FTL crashed!

[Felisse]

Hello,

I just upgraded yesterday PiHole to latest version 3.1 with FTL version 2.9.2.

Everytime I start PiHole, reboot the VM, or just the FTL service, it takes a few minutes and crash.

This is the log file:
[2017-06-21 08:42:46.469] Finished initial log file parsing
[2017-06-21 08:42:46.469] -> Total DNS queries: 18709
[2017-06-21 08:42:46.469] -> Cached DNS queries: 10397
[2017-06-21 08:42:46.469] -> Blocked DNS queries: 169
[2017-06-21 08:42:46.469] -> Unknown DNS queries: 0
[2017-06-21 08:42:46.469] -> Unique domains: 1007
[2017-06-21 08:42:46.470] -> Unique clients: 28
[2017-06-21 08:42:46.470] Successfully accessed setupVars.conf
[2017-06-21 08:42:46.472] Listening on port 4711 for incoming connections
[2017-06-21 08:59:01.094] !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
[2017-06-21 08:59:01.094] ----------------------------> FTL crashed! <----------------------------
[2017-06-21 08:59:01.094] !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
[2017-06-21 08:59:01.094] > Please report a bug at https://github.com/pi-hole/FTL/issues
[2017-06-21 08:59:01.094] > and include in your report already the following details:
[2017-06-21 08:59:01.094] >
[2017-06-21 08:59:01.094] > Received signal: Segmentation fault
[2017-06-21 08:59:01.094] at address: 297783804246
[2017-06-21 08:59:01.094] with code: SEGV_MAPERR (Address not mapped to object)
[2017-06-21 08:59:01.094] > Memory usage (structs): 712908
[2017-06-21 08:59:01.095] > Memory usage (dynamic): 25993
[2017-06-21 08:59:01.095] >
[2017-06-21 08:59:01.095] > Thank you for helping us to improve our FTL engine!
[2017-06-21 08:59:01.095] FTL terminated!

Already tried a pihole repair, without any change.

This is running on an Ubuntu 17.04:
NAME="Ubuntu"
VERSION="17.04 (Zesty Zapus)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 17.04"
VERSION_ID="17.04"

On a VM running with such characteristics:
=> 2 vCPUs
=> 768 Mb RAM

------------------------------------------------------------------<

In raising this issue, I confirm the following (please check boxes, eg [X]) Failure to fill the template will close your issue:

• I have read and understood the contributors guide.
• The issue I am reporting can be replicated
• The issue I am reporting isn't a duplicate

How familiar are you with the codebase?:

1

[BUG | ISSUE] Expected Behaviour:

FTL deamon continues it's work

[BUG | ISSUE] Actual Behaviour:

FTL crashing with "Segmentation Fault"

[BUG | ISSUE] Steps to reproduce:

• Launch FTL (service pihole-FTL restart)
• wait...

Log file output [if available]

See at the beginning.

[DL6ER]

There have been rumors lately that the sqlite3_changes() function is not behaving stable. Since you say the issue is reproducible, could you help us in identifying the bug?

We have compiled a set of instructions for this case here:
https://github.com/pi-hole/FTL#debugging-pihole-ftl

Since FTL is working for you at least temporarily, you can skip steps 4.-7. and use the simplified debugging instructions given underneath.

[k-dannemand]

"i see the same thing. after reboot it works for 5 min, and then i get "lost connection to api "

[Felisse]

Ok so before I left for work, I set up everything following the documentation.

A few minutes (hours?) later, the FTL crashed, as expected. You will find the output as an attachment.

Backtrace is as following:
(gdb) backtrace
#0 0x00005555555d5761 in sqlite3_changes ()
#1 0x000055555556d96b in DB_GC_thread (val=) at database.c:368
#2 0x00007ffff7bc06da in start_thread (arg=0x7ffff4f07700) at pthread_create.c:456
#3 0x00007ffff78fad7f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:105

Thanks.
FTL-Crash - Issue #94 - Output.txt

[DL6ER]

This confirms that sqlite3_changes() is causing the crash. I've been able to reproduce this locally, but there seems to be no easy solution. I'll code a fix and release an updated version of FTL.

Thanks for using Pi-hole!