From 2434dece1fcbd073c9a237201aa95ee9041d646c Mon Sep 17 00:00:00 2001 From: Prashanth K Date: Fri, 5 May 2023 14:48:37 +0530 Subject: [PATCH] FROMGIT: usb: gadget: u_serial: Add null pointer check in gserial_suspend 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 Link: https://lore.kernel.org/r/1683278317-11774-1-git-send-email-quic_prashk@quicinc.com Signed-off-by: Greg Kroah-Hartman Bug: 285495243 (cherry picked from commit 2f6ecb89fe8feb2b60a53325b0eeb9866d88909a https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git/ usb-next) Signed-off-by: Prashanth K Change-Id: I2c5b58eaaa1e3428952ffdbf7f1a39cad519cc5a (cherry picked from commit f51f079fe30f53aca027aca2c7a517e79c45b67f) --- 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 0c429f25d0ac..8673b9a5ab53 100644 --- a/drivers/usb/gadget/function/u_serial.c +++ b/drivers/usb/gadget/function/u_serial.c @@ -1423,10 +1423,19 @@ 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); }