+ /*
+ * As per x86, we may deadlock here. However, since the kernel only
+ * validly references user space from well defined areas of the code,
+ * we can bug out early if this is from code which shouldn't.
+ */
+ if (!down_read_trylock(&mm->mmap_sem)) {
+ if (!user_mode(regs) && !search_exception_tables(regs->ARM_pc))
+ goto no_context;
+ down_read(&mm->mmap_sem);
+ }
+