On Sat, Jul 01, 2006 at 10:42:58PM -0700, Ephraim Dan wrote: > Thanks for the help Tim! You've really done me a great service. > > I have created the following patch, which appears to fix all of the leaks. > Can you please review it, and give it your stamp of approval? I am willing > to use this patch if you approve it, until a new DBI is available with the > fixes.
Looks okay at first sight, except that Newz returns memory that's been reset to zero bytes. You need to add the memzero I suggested previously. Might as well go into malloc_using_sv since it's not performance critical. Um, looks like CLONE plus _clone_dbis plus dbi_bootinit already do the right thing (your patch also fixes a leak on thread creation) so that's okay. INIT_PERINTERP is harder to be sure about, but I think it's okay. I'll apply the patch and add the memzero. Thanks edan. Tim. > Thanks again, > edan > > The patch: > > --- DBI.xs.orig 2006-06-30 10:20:10.000000000 -0400 > +++ DBI.xs 2006-07-02 04:59:32.000000000 -0400 > @@ -171,7 +171,7 @@ > dPERINTERP_SV; dPERINTERP_PTR(PERINTERP_t *, PERINTERP) > # define INIT_PERINTERP \ > dPERINTERP; \ > - Newz(0,PERINTERP,1,PERINTERP_t); \ > + PERINTERP = malloc_using_sv(sizeof(PERINTERP_t)); \ > sv_setiv(perinterp_sv, PTR2IV(PERINTERP)) > > # undef DBIS > @@ -209,13 +209,29 @@ > stc_s, sizeof(dbih_stc_t), fdc_s, sizeof(dbih_fdc_t), msg); > } > > +static void * > +malloc_using_sv(STRLEN len) > +{ > + dTHX; > + SV *sv = newSV(len); > + return SvPVX(sv); > +} > + > +static char * > +savepv_using_sv(char *str) > +{ > + char *buf = malloc_using_sv(strlen(str)); > + strcpy(buf, str); > + return buf; > +} > + > static void > dbi_bootinit(dbistate_t * parent_dbis) > { > dTHX; > INIT_PERINTERP; > > - Newz(dummy, DBIS, 1, dbistate_t); > + DBIS = (struct dbistate_st*)malloc_using_sv(sizeof(struct dbistate_st)); > > /* store version and size so we can spot DBI/DBD version mismatch */ > DBIS->check_version = check_version; > @@ -3793,7 +3809,7 @@ > ima->minargs = (U8)SvIV(*av_fetch(av, 0, 1)); > ima->maxargs = (U8)SvIV(*av_fetch(av, 1, 1)); > svp = av_fetch(av, 2, 0); > - ima->usage_msg = savepv( (svp) ? SvPV(*svp,lna) : ""); > + ima->usage_msg = (svp) ? savepv_using_sv(SvPV(*svp, lna)) : ""; > ima->flags |= IMA_HAS_USAGE; > if (trace_msg && DBIS_TRACE_LEVEL >= 11) > sv_catpvf(trace_msg, ",\n usage: min %d, max %d, '%s'", > > > -----Original Message----- > > From: Tim Bunce [mailto:[EMAIL PROTECTED] > > Sent: Friday, June 30, 2006 16:33 > > To: Ephraim Dan > > Cc: Tim Bunce; dbi-users@perl.org > > Subject: Re: memory leak in DBI XS bootstrap code > > > > On Fri, Jun 30, 2006 at 04:08:46AM -0700, Ephraim Dan wrote: > > > This is why I love the perl community - you're willing to help even > > though you don't have time, since > > > you care about your code, and that other people can benefit from it. > > > > > > But ... you sort of left a dangling "But" in your last post. Do you > > have a suggestion to fix the > > > _install_method problem? > > > > > > I just ran valgrind with your fix - there seems to still be a leak. > > It is reported on DBI.xs line 216: > > > INIT_PERINTERP; > > > That looks to also have a Newz in it - is that what leaks? > > > > Yes. It's basically a plain malloc and there's no mechanism to free it > > later. > > > > > Can you suggest how to fix that one? > > > > The trick is to use newSV to alloc memory in the form of an SV > > so that