wait_event_interruptible_timeout returns a long
The return was being assigned to an int causing an integer overflow when
the remaining jiffies > INT_MAX resulting in random error returns.
Use a long return value and convert to int ioctl return only on error.
On success the ioctl was returning the transfer length of the
usb_control_msg which has no meaning for the user.
Return 0 on success.
Reported-by: Michael Katzmann <vk2bea@xxxxxxxxx>
Fixes: dbf3e7f654c0 ("Implement an ioctl to support the USMTMC-USB488 READ_STATUS_BYTE operation.")
Signed-off-by: Dave Penkler <dpenkler@xxxxxxxxx>
---
drivers/usb/class/usbtmc.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c
index 34e46ef308ab..e24277fef54a 100644
--- a/drivers/usb/class/usbtmc.c
+++ b/drivers/usb/class/usbtmc.c
@@ -482,6 +482,7 @@ static int usbtmc_get_stb(struct usbtmc_file_data *file_data, __u8 *stb)
u8 *buffer;
u8 tag;
int rv;
+ long wait_rv;
dev_dbg(dev, "Enter ioctl_read_stb iin_ep_present: %d\n",
data->iin_ep_present);
@@ -511,16 +512,17 @@ static int usbtmc_get_stb(struct usbtmc_file_data *file_data, __u8 *stb)
}
if (data->iin_ep_present) {
- rv = wait_event_interruptible_timeout(
+ wait_rv = wait_event_interruptible_timeout(
data->waitq,
atomic_read(&data->iin_data_valid) != 0,
file_data->timeout);
- if (rv < 0) {
- dev_dbg(dev, "wait interrupted %d\n", rv);
+ if (wait_rv < 0) {
+ dev_dbg(dev, "wait interrupted %ld\n", wait_rv);
+ rv = wait_rv;
goto exit;
}
- if (rv == 0) {
+ if (wait_rv == 0) {
dev_dbg(dev, "wait timed out\n");
rv = -ETIMEDOUT;
goto exit;
@@ -539,6 +541,8 @@ static int usbtmc_get_stb(struct usbtmc_file_data *file_data, __u8 *stb)
dev_dbg(dev, "stb:0x%02x received %d\n", (unsigned int)*stb, rv);
+ rv = 0;
+
exit:
/* bump interrupt bTag */
data->iin_bTag += 1;
--
2.49.0
