I have been getting some crashes in AOLserver (current cvs version).
AOLserver doesn't exit, but prints the following and stops responding:

'Tcl_SetBooleanObj called with shared object'

Here is a tcl page which exposes the behavior:

-----------
# Script to expose bug with ns_atclose/namespace commands
set store " ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcd
efghijklmnop"
namespace eval ::bug { }

# Commenting out this line leads to bug: 'Tcl_SetBooleanObj called with shar
ed
object'
#namespace eval ::bug::$store { }

proc ::bug::atClose { store } {
ns_log Debug "checking if namespace ::bug::$store exists"
if {[namespace exists ::bug::${store}]} {
ns_log Debug "Deleting namespace ::bug::$store"
namespace delete ::bug::${store}
#log Notice "Closed store (memory delete) $store"
return $store
} else {
ns_log Debug "namespace ::bug::$store does not exist"
}

}

# Comment out one of these and things work fine:
ns_atclose ::bug::atClose $store
#ns_atclose ::bug::atClose $store


ns_return 200 text/plain "ns_atclose bug"

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

The bug doesn't show up under all conditions. If the namespace exists, or ha
d
existed and was deleted, things work as expected. Also, even if the namespac
e
never existed, if ns_atclose is only called once, things work as expected.

However, if the namespace to be deleted never existed, and ns_atclose is
called twice with the same args, none of the ns_log Debug statements print,
and the crash occurs. (But the page is returned)

Not sure what is the cause.

tom jackson

On Friday 03 November 2006 10:31, Alex wrote:
> Oh, well
>
> so I guess it was too early to celebrate. Now I am getting the same
> crashes again, even without "exit" command in the tcl code executed in
> thread.
>
> Seems to me that the same problem now discussed in
> bug 1589968
> https://sourceforge.net/tracker/?fu....aolserver.com/
>
> To Remove yourself from this list, simply send an email to
> <listserv@listserv.aol.com> with the body of "SIGNOFF AOLSERVER" in the
> email message. You can leave the Subject: field of your email blank.

[ Post a follow-up to this message ]

Okay, some more info on this.

ns_atclose has been changed in some strange ways.

First it now requires that you are in an open connection to invoke ns_atclos
e.

ns_atclose used to execute in scheduled procs, which makes sense so that you
can use one method to clean up stuff in case of errors.

It is easy to re-enable adding ns_atclose to scheduled procs by removing a f
ew
lines of code. Now I can call ns_atclose everywhere, but in scheduled procs,
the cleanup scripts don't run.

Question is: why the (silent) change, and
is there something to replace this?

The old description of the command is here:
<http://rmadilo.com/files/nsapi/ns_atclose.html>

I still haven't figured out where exactly the crash is coming from, but _it 
is
not in the NsAtCloseObjCmd or NsRunAtClose... code.

tom jackson

On Sunday 21 January 2007 11:24, Tom Jackson wrote:
> I have been getting some crashes in AOLserver (current cvs version).
> AOLserver doesn't exit, but prints the following and stops responding:
>
> 'Tcl_SetBooleanObj called with shared object'
>
> Here is a tcl page which exposes the behavior:
>
> -----------
> # Script to expose bug with ns_atclose/namespace commands
> set store " ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcd
efghijklmnop"
> namespace eval ::bug { }
>
> # Commenting out this line leads to bug: 'Tcl_SetBooleanObj called with
> shared object'
> #namespace eval ::bug::$store { }
>
> proc ::bug::atClose { store } {
>     ns_log Debug "checking if namespace ::bug::$store exists"
>     if {[namespace exists ::bug::${store}]} {
>         ns_log Debug "Deleting namespace ::bug::$store"
>         namespace delete ::bug::${store}
>         #log Notice "Closed store (memory delete) $store"
>         return $store
>     } else {
>         ns_log Debug "namespace ::bug::$store does not exist"
>     }
>
> }
>
> # Comment out one of these and things work fine:
> ns_atclose ::bug::atClose $store
> #ns_atclose ::bug::atClose $store
>
>
> ns_return 200 text/plain "ns_atclose bug"
>
> -----------------
>
> The bug doesn't show up under all conditions. If the namespace exists, or
> had existed and was deleted, things work as expected. Also, even if the
> namespace never existed, if ns_atclose is only called once, things work as
> expected.
>
> However, if the namespace to be deleted never existed, and ns_atclose is
> called twice with the same args, none of the ns_log Debug statements print
,
> and the crash occurs. (But the page is returned)
>
> Not sure what is the cause.
>
> tom jackson
>
> On Friday 03 November 2006 10:31, Alex wrote: 
>
> --
> AOLserver - http://www.aolserver.com/
>
> To Remove yourself from this list, simply send an email to
> <listserv@listserv.aol.com> with the body of "SIGNOFF AOLSERVER" in the
> email message. You can leave the Subject: field of your email blank.

