Re: amanda vs 2.6

From: Nick Piggin
Date: Thu Nov 27 2003 - 03:42:19 EST




Linus Torvalds wrote:


On Wed, 26 Nov 2003, William Lee Irwin III wrote:


On Wed, Nov 26, 2003 at 02:43:43PM -0500, Gene Heskett wrote:

No, it just hangs forever on the su command, never coming back.
everything else I tried, which wasn't much, seemed to keep on working
as I sent that message with that hung su process in another shell on
another window. I'm an idiot, normally running as root...
I've rebooted, not knowing if an echo 0 to that variable would fix it
or not, I see after the reboot the default value is 0 now.

Okay, then we need to figure out what the hung process was doing.
Can you find its pid and check /proc/$PID/wchan?


I've seen this before, and I'll bet you 5c (yeah, I'm cheap) that it's
trying to log to syslogd.

And syslogd is stopped for some reason - either a bug, a mistaken SIGSTOP,
or simply because the console has been stopped with a simple ^S.

That won't stop "su" working immediately - programs can still log to
syslogd until the logging socket buffer fills up. Which can be _damn_
frsutrating to find (I haven't seen this behaviour lately, but I remember
being perplexed like hell a long time ago).


Same problem here. Been seeing them now and again for quite a while
I have syslogd and klogd sleeping in do_syslog. cron and login are
sleeping in schedule_timeout. A sysrq+T gets things going again but
unfortunately the interesting state probably wasn't captured. I have
the /proc/*/wchan and sysrq+t trace if anyone is interested.

I'll try any suggestions of what I should look at when I hit it again.

Nick


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