From: Liang He <windhl@126.com>
Date: Wed, 15 Mar 2023 06:20:32 +0000 (+0800)
Subject: block: sunvdc: add check for mdesc_grab() returning NULL
X-Git-Tag: baikal/mips/sdk5.8.2~138
X-Git-Url: https://git.baikalelectronics.ru/sdk/?a=commitdiff_plain;h=2d3e4656569db64694179b9f96df1f84063d01a8;p=kernel.git

block: sunvdc: add check for mdesc_grab() returning NULL

[ Upstream commit 6030363199e3a6341afb467ddddbed56640cbf6a ]

In vdc_port_probe(), we should check the return value of mdesc_grab() as
it may return NULL, which can cause potential NPD bug.

Fixes: 136a29bb9255 ("[SPARC64]: Abstract out mdesc accesses for better MD update handling.")
Signed-off-by: Liang He <windhl@126.com>
Link: https://lore.kernel.org/r/20230315062032.1741692-1-windhl@126.com
[axboe: style cleanup]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/drivers/block/sunvdc.c b/drivers/block/sunvdc.c
index 6b2fd630de852..6622dd1aa07b2 100644
--- a/drivers/block/sunvdc.c
+++ b/drivers/block/sunvdc.c
@@ -983,6 +983,8 @@ static int vdc_port_probe(struct vio_dev *vdev, const struct vio_device_id *id)
 	print_version();
 
 	hp = mdesc_grab();
+	if (!hp)
+		return -ENODEV;
 
 	err = -ENODEV;
 	if ((vdev->dev_no << PARTITION_SHIFT) & ~(u64)MINORMASK) {