Postfix suddenly stopped working

[Matthew Dillon]

:I had what may be a similar issue; I found that postfix's "local" daemon
:would stick.  In my case, "local" is configured to deliver through procmail, 
:but it would occasionally just get stuck (it wouldn't get as far as calling
:procmail in this case).  Sometimes a postfix stop and restart would work,
:sometimes not.  Sometimes, a postmaster -h <first entry in queue> followed
:by postmaster -H <same entry> would unclog things (that is postfix-speak for
:"put it on hold" and "take it off hold" (moves it to a different queue
:directory and back).  Sometimes a reboot was required.
:
:I never did get to the bottom of it.  I rebuilt postfix and all of its
:dependencies, with no change in behavior.  I did not ktrace the process,
:but gdb told me that it was sticking on an flock - I never did figure out
:which file though. 
:
:This was all after upgrading from 1.2.x to 1.4 (and then 1.6).  In the end,
:I ran out of time to monkey with it and just switched to sendmail.  I've still
:..
:-- 
:   Jon Hamilton 
:   hamilton at xxxxxxxxx

    If it is stuck on an flock then the vnodeinfo program at
    /usr/src/test/debug/vnodeinfo.c may help:

    cc /usr/src/test/debug/vnodeinfo.c -o /usr/local/bin/vnodeinfo -lkvm

    (NOTE!  you need the latest HEAD for the program to compile properly,
    with the latest /usr/src/test/debug/vnodeinfo.c file and the latest
    /usr/src/sys/sys/fcntl.h copied to /usr/include/sys).

    With postfix stuck, do:

    /usr/local/bin/vnodeinfo -a > /tmp/outfile

    Then look for vnode information structures containing LOCKS or BLKED
    entries that might be related to the problem.

    If there are no blocked locks then it could be a race in our POSIX
    locking sleep/wakeup code.

					-Matt
					Matthew Dillon 
					<dillon at xxxxxxxxxxxxx>