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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 B4A5EC433B4 for ; Fri, 2 Apr 2021 13:37:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 822F4610C7 for ; Fri, 2 Apr 2021 13:37:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235585AbhDBNhP (ORCPT ); Fri, 2 Apr 2021 09:37:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34692 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235204AbhDBNhO (ORCPT ); Fri, 2 Apr 2021 09:37:14 -0400 Received: from ustc.edu.cn (email6.ustc.edu.cn [IPv6:2001:da8:d800::8]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 07C4DC0613E6 for ; Fri, 2 Apr 2021 06:37:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mail.ustc.edu.cn; s=dkim; h=Received:Date:From:To:Cc:Subject: Message-ID:In-Reply-To:References:MIME-Version:Content-Type: Content-Transfer-Encoding; bh=tZ/LaANIi5M7NtxlP10sRG+XBo+hd4rG5q oxm75toyo=; b=PONDGZ1YFHa6lf9fRfKb0aqAiq72Q3hH/M+WnB59LbD4AI3vkb TnEPvgc8X7CZbveXLxz5Gj1RvGzpCbKn6/byBaRxFWMb+Hl8PaTJ906+JSb7p7sZ olfHi/XLf04+d4GMzyBFTuSyzCndjzLzwyz8Qow2ekl0IYgz5yCTkeME8= Received: from xhacker (unknown [101.86.19.180]) by newmailweb.ustc.edu.cn (Coremail) with SMTP id LkAmygAXIqz_HWdgWQSLAA--.8753S2; Fri, 02 Apr 2021 21:37:04 +0800 (CST) Date: Fri, 2 Apr 2021 21:32:06 +0800 From: Jisheng Zhang To: "liaochang (A)" Cc: Masami Hiramatsu , Paul Walmsley , Palmer Dabbelt , Albert Ou , Guo Ren , , Subject: Re: [PATCH] riscv: keep interrupts disabled for BREAKPOINT exception Message-ID: <20210402213206.7db93785@xhacker> In-Reply-To: <096752a7-21f9-8339-2e76-8c65859fa1d7@huawei.com> References: <20210330021624.2b776386@xhacker> <20210330183316.942215efe8e6e8455ad14113@kernel.org> <20210331222244.45a5807c@xhacker> <096752a7-21f9-8339-2e76-8c65859fa1d7@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: LkAmygAXIqz_HWdgWQSLAA--.8753S2 X-Coremail-Antispam: 1UD129KBjvJXoW7WF45trWrAr4xCFW7WF1Dtrb_yoW8AryrpF WDJa15KF4kJw18Cas2yw1F9ryFyayrGrWfur98Cw1ftrsxt3s5JryIgFW3Wr1rGr12kw1S vFWYyry2qa48ArJanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUyFb7Iv0xC_Cr1lb4IE77IF4wAFF20E14v26r4j6ryUM7CY07I2 0VC2zVCF04k26cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28lY4IEw2IIxxk0rw A2F7IY1VAKz4vEj48ve4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Xr0_Ar1l84ACjcxK6xII jxv20xvEc7CjxVAFwI0_Cr0_Gr1UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I 8E87Iv6xkF7I0E14v26rxl6s0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI 64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r106r15McIj6I8E87Iv67AKxVWUJVW8Jw Am72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IY64vIr41l42xK82IYc2Ij64vIr41l4I8I3I0E 4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGV WUWwC2zVAF1VAY17CE14v26r1q6r43MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_ Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r4j6F4UMIIF0xvE42xK8VAvwI8IcIk0rV W3JVWrJr1lIxAIcVC2z280aVAFwI0_Jr0_Gr1lIxAIcVC2z280aVCY1x0267AKxVW8JVW8 JrUvcSsGvfC2KfnxnUUI43ZEXa7IU1GQ6JUUUUU== X-CM-SenderInfo: xmv2xttqjtqzxdloh3xvwfhvlgxou0/ Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 1 Apr 2021 16:49:47 +0800 "liaochang (A)" wrote: > Hi Jisheng, Hi, >=20 > =E5=9C=A8 2021/3/31 22:22, Jisheng Zhang =E5=86=99=E9=81=93: > > On Tue, 30 Mar 2021 18:33:16 +0900 > > Masami Hiramatsu wrote: > > =20 > >> Hi Jisheng, =20 > >=20 > > Hi Masami, > > =20 > >> > >> On Tue, 30 Mar 2021 02:16:24 +0800 > >> Jisheng Zhang wrote: > >> =20 > >>> From: Jisheng Zhang > >>> > >>> Current riscv's kprobe handlers are run with both preemption and > >>> interrupt enabled, this violates kprobe requirements. Fix this issue > >>> by keeping interrupts disabled for BREAKPOINT exception. =20 > >> > >> Not only while the breakpoint exception but also until the end of > >> the single step (maybe you are using __BUG_INSN_32 ??) need to be > >> disable interrupts. Can this do that? > >> =20 > >=20 > > interrupt is disabled during "single step" by kprobes_save_local_irqfla= g() > > and kprobes_restore_local_irqflag(). The code flow looks like:=20 > >=20 > > do_trap_break() // for bp > > kprobe_breakpoint_handler() > > setup_singlestep() > > kprobes_restore_local_irqflag() > >=20 > > do_trap_break() // for ss > > kprobe_single_step_handler() > > kprobes_restore_local_irqflag() =20 >=20 > Recently, kernel hit BUG_ON() on QEMU after I install a probe at "sys_rea= d" via kprobe, TIPS: Each line should not exceed 80 chars > accoriding to my debugging and analysis it looks like caused by the "irq = disable" operation for single-stepping. >=20 > I present a detailed description about this problem in the mail with titl= e "[PATCH] riscv/kprobe: fix kernel panic when invoking sys_read traced by = kprobe". > Looking forward to some feedback,Thanks. >=20 I will comment that patch. thanks