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=-20.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 9B898C07E99 for ; Fri, 9 Jul 2021 11:39:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6DADF613BA for ; Fri, 9 Jul 2021 11:39:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231226AbhGILmT (ORCPT ); Fri, 9 Jul 2021 07:42:19 -0400 Received: from szxga01-in.huawei.com ([45.249.212.187]:14061 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230367AbhGILmS (ORCPT ); Fri, 9 Jul 2021 07:42:18 -0400 Received: from dggemv703-chm.china.huawei.com (unknown [172.30.72.55]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4GLrhg2mcBzbbls; Fri, 9 Jul 2021 19:36:19 +0800 (CST) Received: from dggema774-chm.china.huawei.com (10.1.198.216) by dggemv703-chm.china.huawei.com (10.3.19.46) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.2176.2; Fri, 9 Jul 2021 19:39:31 +0800 Received: from [10.67.102.197] (10.67.102.197) by dggema774-chm.china.huawei.com (10.1.198.216) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2176.2; Fri, 9 Jul 2021 19:39:30 +0800 Subject: Re: [PATCH 4.4.y] arm: kprobes: Allow to handle reentered kprobe on single-stepping To: Masami Hiramatsu , Shaobo Huang CC: , , , , , , , , , , References: <20210709024630.22268-1-huangshaobo6@huawei.com> <20210709180031.adc7260b54645b0292a6f02a@kernel.org> From: Xiaoming Ni Message-ID: <9ca81fb8-8d6e-1708-db01-a29e54c79343@huawei.com> Date: Fri, 9 Jul 2021 19:39:30 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.0.1 MIME-Version: 1.0 In-Reply-To: <20210709180031.adc7260b54645b0292a6f02a@kernel.org> Content-Type: text/plain; charset="gbk"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.67.102.197] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggema774-chm.china.huawei.com (10.1.198.216) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021/7/9 17:00, Masami Hiramatsu wrote: > Hi Shaobo, > > Thanks for backporting! > Greg, it seems this patch can be applied to 4.9 too without any issue. > https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-4.9.y&id=355a04fa1fc23c4fb1d16440e62d46a42691e96b The v4.9 branch has been fixed. Thanks Xiaoming Ni > Thank you, > > On Fri, 9 Jul 2021 10:46:30 +0800 > Shaobo Huang wrote: > >> From: Masami Hiramatsu >> >> commit f3fbd7ec62dec1528fb8044034e2885f2b257941 upstream >> >> This is arm port of commit 6a5022a56ac3 ("kprobes/x86: Allow to >> handle reentered kprobe on single-stepping") >> >> Since the FIQ handlers can interrupt in the single stepping >> (or preparing the single stepping, do_debug etc.), we should >> consider a kprobe is hit in the NMI handler. Even in that >> case, the kprobe is allowed to be reentered as same as the >> kprobes hit in kprobe handlers >> (KPROBE_HIT_ACTIVE or KPROBE_HIT_SSDONE). >> >> The real issue will happen when a kprobe hit while another >> reentered kprobe is processing (KPROBE_REENTER), because >> we already consumed a saved-area for the previous kprobe. >> >> Signed-off-by: Masami Hiramatsu >> Signed-off-by: Jon Medhurst >> Fixes: 24ba613c9d6c ("ARM kprobes: core code") >> Cc: stable@vger.kernel.org #v2.6.25~v4.11 >> Signed-off-by: huangshaobo >> --- >> arch/arm/probes/kprobes/core.c | 6 ++++++ >> 1 file changed, 6 insertions(+) >> >> diff --git a/arch/arm/probes/kprobes/core.c b/arch/arm/probes/kprobes/core.c >> index 3eb018fa1a1f..c3362ddd6c4c 100644 >> --- a/arch/arm/probes/kprobes/core.c >> +++ b/arch/arm/probes/kprobes/core.c >> @@ -270,6 +270,7 @@ void __kprobes kprobe_handler(struct pt_regs *regs) >> switch (kcb->kprobe_status) { >> case KPROBE_HIT_ACTIVE: >> case KPROBE_HIT_SSDONE: >> + case KPROBE_HIT_SS: >> /* A pre- or post-handler probe got us here. */ >> kprobes_inc_nmissed_count(p); >> save_previous_kprobe(kcb); >> @@ -278,6 +279,11 @@ void __kprobes kprobe_handler(struct pt_regs *regs) >> singlestep(p, regs, kcb); >> restore_previous_kprobe(kcb); >> break; >> + case KPROBE_REENTER: >> + /* A nested probe was hit in FIQ, it is a BUG */ >> + pr_warn("Unrecoverable kprobe detected at %p.\n", >> + p->addr); >> + /* fall through */ >> default: >> /* impossible cases */ >> BUG(); >> -- >> 2.12.3 >> > >