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 <[email protected]>
---
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);
}
--
2.17.0