If previous write command is still pending then free it first.
As per the current kernel driver design, write operation prepares a
buffer for FSI write, the actual FSI write is performed on next read
operation. There is a possibility of memory leak if buggy application
sends two back to back writes or two parallel writes.
Signed-off-by: Ninad Palsule <[email protected]>
---
v3:
- Incorporated review comments by Eddie.
---
drivers/fsi/fsi-sbefifo.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/fsi/fsi-sbefifo.c b/drivers/fsi/fsi-sbefifo.c
index a95b32461f8f3..1cc88a78e588a 100644
--- a/drivers/fsi/fsi-sbefifo.c
+++ b/drivers/fsi/fsi-sbefifo.c
@@ -877,6 +877,13 @@ static ssize_t sbefifo_user_write(struct file *file, const char __user *buf,
mutex_lock(&user->file_lock);
+ /* If previous write command is still pending then free it. It is safe
+ * to do that because read cannot be in progress since we hold the
+ * lock.
+ */
+ if (user->pending_cmd)
+ sbefifo_release_command(user);
+
/* Can we use the pre-allocate buffer ? If not, allocate */
if (len <= PAGE_SIZE)
user->pending_cmd = user->cmd_page;
--
2.39.2
On 10/10/23 15:43, Ninad Palsule wrote:
> If previous write command is still pending then free it first.
>
> As per the current kernel driver design, write operation prepares a
> buffer for FSI write, the actual FSI write is performed on next read
> operation. There is a possibility of memory leak if buggy application
> sends two back to back writes or two parallel writes.
Reviewed-by: Eddie James <[email protected]>
>
> Signed-off-by: Ninad Palsule <[email protected]>
> ---
> v3:
> - Incorporated review comments by Eddie.
> ---
> drivers/fsi/fsi-sbefifo.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/drivers/fsi/fsi-sbefifo.c b/drivers/fsi/fsi-sbefifo.c
> index a95b32461f8f3..1cc88a78e588a 100644
> --- a/drivers/fsi/fsi-sbefifo.c
> +++ b/drivers/fsi/fsi-sbefifo.c
> @@ -877,6 +877,13 @@ static ssize_t sbefifo_user_write(struct file *file, const char __user *buf,
>
> mutex_lock(&user->file_lock);
>
> + /* If previous write command is still pending then free it. It is safe
> + * to do that because read cannot be in progress since we hold the
> + * lock.
> + */
> + if (user->pending_cmd)
> + sbefifo_release_command(user);
> +
> /* Can we use the pre-allocate buffer ? If not, allocate */
> if (len <= PAGE_SIZE)
> user->pending_cmd = user->cmd_page;