FreeBSD 6.1 Instability
John Baldwin
jhb at freebsd.org
Mon Oct 9 18:38:49 PDT 2006
On Thursday 05 October 2006 15:44, Charles Ulrich wrote:
> Greetings,
>
> We have been running FreeBSD on our mail servers for about as long as I can
> remember. Recently, we decided to go SMP to handle increased mail load. After
> assembling the hardware, installing the OS and software, and restoring all of
> our data, we noticed in testing that our first machine began hanging
> semi-regularly when it began processing lots of mail. Disabling SMP
> eliminated the hangs completely. We tried it all again on completely
> different hardware with exactly the same result. Our conclusion: somethings's
> buggy in SMP.
>
> Here are the symptoms. The machine hangs, and becomes completely
> unresponsive. It looks like a deadlock. It will sometimes respond to the
> power button and shut down (without being able to first sync and unmount
> filesystems), and sometimes the power button event gets caught in the
> deadlock. Sinceit's not actually a crash, there is no core dump or other
> debugging information. In the most recent situation, it hung at different
> points every time I tried to compile ezm3, after successfully compiling other
> packages.
>
> We're system administrators, not kernel hackers, so this is a plea for help. I
> wouldn't know where to start, but I'm hoping someone can point me in the
> right direction. We're also willing to give a (trustworthy) FreeBSD developer
> root access to the test machine since it's just sitting idle right now. If
> you need to crash it, that's fine. We'll have people during normal business
> hours who know how to push a reset button.
>
> Thanks for your time.
Compile a debug kernel and include 'DDB' in the kernel. When it hangs, break into
the debugger and type 'panic' to have it panic the machine and write out a crash
dump. Once you have the crash dump, download http://www.FreeBSD.org/~jhb/gdb/gdb6
and do this:
$ kgdb /usr/obj/usr/src/sys/FOO/kernel.debug /var/crash/vmcore.X
(where FOO is your kernel config file and X is the right vmcore file)
Then do this:
(gdb) source /path/to/gdb6
(gdb) ps
...
And reply with the output from the 'ps' command.
--
John Baldwin
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