Re: [PATCH] util/cacheinfo: fix crash when compiling with uClibc

[Richard Henderson]

On 12/16/19 1:18 AM, Carlos Santos wrote:
> On Thu, Oct 17, 2019 at 8:06 PM Carlos Santos <address@hidden> wrote:
>>
>> On Thu, Oct 17, 2019 at 9:47 AM Peter Maydell <address@hidden> wrote:
>>>
>>> On Thu, 17 Oct 2019 at 13:39, <address@hidden> wrote:
>>>>
>>>> From: Carlos Santos <address@hidden>
>>>>
>>>> uClibc defines _SC_LEVEL1_ICACHE_LINESIZE and _SC_LEVEL1_DCACHE_LINESIZE
>>>> but the corresponding sysconf calls returns -1, which is a valid result,
>>>> meaning that the limit is indeterminate.
>>>>
>>>> Handle this situation using the fallback values instead of crashing due
>>>> to an assertion failure.
>>>>
>>>> Signed-off-by: Carlos Santos <address@hidden>
>>>> ---
>>>>  util/cacheinfo.c | 10 ++++++++--
>>>>  1 file changed, 8 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/util/cacheinfo.c b/util/cacheinfo.c
>>>> index ea6f3e99bf..d94dc6adc8 100644
>>>> --- a/util/cacheinfo.c
>>>> +++ b/util/cacheinfo.c
>>>> @@ -93,10 +93,16 @@ static void sys_cache_info(int *isize, int *dsize)
>>>>  static void sys_cache_info(int *isize, int *dsize)
>>>>  {
>>>>  # ifdef _SC_LEVEL1_ICACHE_LINESIZE
>>>> -    *isize = sysconf(_SC_LEVEL1_ICACHE_LINESIZE);
>>>> +    int tmp_isize = (int) sysconf(_SC_LEVEL1_ICACHE_LINESIZE);
>>>
>>> Do we need the cast here ?
>>
>> It's there to remind the reader that a type coercion may occur, since
>> sysconf() returns a long and isize is an int.
>>
>>>> +    if (tmp_isize > 0) {
>>>> +        *isize = tmp_isize;
>>>> +    }
>>>>  # endif
>>>>  # ifdef _SC_LEVEL1_DCACHE_LINESIZE
>>>> -    *dsize = sysconf(_SC_LEVEL1_DCACHE_LINESIZE);
>>>> +    int tmp_dsize = (int) sysconf(_SC_LEVEL1_DCACHE_LINESIZE);
>>>> +    if (tmp_dsize > 0) {
>>>> +        *dsize = tmp_dsize;
>>>> +    }
>>>>  # endif
>>>>  }
>>>>  #endif /* sys_cache_info */
>>>> --
>>>
>>> thanks
>>> -- PMM
>>
>> --
>> Carlos Santos
>> Senior Software Maintenance Engineer
>> Red Hat
>> address@hidden    T: +55-11-3534-6186
> 
> Hi,
> 
> Any chance to have this merged for Christmas? :-)

No, but it's queued now.  ;-)


r~