Use libasan to catch a Stack over flow bug

[shahawi-sumup]

Hello Zephyr Team,

I'm trying to use CONFIG_STACK_CANARIES=y with ztest on Zephyr v2.7.1 (Board=native_posix), the problem is in one of my unit tests i get OS Crash

DEBUG   - OUTPUT: @ WEST_TOPDIR/os/kernel/compiler_stack_protect.c:40
DEBUG   - OUTPUT: [00:00:00.000,000] <err> os: >>> ZEPHYR FATAL ERROR 2: Stack overflow on CPU 0
DEBUG   - OUTPUT: [00:00:00.000,000] <err> os: Current thread: 0x8178f80 (idle 00)
DEBUG   - OUTPUT: [00:00:00.000,000] <err> os: Halting system

The unit tests started with the following args:

        ZEPHYR_TOOLCHAIN_VARIANT="zephyr" ZEPHYR_TOOLCHAIN_DIR="/usr/" os/scripts/twister    \
            --enable-asan                                                                  \
            --enable-lsan                                                                  \
            --ninja                                                                          \
            -vv -a posix -p native_posix                                                     \
            -T test/unit/ztest                                                               \
            -O $ZTEST_OUT

tests prj.conf:

CONFIG_ENTROPY_GENERATOR=y
CONFIG_STACK_CANARIES=y
CONFIG_ASAN=y

How can i know the source of the problem ? libasan didn't catch it, unless I raise a trap signal in the fault handler:

void _StackCheckHandler(void)
{
	/* Stack canary error is a software fatal condition; treat it as such.
	 */
	__asm__ volatile("int $3");
	z_except_reason(K_ERR_STACK_CHK_FAIL);
	CODE_UNREACHABLE; /* LCOV_EXCL_LINE */
}

but that also didn't help that much

DEBUG   - OUTPUT: =================================================================
DEBUG   - OUTPUT: ==3794==ERROR: AddressSanitizer: UNKNOWN SIGNAL on unknown address 0x00000000 (pc 0x081001d3 bp 0xfffcb248 sp 0xfffcb240 T0)
DEBUG   - OUTPUT:     #0 0x81001d2 in _StackCheckHandler <zephyrpath>/kernel/compiler_stack_protect.c:39
DEBUG   - OUTPUT: AddressSanitizer can not provide additional info.
DEBUG   - OUTPUT: SUMMARY: AddressSanitizer: UNKNOWN SIGNAL <zephyrpath>/kernel/compiler_stack_protect.c:39 in _StackCheckHandler
DEBUG   - OUTPUT: ==3794==ABORTING

Without CONFIG_STACK_CANARIES tests run smoothly without any problem, but that looks to me as if the problem is hidden until it bites back in the future.

What are some suggestions to help me catch the source of the bug ?
Thanks in advance :)