Python Script Causes Crash, Restart [Resolved]

ziger zigs

Greetings fellow Onioneers!

I've been picking up Python since the ash shell sleep function can't sleep for less than a second and I thought it would be more fun to learn a new language than to relearn one I learned a lifetime ago. That's not to say I'm new to coding. I'm no expert, but I've dabbled for some time.

My issue is coming from a (seemingly) simple script I wrote for Python to play with what I thought would be some simple tasks to eventually build up to a larger project I have in mind a proof of concept if you will.

The script it meant to work as follows:

Script starts 
Pin 0 is set to out, pins 2 and 3 are set to in 
Pin 0 is set high to turn on an LED 
The script loops until the button is pressed, polling pin 2 every .1 second to see if the button has been pressed 
On press, the pin 0 goes low, the script sleeps for 2 seconds 
Script loops until pin 3 reads high, where the script simply stops.

This script doesn't contain anything I haven't used previously in smaller (5-10 line) scripts, but it causes my Omega2 to reboot when run! Is there something in my script in particular that is causing this? I can't read the dump that it gave before restarting, so any direction would be helpful to me.

I am running firmware version 0.1.6 b137 as last I checked, the latest version contained an error that made the Omega2 throw errors when trying to use gpioctl or fast-gpio. If this has changed, let me know!

Here's the code as it was run:

import os
import sys
import time
import subprocess

lampstate = "off"
lamppin = "0"

buttonpin = "2"
stoppin = "3"
loopstate = "start"
#loopstate = "stop" #for debugging

sleeper = "0.1"

readpin = "fast-gpio read "
setpin = "gpioctl dirout-"
high = "high "
low = "low "

os.system("gpioctl dirin " + buttonpin)
os.system("gpioctl dirout " + lamppin)

#sys.exit()
#print("exit did not work")
while(loopstate != "stop"):
        button2 = subprocess.check_output(readpin + stoppin)
        if(button2 == "> Read GPIO" + stoppin + ": 0"):
                loopstate = "stop"
        else:
                button1 = subprocess.check_output(readpin + buttonpin)
                if(button1 == "> Read GPIO" + buttonpin + ": 1" and lampstate == "on" ):
                        os.system(setpin + low + lamppin)
                        lampstate = "off"
                        time.sleep(2)
                elif(lampstate == "on"):
                        time.sleep(sleeper)
                else:
                        os.system(setpin + high + lamppin)

And here's the dump:

