The write code path touches the bbu member in a non atomic manner
without taking the spinlock. Fix it.
The bug is as old as the driver.
Signed-off-by: Oliver Neukum <oneukum@xxxxxxxx>
CC: stable@xxxxxxxxxxxxxxx
---
drivers/usb/misc/yurex.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/misc/yurex.c b/drivers/usb/misc/yurex.c
index 4745a320eae4..4a9859e03f6b 100644
--- a/drivers/usb/misc/yurex.c
+++ b/drivers/usb/misc/yurex.c
@@ -404,7 +404,6 @@ static ssize_t yurex_read(struct file *file, char __user *buffer, size_t count,
struct usb_yurex *dev;
int len = 0;
char in_buffer[MAX_S64_STRLEN];
- unsigned long flags;
dev = file->private_data;
@@ -419,9 +418,9 @@ static ssize_t yurex_read(struct file *file, char __user *buffer, size_t count,
return -EIO;
}
- spin_lock_irqsave(&dev->lock, flags);
+ spin_lock_irq(&dev->lock);
scnprintf(in_buffer, MAX_S64_STRLEN, "%lld\n", dev->bbu);
- spin_unlock_irqrestore(&dev->lock, flags);
+ spin_unlock_irq(&dev->lock);
mutex_unlock(&dev->io_mutex);
return simple_read_from_buffer(buffer, count, ppos, in_buffer, len);
@@ -511,8 +510,11 @@ static ssize_t yurex_write(struct file *file, const char __user *user_buffer,
__func__, retval);
goto error;
}
- if (set && timeout)
+ if (set && timeout) {
+ spin_lock_irq(&dev->lock);
dev->bbu = c2;
+ spin_unlock_irq(&dev->lock);
+ }
return timeout ? count : -EIO;
error:
--
2.45.2
