net: wwan: iosm: Fix tainted pointer delete is case of region creation fail

[ Upstream commit b0c9a26 ]

In case of region creation fail in ipc_devlink_create_region(), previously
created regions delete process starts from tainted pointer which actually
holds error code value.
Fix this bug by decreasing region index before delete.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 4dcd183 ("net: wwan: iosm: devlink registration")
Signed-off-by: Aleksandr Mishin <amishin@t-argos.ru>
Acked-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20240604082500.20769-1-amishin@t-argos.ru
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: Aleksandr Mishin

drivers/net/wwan/iosm/iosm_ipc_devlink.c

@@ -210,7 +210,7 @@ static int ipc_devlink_create_region(struct iosm_devlink *devlink)
 			rc = PTR_ERR(devlink->cd_regions[i]);
 			dev_err(devlink->dev, "Devlink region fail,err %d", rc);
 			/* Delete previously created regions */
-			for ( ; i >= 0; i--)
+			for (i--; i >= 0; i--)
 				devlink_region_destroy(devlink->cd_regions[i]);
 			goto region_create_fail;
 		}