Theodore Y. Ts'o wrote:
On Wed, Apr 25, 2018 at 09:46:42AM +0900, Tetsuo Handa wrote:
Theodore Ts'o wrote:
We can do a sleeping allocation from an irq context when CONFIG_NUMA is enabled. Fix this by initializing the NUMA crng instances in a workqueue.
Offloading to workqueue context itself would be OK, but this patch makes linux.git unbootable because
if (crng == &primary_crng && crng_init < 2) { invalidate_batched_entropy(); numa_crng_init(); // <= Deferred to workqueue context. crng_init = 2; // <= Not waiting for workqueue context, and oops before console becomes ready. ;-) process_random_ready_list(); wake_up_interruptible(&crng_init_wait); pr_notice("random: crng init done\n"); }
Please don't pretend rng_ready() before workqueue context is processed.
Where's the oops?
I assumed an oops happened, for the kernel did not start printing messages even after 1 minute from guest's power on, and CPU usage (seen from host side) says that 1 CPU is busy-looping; which is a phenomenon that the kernel panic()ed at very early stage. And reverting only your patch solved the problem.
But I can no longer reproduce it. I should have saved the kernel config... So, if nobody sees regression, please go with your patch.
-DECLARE_WORK(numa_crng_init_work, do_numa_crng_init); +static DECLARE_WORK(numa_crng_init_work, do_numa_crng_init);