCALE_NUMERIC
USE_LOCALE_TIME
USE_PERLIO
USE_PERL_ATOF
Built under linux
Compiled at Jun 24 2021 16:29:28
%ENV:
PERLBREW_HOME="/home/mreisner/.perlbrew"
PERLBREW_MANPATH="/home/mreisner/perl5/perlbrew/perls/perl-5.34.0/man"
PERLBREW_PATH="/home/mreisner/perl5/perlbrew/bin:/home/mreisner/perl5/perlbrew/perls/perl-5.34.0/bin"
PERLBREW_PERL="perl-5.34.0"
PERLBREW_ROOT="/home/mreisner/perl5/perlbrew"
PERLBREW_SHELLRC_VERSION="0.92"
PERLBREW_VERSION="0.92"
@INC:
/home/mreisner/perl5/perlbrew/perls/perl-5.34.0/lib/site_perl/5.34.0/x86_64-linux
/home/mreisner/perl5/perlbrew/perls/perl-5.34.0/lib/site_perl/5.34.0
/home/mreisner/perl5/perlbrew/perls/perl-5.34.0/lib/5.34.0/x86_64-linux
/home/mreisner/perl5/perlbrew/perls/perl-5.34.0/lib/5.34.0
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