From patchwork Tue May 26 18:53:36 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 225353 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=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, 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 A42E1C433DF for ; Tue, 26 May 2020 19:10:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 77EFC21501 for ; Tue, 26 May 2020 19:10:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590520259; bh=vhhw2Jdi95VXXXtnhoiGlwXjDgEAcBNldmfG9VokCCs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=dXMSK5bHr7Cvu8B9swyD6itfgOCBGR3JiaNkAuLwmBvbC3DytGSIuKBHrf1A5MC2x 0UKKTLMLyhZFcz/PMzIfYibAKLB2MUIF8EQz8uKuXZ48QGFb3tnLYcOo3J83eniQ/g YE10+OZZuX4K9jOzN2DIOVAzWS1I/aeVSCGOdskA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391147AbgEZTKs (ORCPT ); Tue, 26 May 2020 15:10:48 -0400 Received: from mail.kernel.org ([198.145.29.99]:40046 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404023AbgEZTKr (ORCPT ); Tue, 26 May 2020 15:10:47 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 5698620776; Tue, 26 May 2020 19:10:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590520246; bh=vhhw2Jdi95VXXXtnhoiGlwXjDgEAcBNldmfG9VokCCs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jpAwZpta+kn3fIfQDhkFyhKnORoRLRIk9XnU/mm/B9cdl/svkRuGjo4/MTnbgC3Sn /wrsZ5ZNB/Bv2T/v/Mb0b9usDI9nodj6mkGE+Un9gV1fLNNghZFYS+fWh0NccMRxnY ppgwmPgtz8WMIYLOXkElb+IMFJ/OPdOpscHuzFLc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Peter Zijlstra , Daniel Borkmann , Alexei Starovoitov , Sasha Levin Subject: [PATCH 5.4 078/111] bpf: Avoid setting bpf insns pages read-only when prog is jited Date: Tue, 26 May 2020 20:53:36 +0200 Message-Id: <20200526183940.262459918@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200526183932.245016380@linuxfoundation.org> References: <20200526183932.245016380@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Daniel Borkmann [ Upstream commit e1608f3fa857b600045b6df7f7dadc70eeaa4496 ] For the case where the interpreter is compiled out or when the prog is jited it is completely unnecessary to set the BPF insn pages as read-only. In fact, on frequent churn of BPF programs, it could lead to performance degradation of the system over time since it would break the direct map down to 4k pages when calling set_memory_ro() for the insn buffer on x86-64 / arm64 and there is no reverse operation. Thus, avoid breaking up large pages for data maps, and only limit this to the module range used by the JIT where it is necessary to set the image read-only and executable. Suggested-by: Peter Zijlstra Signed-off-by: Daniel Borkmann Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20191129222911.3710-1-daniel@iogearbox.net Signed-off-by: Sasha Levin --- include/linux/filter.h | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/include/linux/filter.h b/include/linux/filter.h index 0367a75f873b..3bbc72dbc69e 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -770,8 +770,12 @@ bpf_ctx_narrow_access_offset(u32 off, u32 size, u32 size_default) static inline void bpf_prog_lock_ro(struct bpf_prog *fp) { - set_vm_flush_reset_perms(fp); - set_memory_ro((unsigned long)fp, fp->pages); +#ifndef CONFIG_BPF_JIT_ALWAYS_ON + if (!fp->jited) { + set_vm_flush_reset_perms(fp); + set_memory_ro((unsigned long)fp, fp->pages); + } +#endif } static inline void bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr)