Patch "tracing: Fix possible double free on failure of allocating trace buffer" has been added to the 4.4-stable tree

Patch "tracing: Fix possible double free on failure of allocating trace buffer" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    tracing: Fix possible double free on failure of allocating trace buffer

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     tracing-fix-possible-double-free-on-failure-of-allocating-trace-buffer.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 4397f04575c44e1440ec2e49b6302785c95fd2f8 Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
Date: Tue, 26 Dec 2017 20:07:34 -0500
Subject: tracing: Fix possible double free on failure of allocating trace buffer

From: Steven Rostedt (VMware) <rostedt@goodmis.org>

commit 4397f04575c44e1440ec2e49b6302785c95fd2f8 upstream.

Jing Xia and Chunyan Zhang reported that on failing to allocate part of the
tracing buffer, memory is freed, but the pointers that point to them are not
initialized back to NULL, and later paths may try to free the freed memory
again. Jing and Chunyan fixed one of the locations that does this, but
missed a spot.

Link: http://lkml.kernel.org/r/20171226071253.8968-1-chunyan.zhang@spreadtrum.com

Fixes: 737223fbca3b1 ("tracing: Consolidate buffer allocation code")
Reported-by: Jing Xia <jing.xia@spreadtrum.com>
Reported-by: Chunyan Zhang <chunyan.zhang@spreadtrum.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 kernel/trace/trace.c |    1 +
 1 file changed, 1 insertion(+)

--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -6531,6 +6531,7 @@ allocate_trace_buffer(struct trace_array
 	buf->data = alloc_percpu(struct trace_array_cpu);
 	if (!buf->data) {
 		ring_buffer_free(buf->buffer);
+		buf->buffer = NULL;
 		return -ENOMEM;
 	}
 


Patches currently in stable-queue which might be from rostedt@goodmis.org are

queue-4.4/tracing-fix-crash-when-it-fails-to-alloc-ring-buffer.patch
queue-4.4/tracing-remove-extra-zeroing-out-of-the-ring-buffer-page.patch
queue-4.4/tracing-fix-possible-double-free-on-failure-of-allocating-trace-buffer.patch