Sendmail eats CPU on r317039 [after -r316874 it may be -r316951 and -r316973 are not enough to fix everything]

[Mark Millard]

Ronald Klop ronald-lists at klop.ws wrote on Tue Apr 18 09:59:50 UTC 2017:

> there is a thread ono this list about a problem in syslogd which made  
> syslog-clients (like sendmail busy-looping on logging.
> That might be related to this. (it is fixed in the source already, so  
> upgrading again might help)
> See the thread with subject like 'Re: r316958: booting a server takes >10  
> minutes!'
> 
> Regards,
> 
> Ronald.


Yes. But Tom V.'s report is for -r317039, which is after the reported
fixes as far as I can tell. Something besides syslogd might also cause
problems?

In my nearly-default -r317015 ardm64 context [as a VirtualBox guest]
I've not seen the problem, where I did before. (The only reason sendmail
runs in my context is for the messages FreeBSD sends to it own local
accounts. I do not otherwise use mail in this context.)

Tom V.'s report vs. others finding lack of a problem suggests that the
coverage of the fixes is incomplete somehow but useful. I happen to not
be doing whatever causes the problem to appear. I've no clue what might
be different or unusual in Tom V.'s context.

There is also the possibility that Tom V.'s report is a fully independent
issue. But such does not seem all that likely on the initial information.


> On 2017-Apr-17, at 7:57 AM, Mark Millard <markmi at dsl-only.net> wrote:
> 
>> Just an FYI of a more recent report of runaway sendmail on a
>> more recent system version ( -r317039 ):
>> 
>> Begin forwarded message:
>> 
>>> From: Tom Vijlbrief <tvijlbrief at gmail.com>
>>> Subject: Sendmail eats CPU on r317039
>>> Date: April 17, 2017 at 3:39:37 AM PDT
>>> To: "freebsd-current at freebsd.org" <freebsd-current at freebsd.org>, freebsd-arm <freebsd-arm at freebsd.org>
>>> 
>>> On a recent kernel sendmail is constantly consuming CPU.
>>> 
>>> truss -p PID
>>> 
>>> shows:
>>> 
>>> sendto(3,"<22>Apr 17 10:30:33 sendmail[362"...,163,0x0,NULL,0) ERR#55 'No
>>> buffer space available'
>>> nanosleep({ 0.000001000 }) = 0 (0x0)
>>> sendto(3,"<22>Apr 17 10:30:33 sendmail[362"...,163,0x0,NULL,0) ERR#55 'No
>>> buffer space available'
>>> nanosleep({ 0.000001000 })
>>> ...
>>> 
>>> This is on an arm64 system
>> 
>> Analysis of Tom V.'s context for this may be required.

===
Mark Millard
markmi at dsl-only.net