[2/2] usb: gadget: r8a66597: Fix a possible sleep-in-atomic-context bugs in r8a66597_queue()

DORMANTno replies

From: Jia-Ju Bai <hidden>
Date: 2018-06-20 03:55:25
Also in: lkml
Subsystem: the rest, usb subsystem · Maintainers: Linus Torvalds, Greg Kroah-Hartman

The driver may sleep in an interrupt handler.
The function call path (from bottom to top) in Linux-4.16.7 is:

[FUNC] r8a66597_queue(GFP_KERNEL)
drivers/usb/gadget/udc/r8a66597-udc.c, 1193: 
		r8a66597_queue in get_status
drivers/usb/gadget/udc/r8a66597-udc.c, 1301: 
		get_status in setup_packet
drivers/usb/gadget/udc/r8a66597-udc.c, 1381: 
		setup_packet in irq_control_stage
drivers/usb/gadget/udc/r8a66597-udc.c, 1508: 
		irq_control_stage in r8a66597_irq (interrupt handler)

To fix this bug, GFP_KERNEL is replaced with GFP_ATOMIC.

This bug is found by my static analysis tool (DSAC-2) and checked by
my code review.

Signed-off-by: Jia-Ju Bai <redacted>
---
 drivers/usb/gadget/udc/r8a66597-udc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/usb/gadget/udc/r8a66597-udc.c b/drivers/usb/gadget/udc/r8a66597-udc.c
index a3ecce62662b..e1292c280a0b 100644
--- a/drivers/usb/gadget/udc/r8a66597-udc.c
+++ b/drivers/usb/gadget/udc/r8a66597-udc.c
@@ -1190,7 +1190,7 @@ __acquires(r8a66597->lock)
 	r8a66597->ep0_req->length = 2;
 	/* AV: what happens if we get called again before that gets through? */
 	spin_unlock(&r8a66597->lock);
-	r8a66597_queue(r8a66597->gadget.ep0, r8a66597->ep0_req, GFP_KERNEL);
+	r8a66597_queue(r8a66597->gadget.ep0, r8a66597->ep0_req, GFP_ATOMIC);
 	spin_lock(&r8a66597->lock);
 }
 
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help