On Mon, 19 Oct 2009, Felipe Contreras wrote: > I still have an unfixed warning: > drivers/usb/core/hcd.c: In function â??rh_stringâ??: > /data/public/src/linux/arch/x86/include/asm/string_32.h:74: warning: > array subscript is above array bounds > > Apparently there's a problem with the optimized memcpy for x86 with this code: > static char const langids[4] = {4, USB_DT_STRING, 0x09, 0x04}; > len = min_t(unsigned, len, sizeof(langids)); > memcpy(data, langids, len); > return len; > > gcc 4.4 is trying to optimize the memcpy, but it's not able to realize > that 'len' will always be <= 4 and the memcpy will not exceed langids. > One way to solve this is by replacing len with the min_t expression: > memcpy(data, langids, min_t(unsigned, len, sizeof(langids))); > > However, that looks ugly and we need the expression again for the > return. Another way is to remove 'const' from langids. > > AFAIK the code is perfectly correct as it is, I think the fact that > gcc 4.4 complains is a bug on gcc side. Yes, it is a well-known bug in gcc. Other places in the kernel get similar warnings. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html