[Tcl-bugs] [ tcl-Bugs-484339 ] [unset; error] in var trace -> bad mem

[<no...@so...>]

Bugs item #484339, was opened at 2001-11-21 12:30
You can respond by visiting: 
http://sourceforge.net/tracker/?func=detail&atid=110894&aid=484339&group_id=10894

Category: 07. Variables
Group: 8.4a4
Status: Open
Resolution: None
Priority: 5
Submitted By: Don Porter (dgp)
Assigned to: miguel sofer (msofer)
Summary: [unset; error] in var trace -> bad mem

Initial Comment:

Here's a patch against the HEAD that adds a
test to tests/trace.test.  Apply it and test
with ElectricFence or something similar
(TCL_MEM_DEBUG? Purify?) and you should see
a problem trying to access varPtr at line 4577
in CallTraces().

Note that although this patch adds the test to
Tcl 8.4, the same bug is in Tcl 8.3.4 too.

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>Comment By: miguel sofer (msofer)
Date: 2001-11-30 07:39

Message:
Logged In: YES 
user_id=148712

With TCL_MEM_DEBUG the output is:

[mig@mini unix]$ ./tcltest ../tests/trace.test 
hi guard byte 5 is 0x60         `
total mallocs                  49700
total frees                    44502
current packets allocated       5198
current bytes allocated       375815
maximum packets allocated       5230
maximum bytes allocated       497758
high guard failed at 81cb990, ./../generic/tclVar.c 1355
131 bytes allocated at (./../generic/tclStringObj.c 842)
Memory validation failure
Aborted (core dumped)

A backtrace on the core file does not show CallTraces, it
appears that the offending call is from Tcl_SetVar2Ex
(generic/tclVar.c:1355)

The difference may be due to the fact that I have already
applied the patch to Bug #484334?

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