[PATCH 5.11 039/775] staging: vchiq: Fix bulk userdata handling

[Greg Kroah-Hartman]

From: Phil Elwell <phil@xxxxxxxxxxxxxxx>

[ Upstream commit 96ae327678eceabf455b11a88ba14ad540d4b046 ]

The addition of the local 'userdata' pointer to
vchiq_irq_queue_bulk_tx_rx omitted the case where neither BLOCKING nor
WAITING modes are used, in which case the value provided by the
caller is not returned to them as expected, but instead it is replaced
with a NULL. This lack of a suitable context may cause the application
to crash or otherwise malfunction.

Fixes: 4184da4f316a ("staging: vchiq: fix __user annotations")
Tested-by: Stefan Wahren <stefan.wahren@xxxxxxxx>
Acked-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Phil Elwell <phil@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20210105162030.1415213-2-phil@xxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
index f500a70438056..2a8883673ba11 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
@@ -958,7 +958,7 @@ static int vchiq_irq_queue_bulk_tx_rx(struct vchiq_instance *instance,
 	struct vchiq_service *service;
 	struct bulk_waiter_node *waiter = NULL;
 	bool found = false;
-	void *userdata = NULL;
+	void *userdata;
 	int status = 0;
 	int ret;
 
@@ -997,6 +997,8 @@ static int vchiq_irq_queue_bulk_tx_rx(struct vchiq_instance *instance,
 			"found bulk_waiter %pK for pid %d", waiter,
 			current->pid);
 		userdata = &waiter->bulk_waiter;
+	} else {
+		userdata = args->userdata;
 	}
 
 	/*
-- 
2.27.0