Re: [naviserver-devel] Buffer overflow detected

[Gustaf N. <ne...@wu...>]

Dear Maksym,

These kind of errors should never happen, but when this happen, this can 
come from NaviServer or Tcl or some C modules/package loaded.

The last time i saw this kind of crash in a NaviServer environment, it 
was triggered from Tcl, where a select() was tried in a situation where 
more than 1024 file descriptors were open (stay away from async Tcl I/O 
operations and use NaviServer built-in features ... e.g. ns_http instead 
of tcllib http). The number of open file descriptors of NaviServer can 
be monitored e.g. by the munin-plugins [2,3].

To debug this situation,
- make sure to compile Tcl and NaviServer with debugging symbols (i.e. 
with compiler flag "-g" [1]),
- make sure, core dumps are enabled, and when you have a core,
- use "gdb /usr/local/ns/bin/nsd YOURCORE" to see exactly, where this 
happened.

all the best

-g

[1] https://openacs.org/forums/message-view?message_id=5537675
[2] https://github.com/gustafn/munin-plugins-ns
[3] 
https://openacs.org/munin/localdomain/localhost.localdomain/naviserver_openacs_lsof.html

On 04.11.21 21:17, Maksym Zinchenko wrote:
> Hi every now and then my server crashes with the last message in the 
> log file *** Buffer overflow detected *** I would really appreciate if 
> someone can point me in the right direction of debugging and figure 
> out what's going on.
> Thank you
> Maksym Zinchenko