Python segmentation error when switching a thread

Question

I am developing an application that should check if a computer is capable of ping google.com. To do this, I use the python subprocess module and make a call, as shown in the code below:

response = subprocess.call("ping -c 1 google.com -q", shell=True) 

However, after starting for some time, the program terminates with a segmentation error.

I have the following code:

daemon.py

def dataset_save(smartphone, mote):
print("DATA LOGGER:\tStarting Now")
with open('dataset.csv', 'a+') as dataset:
    dataset.write(str(datetime.datetime.today()) + ',' + \
            str(datetime.datetime.today().weekday()) + ',' + \
            str(smartphone.connected) + ',' + \
            str(mote.A0_pw) + ',' + \
            str(mote.B00_pw) + ',' + \
            str(mote.B01_pw) + ',' + \
            str(mote.B10_pw) + ',' + \
            str(mote.B11_pw) + ',' + \
            str(presence.get_value()) + ',' + \
            str(temperature.get_value()) + ',' + \
            str(luminosity.get_value()) + '\n')
    print("DATA LOGGER: \tData successfully logged @ %s!" %str(datetime.datetime.today()))
return


def run():
    check_internet()
    while True:
        dataset_save(smartphone, gateway)
        check_presence()

check_internet.py

def check_internet():
response = subprocess.call("ping -c 1 google.com -q", shell=True)
print(response)
if response == 0:
    print ("CONNECTIVITY: \tConnected to internet")
    threading.Timer(1, check_internet).start()
    return

else: 
    print("CONNECTIVITY: \tUnable to connect to internet")
    threading.Timer(1, check_internet).start()
    return

Running this in GDB I get the following trace from a segmentation error:

--- google.com ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 146.626/146.626/146.626/0.000 ms
0
CONNECTIVITY:   Connected to internet
[New Thread 0xb55ffb40 (LWP 4064)]

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0xb65ffb40 (LWP 4043)]
PING google.com (216.58.222.110) 56(84) bytes of data.
__deallocate_stack (pd=0xb65ffb40) at allocatestack.c:760
760 allocatestack.c: No such file or directory.
(gdb) 
--- google.com ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 146.504/146.504/146.504/0.000 ms

(gdb) bt
#0  __deallocate_stack (pd=0xb65ffb40) at allocatestack.c:760
#1  0xb7fc3eab in start_thread (arg=0xb65ffb40) at pthread_create.c:427
#2  0xb7e8164e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:129
(gdb) 

Is there a reason why I should not use threding.Timer as I use? It seems to me that sequential threading is responsible for this segmentation error.

Thank.

Answer 1

, ( , argh). Timer, : , Google:

import threading,subprocess,time

def check_internet():
    while True:
        time.sleep(1)
        response = subprocess.call("ping -n 1 google.com".split())
        print(response)
        if response == 0:
            print("CONNECTIVITY: \tConnected to internet")
        else:
            print("CONNECTIVITY: \tUnable to connect to internet")

t=threading.Thread(target=check_internet)
t.start()

print("Started")
t.join()

1 , 1 ping 1+ ( , ).

EDIT: ping :

import threading,subprocess,time

def check_internet():
    while True:
        time.sleep(1)
        p = subprocess.Popen("ping -n 1 google.com".split(),stdout=subprocess.PIPE,stderr=subprocess.STDOUT)
        out,err = p.communicate()
        response = p.wait()
        if response == 0:
            print("CONNECTIVITY: \tConnected to internet")
        else:
            print("CONNECTIVITY: \tUnable to connect to internet")

t=threading.Thread(target=check_internet)
t.start()

print("Started")
t.join()