Your message dated Sat, 11 May 2013 10:05:52 +0000 with message-id <[email protected]> and subject line Bug#707655: Removed package(s) from unstable has caused the Debian Bug report #386122, regarding syslogd can deadlock with named when receiving log messages from the network to be marked as done.
This means that you claim that the problem has been dealt with. If this is not the case it is now your responsibility to reopen the Bug report if necessary, and/or fix the problem forthwith. (NB: If you are a system administrator and have no idea what this message is talking about, this may indicate a serious mail system misconfiguration somewhere. Please contact [email protected] immediately.) -- 386122: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=386122 Debian Bug Tracking System Contact [email protected] with problems
--- Begin Message ---Package: sysklogd Version: 1.4.1-17 Because calls to syslog(3) are blocking and syslogd is single-threaded and calls gethostbyaddr(3) for each line logged, it is possible for syslogd to deadlock against named. This occurs when all named threads are waiting in syslog(3) (waiting for syslogd to process those packets) and therefore unable to process the DNS requests generated by gethostbyaddr(3). The relevant code is this bit of syslog.c, from line 1123: if (InetInuse && AcceptRemote && FD_ISSET(inetm, &readfds)) { len = sizeof(frominet); memset(line, '\0', sizeof(line)); i = recvfrom(finet, line, MAXLINE - 2, 0, \ (struct sockaddr *) &frominet, &len); dprintf("Message from inetd socket: #%d, host: %s\n", inetm, inet_ntoa(frominet.sin_addr)); if (i > 0) { line[i] = line[i+1] = '\0'; from = (char *)cvthname(&frominet); cvthname (line 2049) calls gethostbyaddr. The workaround for this problem is to put the hostnames and IP addresses of all of the hosts from which syslogd receives log messages in /etc/hosts (or some other source which can be accessed without the risk of deadlock). Where this is not practical an obvious workaround would be to disable calls to gethostbyaddr(3); there's no command-line option for this, but the patch is trivial. A better solution would be for syslogd to use an asynchronous DNS library such as ARES so that name resolution never blocked. A partial solution would be to have syslogd fork a separate process for receiving lines from the network, but this would only help in the case of a *local* DNS server -- it could still deadlock against a DNS server on a remote machine from which it was receiving log lines. See also this linux-kernel discussion: http://www.ussg.iu.edu/hypermail/linux/kernel/0010.2/1130.html though much of it (in particular the suggestion about fsync) is irrelevant. -- Chris Lightfoot mySociety
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--- Begin Message ---Version: 1.5-6.2+rm Dear submitter, as the package sysklogd has just been removed from the Debian archive unstable we hereby close the associated bug reports. We are sorry that we couldn't deal with your issue properly. For details on the removal, please see http://bugs.debian.org/707655 The version of this package that was in Debian prior to this removal can still be found using http://snapshot.debian.org/. This message was generated automatically; if you believe that there is a problem with it please contact the archive administrators by mailing [email protected]. Debian distribution maintenance software pp. Ansgar Burchardt (the ftpmaster behind the curtain)
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