On Thu, Jan 25, 2018 at 8:13 PM, Andrey Ryabinin
wrote:
> On 01/25/2018 08:55 PM, Linus Torvalds wrote:
>> On Thu, Jan 25, 2018 at 12:32 AM, Dmitry Vyukov wrote:
>>> On Wed, Jan 24, 2018 at 6:52 PM, Linus Torvalds
>>> wrote:
So I'd *much* rather have some way to tell KASAN that word-at
On 01/25/2018 08:55 PM, Linus Torvalds wrote:
> On Thu, Jan 25, 2018 at 12:32 AM, Dmitry Vyukov wrote:
>> On Wed, Jan 24, 2018 at 6:52 PM, Linus Torvalds
>> wrote:
>>>
>>> So I'd *much* rather have some way to tell KASAN that word-at-a-time
>>> is going on. Because that approach definitely makes
On Thu, Jan 25, 2018 at 12:32 AM, Dmitry Vyukov wrote:
> On Wed, Jan 24, 2018 at 6:52 PM, Linus Torvalds
> wrote:
>>
>> So I'd *much* rather have some way to tell KASAN that word-at-a-time
>> is going on. Because that approach definitely makes a difference in
>> other places.
>
> The other option
On Thu, Jan 25, 2018 at 9:42 AM, David Laight wrote:
> From: Dmitry Vyukov [mailto:dvyu...@google.com]
>> Sent: 25 January 2018 08:33
>>
>> On Wed, Jan 24, 2018 at 6:52 PM, Linus Torvalds
>> wrote:
>> > On Wed, Jan 24, 2018 at 12:54 AM, Rasmus Villemoes
>> > wrote:
>> >>
>> >> I see something si
From: Dmitry Vyukov [mailto:dvyu...@google.com]
> Sent: 25 January 2018 08:33
>
> On Wed, Jan 24, 2018 at 6:52 PM, Linus Torvalds
> wrote:
> > On Wed, Jan 24, 2018 at 12:54 AM, Rasmus Villemoes
> > wrote:
> >>
> >> I see something similar, but at the 30->31 transition, and the
> >> branch-misses
On Wed, Jan 24, 2018 at 6:52 PM, Linus Torvalds
wrote:
> On Wed, Jan 24, 2018 at 12:54 AM, Rasmus Villemoes
> wrote:
>>
>> I see something similar, but at the 30->31 transition, and the
>> branch-misses remain at 1-3% for higher values, until 42 where it drops
>> back to 0%. Anyway, I highly doub
On Wed, Jan 24, 2018 at 12:54 AM, Rasmus Villemoes
wrote:
>
> I see something similar, but at the 30->31 transition, and the
> branch-misses remain at 1-3% for higher values, until 42 where it drops
> back to 0%. Anyway, I highly doubt we do a lot of string copies of
> strings longer then 32.
So
On Tue, Jan 9, 2018 at 6:37 PM, Andrey Ryabinin wrote:
> strscpy() performs the word-at-a-time optimistic reads. So it may
> may access the memory past the end of the object, which is perfectly fine
> since strscpy() doesn't use that (past-the-end) data and makes sure the
> optimistic read won't c
On 2018-01-09 17:47, Andrey Ryabinin wrote:
> Attached user space program I used to see the difference.
> Usage:
> gcc -02 -o strscpy strscpy_test.c
> ./strscpy {b|w} src_str_len count
>
> src_str_len - length of source string in between 1-4096
> count - how many strscpy() to execute.
On 2018-01-09 17:37, Andrey Ryabinin wrote:
> strscpy() performs the word-at-a-time optimistic reads. So it may
> may access the memory past the end of the object, which is perfectly fine
> since strscpy() doesn't use that (past-the-end) data and makes sure the
> optimistic read won't cross a page
Attached user space program I used to see the difference.
Usage:
gcc -02 -o strscpy strscpy_test.c
./strscpy {b|w} src_str_len count
src_str_len - length of source string in between 1-4096
count - how many strscpy() to execute.
Also I've noticed something strange. I'm not sure w
strscpy() performs the word-at-a-time optimistic reads. So it may
may access the memory past the end of the object, which is perfectly fine
since strscpy() doesn't use that (past-the-end) data and makes sure the
optimistic read won't cross a page boundary.
But KASAN doesn't know anything about tha
12 matches
Mail list logo
