[cups-devel] [UNKN] STR #4550: avahi_client_free() called with NULL pointer during shutdown

Evangelos Foutras noreply at cups.org
Sun Dec 28 04:29:56 PST 2014


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[STR New]

During system shutdown, CUPS logs the following error:

> Unable to communicate with avahi-daemon: An unexpected D-Bus error
occured

Shortly after that, cupsd calls avahi_client_free() with a NULL DNSSDClient
pointer and immediately terminates with SIGABRT.

According to the systemd journal, "Avahi mDNS/DNS-SD Stack" is stopped
before "CUPS Scheduler". My guess is that DNSSDClient is freed and set to
NULL by dnssdClientCallback() following the termination of the Avahi
daemon.

A simple solution would be to check if DNSSDClient is NULL before calling
avahi_client_free() in dnssdStop(). Either a (DNSSDClient != NULL) or
(avahi_running == 1) condition should suffice.

I'm using Arch Linux on x86_64 with the following software:

- - cups 2.0.1
- - systemd 218
- - avahi 0.6.31

Link: https://www.cups.org/str.php?L4550
Version: 2.0.1
Attachment: https://www.cups.org/strfiles.php/3426/gdb.txt
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