Re: Finding the source code for ___tls_get_addr_internal()

[Saul Tamari <stamari at gmail dot com>]

On Fri, Jan 18, 2013 at 12:43 AM, Ian Lance Taylor <iant@google.com> wrote:
>
> On Thu, Jan 17, 2013 at 2:11 PM, Saul Tamari <stamari@gmail.com> wrote:
> > Is there a way to verify if there are wrongly initialized TLS
> > variables in some application or I can only detect such cases when the
> > application fails?
>
> You could probably look at the dynamic relocations and see if there
> are any TLS relocations in the shared library that are not global
> dynamic.


I tried the following:
[root@vm0 ~]# readelf -s ./mylib.so | grep TLS
   808: 00000418     4 TLS     GLOBAL DEFAULT   16 _ZN24MonitorWorkItemOpera
   914: 00000008     4 TLS     GLOBAL DEFAULT   16 _ZN12TQQQScheduler9_instan
  1176: 00000414     4 TLS     GLOBAL DEFAULT   16 time_monitor_list
  2577: 00000000     4 TLS     WEAK   DEFAULT   16 _ZZN6Remote23MultiplexCli
  2788: 00000004     4 TLS     WEAK   DEFAULT   16 _ZZN6Remote23MultiplexCli
   249: 0000000c     4 TLS     LOCAL  DEFAULT   16 _ZL17pthread_qqq_owner
   435: 00000010     1 TLS     LOCAL  DEFAULT   16 _ZL11g_in_syslog
   436: 00000011  1024 TLS     LOCAL  DEFAULT   16 _ZL9g_tls_buf
  2230: 00000418     4 TLS     GLOBAL DEFAULT   16 _ZN24MonitorWorkItemOpera
  2467: 00000000     4 TLS     WEAK   DEFAULT   16 _ZZN6Remote23MultiplexCli
  3375: 00000008     4 TLS     GLOBAL DEFAULT   16 _ZN12QQQScheduler9_instan
  3660: 00000414     4 TLS     GLOBAL DEFAULT   16 time_monitor_list
  3766: 00000004     4 TLS     WEAK   DEFAULT   16 _ZZN6Remote23MultiplexCli

So I see several TLS entries reported as WEAK and LOCAL and they could
cause the TLS issues I was experiencing?

I should probably read your blog to get a better understanding of this.

Thanks,
Saul