From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 53C1337DEAA; Sun, 9 Aug 2026 02:32:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786242738; cv=none; b=QdMgqbYrSjhT2Iv8qV2C1HpRDiAtsaaAAe69AIhopPuw9+2VQoxn8H5xBGmWkFu7gLZm2XL/7c9c3ZOSEmrZIuuOd2Iy9ZKybWEyFJcbjXADhyfpoHRbPZbjtqS9qa/KO+TI2uESHHzr7iLvuy8c0unSpuoRs0fEPI5ajSR+GNk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786242738; c=relaxed/simple; bh=afozUb8E/5FXp1IRFFB2cQW7YrWaCKo+79vBmXSiE/Y=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=hgLeaGC2nqJt3wDDdGgPBb4Ws2RyHux8mBK8qaogJiXQa/Sy/Qus7PrJRvm0nQUulbdvUf23ki6lEdaWUsvmhbJaiJHhZwgosmfJt72my03efqe1T28C4MYIqdO+VWE4KpiKZbxHF5mH94pO16bAw898E56CeDqEkd4sKWaLjLE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Qg/Yjanv; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Qg/Yjanv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8C3BE1F00ADE; Sun, 9 Aug 2026 02:32:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786242736; bh=JrxP5G/FB4r8xdT3E+9AH8xbkYjIv2lSi5v0y68eIGE=; h=Date:From:To:Cc:Subject:References; b=Qg/YjanvPmshHuWNqXtAj6WhQm3/mTZC4lT/wJXUEM5WqCP5DdaRTXlOmdHdX7BEE sf/w1ByR9NeY1RIjCg2y9tfsyfuCKhtA/X6L7IQqSsagFo9tdPjApdYnb2Wt+mbsuz 96QT69JpAK/P8kjV6YZytcC9REBzu2b9Iz43nu+YR7TieWYg4Y4LSdxzeTqRuPn41J iw8NeYujBeSaqLI9l59TyYWlYpoQ0epJcmgBvcVmSLjWj2hGFb83xaxTt946QGa0JO a1jkYEEgfUXTzE9Ed0Kgse/BhmkTr6XHM9NPd1vmO4eOeqhfxZ55fQOeZL/sgMuvzk 8anUHbqqxUnNA== Received: from rostedt by gandalf with local (Exim 4.99.4) (envelope-from ) id 1wstKo-00000001N7C-3ucB; Sat, 08 Aug 2026 22:32:22 -0400 Message-ID: <20260809023222.799156348@kernel.org> User-Agent: quilt/0.69 Date: Sat, 08 Aug 2026 22:31:54 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , stable@vger.kernel.org, syzbot+e0cc44465d6bae735679@syzkaller.appspotmail.com, Vincent Donnefort Subject: [for-linus][PATCH 10/12] ring-buffer: Prevent subbuf order change when resizing is disabled References: <20260809023144.852271250@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 From: Vincent Donnefort Because ring_buffer_subbuf_order_set() frees buffer pages, we can't allow it when resizing is disabled. A non-consuming reader is at risk of use-after-free (rb_advance_iter()). Return -EBUSY on resize_disabled, matching ring_buffer_resize() behaviour. Cc: stable@vger.kernel.org Fixes: f9b94daa542a ("ring-buffer: Set new size of the ring buffer sub page") Link: https://patch.msgid.link/20260806211306.3704194-3-vdonnefort@google.com Reported-by: syzbot+e0cc44465d6bae735679@syzkaller.appspotmail.com Signed-off-by: Vincent Donnefort Signed-off-by: Steven Rostedt --- kernel/trace/ring_buffer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 09d502ef4c55..6cbd80ccef37 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -7360,7 +7360,7 @@ int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order) cpu_buffer = buffer->buffers[cpu]; - if (cpu_buffer->mapped) { + if (atomic_read(&cpu_buffer->resize_disabled)) { err = -EBUSY; goto error; } -- 2.53.0