[PATCH] thunderbolt_tb: add check for return value of 'tb_switch_find_port'

[Natalia Petrova]

Return value of 'tb_switch_find_port' has to be checked to avoid
null pointer dereferences in functions tb_tunnel_alloc_dma() and
tb_port_info().

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

Fixes: 386e5e29d81c ("thunderbolt: Make tb_find_port() available to other files")
Signed-off-by: Natalia Petrova <n.petrova@xxxxxxxxxx>
---
 drivers/thunderbolt/tb.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/thunderbolt/tb.c b/drivers/thunderbolt/tb.c
index 9853f6c7e81d..5d6cded68d46 100644
--- a/drivers/thunderbolt/tb.c
+++ b/drivers/thunderbolt/tb.c
@@ -1156,6 +1156,8 @@ static int tb_approve_xdomain_paths(struct tb *tb, struct tb_xdomain *xd,
 	sw = tb_to_switch(xd->dev.parent);
 	dst_port = tb_port_at(xd->route, sw);
 	nhi_port = tb_switch_find_port(tb->root_switch, TB_TYPE_NHI);
+	if (!nhi_port)
+		return -EIO;
 
 	mutex_lock(&tb->lock);
 	tunnel = tb_tunnel_alloc_dma(tb, nhi_port, dst_port, transmit_path,
-- 
2.34.1