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From:   Jia-Ju Bai <baijiaju1990@gmail.com>
To:     gregkh@linuxfoundation.org, johan@kernel.org,
        felipe.balbi@linux.intel.com
Cc:     linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        Jia-Ju Bai <baijiaju1990@gmail.com>
Subject: [PATCH] usb: host: u132-hcd: Fix a sleep-in-atomic-context bug in u132_get_frame()
Date:   Sat,  1 Sep 2018 17:23:47 +0800
Message-Id: <20180901092347.13146-1-baijiaju1990@gmail.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

i_usX2Y_subs_startup in usbusx2yaudio.c is a completion handler function
for the USB driver. So it should not sleep, but it is can sleep 
according to the function call paths (from bottom to top) in Linux-4.16.

[FUNC] msleep
drivers/usb/host/u132-hcd.c, 2558: 
	msleep in u132_get_frame
drivers/usb/core/hcd.c, 2231: 
	[FUNC_PTR]u132_get_frame in usb_hcd_get_frame_number
drivers/usb/core/usb.c, 822: 
	usb_hcd_get_frame_number in usb_get_current_frame_number
sound/usb/usx2y/usbusx2yaudio.c, 303: 
	usb_get_current_frame_number in i_usX2Y_urb_complete
sound/usb/usx2y/usbusx2yaudio.c, 366: 
	i_usX2Y_urb_complete in i_usX2Y_subs_startup

Note that [FUNC_PTR] means a function pointer call is used.

To fix this bug, msleep() is replaced with mdelay().

This bug is found by my static analysis tool DSAC.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
---
 drivers/usb/host/u132-hcd.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/host/u132-hcd.c b/drivers/usb/host/u132-hcd.c
index 032b8652910a..02f8e08b3ee8 100644
--- a/drivers/usb/host/u132-hcd.c
+++ b/drivers/usb/host/u132-hcd.c
@@ -2555,7 +2555,7 @@ static int u132_get_frame(struct usb_hcd *hcd)
 	} else {
 		int frame = 0;
 		dev_err(&u132->platform_dev->dev, "TODO: u132_get_frame\n");
-		msleep(100);
+		mdelay(100);
 		return frame;
 	}
 }
-- 
2.17.0