possible bug in mcuboot/boot/nxp_mcux_sdk/flashapi/flash_api.c

[mastupristi]

Hi,

I use RT1021 and I'm testing mcuboot.

I want image to be at most 512kB, so in sblconfig.h I define:

#define CONFIG_MCUBOOT_MAX_IMG_SECTORS 128 /*4kB sector * 128 = 512kB */

and in flash_partitioning.h I have defined:

#define BOOT_FLASH_ACT_APP              0x60100000
#define BOOT_FLASH_CAND_APP             0x60180000

However, I get an error:

Failed reading sectors; BOOT_MAX_IMG_SECTORS=128 - too small?

I debugged and found the point where I think there is a bug.

https://github.com/nxp-mcuxpresso/mcuboot/blob/mcux_main/boot/nxp_mcux_sdk/flashapi/flash_api.c#L378

int flash_area_get_sectors(int fa_id, uint32_t *count, struct flash_sector *sectors)
{
    const struct flash_area *fa;
    uint32_t max_cnt = *count;
    uint32_t rem_len;
    int rc = -1;

    if (flash_area_open(fa_id, &fa))
        goto out;

    if (*count < 1)
        goto fa_close_out;

    rem_len = fa->fa_size;
    *count  = 0;
    while ((rem_len > 0) && (*count < max_cnt))
    {
        if (rem_len < MFLASH_SECTOR_SIZE)
        {
            goto fa_close_out;
        }

        sectors[*count].fs_off  = MFLASH_SECTOR_SIZE * (*count);
        sectors[*count].fs_size = MFLASH_SECTOR_SIZE;
        *count                  = *count + 1;
        rem_len -= MFLASH_SECTOR_SIZE;
    }

    if (*count >= max_cnt)
    {
        goto fa_close_out;
    }

    rc = 0;

fa_close_out:
    flash_area_close(fa);
out:
    return rc;
}

If slot size is equal to image size, the while loop iterate until both conditions are false, but it is not an error if rem_len is 0 at the end of loop, it means that I have used al entry in sectors array, but no other  entry is required.

I think that the if condition should be changed in:

    if (rem_len > 0)
    {
        goto fa_close_out;
    }

what do you think about this?

best regards

Max

[EdwinHz]

Hi @mastupristi,

Thanks for reporting this issue.

I will pass it on to the SDK team so they can investigate it further and provide a change if they see it necessary.

BR,
Edwin.