openwrt/target/linux/bcm27xx/patches-5.4/950-0977-USB-gadget-f_hid-avoid-crashes-and-log-spam.patch

From 22198e801db7542c59098a75bdab120bcbc42652 Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.com>
Date: Wed, 30 Sep 2020 19:23:43 +0100
Subject: [PATCH] USB: gadget: f_hid: avoid crashes and log spam

Disconnecting and reconnecting the USB cable can lead to crashes and a
variety of kernel log spam. Try to fix or minimise both.

See: https://github.com/raspberrypi/linux/issues/3870

Signed-off-by: Phil Elwell <phil@raspberrypi.com>
---
 drivers/usb/gadget/function/f_hid.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

--- a/drivers/usb/gadget/function/f_hid.c
+++ b/drivers/usb/gadget/function/f_hid.c
@@ -344,6 +344,11 @@ static ssize_t f_hidg_write(struct file
 
 	spin_lock_irqsave(&hidg->write_spinlock, flags);
 
+	if (!hidg->req) {
+		spin_unlock_irqrestore(&hidg->write_spinlock, flags);
+		return -ESHUTDOWN;
+	}
+
 #define WRITE_COND (!hidg->write_pending)
 try_again:
 	/* write queue */
@@ -364,7 +369,13 @@ try_again:
 	count  = min_t(unsigned, count, hidg->report_length);
 
 	spin_unlock_irqrestore(&hidg->write_spinlock, flags);
-	status = copy_from_user(req->buf, buffer, count);
+	if (req) {
+		status = copy_from_user(req->buf, buffer, count);
+	} else {
+		ERROR(hidg->func.config->cdev, "hidg->req is NULL\n");
+		status = -ESHUTDOWN;
+		goto release_write_pending;
+	}
 
 	if (status != 0) {
 		ERROR(hidg->func.config->cdev,
@@ -393,6 +404,11 @@ try_again:
 
 	spin_unlock_irqrestore(&hidg->write_spinlock, flags);
 
+	if (!hidg->in_ep->enabled) {
+		ERROR(hidg->func.config->cdev, "in_ep is disabled\n");
+		status = -ESHUTDOWN;
+		goto release_write_pending;
+	}
 	status = usb_ep_queue(hidg->in_ep, req, GFP_ATOMIC);
 	if (status < 0) {
 		ERROR(hidg->func.config->cdev,