diff --git a/block/bdev.c b/block/bdev.c
index 979e28a46b98..699739223dcb 100644
--- a/block/bdev.c
+++ b/block/bdev.c

@@ -789,8 +789,11 @@ struct block_device *blkdev_get_by_dev(dev_t dev, 

blk_mode_t mode, void *holder,
         if (holder) {
                 mode |= BLK_OPEN_EXCL;
                 ret = bd_prepare_to_claim(bdev, holder, hops);
-               if (ret)
+               if (ret) {
+                       pr_warn("%s:%s bd_prepare_to_claim return %d\n",
+                               disk->disk_name, current->comm, ret);
                         goto put_blkdev;
+               }
         } else {
                 if (WARN_ON_ONCE(mode & BLK_OPEN_EXCL)) {
                         ret = -EIO;

diff --git a/block/fops.c b/block/fops.c
index eaa98a987213..2d69119c71f6 100644
--- a/block/fops.c
+++ b/block/fops.c

@@ -587,8 +587,11 @@ static int blkdev_open(struct inode *inode, struct 

file *filp)

         bdev = blkdev_get_by_dev(inode->i_rdev, file_to_blk_mode(filp),
                                  filp->private_data, NULL);
-       if (IS_ERR(bdev))
+       if (IS_ERR(bdev)) {
+               pr_warn("%pD:%s blkdev_get_by_dev return %ld\n",
+                       filp, current->comm, PTR_ERR(bdev));
                 return PTR_ERR(bdev);
+       }

         if (bdev_nowait(bdev))
                 filp->f_mode |= FMODE_NOWAIT;

Thanks,
Kuai

quoted

Therefore, could you please help clarify:

1. Which base kernel are you using?

quoted

From the log, you are using 6.5-rc7-706a74159504. However,

I think we cannot cleanly revert 12a6caf273240a on top of
6.5-rc7-706a74159504. Did you manually fix some issue in the
revert? If so, could you please share the revert commit?

2. If you are not using 6.5-rc7-706a74159504 as base kernel, which
one are you using?

Thanks,
Song

quoted

quoted

2. Try with the following change (add debug messages), which hopefully
    shows which command is holding a reference on mddev->openers.

Thanks,
Song

diff --git i/drivers/md/md.c w/drivers/md/md.c
index 78be7811a89f..3e9b718b32c1 100644
--- i/drivers/md/md.c
+++ w/drivers/md/md.c

@@ -7574,11 +7574,15 @@ static int md_ioctl(struct block_device *bdev,

blk_mode_t mode,
                 if (mddev->pers && atomic_read(&mddev->openers) > 1) {
                         mutex_unlock(&mddev->open_mutex);
                         err = -EBUSY;
+                       pr_warn("%s return -EBUSY for %s with
mddev->openers = %d\n",
+                               __func__, mdname(mddev),
atomic_read(&mddev->openers));
                         goto out;
                 }
                 if (test_and_set_bit(MD_CLOSING, &mddev->flags)) {
                         mutex_unlock(&mddev->open_mutex);
                         err = -EBUSY;
+                       pr_warn("%s return -EBUSY for %s with
MD_CLOSING bit set\n",
+                               __func__, mdname(mddev));
                         goto out;
                 }
                 did_set_md_closing = true;

@@ -7789,6 +7793,8 @@ static int md_open(struct gendisk *disk, 

blk_mode_t mode)
                 goto out_unlock;

         atomic_inc(&mddev->openers);
+       pr_info("%s:%s openers++ = %d by %s\n", __func__, 
mdname(mddev),
+               atomic_read(&mddev->openers), current->comm);
         mutex_unlock(&mddev->open_mutex);

         disk_check_media_change(disk);

@@ -7807,6 +7813,8 @@ static void md_release(struct gendisk *disk)

         BUG_ON(!mddev);
         atomic_dec(&mddev->openers);
+       pr_info("%s:%s openers-- = %d by %s\n", __func__, 
mdname(mddev),
+               atomic_read(&mddev->openers), current->comm);
         mddev_put(mddev);
  }

It's pretty strange that I can't reproduce the issue after applied 
the patch.

I tried to figure out which part affect the issue and found when I
comment out the pr_info() In md_release(), the issue could be
reproduced.

-- 
Chia-Lin Kao(AceLan)
http://blog.acelan.idv.tw/
E-Mail: acelan.kaoATcanonical.com (s/AT/@/)

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