[GIT PULL] probes: Fixes for for v7.0-rc3

[Masami Hiramatsu (Google) <mhiramat@kernel.org>]

Hi Linus,

Probes fixes for v7.0-rc3

- kprobes: 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.
- kprobes: Remove unneeded warnings from __arm_kprobe_ftrace()
  Remove unneeded WARN messages which can be kicked 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.


Please pull the latest probes-fixes-v7.0-rc3 tree, which can be found at:


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

Tag SHA1: fc4d86187c58bac3a67170db07dce1eb61a75a17
Head SHA1: 5ef268cb7a0aac55521fd9881f1939fa94a8988e


Masami Hiramatsu (Google) (2):
      kprobes: avoid crash when rmmod/insmod after ftrace killed
      kprobes: Remove unneeded warnings from __arm_kprobe_ftrace()

----
 kernel/kprobes.c | 8 ++++++--
 1 file 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);

-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>