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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 93606C433EF for ; Thu, 9 Sep 2021 13:41:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7C72761207 for ; Thu, 9 Sep 2021 13:41:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1353815AbhIINmM (ORCPT ); Thu, 9 Sep 2021 09:42:12 -0400 Received: from mail.kernel.org ([198.145.29.99]:58618 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1356614AbhIIMzd (ORCPT ); Thu, 9 Sep 2021 08:55:33 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 49BED613D2; Thu, 9 Sep 2021 11:58:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1631188690; bh=BZvm1toZ3Z9QlyIH9RMnJNT1diE06Fi3/45GUdOHi9k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Xk0/nyqvCn1QfSLE8Woty1BbZfxXsFBnQaNYiTiTyf6VMVMhhrILhoIoZvU2Xu5OK 7qxIZgBiDwdHgJhu5laH+WjDAr49RPh0Aa31qFmW7pdoUbcUjeZ4+aDbxwexPDPIsM QPJxFSsxJIAMvvn2JKSMjO/leeUA0av30TFEDtyJFMbw2TgmNmC9RH9Re1mCy7gHKL /deKQX46l3pqElg78JoTCIFGd73WbvLSWbwsP1ee9OmuQAnD95jDy67KX9YC/XQlTU 1aiuJve5npcTtEFYDgp/DPGAKuMHsUG07kPpSBaRIyjuCOmfYcQ8GTg9SujxofB6aR EtFeswrivXhnQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Johan Almbladh , Andrii Nakryiko , Yonghong Song , Sasha Levin , netdev@vger.kernel.org, bpf@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 35/74] bpf: Fix off-by-one in tail call count limiting Date: Thu, 9 Sep 2021 07:56:47 -0400 Message-Id: <20210909115726.149004-35-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210909115726.149004-1-sashal@kernel.org> References: <20210909115726.149004-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org From: Johan Almbladh [ Upstream commit b61a28cf11d61f512172e673b8f8c4a6c789b425 ] Before, the interpreter allowed up to MAX_TAIL_CALL_CNT + 1 tail calls. Now precisely MAX_TAIL_CALL_CNT is allowed, which is in line with the behavior of the x86 JITs. Signed-off-by: Johan Almbladh Signed-off-by: Andrii Nakryiko Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20210728164741.350370-1-johan.almbladh@anyfinetworks.com Signed-off-by: Sasha Levin --- kernel/bpf/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index d2b6d2459aad..b4a35c11bc92 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -1198,7 +1198,7 @@ static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn, u64 *stack) if (unlikely(index >= array->map.max_entries)) goto out; - if (unlikely(tail_call_cnt > MAX_TAIL_CALL_CNT)) + if (unlikely(tail_call_cnt >= MAX_TAIL_CALL_CNT)) goto out; tail_call_cnt++; -- 2.30.2