[lkml]   [2022]   [Dec]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[for-next][PATCH 1/3] tracing: Fix race where eprobes can be called before the event
From: "Steven Rostedt (Google)" <>

The flag that tells the event to call its triggers after reading the event
is set for eprobes after the eprobe is enabled. This leads to a race where
the eprobe may be triggered at the beginning of the event where the record
information is NULL. The eprobe then dereferences the NULL record causing
a NULL kernel pointer bug.

Test for a NULL record to keep this from happening.


Fixes: 7491e2c442781 ("tracing: Add a probe that attaches to trace events")
Reported-by: Rafael Mendonca <>
Signed-off-by: Steven Rostedt (Google) <>
Acked-by: Masami Hiramatsu (Google) <>
Signed-off-by: Masami Hiramatsu (Google) <>
kernel/trace/trace_eprobe.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
index 123d2c0a6b68..352b65e2b910 100644
--- a/kernel/trace/trace_eprobe.c
+++ b/kernel/trace/trace_eprobe.c
@@ -564,6 +564,9 @@ static void eprobe_trigger_func(struct event_trigger_data *data,
struct eprobe_data *edata = data->private_data;

+ if (unlikely(!rec))
+ return;
__eprobe_trace_func(edata, rec);


 \ /
  Last update: 2022-12-10 15:08    [W:0.037 / U:0.716 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site