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This queue is for tickets about the Devel-GC-Helper CPAN distribution.

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The Basics
Id: 21504
Status: new
Priority: 0/
Queue: Devel-GC-Helper

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Owner: Nobody in particular
Requestors: rataxis [...] cpan.org
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Bug Information
Severity: Critical
Broken in: 0.25
Fixed in: (no value)



Subject: SIGSEGV when calling sweep() due to PL_compiling.cop_warnings structure changes (?)
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I get SIGSEGV on perl, v5.8.8 built for i486-linux-gnu-thread-multi when I call Devel::GC::Helper::sweep() Investigation with debugperl and gdb suggests the segfault happens with the following call stack: Program received signal SIGSEGV, Segmentation fault. 0xb7c9218f in gc_note_sv () from /usr/local/lib/perl/5.8.8/auto/Devel/GC/Helper/Helper.so (gdb) bt #0 0xb7c9218f in gc_note_sv () from /usr/local/lib/perl/5.8.8/auto/Devel/GC/Helper/Helper.so #1 0xb7c92b2e in sweep_root () from /usr/local/lib/perl/5.8.8/auto/Devel/GC/Helper/Helper.so #2 0xb7c94026 in XS_Devel__GC__Helper_sweep () from /usr/local/lib/perl/5.8.8/auto/Devel/GC/Helper/Helper.so #3 0x080f3128 in Perl_pp_entersub (my_perl=0x81b9008) at pp_hot.c:2877 #4 0x080cdd51 in Perl_runops_debug (my_perl=0x81b9008) at dump.c:1459 #5 0x08065ba6 in S_run_body (my_perl=0x81b9008, oldscope=1) at perl.c:2366 #6 0x080655db in perl_run (my_perl=0x81b9008) at perl.c:2283 #7 0x0806013e in main (argc=4, argv=0xbfa77944, env=0xbfa77958) at perlmain.c:99 Which corresponds to a call to gc_note_sv() from sweep_root() line 243: 243 gc_note_sv(tbl, PL_compiling.cop_warnings); commenting this line out with /*...*/ and recompiling prevents the segfault behaviour, but presumably at a cost of some SV leak tracking? #perl suggests that this is possibly due to PL_compiling.cop_warnings having changed its structure in 5.8.8 -- what do you think? I don't track perl changes carefully enough to know for sure. Here is a patch to work around the behaviour on 5.8.8 (really just to prevent the segfault): ----------8<----------------------------8<--------------- --- Helper.xs 2006-09-15 00:39:30.000000000 +0100 +++ Helper.xs.old 2006-09-15 00:39:13.000000000 +0100 @@ -240,7 +240,7 @@ ptr_table_store(tbl, &PL_sv_yes, (void*) 1); gc_note_sv(tbl, PL_compiling.cop_io); -/* gc_note_sv(tbl, PL_compiling.cop_warnings); */ + gc_note_sv(tbl, PL_compiling.cop_warnings); gc_note_sv(tbl, PL_patchlevel); ----------8<----------------------------8<--------------- $ uname -a Linux wombat 2.6.17.1 #11 Sun Jul 2 02:20:52 BST 2006 i686 GNU/Linux Tested on the following perl versions: $ perl -V Summary of my perl5 (revision 5 version 8 subversion 8) configuration: Platform: osname=linux, osvers=2.6.15-1-686, archname=i486-linux-gnu-thread-multi uname='linux ulises 2.6.15-1-686 #2 mon mar 6 15:27:08 utc 2006 i686 gnulinux ' config_args='-Dusethreads -Duselargefiles -Dccflags=-DDEBIAN -Dcccdlflags=-fPIC -Darchname=i486-linux-gnu -Dprefix=/usr -Dprivlib=/usr/share/perl/5.8 -Darchlib=/usr/lib/perl/5.8 -Dvendorprefix=/usr -Dvendorlib=/usr/share/perl5 -Dvendorarch=/usr/lib/perl5 -Dsiteprefix=/usr/local -Dsitelib=/usr/local/share/perl/5.8.8 -Dsitearch=/usr/local/lib/perl/5.8.8 -Dman1dir=/usr/share/man/man1 -Dman3dir=/usr/share/man/man3 -Dsiteman1dir=/usr/local/man/man1 -Dsiteman3dir=/usr/local/man/man3 -Dman1ext=1 -Dman3ext=3perl -Dpager=/usr/bin/sensible-pager -Uafs -Ud_csh -Uusesfio -Uusenm -Duseshrplib -Dlibperl=libperl.so.5.8.8 -Dd_dosuid -des' 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='cc', ccflags ='-D_REENTRANT -D_GNU_SOURCE -DTHREADS_HAVE_PIDS -DDEBIAN -fno-strict-aliasing -pipe -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64', optimize='-O2', cppflags='-D_REENTRANT -D_GNU_SOURCE -DTHREADS_HAVE_PIDS -DDEBIAN -fno-strict-aliasing -pipe -I/usr/local/include' ccversion='', gccversion='4.1.2 20060729 (prerelease) (Debian 4.1.1-10)', 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='cc', ldflags =' -L/usr/local/lib' libpth=/usr/local/lib /lib /usr/lib libs=-lgdbm -lgdbm_compat -ldb -ldl -lm -lpthread -lc -lcrypt perllibs=-ldl -lm -lpthread -lc -lcrypt libc=/lib/libc-2.3.6.so, so=so, useshrplib=true, libperl=libperl.so.5.8.8 gnulibc_version='2.3.6' Dynamic Linking: dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E' cccdlflags='-fPIC', lddlflags='-shared -L/usr/local/lib' Characteristics of this binary (from libperl): Compile-time options: MULTIPLICITY PERL_IMPLICIT_CONTEXT PERL_MALLOC_WRAP THREADS_HAVE_PIDS USE_ITHREADS USE_LARGE_FILES USE_PERLIO USE_REENTRANT_API Built under linux Compiled at Aug 6 2006 15:35:16 @INC: /etc/perl /usr/local/lib/perl/5.8.8 /usr/local/share/perl/5.8.8 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.8 /usr/share/perl/5.8 /usr/local/lib/site_perl . $ debugperl -V Summary of my perl5 (revision 5 version 8 subversion 8) configuration: Platform: osname=linux, osvers=2.6.15-1-686, archname=i486-linux-gnu-thread-multi uname='linux ulises 2.6.15-1-686 #2 mon mar 6 15:27:08 utc 2006 i686 gnulinux ' config_args='-Dusethreads -Duselargefiles -Dccflags=-DDEBIAN -Dcccdlflags=-fPIC -Darchname=i486-linux-gnu -Dprefix=/usr -Dprivlib=/usr/share/perl/5.8 -Darchlib=/usr/lib/perl/5.8 -Dvendorprefix=/usr -Dvendorlib=/usr/share/perl5 -Dvendorarch=/usr/lib/perl5 -Dsiteprefix=/usr/local -Dsitelib=/usr/local/share/perl/5.8.8 -Dsitearch=/usr/local/lib/perl/5.8.8 -Dman1dir=/usr/share/man/man1 -Dman3dir=/usr/share/man/man3 -Dsiteman1dir=/usr/local/man/man1 -Dsiteman3dir=/usr/local/man/man3 -Dman1ext=1 -Dman3ext=3perl -Dpager=/usr/bin/sensible-pager -Uafs -Ud_csh -Uusesfio -Uusenm -Duseshrplib -Dlibperl=libperl.so.5.8.8 -Dd_dosuid -des' 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='cc', ccflags ='-D_REENTRANT -D_GNU_SOURCE -DTHREADS_HAVE_PIDS -DDEBIAN -fno-strict-aliasing -pipe -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64', optimize='-O2', cppflags='-D_REENTRANT -D_GNU_SOURCE -DTHREADS_HAVE_PIDS -DDEBIAN -fno-strict-aliasing -pipe -I/usr/local/include' ccversion='', gccversion='4.1.2 20060729 (prerelease) (Debian 4.1.1-10)', 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='cc', ldflags =' -L/usr/local/lib' libpth=/usr/local/lib /lib /usr/lib libs=-lgdbm -lgdbm_compat -ldb -ldl -lm -lpthread -lc -lcrypt perllibs=-ldl -lm -lpthread -lc -lcrypt libc=/lib/libc-2.3.6.so, so=so, useshrplib=true, libperl=libperl.so.5.8.8 gnulibc_version='2.3.6' Dynamic Linking: dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E' cccdlflags='-fPIC', lddlflags='-shared -L/usr/local/lib' Characteristics of this binary (from libperl): Compile-time options: DEBUGGING MULTIPLICITY PERL_IMPLICIT_CONTEXT PERL_MALLOC_WRAP THREADS_HAVE_PIDS USE_ITHREADS USE_LARGE_FILES USE_PERLIO USE_REENTRANT_API Built under linux Compiled at Aug 6 2006 15:46:43 @INC: /etc/perl /usr/local/lib/perl/5.8.8 /usr/local/share/perl/5.8.8 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.8 /usr/share/perl/5.8 /usr/local/lib/site_perl .


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