From: Prashanth K <quic_prashk@xxxxxxxxxxx>
[ Upstream commit 2f6ecb89fe8feb2b60a53325b0eeb9866d88909a ]
Consider a case where gserial_disconnect has already cleared
gser->ioport. And if gserial_suspend gets called afterwards,
it will lead to accessing of gser->ioport and thus causing
null pointer dereference.
Avoid this by adding a null pointer check. Added a static
spinlock to prevent gser->ioport from becoming null after
the newly added null pointer check.
Fixes: aba3a8d01d62 ("usb: gadget: u_serial: add suspend resume callbacks")
Signed-off-by: Prashanth K <quic_prashk@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/1683278317-11774-1-git-send-email-quic_prashk@xxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/usb/gadget/function/u_serial.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/gadget/function/u_serial.c b/drivers/usb/gadget/function/u_serial.c
index 7b54e814aefb1..3b5a6430e2418 100644
--- a/drivers/usb/gadget/function/u_serial.c
+++ b/drivers/usb/gadget/function/u_serial.c
@@ -1421,10 +1421,19 @@ EXPORT_SYMBOL_GPL(gserial_disconnect);
void gserial_suspend(struct gserial *gser)
{
- struct gs_port *port = gser->ioport;
+ struct gs_port *port;
unsigned long flags;
- spin_lock_irqsave(&port->port_lock, flags);
+ spin_lock_irqsave(&serial_port_lock, flags);
+ port = gser->ioport;
+
+ if (!port) {
+ spin_unlock_irqrestore(&serial_port_lock, flags);
+ return;
+ }
+
+ spin_lock(&port->port_lock);
+ spin_unlock(&serial_port_lock);
port->suspended = true;
spin_unlock_irqrestore(&port->port_lock, flags);
}
--
2.39.2
