On Wed, Jul 26, 2017 at 12:12:21PM -0700, Omar Sandoval wrote:

On Wed, Jul 26, 2017 at 10:34:43AM -0700, Christoph Hellwig wrote:

quoted

On Tue, Jul 25, 2017 at 03:24:08PM -0700, Shaohua Li wrote:

quoted

Disable CONIFG_SMP, kernel crashes at boot time, here is the log.

I can reproduce the issue.  Unfortunately the addresss in the bug
doesn't make any sense to me when resolving it using gdb, as t just
points to the line where blk_mq_init_queue calls
blk_alloc_queue_node.

Can you check if you get better results in your build?

It's crashing on that line because ctrl->tagset is NULL, which is
because...

irq_create_affinity_masks() returns NULL on !CONFIG_SMP
-> pci_irq_get_affinity() returns NULL
-> blk_mq_pci_map_queues() returns -EINVAL
-> blk_mq_alloc_tag_set() returns -EINVAL
-> nvme_dev_add() doesn't set ctrl->tagset

The two-fold fix would be to make the nvme driver handle
blk_mq_alloc_tag_set() failing and to fall back to a dumb mapping in
blk_mq_pci_map_queues(), but I don't know what the best way to do those
is.

irq_create_affinity_masks returns null and prints error, could we fix that?