[ Post a follow-up to this message ]

I found the following change fixes the bug:

in nsd/tclresp.c, line 840:

static int
Result(Tcl_Interp *interp, int result)
{
/*  Tcl_SetBooleanObj(Tcl_GetObjResult(inter
p), result == NS_OK ? 1 : 0); */
Tcl_SetObjResult(interp, Tcl_NewBooleanObj((result == NS_OK ? 1 : 0)));
return TCL_OK;
}

I'll commit the change.

tom jackson


On Sunday 21 January 2007 17:06, Tom Jackson wrote:
> Okay, some more info on this.
>
> ns_atclose has been changed in some strange ways.
>
> First it now requires that you are in an open connection to invoke
> ns_atclose.
>
> ns_atclose used to execute in scheduled procs, which makes sense so that
> you can use one method to clean up stuff in case of errors.
>
> It is easy to re-enable adding ns_atclose to scheduled procs by removing a
> few lines of code. Now I can call ns_atclose everywhere, but in scheduled
> procs, the cleanup scripts don't run.
>
> Question is: why the (silent) change, and
> is there something to replace this?
>
> The old description of the command is here:
> <http://rmadilo.com/files/nsapi/ns_atclose.html>
>
> I still haven't figured out where exactly the crash is coming from, but _i
t
> is not in the NsAtCloseObjCmd or NsRunAtClose... code.
>
> tom jackson
>
> On Sunday 21 January 2007 11:24, Tom Jackson wrote: 
>
> --
> AOLserver - http://www.aolserver.com/
>
> To Remove yourself from this list, simply send an email to
> <listserv@listserv.aol.com> with the body of "SIGNOFF AOLSERVER" in the
> email message. You can leave the Subject: field of your email blank.

[ Post a follow-up to this message ]

That's funny actually...I just changed a bunch of these cases in a Tcl exten
sion I help maintain, just earlier today. I happened upon this post that tal
ks about it:

> Okay, some more info on this.
>
> ns_atclose has been changed in some strange ways.
>
> First it now requires that you are in an open connection to invoke
> ns_atclose.
>
> ns_atclose used to execute in scheduled procs, which makes sense so that
> you can use one method to clean up stuff in case of errors.
>
> It is easy to re-enable adding ns_atclose to scheduled procs by removing a
> few lines of code. Now I can call ns_atclose everywhere, but in scheduled
> procs, the cleanup scripts don't run.
>
> Question is: why the (silent) change, and
> is there something to replace this?
>
> The old description of the command is here:
> <[url]http://rmadilo.com/files/nsapi/ns_atclose.html" target="_blank">http://sourceforge.net/mailarchive/...ns_atclose.html>
>
> I still haven't figured out where exactly the crash is coming from, but _i
t
> is not in the NsAtCloseObjCmd or NsRunAtClose... code.
>
> tom jackson
>
> On Sunday 21 January 2007 11:24, Tom Jackson wrote: 
>
> --
> AOLserver - http://www.aolserver.com/
>
> To Remove yourself from this list, simply send an email to
> <listserv@listserv.aol.com> with the body of "SIGNOFF AOLSERVER" in the
> email message. You can leave the Subject: field of your email blank.


--
AOLserver - http://www.aolserver.com/

To Remove yourself from this list, simply send an email to <listserv@listser
v.aol.com> with the
body of "SIGNOFF AOLSERVER" in the email message. You can leave the Subject:
 field of your email blank.






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[ Post a follow-up to this message ]

On Sunday 21 January 2007 23:20, Brett Schwarz wrote:
> That's funny actually...I just changed a bunch of these cases in a Tcl
> extension I help maintain, just earlier today. I happened upon this post
> that talks about it:
> [url]http://sourceforge.net/mailarchive/forum.php?thread_id=30611212&forum_id=43[/url
]
>966
>
> Might be worthwhile doing an audit of the rest of the aolserver code for
> these occurances.

I only found a few in the AOLserver code, I changed about half before I foun
d
the one that stopped the bug.

I even changed one in the tcl codebase that uses this while checking if a
namespace exists.

I have a feeling that the bug shows up for some other reason. ns_atclose
stores scripts and uses a hash array. I'm guessing that two identical script
s
might appear as one at some point. This could change the reference count for
the object, somehow leading to the problem.

tom jackson

[ Post a follow-up to this message ]