[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.

1 files changed, 6 insertions, 0 deletions

diff --git a/elf/dl-reloc.c b/elf/dl-reloc.c
index 42bddc1e2c..dcab666d56 100644
--- a/elf/dl-reloc.c
+++ b/elf/dl-reloc.c
@@ -137,6 +137,12 @@ _dl_nothread_init_static_tls (struct link_map *map)
 # error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
 #endif
 
+  /* Fill in the DTV slot so that a later LD/GD access will find it.  */
+  dtv_t *dtv = THREAD_DTV ();
+  assert (map->l_tls_modid <= dtv[-1].counter);
+  dtv[map->l_tls_modid].pointer.to_free = NULL;
+  dtv[map->l_tls_modid].pointer.val = dest;
+
   /* Initialize the memory.  */
   memset (__mempcpy (dest, map->l_tls_initimage, map->l_tls_initimage_size),
 	  '\0', map->l_tls_blocksize - map->l_tls_initimage_size);