| Andrew Geissler | 95ac1b8 | 2021-03-31 14:34:31 -0500 | [diff] [blame] | 1 | From 92cc3e7f76a545a2cd4828576971f1eea83f4e68 Mon Sep 17 00:00:00 2001 |
| 2 | From: Francis Deslauriers <francis.deslauriers@efficios.com> |
| 3 | Date: Wed, 17 Mar 2021 10:40:56 -0400 |
| 4 | Subject: [PATCH 4/4] Fix: kretprobe: null ptr deref on session destroy |
| 5 | |
| 6 | The `filter_bytecode_runtime_head` list is currently not initialized for |
| 7 | the return event of the kretprobe. This caused a kernel null ptr |
| 8 | dereference when destroying a session. It can reproduced with the |
| 9 | following commands: |
| 10 | |
| 11 | lttng create |
| 12 | lttng enable-event -k --function=lttng_test_filter_event_write my_event |
| 13 | lttng start |
| 14 | lttng stop |
| 15 | lttng destroy |
| 16 | |
| 17 | Upstream-status: backport |
| 18 | |
| 19 | Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com> |
| 20 | Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 21 | Change-Id: I1162ce8b10dd7237a26331531f048346b984eee7 |
| 22 | --- |
| 23 | lttng-events.c | 2 ++ |
| 24 | 1 file changed, 2 insertions(+) |
| 25 | |
| 26 | diff --git a/lttng-events.c b/lttng-events.c |
| 27 | index 984bd341..3450fa40 100644 |
| 28 | --- a/lttng-events.c |
| 29 | +++ b/lttng-events.c |
| 30 | @@ -704,6 +704,8 @@ struct lttng_event *_lttng_event_create(struct lttng_channel *chan, |
| 31 | event_return->enabled = 0; |
| 32 | event_return->registered = 1; |
| 33 | event_return->instrumentation = itype; |
| 34 | + INIT_LIST_HEAD(&event_return->bytecode_runtime_head); |
| 35 | + INIT_LIST_HEAD(&event_return->enablers_ref_head); |
| 36 | /* |
| 37 | * Populate lttng_event structure before kretprobe registration. |
| 38 | */ |
| 39 | -- |
| 40 | 2.19.1 |
| 41 | |