[Tcl-bugs] [ tcl-Bugs-3530230 ] multi-level return from source in safe interps

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

Bugs item #3530230, was opened at 2012-05-28 06:23
Message generated for change (Settings changed) made by andreas_kupries
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=110894&aid=3530230&group_id=10894

Please note that this message will contain a full copy of the comment thread,
including the initial issue submission, for this request,
not just the latest update.
Category: 45. Parsing and Eval
Group: current: 8.5.11
>Status: Open
>Resolution: None
Priority: 8
Private: No
Submitted By: Donal K. Fellows (dkf)
Assigned to: Don Porter (dgp)
Summary: multi-level return from source in safe interps

Initial Comment:
I was trying to ensure that [return -level 2] works inside a sourced script in a safe interpreter (created with safe::interpCreate so using some aliases, including for [source]) and I found that the test below caused a crash. The crash doesn't appear to be related to the implementation of the aliased version of [source]; I tried several and got a crash every time.

test safe-8.10 {safe source and return} -setup {
    set returnScript [makeFile {return -level 2 "ok"} return.tcl]
    catch {safe::interpDelete $i}
} -body {
    safe::interpCreate $i
    set token [safe::interpAddToAccessPath $i [file dirname $returnScript]]
    $i eval [list apply {filename {
	source $filename
	error boom
    }} $token/[file tail $returnScript]]
} -cleanup {
    catch {safe::interpDelete $i}
    removeFile $returnScript
} -result ok

I'm not 100% sure that the test is right, but I'm sure it shouldn't crash…

----------------------------------------------------------------------

>Comment By: Andreas Kupries (andreas_kupries)
Date: 2012-06-11 13:22

Message:
Can this ticket be closed, now that ticket 3532959 is fixed?


----------------------------------------------------------------------

Comment By: Don Porter (dgp)
Date: 2012-06-07 13:28

Message:
Simple demo of the crash problem opened
as ticket 3532959

----------------------------------------------------------------------

Comment By: Don Porter (dgp)
Date: 2012-06-05 13:19

Message:
There's nothing in place to assure that procPtr->iPtr doesn't
hold a (Tcl_Interp *) that's already been freed.  Either something
has to go in place to do that (don't think that's right), or all code
that pulls a value from procPtr->iPtr has to be able to tolerate that
value being an invalid pointer.  Hmmmm....


----------------------------------------------------------------------

Comment By: Don Porter (dgp)
Date: 2012-06-05 12:31

Message:
Trouble is rooted in a Lambda that manages to survive the
death of its interp.

----------------------------------------------------------------------

Comment By: Andreas Kupries (andreas_kupries)
Date: 2012-06-05 11:19

Message:
That field for #280 support, associated proc bodies with line information.
It is keyed by proc body pointers.
However here the whole hashtable seems to not be initialized at all ?!
An issue with safe interps ?


----------------------------------------------------------------------

Comment By: Don Porter (dgp)
Date: 2012-06-05 11:16

Message:
At this point iPtr->linePBodyPtr is NULL, so the
Tcl_FindHashEntry() macro crashes.

----------------------------------------------------------------------

Comment By: Don Porter (dgp)
Date: 2012-06-05 10:48

Message:
Program received signal SIGSEGV, Segmentation fault.
0x00000000004e8dc2 in TclProcCleanupProc (procPtr=0x93d330)
    at /home/dgp/fossil/tcl8.5/unix/../generic/tclProc.c:2205
2205        hePtr = Tcl_FindHashEntry(iPtr->linePBodyPtr, (char *)
procPtr);
(gdb) bt
#0  0x00000000004e8dc2 in TclProcCleanupProc (procPtr=0x93d330)
    at /home/dgp/fossil/tcl8.5/unix/../generic/tclProc.c:2205
#1  0x00000000004e90f2 in FreeLambdaInternalRep (objPtr=0x98f9c0)
    at /home/dgp/fossil/tcl8.5/unix/../generic/tclProc.c:2436
#2  0x00000000004d3e41 in TclFreeObj (objPtr=0x9720a0)
    at /home/dgp/fossil/tcl8.5/unix/../generic/tclObj.c:1439


----------------------------------------------------------------------

Comment By: Don Porter (dgp)
Date: 2012-06-05 10:43

Message:
Same symptoms on tip of core-8-5-branch.  Seeking
a fix there first.

----------------------------------------------------------------------

Comment By: Don Porter (dgp)
Date: 2012-06-05 10:36

Message:
No crash when the test is run alone.  Crash is seen
when combined with other tests, and only after the test
is complete.

When the test is run alone, it errors.

==== safe-8.10 safe source and return FAILED
==== Contents of test case:

safe::interpCreate $i
set token [safe::interpAddToAccessPath $i [file dirname $returnScript]]
$i eval [list apply {filename {
source $filename
error boom
}} $token/[file tail $returnScript]]

---- Test generated error; Return code was: 1
---- Return code should have been one of: 0 2
---- errorInfo: can't read "i": no such variable
    while executing
"safe::interpCreate $i"
    ("uplevel" body line 2)
    invoked from within
"uplevel 1 $script"
---- errorCode: TCL LOOKUP VARNAME i
==== safe-8.10 FAILED


When run with some other safe-8* tests, it passes.

----------------------------------------------------------------------

You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=110894&aid=3530230&group_id=10894