[PATCH 4.4 44/70] usb: cdc-wdm: Fix a sleep-in-atomic-context bug in service_outstanding_interrupt()

From: Greg Kroah-Hartman
Date: Mon Sep 24 2018 - 07:56:25 EST

4.4-stable review patch. If anyone has any objections, please let me know.


From: Jia-Ju Bai <baijiaju1990@xxxxxxxxx>

commit 6e22e3af7bb3a7b9dc53cb4687659f6e63fca427 upstream.

wdm_in_callback() is a completion handler function for the USB driver.
So it should not sleep. But it calls service_outstanding_interrupt(),
which calls usb_submit_urb() with GFP_KERNEL.

To fix this bug, GFP_KERNEL is replaced with GFP_ATOMIC.

This bug is found by my static analysis tool DSAC.

Signed-off-by: Jia-Ju Bai <baijiaju1990@xxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/usb/class/cdc-wdm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/usb/class/cdc-wdm.c
+++ b/drivers/usb/class/cdc-wdm.c
@@ -453,7 +453,7 @@ static int clear_wdm_read_flag(struct wd

set_bit(WDM_RESPONDING, &desc->flags);
- rv = usb_submit_urb(desc->response, GFP_KERNEL);
+ rv = usb_submit_urb(desc->response, GFP_ATOMIC);
if (rv) {