Re: [PATCH] blk-mq: nvme: Fix general protection fault in nvme_setup_descriptor_pools()

On Tue, Mar 10, 2026 at 11:57 AM Caleb Sander Mateos
[off-list ref] wrote:

On Mon, Mar 9, 2026 at 4:55 PM Sungwoo Kim [off-list ref] wrote:

quoted

On Mon, Mar 9, 2026 at 11:31 AM Caleb Sander Mateos
[off-list ref] wrote:

quoted

On Sun, Mar 8, 2026 at 11:30 PM Sungwoo Kim [off-list ref] wrote:

quoted

The numa_node can be < 0 since NUMA_NO_NODE = -1. However,
struct blk_mq_hw_ctx{} defines numa_node as unsigned int. As a result,
numa_node is set to UINT_MAX for NUMA_NO_NODE in blk_mq_alloc_hctx().

The node argument to blk_mq_alloc_hctx() comes from
blk_mq_alloc_and_init_hctx(), which is called by
blk_mq_alloc_and_init_hctx() with int node = blk_mq_get_hctx_node(set,
i). node = NUMA_NO_NODE would suggest that blk_mq_hw_queue_to_node()
doesn't find any CPU affinitized to the queue. Is that even possible?

Thanks for your review, Celeb.

While I'm flattered you consider me a celebrity, my name is Caleb :)

My apologies, Caleb. I'll be more careful.

quoted

blk_mq_hw_queue_to_node() can return NUMA_NO_NODE if the device queues
exceed the
number of CPUs. Afterward, it is adjusted on the caller side to
numa_node = set->numa_node.

I thought the NVMe driver capped the number of queues so every queue
is affinitized to some CPU (see nvme_max_io_queues()). What am I
missing?

Best,
Caleb

You are right, every hw queue should be affinitized. It seems I'm
missing a lot. I'll look into the reasons and get back with V2.

I appreciate your review again.

Sungwoo.