Mailing List Archive

Author: jkaluza
Date: Tue Apr 28 06:51:12 2015
New Revision: 1676417

URL: http://svn.apache.org/r1676417
Log:
Initialize interp->refcnt to 1 in modperl_interp_select.

Reasoning:
1. All calls of MP_INTERPa do not increment interp->refcnt, so refcnt
used to be 0 before this commit. But there is always matching
MP_INTERP_PUTBACK, which calls modperl_interp_unselect which decreases
the refcnt, so it was possible to get negative refcnt or crash with
threaded MPMs, because reference counting has been broken.
2. modperl_interp_select increases the refcount if it finds the PerlInterp in
ccfg, so it makes sense to increase it (it means set to 1) during
initialization too. Otherwise the refcnt would be incremented for the caller
in some cases, but wouldn't be in other.

This commit fixes the crash seen on worker MPM when PerlInterp has been used
by two threads and the first one freed PerlInterp during
modperl_interp_unselect.

Modified:
perl/modperl/trunk/src/modules/perl/modperl_interp.c

Modified: perl/modperl/trunk/src/modules/perl/modperl_interp.c
URL: http://svn.apache.org/viewvc/perl/modperl/trunk/src/modules/perl/modperl_interp.c?rev=1676417&r1=1676416&r2=1676417&view=diff
==============================================================================
--- perl/modperl/trunk/src/modules/perl/modperl_interp.c (original)
+++ perl/modperl/trunk/src/modules/perl/modperl_interp.c Tue Apr 28 06:51:12 2015
@@ -460,7 +460,7 @@ modperl_interp_t *modperl_interp_select(
interp = modperl_interp_get(s);
MP_TRACE_i(MP_FUNC, " --> got %pp (perl=%pp)", interp, interp->perl);
++interp->num_requests; /* should only get here once per request */
- interp->refcnt = 0;
+ interp->refcnt = 1;

/* set context (THX) for this thread */
PERL_SET_CONTEXT(interp->perl);