FAILED: patch "[PATCH] ring-buffer: Initialise reader page order in" failed to apply to 6.12-stable tree

The patch below does not apply to the 6.12-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x 6d014e44b68ddd43f71288d2a4dbb1a259869149
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026081707-pajamas-stoplight-328c@gregkh' --subject-prefix 'PATCH 6.12.y' 'HEAD^..'

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 6d014e44b68ddd43f71288d2a4dbb1a259869149 Mon Sep 17 00:00:00 2001
From: Vincent Donnefort <[email protected]>
Date: Thu, 6 Aug 2026 22:13:03 +0100
Subject: [PATCH] ring-buffer: Initialise reader page order in
 rb_allocate_cpu_buffer()

In rb_allocate_cpu_buffer(), bpage->order was omitted, leaving it as 0.
This is an issue for a ring-buffer with subbufs bigger than PAGE_SIZE if
when freed: free_buffer_page() relies on this value. Align the value
with the actual allocation size (buffer::subbuf_order).

Cc: [email protected]
Fixes: f9b94daa542a ("ring-buffer: Set new size of the ring buffer sub page")
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Vincent Donnefort <[email protected]>
Signed-off-by: Steven Rostedt <[email protected]>

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 6cbd80ccef37..760a00e8505c 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -2510,6 +2510,7 @@ rb_allocate_cpu_buffer(struct trace_buffer *buffer, long nr_pages, int cpu)
 	bpage = alloc_cpu_page(cpu);
 	if (!bpage)
 		return NULL;
+	bpage->order = cpu_buffer->buffer->subbuf_order;
 
 	rb_check_bpage(cpu_buffer, bpage);