On Wed, 6 Sep 2023 14:26:30 +0800
AceLan Kao <acelan@xxxxxxxxx> wrote:
> From previous testing, I don't think it's an issue in systemd, so I
> did a simple test and found the issue is gone.
> You only need to add a small delay in md_release(), then the issue
> can't be reproduced.
>
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index 78be7811a89f..ef47e34c1af5 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -7805,6 +7805,7 @@ static void md_release(struct gendisk *disk)
> {
> struct mddev *mddev = disk->private_data;
>
> + msleep(10);
> BUG_ON(!mddev);
> atomic_dec(&mddev->openers);
> mddev_put(mddev);
I have repro and I tested it on my setup. It is not working for me.
My setup could be more "advanced" to maximalize chance of reproduction:
# cat /proc/mdstat
Personalities : [raid1] [raid6] [raid5] [raid4] [raid10] [raid0]
md121 : active raid0 nvme2n1[1] nvme5n1[0]
7126394880 blocks super external:/md127/0 128k chunks
md122 : active raid10 nvme6n1[3] nvme4n1[2] nvme1n1[1] nvme7n1[0]
104857600 blocks super external:/md126/0 64K chunks 2 near-copies [4/4]
[UUUU]
md123 : active raid5 nvme6n1[3] nvme4n1[2] nvme1n1[1] nvme7n1[0]
2655765504 blocks super external:/md126/1 level 5, 32k chunk, algorithm 0
[4/4] [UUUU]
md124 : active raid1 nvme0n1[1] nvme3n1[0]
99614720 blocks super external:/md125/0 [2/2] [UU]
md125 : inactive nvme3n1[1](S) nvme0n1[0](S)
10402 blocks super external:imsm
md126 : inactive nvme7n1[3](S) nvme1n1[2](S) nvme6n1[1](S) nvme4n1[0](S)
20043 blocks super external:imsm
md127 : inactive nvme2n1[1](S) nvme5n1[0](S)
10402 blocks super external:imsm
I have almost 99% repro ratio, slowly moving forward..
It is endless loop because systemd-shutdown sends ioctl "stop_array" which is
successful but array is not stopped. For that reason it sets "changed = true".
Systemd-shutdown see the change and retries to check if there is something else
which can be stopped now, and again, again...
I will check what is returned first, it could be 0 or it could be positive
errno (nit?) because systemd cares "if(r < 0)".
Thanks,
Mariusz
