From patchwork Mon Dec 19 14:35:19 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Masami Hiramatsu (Google)" X-Patchwork-Id: 34568 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:adf:e747:0:0:0:0:0 with SMTP id c7csp2424751wrn; Mon, 19 Dec 2022 06:37:00 -0800 (PST) X-Google-Smtp-Source: AA0mqf6a19xk/Wsbw8kJoQVRHxM+3ODPLAaT6o5PvjbLLjLFHPVTBYCw462oS3K9+5TESnRBwVBG X-Received: by 2002:a17:906:714b:b0:7c1:6986:2b7c with SMTP id z11-20020a170906714b00b007c169862b7cmr29541586ejj.8.1671460620653; Mon, 19 Dec 2022 06:37:00 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1671460620; cv=none; d=google.com; s=arc-20160816; b=rHd4VuY4Dc2+uPJL0bx33qMbuB/OxXul/xfrzP6To73y05M752gBCwgOSrqE0MeQbc Z79CwVZr1suc290WyrWBIWUZHxngFG3ASbR4PIeAJ5QfQsXa4HDRtw5LMSHYXiPGmdZ5 0AfAUhPngIFTRXU9kEIttH28e1xHBJpiSpRfjfrACpTl3/Ir5DNym5oDStGRD682fyyx +kUdFpGPg0BUwksPyycpYb0T86bKyjb0Scu4zVWThNwU0V6qlpdxGWE56WwSPLHlAccO 2T5UH/b7nqc92pmlauyhnNuQ5cLDnlcGuCcLvcv/lB6ElAUxG8mrbMjZ6VoPF4AytIRw 2+nA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :user-agent:references:in-reply-to:message-id:date:subject:cc:to :from:dkim-signature; bh=WjW6DugKoOVwvf3KAAWEERzMl5ttO562mxtqKpDUCb0=; b=QyJxBkZ80n1WXxNqeDa0GBLU/5U+sn4qklucpUDxCs4xUWeMQNd4dhMHiUWbnpP4iz P8mAT8f80jkOcjUvEAvyqxSxkEMVlWN4LPn3dbJVYw90kcrCnbgfZl41yomSeVibO1CW JFlD7rrD7vYqIt3ybTs7KmP/GMvl4zoH24CYvRqwII0M9Pi2benHNuQ9RMlVCDVU2uEc o3cGO5bNPitDkiatL0gB2J1KdDEIcUcQ4p5vZAseWx9eU/xFtchDNwdiA0PIrpdXswKx MspUYRjNsOMOnCwFJyb5bhy8SlGa65oR6wFGLraXWYno8yoB2zpXLOyv56ca2NBEQpTr 6vbw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@kernel.org header.s=k20201202 header.b="VKmyNk/G"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id fq32-20020a1709069da000b007c040bc1679si6982297ejc.237.2022.12.19.06.36.37; Mon, 19 Dec 2022 06:37:00 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=k20201202 header.b="VKmyNk/G"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232418AbiLSOfw (ORCPT + 99 others); Mon, 19 Dec 2022 09:35:52 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40006 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232350AbiLSOfo (ORCPT ); Mon, 19 Dec 2022 09:35:44 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E1E94BAA; Mon, 19 Dec 2022 06:35:25 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 5AC48B80E47; Mon, 19 Dec 2022 14:35:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5AABEC433F1; Mon, 19 Dec 2022 14:35:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1671460523; bh=EnQDCn6+DxnGRVKzzZhsuaX7OEoKlrHh00hQOt+anfY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VKmyNk/GF2R5MK37W+xC38LM2qUuhTaDb71eCE6vtpI9dfYwRmRU7RYbCmx58dvAG QwEL1oxHSD9VkHZXbP7ljFFQyJNunM7ngpwu/p0KeBbFv05ogAC55baunB1j6psxqa IqS6WMY0krA6NnijbgbFlRqbHcOpHebwOBNY8qSq6JtME6suudObOr+8ghvO+vWR2h sVu+Neo38H+y9nuEGTg6MCDBD5vV8BPAYUu7G4+0Fzgq2g759rIyz1FghlzegeG6pN MbvmHiczzYmBqjxAVq96B+VGYT27+QIJH7Lon6pZjIu0GFyCjzkaA9sgINx9xLdLOv k/c4A9txaI27A== From: "Masami Hiramatsu (Google)" To: x86@kernel.org Cc: Steven Rostedt , Masami Hiramatsu , Ingo Molnar , Suleiman Souhlal , bpf , linux-kernel@vger.kernel.org, Borislav Petkov , Peter Zijlstra , Josh Poimboeuf , Nadav Amit Subject: [PATCH -tip v4 2/2] x86/kprobes: Fix optprobe optimization check with CONFIG_RETHUNK Date: Mon, 19 Dec 2022 23:35:19 +0900 Message-Id: <167146051929.1374301.7419382929328081706.stgit@devnote3> X-Mailer: git-send-email 2.39.0.314.g84b9a713c41-goog In-Reply-To: <167146050052.1374301.10407562178447545337.stgit@devnote3> References: <167146050052.1374301.10407562178447545337.stgit@devnote3> User-Agent: StGit/0.19 MIME-Version: 1.0 X-Spam-Status: No, score=-7.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_HI, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1752653491815967296?= X-GMAIL-MSGID: =?utf-8?q?1752653491815967296?= From: Masami Hiramatsu (Google) Since the CONFIG_RETHUNK and CONFIG_SLS will use INT3 for stopping speculative execution after function return, kprobe jump optimization always fails on the functions with such INT3 inside the function body. (It already checks the INT3 padding between functions, but not inside the function) To avoid this issue, as same as kprobes, check whether the INT3 comes from kgdb or not, and if so, stop decoding and make it fail. The other INT3 will come from CONFIG_RETHUNK/CONFIG_SLS and those can be treated as a one-byte instruction. Signed-off-by: Masami Hiramatsu (Google) Suggested-by: Peter Zijlstra Fixes: e463a09af2f0 ("x86: Add straight-line-speculation mitigation") Cc: stable@vger.kernel.org --- arch/x86/kernel/kprobes/opt.c | 28 ++++++++-------------------- 1 file changed, 8 insertions(+), 20 deletions(-) diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c index e6b8c5362b94..e57e07b0edb6 100644 --- a/arch/x86/kernel/kprobes/opt.c +++ b/arch/x86/kernel/kprobes/opt.c @@ -15,6 +15,7 @@ #include #include #include +#include #include #include #include @@ -279,19 +280,6 @@ static int insn_is_indirect_jump(struct insn *insn) return ret; } -static bool is_padding_int3(unsigned long addr, unsigned long eaddr) -{ - unsigned char ops; - - for (; addr < eaddr; addr++) { - if (get_kernel_nofault(ops, (void *)addr) < 0 || - ops != INT3_INSN_OPCODE) - return false; - } - - return true; -} - /* Decode whole function to ensure any instructions don't jump into target */ static int can_optimize(unsigned long paddr) { @@ -334,15 +322,15 @@ static int can_optimize(unsigned long paddr) ret = insn_decode_kernel(&insn, (void *)recovered_insn); if (ret < 0) return 0; - +#ifdef CONFIG_KGDB /* - * In the case of detecting unknown breakpoint, this could be - * a padding INT3 between functions. Let's check that all the - * rest of the bytes are also INT3. + * If there is a dynamically installed kgdb sw breakpoint, + * this function should not be probed. */ - if (insn.opcode.bytes[0] == INT3_INSN_OPCODE) - return is_padding_int3(addr, paddr - offset + size) ? 1 : 0; - + if (insn.opcode.bytes[0] == INT3_INSN_OPCODE && + kgdb_has_hit_break(addr)) + return 0; +#endif /* Recover address */ insn.kaddr = (void *)addr; insn.next_byte = (void *)(addr + insn.length);