From b6b76dd62c56f257cdd30900ed22668c42a74030 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Mon, 12 Mar 2018 19:00:49 +0900 Subject: error-injection: Fix to prohibit jump optimization Since the kprobe which was optimized by jump can not change the execution path, the kprobe for error-injection must not be optimized. To prohibit it, set a dummy post-handler as officially stated in Documentation/kprobes.txt. Fixes: 4b1a29a7f542 ("error-injection: Support fault injection framework") Signed-off-by: Masami Hiramatsu Signed-off-by: Daniel Borkmann --- kernel/fail_function.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'kernel') diff --git a/kernel/fail_function.c b/kernel/fail_function.c index 21b0122cb39c..1d5632d8bbcc 100644 --- a/kernel/fail_function.c +++ b/kernel/fail_function.c @@ -14,6 +14,15 @@ static int fei_kprobe_handler(struct kprobe *kp, struct pt_regs *regs); +static void fei_post_handler(struct kprobe *kp, struct pt_regs *regs, + unsigned long flags) +{ + /* + * A dummy post handler is required to prohibit optimizing, because + * jump optimization does not support execution path overriding. + */ +} + struct fei_attr { struct list_head list; struct kprobe kp; @@ -56,6 +65,7 @@ static struct fei_attr *fei_attr_new(const char *sym, unsigned long addr) return NULL; } attr->kp.pre_handler = fei_kprobe_handler; + attr->kp.post_handler = fei_post_handler; attr->retval = adjust_error_retval(addr, 0); INIT_LIST_HEAD(&attr->list); } -- cgit v1.2.3