From 3262ad824307c275922161e82c2db1458822f28c Mon Sep 17 00:00:00 2001 From: Jim Baxter <jim_baxter@mentor.com> Date: Thu, 8 Sep 2016 11:18:16 +0200 Subject: [PATCH] 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. 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> --- drivers/usb/gadget/function/f_fs.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c index 998697bd80acd..0aeed85bb5cbb 100644 --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -3502,6 +3502,11 @@ 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(); -- GitLab