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

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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 <baijiaju1990@gmail.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
This commit is contained in:
Jia-Ju Bai 2018-06-20 11:55:08 +08:00 committed by Felipe Balbi
parent 0602088b10
commit f36b507c14
1 changed files with 1 additions and 1 deletions
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2
drivers/usb/gadget/udc/r8a66597-udc.c
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@ -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);
}