> Il giorno 30 ago 2017, alle ore 20:42, Bart Van Assche <bart.vanassche@xxxxxxx> ha scritto:
>
> Make sysfs writes fail for invalid numbers instead of storing
> uninitialized data copied from the stack. This patch removes
> all uninitialized_var() occurrences from the BFQ source code.
>
> Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxx>
> Cc: Paolo Valente <paolo.valente@xxxxxxxxxx>
Acked-by: Paolo Valente <paolo.valente@xxxxxxxxxx>
> ---
> block/bfq-iosched.c | 52 +++++++++++++++++++++++++++++++++++++---------------
> 1 file changed, 37 insertions(+), 15 deletions(-)
>
> diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
> index 8c11c2e827a5..cf92f16eb5f2 100644
> --- a/block/bfq-iosched.c
> +++ b/block/bfq-iosched.c
> @@ -4802,13 +4802,15 @@ static ssize_t bfq_var_show(unsigned int var, char *page)
> return sprintf(page, "%u\n", var);
> }
>
> -static void bfq_var_store(unsigned long *var, const char *page)
> +static int bfq_var_store(unsigned long *var, const char *page)
> {
> unsigned long new_val;
> int ret = kstrtoul(page, 10, &new_val);
>
> - if (ret == 0)
> - *var = new_val;
> + if (ret)
> + return ret;
> + *var = new_val;
> + return 0;
> }
>
> #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \
> @@ -4849,8 +4851,12 @@ static ssize_t \
> __FUNC(struct elevator_queue *e, const char *page, size_t count) \
> { \
> struct bfq_data *bfqd = e->elevator_data; \
> - unsigned long uninitialized_var(__data); \
> - bfq_var_store(&__data, (page)); \
> + unsigned long __data; \
> + int ret; \
> + \
> + ret = bfq_var_store(&__data, (page)); \
> + if (ret) \
> + return ret; \
> if (__data < (MIN)) \
> __data = (MIN); \
> else if (__data > (MAX)) \
> @@ -4877,8 +4883,12 @@ STORE_FUNCTION(bfq_slice_idle_store, &bfqd->bfq_slice_idle, 0, INT_MAX, 2);
> static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count)\
> { \
> struct bfq_data *bfqd = e->elevator_data; \
> - unsigned long uninitialized_var(__data); \
> - bfq_var_store(&__data, (page)); \
> + unsigned long __data; \
> + int ret; \
> + \
> + ret = bfq_var_store(&__data, (page)); \
> + if (ret) \
> + return ret; \
> if (__data < (MIN)) \
> __data = (MIN); \
> else if (__data > (MAX)) \
> @@ -4894,9 +4904,12 @@ static ssize_t bfq_max_budget_store(struct elevator_queue *e,
> const char *page, size_t count)
> {
> struct bfq_data *bfqd = e->elevator_data;
> - unsigned long uninitialized_var(__data);
> + unsigned long __data;
> + int ret;
>
> - bfq_var_store(&__data, (page));
> + ret = bfq_var_store(&__data, (page));
> + if (ret)
> + return ret;
>
> if (__data == 0)
> bfqd->bfq_max_budget = bfq_calc_max_budget(bfqd);
> @@ -4919,9 +4932,12 @@ static ssize_t bfq_timeout_sync_store(struct elevator_queue *e,
> const char *page, size_t count)
> {
> struct bfq_data *bfqd = e->elevator_data;
> - unsigned long uninitialized_var(__data);
> + unsigned long __data;
> + int ret;
>
> - bfq_var_store(&__data, (page));
> + ret = bfq_var_store(&__data, (page));
> + if (ret)
> + return ret;
>
> if (__data < 1)
> __data = 1;
> @@ -4939,9 +4955,12 @@ static ssize_t bfq_strict_guarantees_store(struct elevator_queue *e,
> const char *page, size_t count)
> {
> struct bfq_data *bfqd = e->elevator_data;
> - unsigned long uninitialized_var(__data);
> + unsigned long __data;
> + int ret;
>
> - bfq_var_store(&__data, (page));
> + ret = bfq_var_store(&__data, (page));
> + if (ret)
> + return ret;
>
> if (__data > 1)
> __data = 1;
> @@ -4958,9 +4977,12 @@ static ssize_t bfq_low_latency_store(struct elevator_queue *e,
> const char *page, size_t count)
> {
> struct bfq_data *bfqd = e->elevator_data;
> - unsigned long uninitialized_var(__data);
> + unsigned long __data;
> + int ret;
>
> - bfq_var_store(&__data, (page));
> + ret = bfq_var_store(&__data, (page));
> + if (ret)
> + return ret;
>
> if (__data > 1)
> __data = 1;
> --
> 2.14.1
>
