Merge tag 'probes-fixes-v7.0-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull probes fixes from Masami Hiramatsu:

 - Avoid crash when rmmod/insmod after ftrace killed

   This fixes a kernel crash caused by kprobes on the symbol in a module
   which is unloaded after ftrace_kill() is called.

 - Remove unneeded warnings from __arm_kprobe_ftrace()

   Remove unneeded WARN messages which can be triggered if the kprobe is
   using ftrace and it fails to enable the ftrace. Since kprobes
   correctly handle such failure, we don't need to warn it.

* tag 'probes-fixes-v7.0-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  kprobes: Remove unneeded warnings from __arm_kprobe_ftrace()
  kprobes: avoid crash when rmmod/insmod after ftrace killed

1 files changed, 6 insertions, 2 deletions

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index ab25b4aa9095..bfc89083daa9 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1144,12 +1144,12 @@ static int __arm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops,
 	lockdep_assert_held(&kprobe_mutex);
 
 	ret = ftrace_set_filter_ip(ops, (unsigned long)p->addr, 0, 0);
-	if (WARN_ONCE(ret < 0, "Failed to arm kprobe-ftrace at %pS (error %d)\n", p->addr, ret))
+	if (ret < 0)
 		return ret;
 
 	if (*cnt == 0) {
 		ret = register_ftrace_function(ops);
-		if (WARN(ret < 0, "Failed to register kprobe-ftrace (error %d)\n", ret)) {
+		if (ret < 0) {
 			/*
 			 * At this point, sinec ops is not registered, we should be sefe from
 			 * registering empty filter.
@@ -1178,6 +1178,10 @@ static int __disarm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops,
 	int ret;
 
 	lockdep_assert_held(&kprobe_mutex);
+	if (unlikely(kprobe_ftrace_disabled)) {
+		/* Now ftrace is disabled forever, disarm is already done. */
+		return 0;
+	}
 
 	if (*cnt == 1) {
 		ret = unregister_ftrace_function(ops);