Thread (8 messages) 8 messages, 3 authors, 2022-09-19
STALE1373d REVIEWED: 5 (4M)

[PATCH v2 2/3] md: Remove extra mddev_get() in md_seq_start()

From: Logan Gunthorpe <logang@deltatee.com>
Date: 2022-09-08 16:16:27
Also in: lkml
Subsystem: software raid (multiple disks) support, the rest · Maintainers: Song Liu, Yu Kuai, Linus Torvalds

A regression is seen where mddev devices stay permanently after they
are stopped due to an elevated reference count.

This was tracked down to an extra mddev_get() in md_seq_start().

It only happened rarely because most of the time the md_seq_start()
is called with a zero offset. The path with an extra mddev_get() only
happens when it starts with a non-zero offset.

The commit noted below changed an mddev_get() to check its success
but inadevrtantly left the original call in. Remove the extra call.

Fixes: 12a6caf27324 ("md: only delete entries from all_mddevs when the disk is freed")
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Guoqing Jiang <redacted>
---
 drivers/md/md.c | 1 -
 1 file changed, 1 deletion(-)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index afaf36b2f6ab..9dc0175280b4 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -8154,7 +8154,6 @@ static void *md_seq_start(struct seq_file *seq, loff_t *pos)
 	list_for_each(tmp,&all_mddevs)
 		if (!l--) {
 			mddev = list_entry(tmp, struct mddev, all_mddevs);
-			mddev_get(mddev);
 			if (!mddev_get(mddev))
 				continue;
 			spin_unlock(&all_mddevs_lock);
-- 
2.30.2
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