Running the driver through kasan gives an interesting splat:
BUG: KASAN: global-out-of-bounds in isp1760_register+0x180/0x70c Read of size 20 at addr f1db2e64 by task swapper/0/1 (...) isp1760_register from isp1760_plat_probe+0x1d8/0x220 (...)
This happens because the loop reading the regmap fields for the different ISP1760 variants look like this:
for (i = 0; i < HC_FIELD_MAX; i++) { ... }
Meaning it expects the arrays to be at least HC_FIELD_MAX - 1 long.
However the arrays isp1760_hc_reg_fields[], isp1763_hc_reg_fields[], isp1763_hc_volatile_ranges[] and isp1763_dc_volatile_ranges[] are dynamically sized during compilation.
Fix this by putting an empty assignment to the [HC_FIELD_MAX] and [DC_FIELD_MAX] array member at the end of each array. This will make the array one member longer than it needs to be, but avoids the risk of overwriting whatever is inside [HC_FIELD_MAX - 1] and is simple and intuitive to read. Also add comments explaining what is going on.
Fixes: 1da9e1c06873 ("usb: isp1760: move to regmap for register access") Cc: stable@vger.kernel.org Cc: Rui Miguel Silva rui.silva@linaro.org Cc: Dietmar Eggemann dietmar.eggemann@arm.com Signed-off-by: Linus Walleij linus.walleij@linaro.org --- Found while testing to compile the Vexpress kernel into the vmalloc area in some experimental patches, curiously it did not manifest before, I guess we were lucky with padding etc. --- drivers/usb/isp1760/isp1760-core.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/drivers/usb/isp1760/isp1760-core.c b/drivers/usb/isp1760/isp1760-core.c index d1d9a7d5da17..af88f4fe00d2 100644 --- a/drivers/usb/isp1760/isp1760-core.c +++ b/drivers/usb/isp1760/isp1760-core.c @@ -251,6 +251,8 @@ static const struct reg_field isp1760_hc_reg_fields[] = { [HW_DM_PULLDOWN] = REG_FIELD(ISP176x_HC_OTG_CTRL, 2, 2), [HW_DP_PULLDOWN] = REG_FIELD(ISP176x_HC_OTG_CTRL, 1, 1), [HW_DP_PULLUP] = REG_FIELD(ISP176x_HC_OTG_CTRL, 0, 0), + /* Make sure the array is sized properly during compilation */ + [HC_FIELD_MAX] = {}, };
static const struct reg_field isp1763_hc_reg_fields[] = { @@ -321,6 +323,8 @@ static const struct reg_field isp1763_hc_reg_fields[] = { [HW_DM_PULLDOWN_CLEAR] = REG_FIELD(ISP1763_HC_OTG_CTRL_CLEAR, 2, 2), [HW_DP_PULLDOWN_CLEAR] = REG_FIELD(ISP1763_HC_OTG_CTRL_CLEAR, 1, 1), [HW_DP_PULLUP_CLEAR] = REG_FIELD(ISP1763_HC_OTG_CTRL_CLEAR, 0, 0), + /* Make sure the array is sized properly during compilation */ + [HC_FIELD_MAX] = {}, };
static const struct regmap_range isp1763_hc_volatile_ranges[] = { @@ -405,6 +409,8 @@ static const struct reg_field isp1761_dc_reg_fields[] = { [DC_CHIP_ID_HIGH] = REG_FIELD(ISP176x_DC_CHIPID, 16, 31), [DC_CHIP_ID_LOW] = REG_FIELD(ISP176x_DC_CHIPID, 0, 15), [DC_SCRATCH] = REG_FIELD(ISP176x_DC_SCRATCH, 0, 15), + /* Make sure the array is sized properly during compilation */ + [DC_FIELD_MAX] = {}, };
static const struct regmap_range isp1763_dc_volatile_ranges[] = { @@ -458,6 +464,8 @@ static const struct reg_field isp1763_dc_reg_fields[] = { [DC_CHIP_ID_HIGH] = REG_FIELD(ISP1763_DC_CHIPID_HIGH, 0, 15), [DC_CHIP_ID_LOW] = REG_FIELD(ISP1763_DC_CHIPID_LOW, 0, 15), [DC_SCRATCH] = REG_FIELD(ISP1763_DC_SCRATCH, 0, 15), + /* Make sure the array is sized properly during compilation */ + [DC_FIELD_MAX] = {}, };
static const struct regmap_config isp1763_dc_regmap_conf = {