Remove all the values when deleting a key

When deleting a key using `pthread_key_delete', delete all the values
associated to that key in all the threads available. Otherwise, the
key reuse in `pthread_key_create' can cause new keys to have thread
specific data of the previously used key with the same index.

Add a test for this case, which creates and deletes pairs of keys
checking that they have a NULL thread specific data after creation.

* sysdeps/hurd/pt-key-delete.c (pthread_key_delete): Remove all the
values of the key in all the threads.

* tests/Makefile (CHECK_SRC): Add test-17.c.
* tests/test-17.c: New file.

3 files changed, 77 insertions, 1 deletions

diff --git a/sysdeps/hurd/pt-key-delete.c b/sysdeps/hurd/pt-key-delete.c
index 2426bb1..9d88647 100644
--- a/sysdeps/hurd/pt-key-delete.c
+++ b/sysdeps/hurd/pt-key-delete.c
@@ -35,8 +35,27 @@ pthread_key_delete (pthread_key_t key)
     err = EINVAL;
   else
     {
+      int i;
+
       __pthread_key_destructors[key] = PTHREAD_KEY_INVALID;
       __pthread_key_invalid_count ++;
+
+      pthread_rwlock_rdlock (&__pthread_threads_lock);
+      for (i = 0; i < __pthread_num_threads; ++i)
+	{
+	  struct __pthread *t;
+
+	  t = __pthread_threads[i];
+
+	  if (t == NULL)
+	    continue;
+
+	  /* Just remove the key, no need to care whether it was
+	     already there. */
+	  if (t->thread_specifics)
+	    hurd_ihash_remove (t->thread_specifics, key);
+	}
+      pthread_rwlock_unlock (&__pthread_threads_lock);
     }
 
   __pthread_mutex_unlock (&__pthread_key_lock);
diff --git a/tests/Makefile b/tests/Makefile
index 9509c95..4e2a4a8 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -4,7 +4,7 @@ LDLIBS = -lpthread
 
 CHECK_SRC := test-1.c test-2.c test-3.c test-6.c test-7.c test-8.c	\
 	test-9.c test-10.c test-11.c test-12.c test-13.c test-14.c	\
-	test-15.c test-16.c
+	test-15.c test-16.c test-17.c
 
 CHECK_OBJS := $(addsuffix .o,$(basename $(notdir $(CHECK_SRC))))
 CHECK_PROGS := $(basename $(notdir $(CHECK_SRC))) \
diff --git a/tests/test-17.c b/tests/test-17.c
new file mode 100644
index 0000000..a8bd150
--- /dev/null
+++ b/tests/test-17.c
@@ -0,0 +1,57 @@
+/* Test that the key reuse inside libpthread does not cause thread
+   specific values to persist. */
+
+#define _GNU_SOURCE 1
+
+#include <pthread.h>
+#include <stdio.h>
+#include <assert.h>
+#include <errno.h>
+
+void
+work (int iter)
+{
+  error_t err;
+  pthread_key_t key1;
+  pthread_key_t key2;
+  void *value1;
+  void *value2;
+
+  printf ("work/%d: start\n", iter);
+  err = pthread_key_create (&key1, NULL);
+  assert (err == 0);
+  err = pthread_key_create (&key2, NULL);
+  assert (err == 0);
+
+  value1 = pthread_getspecific (key1);
+  value2 = pthread_getspecific (key2);
+  printf ("work/%d: pre-setspecific: %p,%p\n", iter, value1, value2);
+  assert (value1 == NULL);
+  assert (value2 == NULL);
+  err = pthread_setspecific (key1, (void *)(0x100 + iter));
+  assert (err == 0);
+  err = pthread_setspecific (key2, (void *)(0x200 + iter));
+  assert (err == 0);
+
+  value1 = pthread_getspecific (key1);
+  value2 = pthread_getspecific (key2);
+  printf ("work/%d: post-setspecific: %p,%p\n", iter, value1, value2);
+  assert (value1 == (void *)(0x100 + iter));
+  assert (value2 == (void *)(0x200 + iter));
+
+  err = pthread_key_delete (key1);
+  assert (err == 0);
+  err = pthread_key_delete (key2);
+  assert (err == 0);
+}
+
+int
+main (int argc, char *argv[])
+{
+  int i;
+
+  for (i = 0; i < 8; ++i)
+    work (i + 1);
+
+  return 0;
+}