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authorMasami Hiramatsu <mhiramat@kernel.org>2017-09-19 19:00:19 +0900
committerIngo Molnar <mingo@kernel.org>2017-09-28 09:23:04 +0200
commite863d5396146411b615231cae0c518cb2a23371c (patch)
tree5e687c4220dfce99482755fe51bfeb2102287044 /kernel/kprobes.c
parentcd52edad55fbcd8064877a77d31445b2fb4b85c3 (diff)
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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>
Diffstat (limited to 'kernel/kprobes.c')
-rw-r--r--kernel/kprobes.c5
1 files changed, 4 insertions, 1 deletions
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();
}