tracing: Fix NULL pointer dereference in start_creating

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: 4114fbfd02 ("tracing: Enable creating new instance early boot")
Signed-off-by: Kamal Agrawal <kamaagra@codeaurora.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Kamal Agrawal 2021-07-30 18:53:06 +05:30 committed by Steven Rostedt (VMware)
parent 352384d5c8
commit ff41c28c4b

View File

@ -9135,8 +9135,10 @@ static int trace_array_create_dir(struct trace_array *tr)
return -EINVAL; return -EINVAL;
ret = event_trace_add_tracer(tr->dir, tr); ret = event_trace_add_tracer(tr->dir, tr);
if (ret) if (ret) {
tracefs_remove(tr->dir); tracefs_remove(tr->dir);
return ret;
}
init_tracer_tracefs(tr, tr->dir); init_tracer_tracefs(tr, tr->dir);
__update_tracer_options(tr); __update_tracer_options(tr);