Commit 91862cc7 authored Apr 19, 2019 by Wenwen Wang Committed by Steven Rostedt (VMware) Apr 26, 2019

tracing: Fix a memory leak by early error exit in trace_pid_write()

In trace_pid_write(), the buffer for trace parser is allocated through
kmalloc() in trace_parser_get_init(). Later on, after the buffer is used,
it is then freed through kfree() in trace_parser_put(). However, it is
possible that trace_pid_write() is terminated due to unexpected errors,
e.g., ENOMEM. In that case, the allocated buffer will not be freed, which
is a memory leak bug.

To fix this issue, free the allocated buffer when an error is encountered.

Link: http://lkml.kernel.org/r/1555726979-15633-1-git-send-email-wang6495@umn.edu

Fixes: f4d34a87 ("tracing: Use pid bitmap instead of a pid array for set_event_pid")
Cc: stable@vger.kernel.org
Signed-off-by: Wenwen Wang <wang6495@umn.edu>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

parent b9872226

kernel/trace/trace.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -496,8 +496,10 @@ int trace_pid_write(struct trace_pid_list *filtered_pids,
		* not modified.
		*/
		pid_list = kmalloc(sizeof(*pid_list), GFP_KERNEL);
		if (!pid_list)
		if (!pid_list) {
		trace_parser_put(&parser);
		return -ENOMEM;
		}

		pid_list->pid_max = READ_ONCE(pid_max);

		@@ -507,6 +509,7 @@ int trace_pid_write(struct trace_pid_list *filtered_pids,

		pid_list->pids = vzalloc((pid_list->pid_max + 7) >> 3);
		if (!pid_list->pids) {
		trace_parser_put(&parser);
		kfree(pid_list);
		return -ENOMEM;
		}