On 8/26/25 2:38 PM, Ming Lei wrote:

On Tue, Aug 26, 2025 at 02:00:56PM +0530, Venkat Rao Bagalkote wrote:

quoted

Greetings!!!


IBM CI has reported a kernel OOPs, while running blktest suite(nvme/058
test).


Kernel Repo:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Traces:


[37496.800225] BUG: Kernel NULL pointer dereference at 0x00000000
[37496.800230] Faulting instruction address: 0xc0000000008a34b0
[37496.800235] Oops: Kernel access of bad area, sig: 11 [#1]

...

quoted

[37496.800365] GPR28: 0000000000000001 0000000000000001 c0000000b005c400
0000000000000000
[37496.800424] NIP [c0000000008a34b0] __rq_qos_done_bio+0x3c/0x88

It looks regression from 370ac285f23a ("block: avoid cpu_hotplug_lock depedency on freeze_lock"),
For nvme mpath, same bio crosses two drivers, so QUEUE_FLAG_QOS_ENABLED & q->rq_qos check can't
be skipped.

Thanks Ming for looking at it. And yes you were correct, we can't skip
QUEUE_FLAG_QOS_ENABLED & q->rq_qos for NVMe, However this issue only
manifests with NVMe multipath enabled, as that would create the stacked
NVMe devices. So shall I send the fix or are you going to send the patch
with fix?

Thanks,
--Nilay