On 03/23/2017 03:41 PM, Mark Rutland wrote:
> On Thu, Mar 23, 2017 at 02:49:16PM +0300, Andrey Ryabinin wrote:
>> + kasan_multi_shot
>> + [KNL] Enforce KASAN (Kernel Address Sanitizer) to print
>> + report on every invalid memory access. Without this
>> + parameter KASAN will print report only for the first
>> + invalid access.
>> +
>
> The option looks fine to me.
>
>> static int __init kmalloc_tests_init(void)
>> {
>> + /* Rise reports limit high enough to see all the following bugs */
>> + atomic_add(100, &kasan_report_count);
>
>> +
>> + /*
>> + * kasan is unreliable now, disable reports if
>> + * we are in single shot mode
>> + */
>> + atomic_sub(100, &kasan_report_count);
>> return -EAGAIN;
>> }
>
> ... but these magic numbers look rather messy.
>
> [...]
>
>> +atomic_t kasan_report_count = ATOMIC_INIT(1);
>> +EXPORT_SYMBOL_GPL(kasan_report_count);
>> +
>> +static int __init kasan_set_multi_shot(char *str)
>> +{
>> + atomic_set(&kasan_report_count, 1000000000);
>> + return 1;
>> +}
>> +__setup("kasan_multi_shot", kasan_set_multi_shot);
>
> ... likewise.
>
> Rather than trying to pick an arbitrarily large number, how about we use
> separate flags to determine whether we're in multi-shot mode, and
> whether a (oneshot) report has been made.
>
> How about the below?
Yes, it deferentially looks better.
Can you send a patch with a changelog, or do you want me to care of it?
> Thanks,
> Mark.
>
> diff --git a/mm/kasan/report.c b/mm/kasan/report.c
> index f479365..f1c5892 100644
> --- a/mm/kasan/report.c
> +++ b/mm/kasan/report.c
> @@ -13,6 +13,7 @@
> *
> */
>
> +#include <linux/bitops.h>
> #include <linux/ftrace.h>
We also need <linux/init.h> for __setup().
> #include <linux/kernel.h>
> #include <linux/mm.h>
> @@ -293,6 +294,40 @@ static void kasan_report_error(struct kasan_access_info
> *info)