root@Omega-9D45:/csm/learning# python button.py
[ 2219.519209] CPU 0 Unable to handle kernel paging request at virtual address 00000098, epc == 00000098, ra == 8004f1fc
[ 2219.529986] Oops[#1]:
[ 2219.532301] CPU: 0 PID: 1773 Comm: python Tainted: G        W       4.4.39 #0
[ 2219.539540] task: 839c5e00 ti: 82fce000 task.ti: 82fce000
[ 2219.545013] $ 0   : 00000000 7ffaa930 00000098 803d0000
[ 2219.550332] $ 4   : 803d1890 00b33790 00000018 00b33790
[ 2219.555644] $ 8   : 1100e400 1000001f 6e656720 74617265
[ 2219.560955] $12   : 62206465 771052b0 00000000 72732079
[ 2219.566268] $16   : 803d1880 803d6100 00b33790 fffffffe
[ 2219.571581] $20   : 00b33788 00b33770 00000017 00b337d0
[ 2219.576893] $24   : 00000000 770cd9c8
[ 2219.582205] $28   : 82fce000 82fcfed8 76ed6000 8004f1fc
[ 2219.587520] Hi    : 00000008
[ 2219.590437] Lo    : 00000000
[ 2219.593361] epc   : 00000098 0x98
[ 2219.596744] ra    : 8004f1fc handle_percpu_irq+0x48/0x80
[ 2219.602125] Status: 1100e402 KERNEL EXL
[ 2219.606113] Cause : 50808008 (ExcCode 02)
[ 2219.610174] BadVA : 00000098
[ 2219.613094] PrId  : 00019655 (MIPS 24KEc)
[ 2219.617154] Modules linked in: pppoe ppp_async iptable_nat w1_therm w1_gpio uvcvideo snd_usb_audio pppox ppp_generic pl2303 nf_nat_ipv4 nf_conntrack_ipv6 nf_conntrack_ipv4 ipt_REJECT ipt_MASQUERADE ftdi_sio cp210x ch341 xt_time xt_tcpudp xt_state xt_nat xt_multiport xt_mark xt_mac xt_limit xt_conntrack xt_comment xt_TCPMSS xt_REDIRECT xt_LOG wire videobuf2_v4l2 usbserial usblp usbhid ums_usbat ums_sddr55 ums_sddr09 ums_karma ums_jumpshot ums_isd200 ums_freecom ums_datafab ums_cypress ums_alauda uinput spidev snd_usbmidi_lib slhc rfcomm nf_reject_ipv4 nf_nat_redirect nf_nat_masquerade_ipv4 nf_nat nf_log_ipv4 nf_defrag_ipv6 nf_defrag_ipv4 nf_conntrack_rtcache nf_conntrack iptable_mangle iptable_filter ip_tables hidp hid_generic hci_uart crc_ccitt cdc_acm btusb btintel bnep bluetooth snd_soc_simple_card snd_soc_ralink_i2s snd_soc_wm8960 videobuf2_vmalloc videobuf2_memops videobuf2_core hid v4l2_common videodev evdev snd_soc_core ralink_gdma virt_dma mt76x8 ralink_eeprom_api ledtrig_oneshot ledtrig_morse ledtrig_heartbeat ledtrig_gpio ip6t_REJECT nf_reject_ipv6 nf_log_ipv6 nf_log_common ip6table_mangle ip6table_filter ip6_tables x_tables msdos snd_pcm_dmaengine snd_compress snd_pcm_oss snd_mixer_oss snd_pcm snd_timer snd_rawmidi snd_seq_device snd_hwdep snd input_core soundcore vfat fat ntfs autofs4 nls_utf8 nls_iso8859_1 nls_cp437 regmap_i2c dma_shared_buffer ecb cmac usb_storage sdhci_pltfm sdhci leds_gpio ohci_platform ohci_hcd ledtrig_transient ehci_platform ehci_hcd sd_mod scsi_mod gpio_button_hotplug ext4 jbd2 mbcache exfat usbcore nls_base usb_common crc16 cryptomgr aead crypto_null crc32c_generic crypto_hash
[ 2219.762702] Process python (pid: 1773, threadinfo=82fce000, task=839c5e00, tls=77106e50)
[ 2219.770900] Stack : 01f00006 800c30f8 00000001 00400000 82fcff08 00000007 00000020 8004b6c8
          803cb360 80368188 00000000 770370c8 00001800 80011530 76fe7934 00af46e0
          00000001 7ffaa95f 00000000 80004430 00000001 77c67320 00000001 00000000
          771052b0 00bca800 7ffaa95f 00000000 00000000 7ffaa930 00b337e0 00b337e0
          00b337f0 00b33790 00000018 00b33790 770f013e fefefeff 6e656720 74617265
          ...
[ 2219.807029] Call Trace:
[ 2219.809521] [<800c30f8>] __fdget_pos+0x14/0x60
[ 2219.814066] [<8004b6c8>] generic_handle_irq+0x24/0x3c
[ 2219.819209] [<80011530>] do_IRQ+0x1c/0x2c
[ 2219.823277] [<80004430>] ret_from_irq+0x0/0x4
[ 2219.827696]
[ 2219.829202]
Code: (Bad address in epc)
[ 2219.833179]
[ 2219.834776] ---[ end trace 09977ba32a719a8d ]---
[ 2219.843451] Kernel panic - not syncing: Fatal exception in interrupt
[ 2219.852185] Rebooting in 3 seconds..

ziger zigs

For anyone having the same issue, I believe I solved the issue after some tweaking.

The issue seems to be that I wasn't setting pin 3 to be input before trying to read from it.

Adding the line os.system("gpioctl dirin 3") solved the crashing issue. Alternatively you could replace gpioctl dirin 3 with fast-gpio set-input 3.

I'm a little concerned that the error wasn't handled better. I don't know if that fault is on Python or my Omega2, though.

Anyways, happy coding everyone!