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usb: gadget: u_serial: Add null pointer check in gserial_suspend

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[ Upstream commit 2f6ecb89fe ]

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: aba3a8d01d ("usb: gadget: u_serial: add suspend resume callbacks")
Signed-off-by: Prashanth K <quic_prashk@quicinc.com>
Link: https://lore.kernel.org/r/1683278317-11774-1-git-send-email-quic_prashk@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Prashanth K 2023-05-05 14:48:37 +05:30 committed by Greg Kroah-Hartman
parent c3b322b84a
commit e60a827ac0
1 changed files with 11 additions and 2 deletions
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13
drivers/usb/gadget/function/u_serial.c
View file

@ -1419,10 +1419,19 @@ 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);
}