[bug report] WARNING: CPU: 3 PID: 522 at block/genhd.c:144 bdev_count_inflight_rw+0x26e/0x410

[Breno Leitao]

Hello Jens,

On Mon, Jun 09, 2025 at 08:22:35AM -0600, Jens Axboe wrote:
> On 6/9/25 3:14 AM, Breno Leitao wrote:
> > On Fri, Jun 06, 2025 at 11:31:06AM +0800, Yi Zhang wrote:
> >> Hello
> >>
> >> The following WARNING was triggered by blktests nvme/fc nvme/012,
> >> please help check and let me know if you need any info/test, thanks.
> >>
> >> commit: linux-block: 38f4878b9463 (HEAD, origin/for-next) Merge branch
> >> 'block-6.16' into for-next
> > 
> > I am seeing a similar issue on Linus' recent tree as e271ed52b344
> > ("Merge tag 'pm-6.16-rc1-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm").
> > CCing Jens.
> > 
> > This is my stack, in case it is useful.
> 
> What does your storage setup look like? Likely not a new issue, only
> change is that we now report/warn if these counters ever hit < 0. Adding
> Yu to the CC as he recently worked in this area, and added the patch
> that triggers the warning now.

Basically a host with a bunch of nvme:

	# lsblk
	NAME        MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS
	nvme1n1     259:0    0 238.5G  0 disk
	├─nvme1n1p1 259:2    0   243M  0 part /boot/efi
	├─nvme1n1p2 259:3    0   488M  0 part /boot
	├─nvme1n1p3 259:4    0   1.9G  0 part [SWAP]
	└─nvme1n1p4 259:5    0 235.8G  0 part /
	nvme0n1     259:1    0   1.6T  0 disk
	├─nvme0n1p1 259:6    0 838.4G  0 part
	└─nvme0n1p2 259:7    0 838.4G  0 part

	# dmesg | grep nvme
	[  435.301782] nvme nvme0: pci function 0000:b4:00.0
	[  435.412268] nvme nvme1: pci function 0000:64:00.0
	[  435.459601] nvme nvme0: D3 entry latency set to 8 seconds
	[  435.848628] nvme nvme1: 32/0/0 default/read/poll queues
	[  435.944582] nvme nvme0: 52/0/0 default/read/poll queues
	[  436.135123]  nvme1n1: p1 p2 p3 p4
	[  436.316921]  nvme0n1: p1 p2
	[  500.912739] BTRFS: device label / devid 1 transid 2052 /dev/nvme1n1p4 (259:5) scanned by mount (837)
	[  501.583187] BTRFS info (device nvme1n1p4): first mount of filesystem 0568aa14-1bee-4c76-b409-662d748eefad
	[  501.602891] BTRFS info (device nvme1n1p4): using crc32c (crc32c-x86) checksum algorithm
	[  501.618986] BTRFS info (device nvme1n1p4): using free-space-tree
	[  562.737848] systemd[1]: Expecting device dev-nvme0n1p3.device - /dev/nvme0n1p3...
	[  567.865384] BTRFS info (device nvme1n1p4 state M): force zstd compression, level 3
	[  603.745650] EXT4-fs (nvme1n1p2): mounted filesystem 57120c82-6f1a-4e1f-a8c3-6aa17bffb1f2 r/w with ordered data mode. Quota mode: none.
	[  604.103672] FAT-fs (nvme1n1p1): Volume was not properly unmounted. Some data may be corrupt. Please run fsck.
	[  658.986835]        nvme_alloc_ns+0x204/0x2ee0
	[  658.986842]        nvme_scan_ns+0x53f/0x8b0
	[  660.888749] nvme nvme0: using unchecked data buffer
	[  859.589752] Adding 2000892k swap on /dev/nvme1n1p3.  Priority:5 extents:1 across:2000892k SS
	[ 1698.294280] block nvme1n1: No UUID available providing old NGUID
	[ 1698.356183] block nvme1n1: the capability attribute has been deprecated.
	[ 1807.416851] Adding 2000892k swap on /dev/nvme1n1p3.  Priority:5 extents:1 across:2000892k SS

This was happening while a HTTP server was being executed.

Does it answer your question?

Thanks for the reply,
--breno