From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 888C5C433DF for ; Mon, 12 Oct 2020 13:48:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4E43C20878 for ; Mon, 12 Oct 2020 13:48:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602510494; bh=4fRAaOVTv/qlBcCTxLcq0CDp/BUdDur046Ay1mTLBCQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=q29cGInBBD5CBWEpXvtsDaRS3kGgxPINbFoRW8XE7qGWOWqo/oZ0w04Zgk91k4e+n jsuUXw7c0RIiBEShfbcAy4dtvYO2je8qXbzZUYsMMCgFS33L9ZxBccRvh030c0d1Wc GfdjMTW0CQ2JzrCdtt3sSj8XPCMG4z5IsANeINPI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731844AbgJLNsM (ORCPT ); Mon, 12 Oct 2020 09:48:12 -0400 Received: from mail.kernel.org ([198.145.29.99]:48538 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389761AbgJLNpz (ORCPT ); Mon, 12 Oct 2020 09:45:55 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id DC76B22370; Mon, 12 Oct 2020 13:45:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602510329; bh=4fRAaOVTv/qlBcCTxLcq0CDp/BUdDur046Ay1mTLBCQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QkqkmWvNDSUdhNy8rRo8+/9D+qp6+3XmrDZS53SPHiRQjvZ7n3f0+yuaQtziK4pWo twqHLQtgAZ6+xLnwcqab1Bte2KvZTKWWroBAmOWddH0ngbtmTovjJAkygZw++d7KXe xt2Myczhui1YRbsaEqZKRyv1Tm6fTtGVVHiEuRms= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Tony Ambardar , Daniel Borkmann , John Fastabend , Andrii Nakryiko Subject: [PATCH 5.8 022/124] bpf: Prevent .BTF section elimination Date: Mon, 12 Oct 2020 15:30:26 +0200 Message-Id: <20201012133147.919333925@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201012133146.834528783@linuxfoundation.org> References: <20201012133146.834528783@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Tony Ambardar commit 65c204398928f9c79f1a29912b410439f7052635 upstream. Systems with memory or disk constraints often reduce the kernel footprint by configuring LD_DEAD_CODE_DATA_ELIMINATION. However, this can result in removal of any BTF information. Use the KEEP() macro to preserve the BTF data as done with other important sections, while still allowing for smaller kernels. Fixes: 90ceddcb4950 ("bpf: Support llvm-objcopy for vmlinux BTF") Signed-off-by: Tony Ambardar Signed-off-by: Daniel Borkmann Acked-by: John Fastabend Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/a635b5d3e2da044e7b51ec1315e8910fbce0083f.1600417359.git.Tony.Ambardar@gmail.com Signed-off-by: Greg Kroah-Hartman --- include/asm-generic/vmlinux.lds.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -641,7 +641,7 @@ #define BTF \ .BTF : AT(ADDR(.BTF) - LOAD_OFFSET) { \ __start_BTF = .; \ - *(.BTF) \ + KEEP(*(.BTF)) \ __stop_BTF = .; \ } #else