md: Put the right device in md_seq_next

If there are multiple arrays in system and one mddevice is marked
with MD_DELETED and md_seq_next() is called in the middle of removal
then it _get()s proper device but it may _put() deleted one. As a result,
active counter may never be zeroed for mddevice and it cannot
be removed.

Put the device which has been _get with previous md_seq_next() call.

Cc: [email protected]
Fixes: 12a6caf27324 ("md: only delete entries from all_mddevs when the disk is freed")
Reported-by: AceLan Kao <[email protected]>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217798
Cc: Yu Kuai <[email protected]>
Signed-off-by: Mariusz Tkaczyk <[email protected]>
Signed-off-by: Song Liu <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 73758b75412759ee16527f5ae57a29a243b7754f..a104a025084dc726056c42b0b1a0dd37ea774803 100644 (file)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -8265,7 +8265,7 @@ static void *md_seq_next(struct seq_file *seq, void *v, loff_t *pos)
        spin_unlock(&all_mddevs_lock);
 
        if (to_put)
-               mddev_put(mddev);
+               mddev_put(to_put);
        return next_mddev;
 
 }