[PATCH v2] usb: gadget: r8a66597-udc: Fix double free in r8a66597_probe

[PATCH v2] usb: gadget: r8a66597-udc: Fix double free in r8a66597_probe

[Mikhail Arkhipov]

The function r8a66597_free_request is already called in the err_add_udc
block, and freeing r8a66597->ep0_req twice may lead to a double free error.

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.

Remove the redundant call to r8a66597_free_request in the clean_up2 block.

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@rosa.ru>
---
v2: Remove redundant call to r8a66597_free_request in clean_up2 block 
instead of assigning r8a66597->ep0_req to NULL, as suggested by 
Sebastian Andrzej Siewior <bigeasy@linutronix.de>.
 drivers/usb/gadget/udc/r8a66597-udc.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/usb/gadget/udc/r8a66597-udc.c b/drivers/usb/gadget/udc/r8a66597-udc.c
index db4a10a979f9..a9b82f371abb 100644
--- a/drivers/usb/gadget/udc/r8a66597-udc.c
+++ b/drivers/usb/gadget/udc/r8a66597-udc.c
@@ -1956,9 +1956,6 @@ static int r8a66597_probe(struct platform_device *pdev)
 	if (r8a66597->pdata->on_chip)
 		clk_disable_unprepare(r8a66597->clk);
 
-	if (r8a66597->ep0_req)
-		r8a66597_free_request(&r8a66597->ep[0].ep, r8a66597->ep0_req);
-
 	return ret;
 }
 
-- 
2.39.3 (Apple Git-146)

Re: [PATCH v2] usb: gadget: r8a66597-udc: Fix double free in r8a66597_probe

[Sebastian Andrzej Siewior]

On 2024-09-23 23:20:19 [+0300], Mikhail Arkhipov wrote:
> The function r8a66597_free_request is already called in the err_add_udc
> block, and freeing r8a66597->ep0_req twice may lead to a double free error.
> 
> 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.
> 
> Remove the redundant call to r8a66597_free_request in the clean_up2 block.
> 
> 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@rosa.ru>

Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

Sebastian