uClibc 0.9.30 segfault + fix

[Kevin Day]

On Fri, Jan 16, 2009 at 5:02 AM, Carmelo AMOROSO <carmelo.amoroso at st.com> wrote:
> Kevin Day wrote:
>> This is more a less a fix of the symptom, the cause of why this memory
>> is assumed to be allocated and how is it not being allocated.
>>
>> The segfault:
>> ==31258== Process terminating with default action of signal 11
>> (SIGSEGV): dumping core
>> ==31258==  Access not within mapped region at address 0x0
>> ==31258==    at 0x40136C8: strlen (in
>> /toolchain/lib/valgrind/x86-linux/vgpreload_memcheck.so)
>> ==31258==    by 0x403362F: _locale_set_l (locale.c:809)
>> ==31258==    by 0x403388B: _locale_init_l (locale.c:932)
>> ==31258==    by 0x40338B6: _locale_init (locale.c:941)
>> ==31258==    by 0x40860E1: __uClibc_init (__uClibc_main.c:223)
>> ==31258==    by 0x40040A9: _dl_get_ready_to_run (ldso.c:827)
>> ==31258==    by 0x4001A42: ??? (dl-startup.c:311)
>> ==31258==    by 0x4000AF8: _start (in /tools/lib/ld-uClibc-0.9.30.so)
>>
>> Which happens to be the lines:
>> for (c = 0 ; c < 10 ; c++) {
>>  ((unsigned char *)d)[c] = strlen(x[c]);
>>  assert(d[c] > 0);
>> }
>>
>> I am not sure whether it is than x is not being allocated or some x[c]
>> is not being allocated so I checked both cases:
>>  if (x){
>>   for (c = 0 ; c < 10 && x[c]; c++) {
>>   ((unsigned char *)d)[c] = strlen(x[c]);
>>   assert(d[c] > 0);
>>   }
>> }
>>
>> This seems to prevent the segfault.
>> But again, this is a fix for the symptom and not the cause.
>>
> indeed the final effect of the patch is to hide a real, likely obscure,
> bug. So we should understand what is going wrong.
> I'm not familiar with valgrind tools.
> I think it should be better if you can create a simpler test case
> showing the problem.
>
> Cheers,
> carmelo

It appears that the problem occurs when using the pre-generated
locale: uClibc-locale-030818.tgz.
That's about as much as I have been able to find out so far..

Another note:
 with my supplied patch in place, a bootstrapped system eventually
crashed on the setlocale function:
  GEN extra/locale/c8tables.h
setlocale(LC_CTYPE,"en_US.UTF-8") failed!
make: *** [extra/locale/c8tables.h] Error 1

Hopefully this is nothing more than a compatibility issue between the
old locale and the new.

-- 
Kevin Day