2018-09-01 09:25:15

by Jia-Ju Bai

[permalink] [raw]
Subject: [PATCH] usb: host: u132-hcd: Fix a sleep-in-atomic-context bug in u132_get_frame()

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 <[email protected]>
---
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