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 0293C12A14D; Tue, 23 Jan 2024 00:12:16 +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=1705968737; cv=none; b=NpGaFx+cGT8JkH1dIjSO7J0hL7ozIt3LoZpCm+woH3IsQw9fOWrAxtxcDfwJ03sgEF42Sep8CzpA7nrF/R7UTK8d4oZMY3I06fT4USb2g6vXEaI47nG4drYa8g4184rxXNBONL9ifJpJfpfwh143620L6FX4HtYy4kEibAZqa/w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705968737; c=relaxed/simple; bh=b/2Ycj//bWZk+XsmXV836jef0UT9YkbmpPdk0GSxmTY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=eLhbzOdYqpvkTdYLQmJ/Ud/DCCPjqg/rpRT3BjyL5FmTeEqKOiD/75Ocjx0aB/lg6SP5qAbKpNbEOIrMxh+msCV1yFhInKZ53BY5tidyOne241zLGmGY5Zf7bdqEqJx5Q/zEA9czyZVMOdom989Uu02nAZYJE9NNo0/iKz6nuCo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=VAwxLeL7; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="VAwxLeL7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B8D68C43399; Tue, 23 Jan 2024 00:12:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1705968736; bh=b/2Ycj//bWZk+XsmXV836jef0UT9YkbmpPdk0GSxmTY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VAwxLeL7td2g90+BWSeVKrOWL1Htp22+fBvUbhSht7PG42QIaiZuvy9Dp9zxxGZe5 jkyL/UCxQWMfQk8k9E8vh5b36xAswNVhBpXMjBQnTk7RSzp0blolgWfvyUPICtxp/M ALZByHEFrLUN9jWb5d6cBJvjRRMKJ+J3TsnkOSnU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , "Steven Rostedt (Google)" , Sasha Levin Subject: [PATCH 5.4 022/194] ring-buffer: Do not record in NMI if the arch does not support cmpxchg in NMI Date: Mon, 22 Jan 2024 15:55:52 -0800 Message-ID: <20240122235720.178239115@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240122235719.206965081@linuxfoundation.org> References: <20240122235719.206965081@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Steven Rostedt (Google) [ Upstream commit 712292308af2265cd9b126aedfa987f10f452a33 ] As the ring buffer recording requires cmpxchg() to work, if the architecture does not support cmpxchg in NMI, then do not do any recording within an NMI. Link: https://lore.kernel.org/linux-trace-kernel/20231213175403.6fc18540@gandalf.local.home Cc: Masami Hiramatsu Cc: Mark Rutland Cc: Mathieu Desnoyers Signed-off-by: Steven Rostedt (Google) Signed-off-by: Sasha Levin --- kernel/trace/ring_buffer.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 4a03eac43aaf..0c0ca21d807d 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -2976,6 +2976,12 @@ rb_reserve_next_event(struct ring_buffer *buffer, int nr_loops = 0; u64 diff; + /* ring buffer does cmpxchg, make sure it is safe in NMI context */ + if (!IS_ENABLED(CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG) && + (unlikely(in_nmi()))) { + return NULL; + } + rb_start_commit(cpu_buffer); #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP -- 2.43.0