Nicholas Clark wrote:
On Mon, Apr 27, 2009 at 12:27:02AM -0500, John E. Malmberg wrote:
I just started looking into a failure of 19_CPANPLUS-Dist. I have not
determined what exactly is wrong, and am out of time for the moment.
I will try to get some more information later.
It is failing from an access violation in SV.C.
ok 57 - Perl version not high enough
%SYSTEM-F-ACCVIO, access violation, reason mask=00, virtual
address=000000000000002C, PC=00000000000F9AB8, PS=0000001B
%TRACE-F-TRACEBACK, symbolic stack dump follows
image module routine line rel PC
abs PC
DBGPERLSHR SV Perl_sv_upgrade 73671 0000000000001F58
00000000000F9AB8
DBGPERLSHR SV Perl_sv_setsv_flags 76204 000000000000AC88
00000000001027E8
EAGLE> search [-]sv.lis/window=10 73671
2 73667 /* We always allocated the full length item
with PURIFY.
To do this
2 73668 we fake things so that arena is false for
all 16 type
s.. */
3 73669 if(new_type_details->arena) {
3 73670 /* This points to the start of the
allocated area.
*/
3 73671 new_body_inline(new_body, new_type);
#define new_body_inline(xpv, sv_type) \
STMT_START { \
void ** const r3wt = &PL_body_roots[sv_type]; \
xpv = (PTR_TBL_ENT_t*) (*((void **)(r3wt)) \
? *((void **)(r3wt)) : more_bodies(sv_type)); \
*(r3wt) = *(void**)(xpv); \
} STMT_END
I'm curious what the value of sv_type is. It's the second (real) parameter:
void
Perl_sv_upgrade(pTHX_ register SV *const sv, svtype new_type)
case SVt_PVMG:
...
new_body_inline(new_body, new_type);
new_type = SVt_PVMG,
SVt_PVMG has a value of 7.
new_body = 44.
PL_Body_roots[sv_type] = 44.
From the code, it looks like this was expected to contain a valid pointer.
Looking at the source, the Macro PURIFY is not defined.
new_body_inline() was invoked there with the same arguments, yet here it
did not access violate.
Looking at sv->sv_any, it contains 0 at the time of the access violation.
At the time of the access violation, new_type_details->offset is 0.
If I set the breakpoints closer to where the access violation occurs, I
do not see an access violation. In the past, when that happens, it
indicates an uninitialized variable.
Regards,
-John
wb8...@qsl.net
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