[v5,1/2] elf: Clarify and invert second argument of _dl_allocate_tls_init

Message ID 86ff3e8442162298b82734abe00ed28a84f006f2.1719420465.git.fweimer@redhat.com
State New
Headers
Series elf: Avoid re-initializing already allocated TLS in dlopen (bug 31717) |

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redhat-pt-bot/TryBot-apply_patch success Patch applied to master at the time it was sent
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Commit Message

Florian Weimer June 26, 2024, 4:50 p.m. UTC
  ---
 elf/dl-tls.c               | 10 +++-------
 elf/rtld.c                 |  2 +-
 nptl/allocatestack.c       |  2 +-
 sysdeps/generic/ldsodefs.h | 13 ++++++++++++-
 4 files changed, 17 insertions(+), 10 deletions(-)
  

Patch

diff --git a/elf/dl-tls.c b/elf/dl-tls.c
index 670dbc42fc..67ce4771e3 100644
--- a/elf/dl-tls.c
+++ b/elf/dl-tls.c
@@ -514,12 +514,8 @@  _dl_resize_dtv (dtv_t *dtv, size_t max_modid)
 }
 
 
-/* Allocate initial TLS.  RESULT should be a non-NULL pointer to storage
-   for the TLS space.  The DTV may be resized, and so this function may
-   call malloc to allocate that space.  The loader's GL(dl_load_tls_lock)
-   is taken when manipulating global TLS-related data in the loader.  */
 void *
-_dl_allocate_tls_init (void *result, bool init_tls)
+_dl_allocate_tls_init (void *result, bool main_thread)
 {
   if (result == NULL)
     /* The memory allocation failed.  */
@@ -598,7 +594,7 @@  _dl_allocate_tls_init (void *result, bool init_tls)
 	     because it would already be set by the audit setup.  However,
 	     subsequent thread creation would need to follow the default
 	     behaviour.   */
-	  if (map->l_ns != LM_ID_BASE && !init_tls)
+	  if (map->l_ns != LM_ID_BASE && main_thread)
 	    continue;
 	  memset (__mempcpy (dest, map->l_tls_initimage,
 			     map->l_tls_initimage_size), '\0',
@@ -626,7 +622,7 @@  _dl_allocate_tls (void *mem)
 {
   return _dl_allocate_tls_init (mem == NULL
 				? _dl_allocate_tls_storage ()
-				: allocate_dtv (mem), true);
+				: allocate_dtv (mem), false);
 }
 rtld_hidden_def (_dl_allocate_tls)
 
diff --git a/elf/rtld.c b/elf/rtld.c
index e9525ea987..da0d115c69 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -2336,7 +2336,7 @@  dl_main (const ElfW(Phdr) *phdr,
      into the main thread's TLS area, which we allocated above.
      Note: thread-local variables must only be accessed after completing
      the next step.  */
-  _dl_allocate_tls_init (tcbp, false);
+  _dl_allocate_tls_init (tcbp, true);
 
   /* And finally install it for the main thread.  */
   if (! __rtld_tls_init_tp_called)
diff --git a/nptl/allocatestack.c b/nptl/allocatestack.c
index f35a8369bd..2cb562f8ea 100644
--- a/nptl/allocatestack.c
+++ b/nptl/allocatestack.c
@@ -139,7 +139,7 @@  get_cached_stack (size_t *sizep, void **memp)
   memset (dtv, '\0', (dtv[-1].counter + 1) * sizeof (dtv_t));
 
   /* Re-initialize the TLS.  */
-  _dl_allocate_tls_init (TLS_TPADJ (result), true);
+  _dl_allocate_tls_init (TLS_TPADJ (result), false);
 
   return result;
 }
diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h
index 50f58a60e3..2bccac3f7c 100644
--- a/sysdeps/generic/ldsodefs.h
+++ b/sysdeps/generic/ldsodefs.h
@@ -1203,7 +1203,18 @@  extern void _dl_allocate_static_tls (struct link_map *map) attribute_hidden;
 /* These are internal entry points to the two halves of _dl_allocate_tls,
    only used within rtld.c itself at startup time.  */
 extern void *_dl_allocate_tls_storage (void) attribute_hidden;
-extern void *_dl_allocate_tls_init (void *, bool);
+
+
+/* Allocate initial TLS.  RESULT should be a non-NULL pointer to storage
+   for the TLS space.  The DTV may be resized, and so this function may
+   call malloc to allocate that space.  The loader's GL(dl_load_tls_lock)
+   is taken when manipulating global TLS-related data in the loader.
+
+   If MAIN_THREAD, this is the first call during process
+   initialization.  In this case, TLS initialization for secondary
+   (audit) namespaces is skipped because that has already been handled
+   by dlopen.  */
+extern void *_dl_allocate_tls_init (void *result, bool main_thread);
 rtld_hidden_proto (_dl_allocate_tls_init)
 
 /* True if the TCB has been set up.  */