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=-18.8 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, 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 758C6C43470 for ; Mon, 5 Apr 2021 09:15:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 51CA7611C1 for ; Mon, 5 Apr 2021 09:15:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240229AbhDEJOz (ORCPT ); Mon, 5 Apr 2021 05:14:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:58684 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239020AbhDEJLs (ORCPT ); Mon, 5 Apr 2021 05:11:48 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 38593613B3; Mon, 5 Apr 2021 09:11:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1617613877; bh=G8Qg84PWMT9VQAkv24V0rf8JejJZcpYP2MBZLk/qk30=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Fcbb3M0L+7nMpchK54IMBQuAf+Ir2OxOF4HjlVGWUhY/M+UQANtO8J/5EoWurjGik Eg8yZBiOg5TwqBH/6bJBPX4LojIBr2NP7b+HU5YP2zGC4rwRfBcV5+NUxA30h3odRh PJerJ3VTliD7PStT5voh65cv0MHUuChC8zG+UKMw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Stanislav Fomichev , Alexei Starovoitov Subject: [PATCH 5.10 126/126] bpf: Use NOP_ATOMIC5 instead of emit_nops(&prog, 5) for BPF_TRAMP_F_CALL_ORIG Date: Mon, 5 Apr 2021 10:54:48 +0200 Message-Id: <20210405085035.204608164@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210405085031.040238881@linuxfoundation.org> References: <20210405085031.040238881@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: Stanislav Fomichev commit b9082970478009b778aa9b22d5561eef35b53b63 upstream. __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: Greg Kroah-Hartman --- arch/x86/net/bpf_jit_comp.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- 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 b /* 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) {