[PATCH] kprobes: fix trace_probe flags in enable_trace_kprobe

From: Artem Savkov
Date: Wed Jul 25 2018 - 06:28:56 EST


If enable_trace_kprobe fails to enable the probe in enable_k(ret)probe
it returns an error, but does not unset the tp flags it set previosly.
This results in a probe being considered enabled and failures like being
unable to remove the probe through kprobe_events file since probes_open()
expects every probe to be disabled.

Signed-off-by: Artem Savkov <asavkov@xxxxxxxxxx>
---
kernel/trace/trace_kprobe.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 21f718472942..fb887ced5056 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -400,11 +400,10 @@ static struct trace_kprobe *find_trace_kprobe(const char *event,
static int
enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
{
+ struct event_file_link *link;
int ret = 0;

if (file) {
- struct event_file_link *link;
-
link = kmalloc(sizeof(*link), GFP_KERNEL);
if (!link) {
ret = -ENOMEM;
@@ -424,6 +423,16 @@ enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
else
ret = enable_kprobe(&tk->rp.kp);
}
+
+ if (ret) {
+ if (file) {
+ list_del(&link->list);
+ kfree(link);
+ tk->tp.flags &= ~TP_FLAG_TRACE;
+ } else {
+ tk->tp.flags &= ~TP_FLAG_PROFILE;
+ }
+ }
out:
return ret;
}
--
2.13.6