usb: gadget: f_fs: Fix kernel panic if use_os_string not set

If c->cdev->use_os_string flag is not set,
don't need to invoke ffs_do_os_descs() in _ffs_func_bind.
So uninitialized ext_compat_id pointer won't be accessed by
__ffs_func_bind_do_os_desc to cause kernel panic.

Signed-off-by: Jim Lin <jilin@nvidia.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index 9ac6e868946d7797c34c6b094ee8617964ca3926..cc33d26674080a1359ed7be97410bb640453b469 100644 (file)
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -2849,7 +2849,7 @@ static int _ffs_func_bind(struct usb_configuration *c,
                goto error;
 
        func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
-       if (c->cdev->use_os_string)
+       if (c->cdev->use_os_string) {
                for (i = 0; i < ffs->interfaces_count; ++i) {
                        struct usb_os_desc *desc;
 
@@ -2860,13 +2860,15 @@ static int _ffs_func_bind(struct usb_configuration *c,
                                vla_ptr(vlabuf, d, ext_compat) + i * 16;
                        INIT_LIST_HEAD(&desc->ext_prop);
                }
-       ret = ffs_do_os_descs(ffs->ms_os_descs_count,
-                             vla_ptr(vlabuf, d, raw_descs) +
-                             fs_len + hs_len + ss_len,
-                             d_raw_descs__sz - fs_len - hs_len - ss_len,
-                             __ffs_func_bind_do_os_desc, func);
-       if (unlikely(ret < 0))
-               goto error;
+               ret = ffs_do_os_descs(ffs->ms_os_descs_count,
+                                     vla_ptr(vlabuf, d, raw_descs) +
+                                     fs_len + hs_len + ss_len,
+                                     d_raw_descs__sz - fs_len - hs_len -
+                                     ss_len,
+                                     __ffs_func_bind_do_os_desc, func);
+               if (unlikely(ret < 0))
+                       goto error;
+       }
        func->function.os_desc_n =
                c->cdev->use_os_string ? ffs->interfaces_count : 0;