UPSTREAM: usb: gadget: f_fs: Stop ffs_closed NULL pointer dereference

The struct ffs_data::private_data has a pointer to
ffs_dev stored in it during the ffs_fs_mount() function
however it is not cleared when the ffs_dev is freed
later which causes the ffs_closed function to crash
with "Unable to handle kernel NULL pointer dereference"
error when using the data in ffs_data::private_data.

This clears this pointer during the ffs_free_dev clean
up function.

Change-Id: I1fde26421cb44084d73e8c2a1786ea3f09f952fc
Signed-off-by: Jim Baxter <jim_baxter@mentor.com>
Signed-off-by: Jiada Wang <jiada_wang@mentor.com>
Signed-off-by: Harish Jenny K N <harish_kandiga@mentor.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: William Wu <william.wu@rock-chips.com>
(cherry picked from commit 3262ad8243)
This commit is contained in:
Jim Baxter
2016-09-08 11:18:16 +02:00
committed by Tao Huang
parent 411314c56d
commit 67bb2799fb

View File

@@ -3381,6 +3381,11 @@ static void _ffs_free_dev(struct ffs_dev *dev)
list_del(&dev->entry);
if (dev->name_allocated)
kfree(dev->name);
/* Clear the private_data pointer to stop incorrect dev access */
if (dev->ffs_data)
dev->ffs_data->private_data = NULL;
kfree(dev);
if (list_empty(&ffs_devices))
functionfs_cleanup();