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

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