klp_enable_patch
+ klp_init_patch
+ if (patch->replace)
klp_add_nops(patch); <<<< set all old patches to nop
+ __klp_enable_patch
+ klp_patch_object
+ klp_patch_func
+ ops = klp_find_ops(func->old_func);
+ if (ops)
// add the new patch to the func_stack list
list_add_rcu(&func->stack_node, &ops->func_stack);
klp_ftrace_handler
+ func = list_first_or_null_rcu(&ops->func_stack, struct klp_func
+ if (func->nop)
goto unlock;
+ ftrace_regs_set_instruction_pointer(fregs, (unsigned long)func->new_func);
Before the new atomic replace patch is added to the func_stack list,
the old patch is already set to nop. If klp_ftrace_handler() is
triggered at this point, it will effectively do nothingâ??in other
words, it will execute the original function.
I might be wrong.
--
Regards
Yafang
