On Mon, Jan 31, 2022 at 11:30 PM Kees Cook keescook@chromium.org wrote:
On Sun, Jan 30, 2022 at 01:00:43AM +0000, ci_notify@linaro.org wrote:
For example, extracting from the build log, I can see more:
00:00:53 In file included from ./include/linux/io.h:13, 00:00:53 from arch/arm/mach-cns3xxx/pm.c:8: 00:00:53 In function ‘__raw_readl’, 00:00:53 inlined from ‘cns3xxx_pwr_clk_en’ at arch/arm/mach-cns3xxx/pm.c:17:12: 00:00:53 ./arch/arm/include/asm/io.h:113:9: error: array subscript 0 is outside array bounds of ‘const volatile void[0]’ [-Werror=array-bounds] 00:00:53 113 | asm volatile("ldr %0, %1" 00:00:53 | ^~~
Looks like something sees a "void" type... this smells like a compiler bug. I haven't been able to reproduce this warning yet.
I suspect this is a variation of https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578
When gcc sees a pointer dereference of a literal address like *(int *)(void *)0x1234000, this is sometimes interpreted as a NULL pointer with an offset, which in turn is assumed to have zero bytes that can be dereferenced.
Arnd