usbatm: fix tiny race

If usbatm_do_heavy_init finishes before usbatm_heavy_init
writes the pid, the disconnect method could shoot down the
wrong process if the pid has been recycled.

Signed-off-by: Duncan Sands <baldrick@free.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 1 insertions, 4 deletions

diff --git a/drivers/usb/atm/usbatm.c b/drivers/usb/atm/usbatm.c
index 309073f6433a..ab091fa4c86b 100644
--- a/drivers/usb/atm/usbatm.c
+++ b/drivers/usb/atm/usbatm.c
@@ -1001,6 +1001,7 @@ static int usbatm_do_heavy_init(void *arg)
 
         daemonize(instance->driver->driver_name);
         allow_signal(SIGTERM);
+        instance->thread_pid = get_current()->pid;
 
         complete(&instance->thread_started);
 
@@ -1025,10 +1026,6 @@ static int usbatm_heavy_init(struct usbatm_data *instance)
                 return ret;
         }
 
-        mutex_lock(&instance->serialize);
-        instance->thread_pid = ret;
-        mutex_unlock(&instance->serialize);
-
         wait_for_completion(&instance->thread_started);
 
         return 0;