nvme-6.3: blktests nvme/003 null pointer for fc transport

[James Smart]

On 1/30/2023 3:15 AM, Daniel Wagner wrote:
> Hi,
> 
> Hannes added support to blktest to enable the FC transport for it. And as result
> blktests is able to crash the kernel. Haven't startet to look into it yet.
> 
>   run blktests nvme/003 at 2023-01-30 12:08:28
>   nvmet: adding nsid 1 to subsystem blktests-subsystem-1
>   BUG: kernel NULL pointer dereference, address: 0000000000000010
>   #PF: supervisor read access in kernel mode
>   #PF: error_code(0x0000) - not-present page
>   PGD 0 P4D 0
>   Oops: 0000 [#1] PREEMPT SMP NOPTI
>   CPU: 3 PID: 14200 Comm: nvme Not tainted 6.2.0-rc4+ #1 c9afca57e89c2aa3234427c2cd6cd4dd2984ae8c
>   Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
>   RIP: 0010:nvme_alloc_admin_tag_set+0x38/0x120 [nvme_core]

bingo...

The cleanup patch "nvme-fc: use the tagset alloc/free helpers" 
introduced it.

See the fix patch "nvme-fc: Fix initialization order" about 10 days ago 
that corrects it.

-- james