| From 92cc3e7f76a545a2cd4828576971f1eea83f4e68 Mon Sep 17 00:00:00 2001 |
| From: Francis Deslauriers <francis.deslauriers@efficios.com> |
| Date: Wed, 17 Mar 2021 10:40:56 -0400 |
| Subject: [PATCH 4/4] Fix: kretprobe: null ptr deref on session destroy |
| |
| The `filter_bytecode_runtime_head` list is currently not initialized for |
| the return event of the kretprobe. This caused a kernel null ptr |
| dereference when destroying a session. It can reproduced with the |
| following commands: |
| |
| lttng create |
| lttng enable-event -k --function=lttng_test_filter_event_write my_event |
| lttng start |
| lttng stop |
| lttng destroy |
| |
| Upstream-status: backport |
| |
| Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com> |
| Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| Change-Id: I1162ce8b10dd7237a26331531f048346b984eee7 |
| --- |
| lttng-events.c | 2 ++ |
| 1 file changed, 2 insertions(+) |
| |
| diff --git a/lttng-events.c b/lttng-events.c |
| index 984bd341..3450fa40 100644 |
| --- a/lttng-events.c |
| +++ b/lttng-events.c |
| @@ -704,6 +704,8 @@ struct lttng_event *_lttng_event_create(struct lttng_channel *chan, |
| event_return->enabled = 0; |
| event_return->registered = 1; |
| event_return->instrumentation = itype; |
| + INIT_LIST_HEAD(&event_return->bytecode_runtime_head); |
| + INIT_LIST_HEAD(&event_return->enablers_ref_head); |
| /* |
| * Populate lttng_event structure before kretprobe registration. |
| */ |
| -- |
| 2.19.1 |
| |