when the interpreter is destroyed the SV memory gets freed > > automatically. > > > > > The _install_method leak is reported on line 3800 (in my modified > > DBI.xs) which validates your theory: > > > ima->usage_msg = savepv( (svp) ? SvPV(*svp,lna) : ""); > > > If you can fix these, I'll be forever in your debt... > > > > As above, and as outlined previously, use an SV. > > Something like this (completely untested): > > > > static void * > > malloc_using_sv(STRLEN len) { > > SV *sv = newSV(len); > > return SvPVX(sv); > > } > > > > static char * > > savepv_using_sv(char *str) { > > char *buf = malloc_using_sv(strlen(str)); > > strcpy(buf, str); > > return buf; > > } > > > > Tim. > > > > > --edan > > > > > > --------------------------------------------------------------------- > > ----------------------------------- > > > > > > From: Tim Bunce [mailto:[EMAIL PROTECTED] > > > Sent: Fri 6/30/2006 11:35 > > > To: Ephraim Dan > > > Cc: Tim Bunce; dbi-users@perl.org > > > Subject: Re: memory leak in DBI XS bootstrap code > > > > > > On Fri, Jun 30, 2006 at 12:24:33AM -0700, Ephraim Dan wrote: > > > > > > I don't see what you mean in the "INSTALL" that comes with perl > > 5.8.0 (that's what we're using). > > > > > The file called INSTALL in the perl source code directory. > > > > > > > > That I knew. What are the special instructions that I'm supposed > > to > > > > find there? Am I supposed to build it with debugging? Can you > > > > specify what special configuration exactly you meant that I should > > use? > > > > > > I'm sorry. I should have checked myself first. You can build perl > > with > > > -DPURIFY to enable more precise leak detection. > > > > > > > It looks like the leak in boot_DBI is on purpose: > > > > /* Remember the last handle used. BEWARE! Sneaky stuff here! > > */ > > > > /* We want a handle reference but we don't want to increment > > */ > > > > /* the handle's reference count and we don't want perl to try > > */ > > > > /* to destroy it during global destruction. Take care! > > */ > > > > DBI_UNSET_LAST_HANDLE; /* ensure setup the correct way > > */ > > > > > > > > Why is this being done, and does anyone have a way to fix it? Why > > don't we want perl to destroy it? > > > Me, that's exactly what I want. > > > > > > I don't believe that's a leak. It's just using an SV as a reference > > > without telling perl its a reference. If perl knew it was a reference > > > we'd get double-free warnings as the referenced value would be freed > > twice. > > > > > > The leak is probably the DBIS structure itself: > > > > > > Newz(dummy, DBIS, 1, dbistate_t); > > > > > > That should probably be using along the lines of: > > > > > > sv = newSV(sizeof(struct dbistate_st)); > > > DBIS = (struct dbistate_st*)SvPVX(sv); > > > memzero(DBIS, sizeof(struct dbistate_st)); > > > > > > So the memory is allocated within an SV so gets freed on global > > destruction. > > > > > > > Still looking into the other leak in _install_method... any > > pointers still appreciated... Thanks for > > > your help so far, Tim. > > > > > > I've taken a look at the code. I'd guess that it's due to savepnv: > > > > > > ima->usage_msg = savepv( (svp) ? SvPV(*svp,lna) : ""); > > > > > > But > > > > > > Tim. > > > > > > > -edan > > > > > > > > > > -----Original Message----- > > > > > > From: Tim Bunce [[1]mailto:[EMAIL PROTECTED] > > > > > > Sent: Thursday, June 29, 2006 14:47 > > > > > > To: