From: Mathieu Desnoyers Date: Mon, 13 Jul 2020 18:59:33 +0000 (-0400) Subject: Fix: Lock metadata cache on session destroy X-Git-Tag: v2.11.5~2 X-Git-Url: https://git.lttng.org/?p=lttng-modules.git;a=commitdiff_plain;h=b8363d6a0a8e507bd52318305e6a8b4f116792bc 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 f5948f07..bb72156a 100644 --- a/lttng-events.c +++ b/lttng-events.c @@ -199,8 +199,10 @@ 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); if (session->pid_tracker) lttng_pid_tracker_destroy(session->pid_tracker); kref_put(&session->metadata_cache->refcount, metadata_cache_destroy);