The appended adds assertions to make sure we do not longjmp with page
locks held. Some notes:
- user-mode has nothing to check, since page_locks are !user-mode only.
- The checks only apply to page collections, since these have relatively
complex callers.
- Some simple page_lock/unlock callers have been left unchecked --
namely page_lock_tb, tb_phys_invalidate and tb_link_page.
Signed-off-by: Emilio G. Cota <c...@braap.org>
---
accel/tcg/cpu-exec.c | 1 +
accel/tcg/translate-all.c | 22 ++++++++++++++++++++++
include/exec/exec-all.h | 8 ++++++++
3 files changed, 31 insertions(+)
diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c
index 8c68727..7c83887 100644
--- a/accel/tcg/cpu-exec.c
+++ b/accel/tcg/cpu-exec.c
@@ -271,6 +271,7 @@ void cpu_exec_step_atomic(CPUState *cpu)
tcg_debug_assert(!have_mmap_lock());
#endif
tb_lock_reset();
+ assert_page_collection_locked(false);
}
if (in_exclusive_region) {
diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
index 07527d5..82832ef 100644
--- a/accel/tcg/translate-all.c
+++ b/accel/tcg/translate-all.c
@@ -605,6 +605,24 @@ void page_collection_unlock(struct page_collection *set)
{ }
#else /* !CONFIG_USER_ONLY */
+#ifdef CONFIG_DEBUG_TCG
+static __thread bool page_collection_locked;
+
+void assert_page_collection_locked(bool val)
+{
+ tcg_debug_assert(page_collection_locked == val);
+}
+
+static inline void set_page_collection_locked(bool val)
+{
+ page_collection_locked = val;
+}
+#else
+static inline void set_page_collection_locked(bool val)
+{
+}
+#endif /* !CONFIG_DEBUG_TCG */
+
static inline void page_lock(PageDesc *pd)
{
qemu_spin_lock(&pd->lock);
@@ -677,6 +695,7 @@ static void do_page_entry_lock(struct page_entry *pe)
page_lock(pe->pd);
g_assert(!pe->locked);
pe->locked = true;
+ set_page_collection_locked(true);
}
static gboolean page_entry_lock(gpointer key, gpointer value, gpointer data)
@@ -769,6 +788,7 @@ page_collection_lock(tb_page_addr_t start, tb_page_addr_t
end)
set->tree = g_tree_new_full(tb_page_addr_cmp, NULL, NULL,
page_entry_destroy);
set->max = NULL;
+ assert_page_collection_locked(false);
retry:
g_tree_foreach(set->tree, page_entry_lock, NULL);
@@ -787,6 +807,7 @@ page_collection_lock(tb_page_addr_t start, tb_page_addr_t
end)
page_trylock_add(set, tb->page_addr[1]))) {
/* drop all locks, and reacquire in order */
g_tree_foreach(set->tree, page_entry_unlock, NULL);
+ set_page_collection_locked(false);
goto retry;
}
}
@@ -799,6 +820,7 @@ void page_collection_unlock(struct page_collection *set)
/* entries are unlocked and freed via page_entry_destroy */
g_tree_destroy(set->tree);
g_free(set);
+ set_page_collection_locked(false);
}
#endif /* !CONFIG_USER_ONLY */
diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h
index aeaa127..7911e69 100644
--- a/include/exec/exec-all.h
+++ b/include/exec/exec-all.h
@@ -431,6 +431,14 @@ void tb_lock(void);
void tb_unlock(void);
void tb_lock_reset(void);
+#if !defined(CONFIG_USER_ONLY) && defined(CONFIG_DEBUG_TCG)
+void assert_page_collection_locked(bool val);
+#else
+static inline void assert_page_collection_locked(bool val)
+{
+}
+#endif
+
#if !defined(CONFIG_USER_ONLY)
struct MemoryRegion *iotlb_to_region(CPUState *cpu,
--
2.7.4
