net: dsa: sja1105: fix buffer overflow in sja1105_setup_devlink_regions()

stable inclusion
from stable-v5.10.138
commit 7983e1e44cb322eba6af84160b6d18df80603fb8
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I60QFD

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=7983e1e44cb322eba6af84160b6d18df80603fb8

--------------------------------

commit fd8e899c upstream.

If an error occurs in dsa_devlink_region_create(), then 'priv->regions'
array will be accessed by negative index '-1'.

Found by Linux Verification Center (linuxtesting.org) with SVACE.
Signed-off-by: NRustam Subkhankulov <subkhankulov@ispras.ru>
Fixes: bf425b82 ("net: dsa: sja1105: expose static config as devlink region")
Link: https://lore.kernel.org/r/20220817003845.389644-1-subkhankulov@ispras.ruSigned-off-by: NJakub Kicinski <kuba@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: NWei Li <liwei391@huawei.com>

drivers/net/dsa/sja1105/sja1105_devlink.c

@@ -93,7 +93,7 @@ static int sja1105_setup_devlink_regions(struct dsa_switch *ds)
 
 		region = dsa_devlink_region_create(ds, ops, 1, size);
 		if (IS_ERR(region)) {
-			while (i-- >= 0)
+			while (--i >= 0)
 				dsa_devlink_region_destroy(priv->regions[i]);
 			return PTR_ERR(region);
 		}