8-STABLE/amd64 semi-regular crash with "kernel trap 12 with interrupts disabled" in "process 12 (swi4: clock)"

[Eugene Grosbein]

On 19.01.2011 15:00, Lev Serebryakov wrote:
> Hello, Eugene.
> You wrote 19 января 2011 г., 11:44:01:
> 
>> There is known instability in em(4) driver in 8.2-RELEASE,
>> it may panic due to some lack of NULL pointer checks.
>> You should update to RELENG_8 containting fix and retest.
>  uname -v
>  FreeBSD 8.2-PRERELEASE #5: Sat Jan  8 14:38:46 MSK 2011
> 
>  It is built about hour after cvsup.

Yes, I've missed it's PRERELEASE already.
Backtrace points to the problem in em_local_timer() fixed in CURRENT
7 days ago, take a look:

http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/dev/e1000/if_em.c#rev1.65

I run my servers with this commit backported manually as
it has not been MFC'd yet.

Eugene Grosbein