2015-05-06 13:16:41

by Ludovic Desroches

Subject: [PATCH] mmc: atmel-mci: fix bad variable type for clkdiv

clkdiv is declared as an u32 but it can be set to a negative value
causing a huge divisor value. Change its type to int to avoid this case.

Signed-off-by: Ludovic Desroches <[email protected]>
Cc: <[email protected]> # 3.4 and later
---
drivers/mmc/host/atmel-mci.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
index 03d7c75..9a39e0b 100644
--- a/drivers/mmc/host/atmel-mci.c
+++ b/drivers/mmc/host/atmel-mci.c
@@ -1304,7 +1304,7 @@ static void atmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)

if (ios->clock) {
unsigned int clock_min = ~0U;
- u32 clkdiv;
+ int clkdiv;

spin_lock_bh(&host->lock);
if (!host->mode_reg) {
@@ -1328,7 +1328,12 @@ static void atmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
/* Calculate clock divider */
if (host->caps.has_odd_clk_div) {
clkdiv = DIV_ROUND_UP(host->bus_hz, clock_min) - 2;
- if (clkdiv > 511) {
+ if (clkdiv < 0) {
+ dev_warn(&mmc->class_dev,
+ "clock %u too fast; using %lu\n",
+ clock_min, host->bus_hz / 2);
+ clkdiv = 0;
+ } else if (clkdiv > 511) {
dev_warn(&mmc->class_dev,
"clock %u too slow; using %lu\n",
clock_min, host->bus_hz / (511 + 2));
--
2.2.0

2015-05-11 10:30:33

by Ulf Hansson

Subject: Re: [PATCH] mmc: atmel-mci: fix bad variable type for clkdiv

On 6 May 2015 at 15:16, Ludovic Desroches <[email protected]> wrote:
> clkdiv is declared as an u32 but it can be set to a negative value
> causing a huge divisor value. Change its type to int to avoid this case.
>
> Signed-off-by: Ludovic Desroches <[email protected]>
> Cc: <[email protected]> # 3.4 and later

Thanks, applied for fixes!

Kind regards
Uffe

> ---
> drivers/mmc/host/atmel-mci.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
> index 03d7c75..9a39e0b 100644
> --- a/drivers/mmc/host/atmel-mci.c
> +++ b/drivers/mmc/host/atmel-mci.c
> @@ -1304,7 +1304,7 @@ static void atmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
>
> if (ios->clock) {
> unsigned int clock_min = ~0U;
> - u32 clkdiv;
> + int clkdiv;
>
> spin_lock_bh(&host->lock);
> if (!host->mode_reg) {
> @@ -1328,7 +1328,12 @@ static void atmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
> /* Calculate clock divider */
> if (host->caps.has_odd_clk_div) {
> clkdiv = DIV_ROUND_UP(host->bus_hz, clock_min) - 2;
> - if (clkdiv > 511) {
> + if (clkdiv < 0) {
> + dev_warn(&mmc->class_dev,
> + "clock %u too fast; using %lu\n",
> + clock_min, host->bus_hz / 2);
> + clkdiv = 0;
> + } else if (clkdiv > 511) {
> dev_warn(&mmc->class_dev,
> "clock %u too slow; using %lu\n",
> clock_min, host->bus_hz / (511 + 2));
> --
> 2.2.0
>