x86: some lock annotations for user copy paths, v2
- introduce might_fault()
- handle the atomic user copy paths correctly
[ mingo@elte.hu: move might_sleep() outside of in_atomic(). ]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/mm/memory.c b/mm/memory.c
index 1002f47..b8fdf4e 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3016,3 +3016,18 @@
}
up_read(¤t->mm->mmap_sem);
}
+
+#ifdef CONFIG_PROVE_LOCKING
+void might_fault(void)
+{
+ might_sleep();
+ /*
+ * it would be nicer only to annotate paths which are not under
+ * pagefault_disable, however that requires a larger audit and
+ * providing helpers like get_user_atomic.
+ */
+ if (!in_atomic() && current->mm)
+ might_lock_read(¤t->mm->mmap_sem);
+}
+EXPORT_SYMBOL(might_fault);
+#endif