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Fix erroneous ioctl returns

PATCH Superseded Dave Penkler 1 participant 4 messages Apr 27, 2025

Subsystems (2)

v2 of 3 Superseded Latest is v3 →

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#0 lore raw

v2 cover Fix erroneous ioctl returns

Recent tests with timeouts > INT_MAX produced random error returns with usbtmc_get_stb. This was caused by assigning the return value of wait_event_interruptible_timeout to an int which overflowed to negative values. Also return value on success was the remaining number of jiffies instead of 0.

These patches fix all the cases where the return of wait_event_interruptible_timeout was assigned to an int and the case of the remaining jiffies return in usbtmc_get_stb.

Patch 1: Fixes usbtmc_get_stb
Patch 2: Fixes usbtmc488_ioctl_wait_srq
Patch 3: Fixes usbtmc_generic_read

Dave Penkler (3):
usb: usbtmc: Fix erroneous get_stb ioctl error returns
usb: usbtmc: Fix erroneous wait_srq ioctl return
usb: usbtmc: Fix erroneous generic_read ioctl return

 drivers/usb/class/usbtmc.c | 53 ++++++++++++++++++++++----------------
 1 file changed, 31 insertions(+), 22 deletions(-)

--
Changes V1 => V2 Add cc to stable line
2.49.0

#1 lore raw

PATCH v3 1/3 usb: usbtmc: Fix erroneous get_stb ioctl error returns

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.

When the return value of wait_event_interruptible_timeout was <= INT_MAX the number of remaining jiffies was returned which has no meaning for the user. Return 0 on success.

Fixes dbf3e7f654c0 ("Implement an ioctl to support the USMTMC-USB488 READ_STATUS_BYTE operation.")

---
Change V1 -> V2
Correct commit message wrongly stating the return value on success was from usb_control_msg

Change V2 -> V3
Add cc to stable line

 drivers/usb/class/usbtmc.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)
drivers/usb/class/usbtmc.c +8 -4
index 34e46ef308ab..e24277fef54a 100644
@@ -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;
Signature · 1 line
2.49.0
#2 lore raw

PATCH v2 2/3 usb: usbtmc: Fix erroneous wait_srq ioctl return

In reply to Dave Penkler

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, converting to the int ioctl return only on error.

Fixes 739240a9f6ac ("usb: usbtmc: Add ioctl USBTMC488_IOCTL_WAIT_SRQ")

---
Change V1 -> V2
Add cc to stable line

 drivers/usb/class/usbtmc.c | 23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)
drivers/usb/class/usbtmc.c +11 -12
index e24277fef54a..b3ca89b0dab7 100644
@@ -606,9 +606,9 @@ static int usbtmc488_ioctl_wait_srq(struct usbtmc_file_data *file_data,
 {
 	struct usbtmc_device_data *data = file_data->data;
 	struct device *dev = &data->intf->dev;
-	int rv;
 	u32 timeout;
 	unsigned long expire;
+	long wait_rv;
 
 	if (!data->iin_ep_present) {
 		dev_dbg(dev, "no interrupt endpoint present\n");
@@ -622,25 +622,24 @@ static int usbtmc488_ioctl_wait_srq(struct usbtmc_file_data *file_data,
 
 	mutex_unlock(&data->io_mutex);
 
-	rv = wait_event_interruptible_timeout(
-			data->waitq,
-			atomic_read(&file_data->srq_asserted) != 0 ||
-			atomic_read(&file_data->closing),
-			expire);
+	wait_rv = wait_event_interruptible_timeout(
+		data->waitq,
+		atomic_read(&file_data->srq_asserted) != 0 ||
+		atomic_read(&file_data->closing),
+		expire);
 
 	mutex_lock(&data->io_mutex);
 
 	/* Note! disconnect or close could be called in the meantime */
 	if (atomic_read(&file_data->closing) || data->zombie)
-		rv = -ENODEV;
+		return -ENODEV;
 
-	if (rv < 0) {
-		/* dev can be invalid now! */
-		pr_debug("%s - wait interrupted %d\n", __func__, rv);
-		return rv;
+	if (wait_rv < 0) {
+		dev_dbg(dev, "%s - wait interrupted %ld\n", __func__, wait_rv);
+		return wait_rv;
 	}
 
-	if (rv == 0) {
+	if (wait_rv == 0) {
 		dev_dbg(dev, "%s - wait timed out\n", __func__);
 		return -ETIMEDOUT;
 	}
Signature · 1 line
2.49.0
#3 lore raw

PATCH v2 3/3 usb: usbtmc: Fix erroneous generic_read ioctl return

In reply to Dave Penkler

wait_event_interruptible_timeout returns a long
The return value was being assigned to an int causing an integer overflow when the remaining jiffies > INT_MAX which resulted in random error returns.

Use a long return value, converting to the int ioctl return only on error.

Fixes bb99794a4792 ("usb: usbtmc: Add ioctl for vendor specific read")

---
Change V1 -> V2
Acc cc to stable line

 drivers/usb/class/usbtmc.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)
drivers/usb/class/usbtmc.c +12 -6
index b3ca89b0dab7..025a7aa795e3 100644
@@ -833,6 +833,7 @@ static ssize_t usbtmc_generic_read(struct usbtmc_file_data *file_data,
 	unsigned long expire;
 	int bufcount = 1;
 	int again = 0;
+	long wait_rv;
 
 	/* mutex already locked */
 
@@ -945,19 +946,24 @@ static ssize_t usbtmc_generic_read(struct usbtmc_file_data *file_data,
 		if (!(flags & USBTMC_FLAG_ASYNC)) {
 			dev_dbg(dev, "%s: before wait time %lu\n",
 				__func__, expire);
-			retval = wait_event_interruptible_timeout(
+			wait_rv = wait_event_interruptible_timeout(
 				file_data->wait_bulk_in,
 				usbtmc_do_transfer(file_data),
 				expire);
 
-			dev_dbg(dev, "%s: wait returned %d\n",
-				__func__, retval);
+			dev_dbg(dev, "%s: wait returned %ld\n",
+				__func__, wait_rv);
+
+			if (wait_rv < 0) {
+				retval = wait_rv;
+				goto error;
+			}
 
-			if (retval <= 0) {
-				if (retval == 0)
-					retval = -ETIMEDOUT;
+			if (wait_rv == 0) {
+				retval = -ETIMEDOUT;
 				goto error;
 			}
+
 		}
 
 		urb = usb_get_from_anchor(&file_data->in_anchor);
Signature · 1 line
2.49.0