Commit e863d539 authored Sep 19, 2017 by Masami Hiramatsu Committed by Ingo Molnar Sep 28, 2017

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 <mhiramat@kernel.org>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/150581521955.32348.3615624715034787365.stgit@devbox


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent cd52edad

kernel/kprobes.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -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();
		}