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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Dan Carpenter <dan.carpenter@oracle.com>,
        Dmitry Fomichev <dmitry.fomichev@wdc.com>,
        Mike Snitzer <snitzer@redhat.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.14 61/62] dm zoned: fix potential NULL dereference in dmz_do_reclaim()
Date:   Tue, 27 Aug 2019 09:51:06 +0200
Message-Id: <20190827072704.012827908@linuxfoundation.org>
In-Reply-To: <20190827072659.803647352@linuxfoundation.org>
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[ Upstream commit e0702d90b79d430b0ccc276ead4f88440bb51352 ]

This function is supposed to return error pointers so it matches the
dmz_get_rnd_zone_for_reclaim() function.  The current code could lead to
a NULL dereference in dmz_do_reclaim()

Fixes: b234c6d7a703 ("dm zoned: improve error handling in reclaim")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Dmitry Fomichev <dmitry.fomichev@wdc.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/md/dm-zoned-metadata.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/md/dm-zoned-metadata.c b/drivers/md/dm-zoned-metadata.c
index ccf17eb6adaa2..b322821a6323b 100644
--- a/drivers/md/dm-zoned-metadata.c
+++ b/drivers/md/dm-zoned-metadata.c
@@ -1579,7 +1579,7 @@ static struct dm_zone *dmz_get_seq_zone_for_reclaim(struct dmz_metadata *zmd)
 	struct dm_zone *zone;
 
 	if (list_empty(&zmd->map_seq_list))
-		return NULL;
+		return ERR_PTR(-EBUSY);
 
 	list_for_each_entry(zone, &zmd->map_seq_list, link) {
 		if (!zone->bzone)
@@ -1588,7 +1588,7 @@ static struct dm_zone *dmz_get_seq_zone_for_reclaim(struct dmz_metadata *zmd)
 			return zone;
 	}
 
-	return NULL;
+	return ERR_PTR(-EBUSY);
 }
 
 /*
-- 
2.20.1