[Bug 1809438] [NEW] systemd-resolved segfaults

[OlivierS]

Public bug reported:

I regularly (once almost every hour) get segfaults resported in systemd-
resolved. The syslog is not always the same:

Dec 21 06:59:21 marshall kernel: [988042.071003] systemd-resolve[15794]: segfault at e60e8ad514 ip 000000e60e8ad514 sp 00007ffe0376e748 error 14 in systemd-resolved[556f74bcf000+59000]
Dec 21 06:59:21 marshall systemd[1]: systemd-resolved.service: Main process exited, code=dumped, status=11/SEGV
Dec 21 06:59:21 marshall systemd[1]: systemd-resolved.service: Failed with result 'core-dump'.

Dec 21 08:17:47 marshall kernel: [992748.334333] systemd-resolve[16943]: segfault at 2a11d9b0 ip 00007f4810f5ad26 sp 00007fff544db0f0 error 4 in libsystemd-shared-237.so[7f4810e1f000+1b5000]
Dec 21 08:17:47 marshall systemd[1]: systemd-resolved.service: Main process exited, code=dumped, status=11/SEGV
Dec 21 08:17:47 marshall systemd[1]: systemd-resolved.service: Failed with result 'core-dump'.

Dec 21 06:22:45 marshall systemd-resolved[15727]: Assertion 'p->n_ref > 0' failed at ../src/resolve/resolved-dns-packet.c:210, function dns_packet_unref(). Aborting.
Dec 21 06:22:45 marshall systemd[1]: systemd-resolved.service: Main process exited, code=dumped, status=6/ABRT
Dec 21 06:22:45 marshall systemd[1]: systemd-resolved.service: Failed with result 'core-dump'.

Dec 21 06:17:46 marshall systemd-resolved[15662]: Assertion 'DNS_TRANSACTION_IS_LIVE(q->state)' failed at ../src/resolve/resolved-dns-query.c:540, function dns_query_complete(). Aborting.
Dec 21 06:17:46 marshall systemd[1]: systemd-resolved.service: Main process exited, code=dumped, status=6/ABRT
Dec 21 06:17:46 marshall systemd[1]: systemd-resolved.service: Failed with result 'core-dump'.

The system in question uses dnsmasq as local DNS server. Logging that is probably unrelated, but often seen (possibly due to the setup with dnsmasq) is:
dec 21 10:22:00 marshall systemd-resolved[3183]: Server returned error NXDOMAIN, mitigating potential DNS violation DVE-2018-0001, retrying transaction with reduced feature level UDP.
dec 21 10:17:15 marshall systemd-resolved[3183]: Using degraded feature set (TCP) for DNS server 127.0.0.1.


# dpkg --status systemd
Package: systemd
Installed-Size: 12444
Maintainer: Ubuntu Developers <ubuntu-devel-discuss at lists.ubuntu.com>
Architecture: amd64
Multi-Arch: foreign
Version: 237-3ubuntu10.9

** Affects: systemd (Ubuntu)
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1809438

Title:
  systemd-resolved segfaults

Status in systemd package in Ubuntu:
  New

Bug description:
  I regularly (once almost every hour) get segfaults resported in
  systemd-resolved. The syslog is not always the same:

  Dec 21 06:59:21 marshall kernel: [988042.071003] systemd-resolve[15794]: segfault at e60e8ad514 ip 000000e60e8ad514 sp 00007ffe0376e748 error 14 in systemd-resolved[556f74bcf000+59000]
  Dec 21 06:59:21 marshall systemd[1]: systemd-resolved.service: Main process exited, code=dumped, status=11/SEGV
  Dec 21 06:59:21 marshall systemd[1]: systemd-resolved.service: Failed with result 'core-dump'.

  Dec 21 08:17:47 marshall kernel: [992748.334333] systemd-resolve[16943]: segfault at 2a11d9b0 ip 00007f4810f5ad26 sp 00007fff544db0f0 error 4 in libsystemd-shared-237.so[7f4810e1f000+1b5000]
  Dec 21 08:17:47 marshall systemd[1]: systemd-resolved.service: Main process exited, code=dumped, status=11/SEGV
  Dec 21 08:17:47 marshall systemd[1]: systemd-resolved.service: Failed with result 'core-dump'.

  Dec 21 06:22:45 marshall systemd-resolved[15727]: Assertion 'p->n_ref > 0' failed at ../src/resolve/resolved-dns-packet.c:210, function dns_packet_unref(). Aborting.
  Dec 21 06:22:45 marshall systemd[1]: systemd-resolved.service: Main process exited, code=dumped, status=6/ABRT
  Dec 21 06:22:45 marshall systemd[1]: systemd-resolved.service: Failed with result 'core-dump'.

  Dec 21 06:17:46 marshall systemd-resolved[15662]: Assertion 'DNS_TRANSACTION_IS_LIVE(q->state)' failed at ../src/resolve/resolved-dns-query.c:540, function dns_query_complete(). Aborting.
  Dec 21 06:17:46 marshall systemd[1]: systemd-resolved.service: Main process exited, code=dumped, status=6/ABRT
  Dec 21 06:17:46 marshall systemd[1]: systemd-resolved.service: Failed with result 'core-dump'.

  The system in question uses dnsmasq as local DNS server. Logging that is probably unrelated, but often seen (possibly due to the setup with dnsmasq) is:
  dec 21 10:22:00 marshall systemd-resolved[3183]: Server returned error NXDOMAIN, mitigating potential DNS violation DVE-2018-0001, retrying transaction with reduced feature level UDP.
  dec 21 10:17:15 marshall systemd-resolved[3183]: Using degraded feature set (TCP) for DNS server 127.0.0.1.

  
  # dpkg --status systemd
  Package: systemd
  Installed-Size: 12444
  Maintainer: Ubuntu Developers <ubuntu-devel-discuss at lists.ubuntu.com>
  Architecture: amd64
  Multi-Arch: foreign
  Version: 237-3ubuntu10.9

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