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    Subject[PATCH 3.18 11/56] usb: gadget: r8a66597: Fix a possible sleep-in-atomic-context bugs in r8a66597_queue()
    Date
    3.18-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Jia-Ju Bai <baijiaju1990@gmail.com>

    [ Upstream commit f36b507c14c4b6e634463a610294e9cb0065c8ea ]

    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>
    Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    drivers/usb/gadget/udc/r8a66597-udc.c | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    --- a/drivers/usb/gadget/udc/r8a66597-udc.c
    +++ b/drivers/usb/gadget/udc/r8a66597-udc.c
    @@ -1193,7 +1193,7 @@ __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);
    }


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