[RFC PATCH] nptl_db/db_info: fix the incorrect initial size for dtvp

[Junling Zheng]

On 2015/8/8 16:03, Bernhard Reutner-Fischer wrote:
> On August 7, 2015 4:28:10 AM GMT+02:00, Junling Zheng <zhengjunling at huawei.com> wrote:
>> Ping again...
> 
> Sorry for the delay, will apply the outstanding patches this weekend.

Hi, Bernhard

I found that uclibc-ng had already contained this fix.

Should it be applied into uClibc?

Thanks

Junling

> 
> Cheers,
>>
>> This patch fixed the following issue:
>> http://lists.uclibc.org/pipermail/uclibc/2015-May/048966.html
>>
>> Does anybody suffer this problem ?
>>
>> On 2015/7/31 18:37, Junling Zheng wrote:
>>> Ping...
>>>
>>> On 2015/7/20 21:33, Junling Zheng wrote:
>>>> When debugging a program on ARMv7 with thread-local storage declared
>> using
>>>> "__thread", attempting to print a thread-local variable will result
>> in the
>>>> following message:
>>>>
>>>> Cannot find thread-local storage for Thread <snip> (LWP <snip>),
>> executable
>>>> file /tmp/tls: capability not available
>>>>
>>>> This can be traced back to uclibc
>> libpthread/nptl_db/td_thr_tls_get_addr.c
>>>> which gdb uses to look up the address of the TLS. The function
>> returns
>>>> TD_NOCAPAB due to a mismatch in size between the DTV pointer and the
>> size
>>>> recorded in the db description. The problem lies in
>> libpthread/nptl_db/db_info.c
>>>> which initializes the db with the sizeof the union dtv. Instead it
>> should
>>>> be the sizeof a pointer to union dtv.
>>>>
>>>> Fixed the initial size for dtvp to sizeof a pointer, instead of
>> sizeof
>>>> the union.
>>>>
>>>> Refer to:
>>>> http://sourceware.org/ml/libc-alpha/2006-10/msg00088.html
>>>>
>> https://sourceware.org/git/?p=glibc.git;a=commitdiff;h=416b630981788c1f08e746e19765aa0e5c2a1360
>>>>
>>>> Signed-off-by: Junling Zheng <zhengjunling at huawei.com>
>>>> ---
>>>>  libpthread/nptl_db/db_info.c | 2 +-
>>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/libpthread/nptl_db/db_info.c
>> b/libpthread/nptl_db/db_info.c
>>>> index a57a053..159a027 100644
>>>> --- a/libpthread/nptl_db/db_info.c
>>>> +++ b/libpthread/nptl_db/db_info.c
>>>> @@ -60,7 +60,7 @@ extern bool __nptl_initial_report_events;
>>>>     i.e. at the very end of the area covered by TLS_PRE_TCB_SIZE. 
>> */
>>>>  DESC (_thread_db_pthread_dtvp,
>>>>        TLS_PRE_TCB_SIZE + offsetof (tcbhead_t, dtv)
>>>> -      - (TLS_TCB_SIZE == 0 ? sizeof (tcbhead_t) : 0), union dtv)
>>>> +      - (TLS_TCB_SIZE == 0 ? sizeof (tcbhead_t) : 0), union dtv *)
>>>>  #endif
>>>>  
>>>>  
>>>>
>>>
>>>
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>>>
>>
>>
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> 
> 
> 
> .
>