Commit-ID: e863d5396146411b615231cae0c518cb2a23371c Gitweb: https://git.kernel.org/tip/e863d5396146411b615231cae0c518cb2a23371c Author: Masami Hiramatsu <mhira...@kernel.org> AuthorDate: Tue, 19 Sep 2017 19:00:19 +0900 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Thu, 28 Sep 2017 09:23:04 +0200
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 <mhira...@kernel.org> Cc: Alexei Starovoitov <a...@fb.com> Cc: Alexei Starovoitov <a...@kernel.org> Cc: Ananth N Mavinakayanahalli <ana...@linux.vnet.ibm.com> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Paul E . McKenney <paul...@linux.vnet.ibm.com> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Steven Rostedt <rost...@goodmis.org> Cc: Thomas Gleixner <t...@linutronix.de> Link: http://lkml.kernel.org/r/150581521955.32348.3615624715034787365.stgit@devbox Signed-off-by: Ingo Molnar <mi...@kernel.org> --- kernel/kprobes.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 15fba7f..2d28377 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(); }
