Commit d0a1945f authored by Jungo Lin's avatar Jungo Lin Committed by Carles Cufi
Browse files

arch: arm64: enhance backtrace dump check 



Examine the FP and LR values of each frame to prevent nested
exceptions caused by data aborts. Sometimes, abnormal FP and LR
values are not mapped by the MMU. If we access memory addresses
based on FP or LR values, a CPU data abort will occur. This issue
often accompanies stack overflow occurrences.

Based on this, it is safe to check the validity of memory mapping
with FP and LR values before accessing them.

Signed-off-by: default avatarJungo Lin <jungolin.tw@gmail.com>
parent 91af849c

arch/arm64/core/fatal.c

+33 −0
Original line number Diff line number Diff line
@@ -17,9 +17,11 @@ 
#include <zephyr/drivers/pm_cpu_ops.h>

#include <zephyr/arch/common/exc_handle.h>

#include <zephyr/kernel.h>

#include <zephyr/linker/linker-defs.h>

#include <zephyr/logging/log.h>

#include <zephyr/sys/poweroff.h>

#include <kernel_arch_func.h>

#include <kernel_arch_interface.h>



#include "paging.h"
@@ -201,6 +203,33 @@ static void esf_dump(const struct arch_esf *esf) 
#ifdef CONFIG_ARCH_STACKWALK

typedef bool (*arm64_stacktrace_cb)(void *cookie, unsigned long addr, void *fp);



static bool is_address_mapped(uint64_t *addr)

{

	uintptr_t *phys = NULL;



	if (*addr == 0U)

		return false;



	/* Check alignment. */

	if ((*addr & (sizeof(uint32_t) - 1U)) != 0U)

		return false;



	return !arch_page_phys_get((void *) addr, phys);

}



static bool is_valid_jump_address(uint64_t *addr)

{

	if (*addr == 0U)

		return false;



	/* Check alignment. */

	if ((*addr & (sizeof(uint32_t) - 1U)) != 0U)

		return false;



	return ((*addr >= (uint64_t)__text_region_start) &&

		(*addr <= (uint64_t)(__text_region_end)));

}



static void walk_stackframe(arm64_stacktrace_cb cb, void *cookie, const struct arch_esf *esf,

			    int max_frames)

{
@@ -234,7 +263,11 @@ static void walk_stackframe(arm64_stacktrace_cb cb, void *cookie, const struct a 
	}



	for (int i = 0; (fp != NULL) && (i < max_frames); i++) {

		if (!is_address_mapped(fp))

			break;

		lr = fp[1];

		if (!is_valid_jump_address(&lr))

			break;

		if (!cb(cookie, lr, fp)) {

			break;

		}

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