[RFC][PATCH 3/5] kprobes: Take get_online_cpus() before taking jump_label_lock()

[Steven Rostedt <rostedt@goodmis.org>]

[-- Attachment #1: 0003-kprobes-Take-get_online_cpus-before-taking-jump_labe.patch --]
[-- Type: text/plain, Size: 1299 bytes --]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

jump_label_lock() is taken under get_online_cpus(). Make sure that kprobes
follows suit.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/kprobes.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index d733479a10ee..57cf73aef488 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1294,13 +1294,13 @@ static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p)
 	int ret = 0;
 	struct kprobe *ap = orig_p;
 
-	/* For preparing optimization, jump_label_text_reserved() is called */
-	jump_label_lock();
 	/*
 	 * Get online CPUs to avoid text_mutex deadlock.with stop machine,
 	 * which is invoked by unoptimize_kprobe() in add_new_kprobe()
 	 */
 	get_online_cpus();
+	/* For preparing optimization, jump_label_text_reserved() is called */
+	jump_label_lock();
 	mutex_lock(&text_mutex);
 
 	if (!kprobe_aggrprobe(orig_p)) {
@@ -1348,8 +1348,8 @@ static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p)
 
 out:
 	mutex_unlock(&text_mutex);
-	put_online_cpus();
 	jump_label_unlock();
+	put_online_cpus();
 
 	if (ret == 0 && kprobe_disabled(ap) && !kprobe_disabled(p)) {
 		ap->flags &= ~KPROBE_FLAG_DISABLED;
-- 
2.10.2