libc: Extend __libc_freeres framework (Bug 23329).

The __libc_freeres framework does not extend to non-libc.so objects.
This causes problems in general for valgrind and mtrace detecting
unfreed objects in both libdl.so and libpthread.so.  This change is
a pre-requisite to properly moving the malloc hooks out of malloc
since such a move now requires precise accounting of all allocated
data before destructors are run.

This commit adds a proper hook in libc.so.6 for both libdl.so and
for libpthread.so, this ensures that shm-directory.c which uses
freeit () to free memory is called properly.  We also remove the
nptl_freeres hook and fall back to using weak-ref-and-check idiom
for a loaded libpthread.so, thus making this process similar for
all DSOs.

Lastly we follow best practice and use explicit free calls for
both libdl.so and libpthread.so instead of the generic hook process
which has undefined order.

Tested on x86_64 with no regressions.

Signed-off-by: DJ Delorie <dj@redhat.com>
Signed-off-by: Carlos O'Donell <carlos@redhat.com>

7 files changed, 45 insertions, 29 deletions

diff --git a/nptl/Makefile b/nptl/Makefile
index 0f9c44a..2f2bb05 100644
--- a/nptl/Makefile
+++ b/nptl/Makefile
@@ -45,7 +45,7 @@ pthread-compat-wrappers = \
 		      sigwait sigsuspend \
 		      recvmsg sendmsg
 
-libpthread-routines = nptl-init vars events version pt-interp \
+libpthread-routines = nptl-init nptlfreeres vars events version pt-interp \
 		      pthread_create pthread_exit pthread_detach \
 		      pthread_join pthread_tryjoin pthread_timedjoin \
 		      pthread_join_common \
diff --git a/nptl/Versions b/nptl/Versions
index 0ae5def..b1c2da0 100644
--- a/nptl/Versions
+++ b/nptl/Versions
@@ -271,5 +271,6 @@ libpthread {
     __pthread_unwind; __pthread_get_minstack;
     __pthread_barrier_init; __pthread_barrier_wait;
     __shm_directory;
+    __libpthread_freeres;
   }
 }
diff --git a/nptl/allocatestack.c b/nptl/allocatestack.c
index 9c10b99..f9e053f 100644
--- a/nptl/allocatestack.c
+++ b/nptl/allocatestack.c
@@ -251,8 +251,8 @@ get_cached_stack (size_t *sizep, void **memp)
 
 
 /* Free stacks until cache size is lower than LIMIT.  */
-void
-__free_stacks (size_t limit)
+static void
+free_stacks (size_t limit)
 {
   /* We reduce the size of the cache.  Remove the last entries until
      the size is below the limit.  */
@@ -288,6 +288,12 @@ __free_stacks (size_t limit)
     }
 }
 
+/* Free all the stacks on cleanup.  */
+void
+__nptl_stacks_freeres (void)
+{
+  free_stacks (0);
+}
 
 /* Add a stack frame which is not used anymore to the stack.  Must be
    called with the cache lock held.  */
@@ -302,7 +308,7 @@ queue_stack (struct pthread *stack)
 
   stack_cache_actsize += stack->stackblock_size;
   if (__glibc_unlikely (stack_cache_actsize > stack_cache_maxsize))
-    __free_stacks (stack_cache_maxsize);
+    free_stacks (stack_cache_maxsize);
 }
 
 
diff --git a/nptl/libc_pthread_init.c b/nptl/libc_pthread_init.c
index f390480..e254ea2 100644
--- a/nptl/libc_pthread_init.c
+++ b/nptl/libc_pthread_init.c
@@ -77,11 +77,3 @@ __libc_pthread_init (unsigned long int *ptr, void (*reclaim) (void),
   return &__libc_multiple_threads;
 #endif
 }
-
-#ifdef SHARED
-libc_freeres_fn (freeres_libptread)
-{
-  if (__libc_pthread_functions_init)
-    PTHFCT_CALL (ptr_freeres, ());
-}
-#endif
diff --git a/nptl/nptl-init.c b/nptl/nptl-init.c
index 1d3790f..907411d 100644
--- a/nptl/nptl-init.c
+++ b/nptl/nptl-init.c
@@ -78,9 +78,6 @@ extern
 void __nptl_set_robust (struct pthread *);
 
 #ifdef SHARED
-static void nptl_freeres (void);
-
-
 static const struct pthread_functions pthread_functions =
   {
     .ptr_pthread_attr_destroy = __pthread_attr_destroy,
@@ -140,8 +137,6 @@ static const struct pthread_functions pthread_functions =
 # ifdef SIGSETXID
     .ptr__nptl_setxid = __nptl_setxid,
 # endif
-    /* For now only the stack cache needs to be freed.  */
-    .ptr_freeres = nptl_freeres,
     .ptr_set_robust = __nptl_set_robust
   };
 # define ptr_pthread_functions &pthread_functions
@@ -151,16 +146,6 @@ static const struct pthread_functions pthread_functions =
 
 
 #ifdef SHARED
-/* This function is called indirectly from the freeres code in libc.  */
-static void
-__libc_freeres_fn_section
-nptl_freeres (void)
-{
-  __unwind_freeres ();
-  __free_stacks (0);
-}
-
-
 static
 #endif
 void
diff --git a/nptl/nptlfreeres.c b/nptl/nptlfreeres.c
new file mode 100644
index 0000000..cfa54e1
--- /dev/null
+++ b/nptl/nptlfreeres.c
@@ -0,0 +1,31 @@
+/* Clean up allocated libpthread memory on demand.
+   Copyright (C) 2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <set-hooks.h>
+#include <libc-symbols.h>
+#include <pthreadP.h>
+
+/* Free libpthread.so resources.
+   Note: Caller ensures we are called only once.  */
+void
+__libpthread_freeres (void)
+{
+  call_function_static_weak (__nptl_stacks_freeres);
+  call_function_static_weak (__shm_directory_freeres);
+  call_function_static_weak (__nptl_unwind_freeres);
+}
diff --git a/nptl/pthreadP.h b/nptl/pthreadP.h
index 075530c..3cba0b6 100644
--- a/nptl/pthreadP.h
+++ b/nptl/pthreadP.h
@@ -279,8 +279,8 @@ hidden_proto (__pthread_register_cancel)
 hidden_proto (__pthread_unregister_cancel)
 # ifdef SHARED
 extern void attribute_hidden pthread_cancel_init (void);
-extern void __unwind_freeres (void);
 # endif
+extern void __nptl_unwind_freeres (void) attribute_hidden;
 #endif
 
 
@@ -597,7 +597,8 @@ extern int __nptl_setxid (struct xid_command *cmdp) attribute_hidden;
 extern void __nptl_set_robust (struct pthread *self);
 #endif
 
-extern void __free_stacks (size_t limit) attribute_hidden;
+extern void __nptl_stacks_freeres (void) attribute_hidden;
+extern void __shm_directory_freeres (void) attribute_hidden;
 
 extern void __wait_lookup_done (void) attribute_hidden;