security: Update file_set_fowner documentation

Highlight that the file_set_fowner hook is now called with a lock held.

Cc: Al Viro <[email protected]>
Cc: Casey Schaufler <[email protected]>
Cc: Christian Brauner <[email protected]>
Cc: James Morris <[email protected]>
Cc: Jann Horn <[email protected]>
Cc: Ondrej Mosnacek <[email protected]>
Cc: Paul Moore <[email protected]>
Cc: Serge E. Hallyn <[email protected]>
Cc: Stephen Smalley <[email protected]>
Signed-off-by: Mickaël Salaün <[email protected]>
Signed-off-by: Paul Moore <[email protected]>

Author: l0kod

security/security.c

@@ -3048,6 +3048,8 @@ int security_file_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
  * Save owner security information (typically from current->security) in
  * file->f_security for later use by the send_sigiotask hook.
  *
+ * This hook is called with file->f_owner.lock held.
+ *
  * Return: Returns 0 on success.
  */
 void security_file_set_fowner(struct file *file)