It looks like gdb is not returning the exact line number of the NsTclConnChanProc
Probably. Maybe, the function pointer and optimization contributes to the confusion. One should turn off optimization and turn on assertions, so it becomes easier to identify the root cause.
Since the flag "-DNDEBUG" is inherited from Tcl, the easiest thing is to remove the flag manually from the Makefile, eg. with sed, as shown below. Note that i have as well adjusted the optimize flags.
All the best
-g
cd /usr/local/src/naviserver-4.99.22
sed -i 's/-DNDEBUG//' include/Makefile.global
make clean all install "CFLAGS_OPTIMIZE=-O0 -g"
