commit a1f8f5e26fa59b84e333c0bd0e26cf101ba7d33a
author Jim Lin <jilin@nvidia.com> Fri May 13 20:32:16 2016 +0800
committer Farid Zare Seisan <faridzs@google.com> Wed Apr 04 21:07:50 2018 +0000
tree 4cf9e24be8403a8faeaa0b49a6d937266a6478d6
parent f5df27f595f973075309bc1a1070a4f3fba9deed

UPSTREAM: 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.

Bug: 36653937
Bug: 77585730
Test: No crash when enabling adb debugging.
Signed-off-by: Jim Lin <jilin@nvidia.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Badhri Jagan Sridharan <Badhri@google.com>
Change-Id: I385e4b8a8a80102c972c1f9eabf8d8379bc30b44

drivers/usb/gadget/function/f_fs.c

diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index 6c2befa..7854e9d 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -3304,7 +3304,7 @@
 		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;
 
@@ -3315,13 +3315,15 @@
 				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;