On Thu, Dec 16, 2021 at 03:55:43PM +0800, Vladimir Nikishkin wrote: > Hello, everyone > > Recently I had a problem: my system is losing network connectivity, > although the interface (vio0 on KVM) seemed up. Restarting the > connection with `ifconfig vio0 down` and `ifconfig vio0 up` restores the > connection. > > However, when I timed the execution, I found that the second `up` can > take up to 15 minutes. (Hugely unexpected!) To find out where the > program is waiting, I decided to recompile ifconfig from source with > debugging and profiling support. > > Slightly adjusting the commands provided by the Makefile, I came up with > the following commands: > > ``` > egcc -O0 -g -pg -fPIC -Werror-implicit-function-declaration -c ifconfig.c > egcc -O0 -g -pg -fPIC -Werror-implicit-function-declaration -c brconfig.c > egcc -O0 -g -pg -fPIC -Werror-implicit-function-declaration -c sff.c > egcc -g -pg -shared -pie -o ifconfig ifconfig.o brconfig.o sff.o -lc -pg > ``` > > However, when I run ./ifconfig compiled like this, I am getting (besides > the output of ifconfig itself) the following error message: > > ``` > gmon.out: No such file or directory > ``` > > I find this unexpected. Compiling and linking a simple helloworld with > -pg -g seems to be working fine, and gmon.out is produced as expected. > > What am I doing wrong? Is there something specific that needs to be > permitted to profile ifconfig?
I doubt the problem is in ifconfig(8) itself but more an ioctl that takes long to finish. Anyway for prfiling to work you need to neuter unveil() in ifconfig. e.g. by changing the code. With unveil on the gmon.out file written in the atexit handler can't be created. -- :wq Claudio
