From e863d5396146411b615231cae0c518cb2a23371c Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Tue, 19 Sep 2017 19:00:19 +0900 Subject: kprobes: Warn if optprobe handler tries to change execution path Warn if optprobe handler tries to change execution path. As described in Documentation/kprobes.txt, with optprobe user handler can not change instruction pointer. In that case user must avoid optimizing the kprobes by setting post_handler or break_handler. Signed-off-by: Masami Hiramatsu Cc: Alexei Starovoitov Cc: Alexei Starovoitov Cc: Ananth N Mavinakayanahalli Cc: Linus Torvalds Cc: Paul E . McKenney Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/150581521955.32348.3615624715034787365.stgit@devbox Signed-off-by: Ingo Molnar --- kernel/kprobes.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'kernel/kprobes.c') diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 15fba7fe57c8..2d28377a0e32 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -387,7 +387,10 @@ void opt_pre_handler(struct kprobe *p, struct pt_regs *regs) list_for_each_entry_rcu(kp, &p->list, list) { if (kp->pre_handler && likely(!kprobe_disabled(kp))) { set_kprobe_instance(kp); - kp->pre_handler(kp, regs); + if (kp->pre_handler(kp, regs)) { + if (WARN_ON_ONCE(1)) + pr_err("Optprobe ignores instruction pointer changing.(%pF)\n", p->addr); + } } reset_kprobe_instance(); } -- cgit v1.2.3-55-g7522