Ephraim Dan > > > > > > Cc: dbi-users@perl.org > > > > > > Subject: Re: memory leak in DBI XS bootstrap code > > > > > > > > > > > > Try building perl with options to make valgrind leak tracing > > more > > > > > > effective (see perl's INSTALL file). That may help you pinpoint > > > > > > the problem. > > > > > > > > > > > > Tim. > > > > > > > > > > > > On Thu, Jun 29, 2006 at 04:33:40AM -0700, Ephraim Dan wrote: > > > > > > > I am experiencing what I believe to be a memory leak in the > > DBI > > > > > > bootstrap code. This is a problem for me because I am > > embedding perl in a > > > > > > long-running program, and DBI is being loaded over and over, so > > my program > > > > > > grows and grows. > > > > > > > > > > > > > > The problem appears to be in the following routines: > > > > > > > > > > > > > > boot_DBI (in /usr/lib/perl5/vendor_perl/5.8.0/i386-linux- > > thread- > > > > > > multi/auto/DBI/DBI.so) > > > > > > > XS_DBI__install_method (in > > /usr/lib/perl5/vendor_perl/5.8.0/i386-linux- > > > > > > thread-multi/auto/DBI/DBI.so) > > > > > > > > > > > > > > I am using DBI 1.51 > > > > > > > > > > > > > > The tool "valgrind" ([2]http://valgrind.org > > <[3]http://valgrind.org/> ) can be used to reproduce > > > the > > > > > > leak using the following code: > > > > > > > > > > > > > > --- > > > > > > > File: embed_test.c > > > > > > > --- > > > > > > > > > > > > > > #include <EXTERN.h> /* from the Perl > > distribution */ > > > > > > > #include <perl.h> /* from the Perl > > distribution */ > > > > > > > > > > > > > > static PerlInterpreter *my_perl; /*** The Perl > > interpreter ***/ > > > > > > > EXTERN_C void xs_init (pTHX); /*** init dyn. loading > > ***/ > > > > > > > > > > > > > > int main(int argc, char **argv, char **env) > > > > > > > { > > > > > > > char *embedding[] = { "", "-e", "0" }; > > > > > > > my_perl = perl_alloc(); > > > > > > > perl_construct(my_perl); > > > > > > > perl_parse(my_perl, xs_init, 3, embedding, (char > > **)NULL); > > > > > > > PL_exit_flags |= PERL_EXIT_DESTRUCT_END; > > > > > > > perl_run(my_perl); > > > > > > > eval_pv("use DBI", TRUE); > > > > > > > perl_destruct(my_perl); > > > > > > > perl_free(my_perl); > > > > > > > } > > > > > > > > > > > > > > --- > > > > > > > File: Makefile > > > > > > > --- > > > > > > > > > > > > > > CC_OPTS = $(shell perl -MExtUtils::Embed -e ccopts) > > > > > > > LD_OPTS = $(shell perl -MExtUtils::Embed -e ldopts) > > > > > > > > > > > > > > EXE = embed_test > > > > > > > > > > > > > > $(EXE): xsinit.o embed_test.o > > > > > > > gcc -o $(EXE) embed_test.o xsinit.o $(LD_OPTS) > > > > > > > > > > > > > > embed_test.o: embed_test.c > > > > > > > gcc -c embed_test.c $(CC_OPTS) > > > > > > > > > > > > > > xsinit.o: xsinit.c > > > > > > > gcc -c xsinit.c $(CC_OPTS) > > > > > > > > > > > > > > xsinit.c: > > > > > > > perl -MExtUtils::Embed -e xsinit -- -o xsinit.c > > > > > > > > > > > > > > clean: > > > > > > > rm -f *.o xsinit.c $(EXE) > > > > > > > > > > > > > > --- > > > > > > > EOF > > > > > > > --- > > > > > > > > > > > > > > Can anyone suggest a fix for this? I'd be more than willing > > to take a > > > > > > patch to DBI 1.51 as soon as someone has one. > > > > > > > > > > > > > > Thanks, > > > > > > > Ephraim Dan > > > > > > > > > > > > > > > > > References > > > > > > Visible links > > > 1. mailto:[EMAIL PROTECTED] > > > 2. http://valgrind.org/ > > > 3. http://valgrind.org/