326273 – Thread local storage miscompiles

Bug 326273 - Thread local storage miscompiles

Summary: Thread local storage miscompiles

Status:	RESOLVED OBSOLETE

Alias:	None

Product:	Gentoo Linux
Classification:	Unclassified
Component:	Hardened (show other bugs)
Hardware:	All Linux

Importance:	High major (vote)
Assignee:	The Gentoo Linux Hardened Team

URL:
Whiteboard:
Keywords:

Depends on:
Blocks:

Reported:	2010-06-30 08:39 UTC by Łukasz Michalik
Modified:	2015-07-04 15:08 UTC (History)
CC List:	1 user (show)

See Also:
Package list:
Runtime testing required:	---

Attachments
minimal testcase (tls.cc,572 bytes, text/plain) 2010-06-30 08:40 UTC, Łukasz Michalik	Details
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Description Łukasz Michalik 2010-06-30 08:39:51 UTC

Reproducable only on x86 hardened with PIE enabled and at least -O2.

Comment 1 Łukasz Michalik 2010-06-30 08:40:31 UTC

Created attachment 237007 [details]
minimal testcase

Comment 2 Magnus Granberg gentoo-dev

2010-07-01 00:23:36 UTC

The only change we have done it in the TLS code so it behave as the gcc 3.4.6
did else you may get soemthing like this
/usr/lib/gcc/x86_64-pc-linux-gnu/4.2.3/../../../../x86_64-pc-linux-gnu/bin/ld: ../../lib/libuuid.a(gen_uuid.o): relocation R_X86_64_TPOFF32 against `a local symbol' can not be used when making a shared object; recompile with -fPIC ../../lib/libuuid.a: could not read symbols: Bad value
see more in
http://bugs.gentoo.org/show_bug.cgi?id=232601
http://gcc.gnu.org/ml/gcc-patches/2005-03/msg00923.html
The code change
@@ -5607,7 +5607,11 @@
   bool is_local;
 
   is_local = targetm.binds_local_p (decl);
-  if (!flag_shlib)
+  #ifdef ENABLE_ESP
+    if (!flag_pic)
+  #else
+    if (!flag_shlib)
+  #endif
     {
       if (is_local)
 	kind = TLS_MODEL_LOCAL_EXEC;