From: Mathieu Desnoyers Date: Mon, 13 Jul 2020 18:59:33 +0000 (-0400) Subject: Fix: Lock metadata cache on session destroy X-Git-Tag: v2.12.2~1 X-Git-Url: https://git.lttng.org/?p=lttng-modules.git;a=commitdiff_plain;h=5a4afa8ac8dbe6090a73583b0f5e38760705f884 Fix: Lock metadata cache on session destroy commit 92143b2c5656 ("Fix: metadata stream leak, missing list removal and locking") missed taking a lock protecting the metadata stream list iteration on session destroy. This opens a race window between iteration and item removal/free which triggers kernel OOPS. Signed-off-by: Mathieu Desnoyers --- diff --git a/lttng-events.c b/lttng-events.c index 59b37b93..be7e3897 100644 --- a/lttng-events.c +++ b/lttng-events.c @@ -210,8 +210,10 @@ void lttng_session_destroy(struct lttng_session *session) BUG_ON(chan->channel_type == METADATA_CHANNEL); _lttng_channel_destroy(chan); } + mutex_lock(&session->metadata_cache->lock); list_for_each_entry(metadata_stream, &session->metadata_cache->metadata_stream, list) _lttng_metadata_channel_hangup(metadata_stream); + mutex_unlock(&session->metadata_cache->lock); lttng_id_tracker_destroy(&session->pid_tracker, false); lttng_id_tracker_destroy(&session->vpid_tracker, false); lttng_id_tracker_destroy(&session->uid_tracker, false);