On 10/20/2016 08:41 PM, William Tu wrote:
On Thu, Oct 20, 2016 at 9:58 AM, Alexei Starovoitov
wrote:
On Thu, Oct 20, 2016 at 06:04:38PM +0200, Daniel Borkmann wrote:
diff --git a/tools/testing/selftests/bpf/test_maps.c
b/tools/testing/selftests/bpf/test_maps.c
index ee384f0..d4832e8 100644
-
> Documentation/cputopology.txt +106 says /sys/devices/system/cpu/possible
> outputs cpu_possible_mask. That is the same as in num_possible_cpus(), so
> first step would be to fix the buggy example code, imho.
>
> What perhaps could be done in a second step to reduce overhead is an option
> for bpf
On Thu, Oct 20, 2016 at 9:58 AM, Alexei Starovoitov
wrote:
> On Thu, Oct 20, 2016 at 06:04:38PM +0200, Daniel Borkmann wrote:
>>
>> diff --git a/tools/testing/selftests/bpf/test_maps.c
>> b/tools/testing/selftests/bpf/test_maps.c
>> index ee384f0..d4832e8 100644
>> --- a/tools/testing/selftests/b
On Thu, Oct 20, 2016 at 06:04:38PM +0200, Daniel Borkmann wrote:
>
> diff --git a/tools/testing/selftests/bpf/test_maps.c
> b/tools/testing/selftests/bpf/test_maps.c
> index ee384f0..d4832e8 100644
> --- a/tools/testing/selftests/bpf/test_maps.c
> +++ b/tools/testing/selftests/bpf/test_maps.c
> @
On 10/19/2016 05:15 PM, Daniel Borkmann wrote:
On 10/19/2016 07:31 AM, William Tu wrote:
...
- if (copy_to_user(uvalue, value, value_size) != 0)
+ if (copy_to_user(uvalue, value, min_t(u32, usize, value_size)) != 0)
goto free_value;
I think such approach won't actually
On 10/19/2016 07:31 AM, William Tu wrote:
...
- if (copy_to_user(uvalue, value, value_size) != 0)
+ if (copy_to_user(uvalue, value, min_t(u32, usize, value_size)) != 0)
goto free_value;
I think such approach won't actually fix anything. User space
may lose some of the va
On 10/19/2016 07:31 AM, William Tu wrote:
...
- if (copy_to_user(uvalue, value, value_size) != 0)
+ if (copy_to_user(uvalue, value, min_t(u32, usize, value_size)) != 0)
goto free_value;
I think such approach won't actually fix anything. User space
may lose some of the va
> ...
>> - if (copy_to_user(uvalue, value, value_size) != 0)
>> + if (copy_to_user(uvalue, value, min_t(u32, usize, value_size)) != 0)
>> goto free_value;
>
> I think such approach won't actually fix anything. User space
> may lose some of the values and won't have any idea wh
On Sun, Oct 16, 2016 at 09:41:28AM -0700, William Tu wrote:
> When running bpf_map_lookup on percpu elements, the bytes copied to
> userspace depends on num_possible_cpus() * value_size, which could
> potentially be larger than memory allocated from user, which depends
> on sysconf(_SC_NPROCESSORS_
When running bpf_map_lookup on percpu elements, the bytes copied to
userspace depends on num_possible_cpus() * value_size, which could
potentially be larger than memory allocated from user, which depends
on sysconf(_SC_NPROCESSORS_CONF) to get the current cpu num. As a
result, the inconsistency mi
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