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authorAlexandre Oliva <aoliva@redhat.com>2016-09-21 22:01:16 -0300
committerAlexandre Oliva <aoliva@redhat.com>2016-09-21 22:01:16 -0300
commit17af5da98cd2c9ec958421ae2108f877e0945451 (patch)
tree6f1e45cb0947ef6c28d931f9c07b5a0f1292885c /elf/dl-tls.c
parent444eacba82f675d4657ad55da67b355536be90ab (diff)
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[PR19826] fix non-LE TLS in static programs
An earlier fix for TLS dropped early initialization of DTV entries for
modules using static TLS, leaving it for __tls_get_addr to set them
up.  That worked on platforms that require the GD access model to be
relaxed to LE in the main executable, but it caused a regression on
platforms that allow GD in the main executable, particularly in
statically-linked programs: they use a custom __tls_get_addr that does
not update the DTV, which fails when the DTV early initialization is
not performed.

In static programs, __libc_setup_tls performs the DTV initialization
for the main thread, but the DTV of other threads is set up in
_dl_allocate_tls_init, so that's the fix that matters.

Restoring the initialization in the remaining functions modified by
this patch was just for uniformity.  It's not clear that it is ever
needed: even on platforms that allow GD in the main executable, the
dynamically-linked version of __tls_get_addr would set up the DTV
entries, even for static TLS modules, while updating the DTV counter.

for  ChangeLog

	[BZ #19826]
	* elf/dl-tls.c (_dl_allocate_tls_init): Restore DTV early
	initialization of static TLS entries.
	* elf/dl-reloc.c (_dl_nothread_init_static_tls): Likewise.
	* nptl/allocatestack.c (init_one_static_tls): Likewise.
Diffstat (limited to 'elf/dl-tls.c')
-rw-r--r--elf/dl-tls.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/elf/dl-tls.c b/elf/dl-tls.c
index 17567ad1b3..60f4c1da5c 100644
--- a/elf/dl-tls.c
+++ b/elf/dl-tls.c
@@ -538,6 +538,10 @@ _dl_allocate_tls_init (void *result)
 # error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
 #endif
 
+	  /* Set up the DTV entry.  The simplified __tls_get_addr that
+	     some platforms use in static programs requires it.  */
+	  dtv[map->l_tls_modid].pointer.val = dest;
+
 	  /* Copy the initialization image and clear the BSS part.  */
 	  memset (__mempcpy (dest, map->l_tls_initimage,
 			     map->l_tls_initimage_size), '\0',