[Tcl-bugs] [ tcl-Bugs-705917 ] segfault in stack.test with threaded build on SuSE 8.0

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Bugs item #705917, was opened at 2003-03-18 19:46
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Category: 44. Bytecode Compiler
Group: 8.5a0
Status: Open
Resolution: None
Priority: 5
Submitted By: Michael Schlenker (mic42)
Assigned to: miguel sofer (msofer)
Summary: segfault in stack.test with threaded build on SuSE 8.0

Initial Comment:
The threaded build from todays HEAD (18. March 2003)
crashes in stack.test on SuSE 8.0 (x86).

It doesn't crash on Redhat 7.3, according to migul sofer.
No crash on windows 2000 either.

This happens for both static and shared builds of tcl.

The crash happens in the first test stack 1.1 in
stack.test, the stack trace isn't nice (over 800
entries long, i didn't scroll to the end).



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>Comment By: miguel sofer (msofer)
Date: 2003-03-29 13:16

Message:
Logged In: YES 
user_id=148712

From the tcl'ers chat: JJM's build was threaded, patthoyts
reports instead

 OpenBSD Tcl 8.4: at 1000: to many nested calls to Tcl_Eval.
 OpenBSD tcl 8.4.2: at 1000: too many nested evaluations
(infinite loop?)
 Neither of mine are threaded.
 Ooooo Win2K Tcl 8.4.2 at 863: got the windows unknown
software exception dialog

Questions:
(a) for Joe and Michael: what happens in a non-threaded build?
(b) for Joe and Michael: what is the output of 'ulimit -s'
(b) for Pat: Was that a threaded build on Win2K?
(c) for all: does the failure happen also on older releases?

Comments:
Tcl checks for stack overflow in an indirect manner: it
counts the nesting depth, and errors-out when it hits its
maximum (1000 per default, configurable). What we are seeing
is that the C-stack is exhausted before we hit the 1000
limit, i.e., that we may have to use a smaller default max
nesting depth. I'm trying to find out if the stack usage of
Tcl grew lately ...

On Win2K the matter is probably worse: there is a further
check by the OS to prevent stack overflow, it is apparently
not behaving correctly (per Pat's report).


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Comment By: Nobody/Anonymous (nobody)
Date: 2003-03-28 20:33

Message:
Logged In: NO 

(let's try this again, the SF interface is not working right)

bug confirmed with Tcl 8.4.2 on FreeBSD 4.8-RC.

i get the error "Bus error (core dumped)" from "proc 
recurse i {puts $i; recurse [incr i]}; recurse 1" at 518 
deep.

JJM


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Comment By: Nobody/Anonymous (nobody)
Date: 2003-03-28 20:21

Message:
Logged In: NO 


bug confirmed with Tcl 8.4.2 on FreeBSD 4.8-RC.

i get the error "Bus error (core dumped)" from "proc 
recurse i {puts $i; recurse [incr i]}; recurse 1" at only 518 
times.

JJM


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Comment By: miguel sofer (msofer)
Date: 2003-03-28 19:45

Message:
Logged In: YES 
user_id=148712

The stack.test failure mode is supposed to be a crash, and
the stack trace will indeed be very deep: we are testing the
max nest size there.

Michael: what stack size do you see with 'ulimit'? Could you
run the following script (WARNING: it will run for a while,
fill your terminal with numbers and finally crash) and
report the last number it outputs?

    proc recurse i {puts $i; recurse [incr i]}
    recurse 1

Can anybody else confirm the bug on SuSE 8.0?

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