From patchwork Mon Mar 29 07:58:59 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 411281 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=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham 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 BBFC6C433E2 for ; Mon, 29 Mar 2021 08:40:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9C509619D6 for ; Mon, 29 Mar 2021 08:40:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234929AbhC2Ijt (ORCPT ); Mon, 29 Mar 2021 04:39:49 -0400 Received: from mail.kernel.org ([198.145.29.99]:60912 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233825AbhC2Ii1 (ORCPT ); Mon, 29 Mar 2021 04:38:27 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 277EF61580; Mon, 29 Mar 2021 08:38:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1617007106; bh=eghLgthahG554ZGl0095jz9fFgId/FojoOKssZKR2NU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aNbQ1tpsgjYuByZl4Efts4V9ffm6OVM5GecAC/F/jWztsgnV49frgpWWo1t2VfgSP 6hL4RhCXIUvnUVNj30NXUK4+3Er/18e6aZvEl5HlTdCPYrnxQJqbx5NJXP3oav6aWj OAhqdPOa7ivFoWOwN+koUGFddlV616TWj8xCnlTo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Stanislav Fomichev , Alexei Starovoitov , Sasha Levin Subject: [PATCH 5.11 223/254] bpf: Use NOP_ATOMIC5 instead of emit_nops(&prog, 5) for BPF_TRAMP_F_CALL_ORIG Date: Mon, 29 Mar 2021 09:58:59 +0200 Message-Id: <20210329075640.419966788@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210329075633.135869143@linuxfoundation.org> References: <20210329075633.135869143@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Stanislav Fomichev [ Upstream commit b9082970478009b778aa9b22d5561eef35b53b63 ] __bpf_arch_text_poke does rewrite only for atomic nop5, emit_nops(xxx, 5) emits non-atomic one which breaks fentry/fexit with k8 atomics: P6_NOP5 == P6_NOP5_ATOMIC (0f1f440000 == 0f1f440000) K8_NOP5 != K8_NOP5_ATOMIC (6666906690 != 6666666690) Can be reproduced by doing "ideal_nops = k8_nops" in "arch_init_ideal_nops() and running fexit_bpf2bpf selftest. Fixes: e21aa341785c ("bpf: Fix fexit trampoline.") Signed-off-by: Stanislav Fomichev Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20210320000001.915366-1-sdf@google.com Signed-off-by: Sasha Levin --- arch/x86/net/bpf_jit_comp.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 652bd64e422d..023ac12f54a2 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -1811,7 +1811,8 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i /* remember return value in a stack for bpf prog to access */ emit_stx(&prog, BPF_DW, BPF_REG_FP, BPF_REG_0, -8); im->ip_after_call = prog; - emit_nops(&prog, 5); + memcpy(prog, ideal_nops[NOP_ATOMIC5], X86_PATCH_SIZE); + prog += X86_PATCH_SIZE; } if (fmod_ret->nr_progs) {