From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 8FB8D430BB5; Sun, 1 Mar 2026 01:29:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772328589; cv=none; b=X6ek9W3+yuIEf/O7V0T/yODDJBsjNZhjIIbsAJLk3n6rqqdz5aAqYBepj/xCEloT+zaon+HAq0FtY5KBvsY6gmMQ3IyMjBSeidu6r5J14hJRylzUWTsLAwAXuhz0KaE7run3ERac3U1EWOTL9yHPSjudREZi4QrZPPGze+mY5Nw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772328589; c=relaxed/simple; bh=ylevKCBCWcRYXoqDCQYKjh/MazvjuVPCqwnZmq72niI=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=Vns7jyC2/sbWIdkH8/rclHFqkT37gwpFHV2FFiQgPGNHmlQjOAcn4Ndw5ZGzJaBJ9PcQ+rXOsZTlRhwKio4ooGkYWGTiab060xcjObmLNxKCPrsBU+r5EIo7C4LvTX+G3zKUEIVWW7gORktFJJNCZ/GikzAgnEn0LLSpPPtg2wk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=BRYcZQCx; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="BRYcZQCx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DFFE7C19421; Sun, 1 Mar 2026 01:29:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772328589; bh=ylevKCBCWcRYXoqDCQYKjh/MazvjuVPCqwnZmq72niI=; h=From:To:Cc:Subject:Date:From; b=BRYcZQCxd1cqbaqv37KZXaFZGoZbTuM9qws7gmn/BwaO3L6SdpzuuieEWZ8yL1F79 KPFYbcyh/lMWuKYOFAG+4pNdJ2Rh4K23nzgEsvPL+dyJhtMDLr7uQA113fFs2FLCjt fIdVlT4RUPSR2VnxVq0+XpEqDc4SyJvzDaeaN5p9LlHyp61BSLpBYz/hxXL3W493Uu C5GPwh5Kx3Aq+CSXugXcP7fWISXA9hI0apsCgyCRspwClsbWqba6UEQ0t7kNaQ+Pff pT9+AESUGOLC5VJLPHYjfKqFgzCVu0kw73HNPubjCfIirlfCoR+5Q7lHfrmK2jOJEV 14HjSNYOfxyZQ== From: Sasha Levin To: stable@vger.kernel.org, mhiramat@kernel.org Cc: Mathieu Desnoyers , "Steven Rostedt (Google)" , linux-trace-kernel@vger.kernel.org Subject: FAILED: Patch "tracing: ring-buffer: Fix to check event length before using" failed to apply to 6.12-stable tree Date: Sat, 28 Feb 2026 20:29:47 -0500 Message-ID: <20260301012947.1687657-1-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Hint: ignore X-stable: review Content-Transfer-Encoding: 8bit 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 . Thanks, Sasha ------------------ original commit in Linus's tree ------------------ >From 912b0ee248c529a4f45d1e7f568dc1adddbf2a4a Mon Sep 17 00:00:00 2001 From: "Masami Hiramatsu (Google)" Date: Mon, 16 Feb 2026 18:30:15 +0900 Subject: [PATCH] tracing: ring-buffer: Fix to check event length before using Check the event length before adding it for accessing next index in rb_read_data_buffer(). Since this function is used for validating possibly broken ring buffers, the length of the event could be broken. In that case, the new event (e + len) can point a wrong address. To avoid invalid memory access at boot, check whether the length of each event is in the possible range before using it. Cc: stable@vger.kernel.org Cc: Mathieu Desnoyers Fixes: 5f3b6e839f3c ("ring-buffer: Validate boot range memory events") Link: https://patch.msgid.link/177123421541.142205.9414352170164678966.stgit@devnote2 Signed-off-by: Masami Hiramatsu (Google) Signed-off-by: Steven Rostedt (Google) --- kernel/trace/ring_buffer.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index bdc8010d8f482..1e7a34a31851c 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1849,6 +1849,7 @@ static int rb_read_data_buffer(struct buffer_data_page *dpage, int tail, int cpu struct ring_buffer_event *event; u64 ts, delta; int events = 0; + int len; int e; *delta_ptr = 0; @@ -1856,9 +1857,12 @@ static int rb_read_data_buffer(struct buffer_data_page *dpage, int tail, int cpu ts = dpage->time_stamp; - for (e = 0; e < tail; e += rb_event_length(event)) { + for (e = 0; e < tail; e += len) { event = (struct ring_buffer_event *)(dpage->data + e); + len = rb_event_length(event); + if (len <= 0 || len > tail - e) + return -1; switch (event->type_len) { -- 2.51.0