Dumb question: BKL on reboot ?

Hannes Reinecke
2003-08-20T10:22:12Z

Hiya,

I've got a dumb question: Why is the BKL held on entering sys_reboot()
in kernel/sys.c:405 ?
It is getting especially interesting on SMP, when one cpu is entering
sys_reboot, acquires the BKL and then waits (via machine_restart) for
all other cpus to shut down. If any of the other cpus is executing a
task which also needs the BKL, we have a nice deadlock.
We've seen this here on 2-way s390, where the other cpu tried to execute
kupdated() (what did it try that for? Anyway...), which of course
resulted in a deadlock.

Any enlightenment welcome.

Cheers,

Hannes
P.S.: Please cc me directly, I'm not subscribed.
--
Dr. Hannes Reinecke hare@suse.de
SuSE Linux AG S390 & zSeries
Deutschherrnstr. 15-19 +49 911 74053 688
90429 Nürnberg http://www.suse.de