From 046e12323ab459f20082d57ed16b055a14f0f6dc Mon Sep 17 00:00:00 2001 From: Kamal Agrawal Date: Fri, 30 Jul 2021 18:53:06 +0530 Subject: [PATCH] tracing: Fix NULL pointer dereference in start_creating commit ff41c28c4b54052942180d8b3f49e75f1445135a upstream. The event_trace_add_tracer() can fail. In this case, it leads to a crash in start_creating with below call stack. Handle the error scenario properly in trace_array_create_dir. Call trace: down_write+0x7c/0x204 start_creating.25017+0x6c/0x194 tracefs_create_file+0xc4/0x2b4 init_tracer_tracefs+0x5c/0x940 trace_array_create_dir+0x58/0xb4 trace_array_create+0x1bc/0x2b8 trace_array_get_by_name+0xdc/0x18c Link: https://lkml.kernel.org/r/1627651386-21315-1-git-send-email-kamaagra@codeaurora.org Cc: stable@vger.kernel.org Fixes: 4114fbfd02f1 ("tracing: Enable creating new instance early boot") Signed-off-by: Kamal Agrawal Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman --- kernel/trace/trace.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 625034c44d5f..e4f154119e52 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -8683,8 +8683,10 @@ static int trace_array_create_dir(struct trace_array *tr) return -EINVAL; ret = event_trace_add_tracer(tr->dir, tr); - if (ret) + if (ret) { tracefs_remove(tr->dir); + return ret; + } init_tracer_tracefs(tr, tr->dir); __update_tracer_options(tr);