[lvc-project] [PATCH] usb: gadget: r8a66597-udc: Fix double free in r8a66597_probe

[Mikhail Arkhipov]

The function r8a66597_free_request is called to free r8a66597->ep0_req,
but the pointer is not set to NULL afterward, which may lead to a double
free if the function is called again.

If the probe process fails and the r8a66597_probe function subsequently
goes through its error handling path. Since r8a66597_free_request is called
multiple times in different error handling sections, it leads to an attempt
to free the same memory twice.

Set r8a66597->ep0_req to NULL after calling r8a66597_free_request
to prevent any further attempts to free this pointer.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 0f91349b89f3 ("usb: gadget: convert all users to the new udc infrastructure")
Signed-off-by: Mikhail Arkhipov <m.arhipov at rosa.ru>
---
 drivers/usb/gadget/udc/r8a66597-udc.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/usb/gadget/udc/r8a66597-udc.c b/drivers/usb/gadget/udc/r8a66597-udc.c
index db4a10a979f9..43b81cae7d17 100644
--- a/drivers/usb/gadget/udc/r8a66597-udc.c
+++ b/drivers/usb/gadget/udc/r8a66597-udc.c
@@ -1952,12 +1952,14 @@ static int r8a66597_probe(struct platform_device *pdev)
 
 err_add_udc:
 	r8a66597_free_request(&r8a66597->ep[0].ep, r8a66597->ep0_req);
+	r8a66597->ep0_req = NULL;
 clean_up2:
 	if (r8a66597->pdata->on_chip)
 		clk_disable_unprepare(r8a66597->clk);
 
 	if (r8a66597->ep0_req)
 		r8a66597_free_request(&r8a66597->ep[0].ep, r8a66597->ep0_req);
+		r8a66597->ep0_req = NULL;
 
 	return ret;
 }
-- 
2.39.3 (Apple Git-146)