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 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

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-4.9 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 @@ -6955,6 +6955,7 @@ 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-4.9/tracing-fix-crash-when-it-fails-to-alloc-ring-buffer.patch queue-4.9/tracing-remove-extra-zeroing-out-of-the-ring-buffer-page.patch queue-4.9/tracing-fix-possible-double-free-on-failure-of-allocating-trace-buffer.patch