This is a note to let you know that I've just added the patch titled
ring_buffer: Do not deactivate non-existant pages
to the 4.9-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:
ring_buffer-do-not-deactivate-non-existant-pages.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@xxxxxxxxxxxxxxx> know about it.
>From 56f4ca0a79a9f1af98f26c54b9b89ba1f9bcc6bd Mon Sep 17 00:00:00 2001
From: Daniil Tatianin <d-tatianin@xxxxxxxxxxxxxx>
Date: Mon, 14 Nov 2022 17:31:29 +0300
Subject: ring_buffer: Do not deactivate non-existant pages
From: Daniil Tatianin <d-tatianin@xxxxxxxxxxxxxx>
commit 56f4ca0a79a9f1af98f26c54b9b89ba1f9bcc6bd upstream.
rb_head_page_deactivate() expects cpu_buffer to contain a valid list of
->pages, so verify that the list is actually present before calling it.
Found by Linux Verification Center (linuxtesting.org) with the SVACE
static analysis tool.
Link: https://lkml.kernel.org/r/20221114143129.3534443-1-d-tatianin@xxxxxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 77ae365eca895 ("ring-buffer: make lockless")
Signed-off-by: Daniil Tatianin <d-tatianin@xxxxxxxxxxxxxx>
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/trace/ring_buffer.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -1267,9 +1267,9 @@ static void rb_free_cpu_buffer(struct ri
free_buffer_page(cpu_buffer->reader_page);
- rb_head_page_deactivate(cpu_buffer);
-
if (head) {
+ rb_head_page_deactivate(cpu_buffer);
+
list_for_each_entry_safe(bpage, tmp, head, list) {
list_del_init(&bpage->list);
free_buffer_page(bpage);
Patches currently in stable-queue which might be from d-tatianin@xxxxxxxxxxxxxx are
queue-4.9/ring_buffer-do-not-deactivate-non-existant-pages.patch
