From 6bc3f3979edce0b11deb685a4c817abb7d74b227 Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Thu, 20 Feb 2020 07:20:17 -0600 Subject: USB: Replace zero-length array with flexible-array member The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva Link: https://lore.kernel.org/r/20200220132017.GA29262@embeddedor Signed-off-by: Greg Kroah-Hartman --- drivers/usb/atm/usbatm.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/usb/atm') diff --git a/drivers/usb/atm/usbatm.h b/drivers/usb/atm/usbatm.h index d3bdc4cc47aa..8725755bd53d 100644 --- a/drivers/usb/atm/usbatm.h +++ b/drivers/usb/atm/usbatm.h @@ -164,7 +164,7 @@ struct usbatm_data { unsigned char *cell_buf; /* holds partial rx cell */ unsigned int buf_usage; - struct urb *urbs[0]; + struct urb *urbs[]; }; static inline void *to_usbatm_driver_data(struct usb_interface *intf) -- cgit v1.2.3