| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.0 28/55] usb: gadget: f_fs: add extra check before unregister_gadget_item | Date | Wed, 8 Jul 2015 00:35:03 -0700 |
| |
4.0-stable review patch. If anyone has any objections, please let me know.
------------------
From: Rui Miguel Silva <rui.silva@linaro.org>
commit f14e9ad17f46051b02bffffac2036486097de19e upstream.
ffs_closed can race with configfs_rmdir which will call config_item_release, so add an extra check to avoid calling the unregister_gadget_item with an null gadget item.
Signed-off-by: Rui Miguel Silva <rui.silva@linaro.org> Signed-off-by: Felipe Balbi <balbi@ti.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/usb/gadget/function/f_fs.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
--- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -3433,6 +3433,7 @@ done: static void ffs_closed(struct ffs_data *ffs) { struct ffs_dev *ffs_obj; + struct f_fs_opts *opts; ENTER(); ffs_dev_lock(); @@ -3446,8 +3447,13 @@ static void ffs_closed(struct ffs_data * if (ffs_obj->ffs_closed_callback) ffs_obj->ffs_closed_callback(ffs); - if (!ffs_obj->opts || ffs_obj->opts->no_configfs - || !ffs_obj->opts->func_inst.group.cg_item.ci_parent) + if (ffs_obj->opts) + opts = ffs_obj->opts; + else + goto done; + + if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent + || !atomic_read(&opts->func_inst.group.cg_item.ci_kref.refcount)) goto done; unregister_gadget_item(ffs_obj->opts->
|