[pypy-commit] stmgc default: In tests, we don't save and restore the shadowstack correctly.

[arigo]

Author: Armin Rigo <arigo at tunes.org>
Branch: 
Changeset: r1301:e691086e6ef0
Date: 2014-08-12 16:43 +0200
http://bitbucket.org/pypy/stmgc/changeset/e691086e6ef0/

Log:	In tests, we don't save and restore the shadowstack correctly.

diff --git a/c7/stm/core.c b/c7/stm/core.c
--- a/c7/stm/core.c
+++ b/c7/stm/core.c
@@ -987,8 +987,16 @@
        value before the transaction start.  Also restore the content
        of the shadowstack here. */
     stm_thread_local_t *tl = pseg->pub.running_thread;
+#ifdef STM_NO_AUTOMATIC_SETJMP
+    /* In tests, we don't save and restore the shadowstack correctly.
+       Be sure to not change items below shadowstack_at_start_of_transaction.
+       There is no such restrictions in non-Python-based tests. */
+    assert(tl->shadowstack >= pseg->shadowstack_at_start_of_transaction);
+    tl->shadowstack = pseg->shadowstack_at_start_of_transaction;
+#else
     stm_rewind_jmp_restore_shadowstack(tl);
     assert(tl->shadowstack == pseg->shadowstack_at_start_of_transaction);
+#endif
     tl->thread_local_obj = pseg->threadlocal_at_start_of_transaction;
     tl->last_abort__bytes_in_nursery = bytes_in_nursery;
 
diff --git a/c7/stmgc.h b/c7/stmgc.h
--- a/c7/stmgc.h
+++ b/c7/stmgc.h
@@ -340,8 +340,8 @@
     rewind_jmp_longjmp(&(tl)->rjthread)
 #define stm_rewind_jmp_forget(tl)                  \
     rewind_jmp_forget(&(tl)->rjthread)
-#define stm_rewind_jmp_restore_shadowstack(tl)     \
-    ((tl)->shadowstack = (struct stm_shadowentry_s *) \
+#define stm_rewind_jmp_restore_shadowstack(tl)           \
+    ((tl)->shadowstack = (struct stm_shadowentry_s *)    \
         rewind_jmp_restore_shadowstack(&(tl)->rjthread))
 
 /* Starting and ending transactions.  stm_read(), stm_write() and
diff --git a/c7/test/test_basic.py b/c7/test/test_basic.py
--- a/c7/test/test_basic.py
+++ b/c7/test/test_basic.py
@@ -427,6 +427,19 @@
         self.abort_transaction()
         py.test.raises(EmptyStack, self.pop_root)
 
+    def test_abort_restores_shadowstack_inv(self):
+        py.test.skip("the logic to save/restore the shadowstack doesn't "
+                     "work in these tests")
+        self.push_root(ffi.cast("object_t *", 1234))
+        self.start_transaction()
+        p = self.pop_root()
+        assert p == ffi.cast("object_t *", 1234)
+        self.push_root(ffi.cast("object_t *", 5678))
+        self.pop_root()
+        self.abort_transaction()
+        p = self.pop_root()
+        assert p == ffi.cast("object_t *", 1234)
+
     def test_check_content_after_commit(self):
         self.start_transaction()
         lp1 = stm_allocate(16)