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 Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B426FC433EF for ; Thu, 19 May 2022 17:28:23 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4L3xdy2scnz3bhy for ; Fri, 20 May 2022 03:28:22 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=csgroup.eu (client-ip=93.17.235.10; helo=pegase2.c-s.fr; envelope-from=christophe.leroy@csgroup.eu; receiver=) Received: from pegase2.c-s.fr (pegase2.c-s.fr [93.17.235.10]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4L3xdW19yPz2ywN for ; Fri, 20 May 2022 03:27:58 +1000 (AEST) Received: from localhost (mailhub3.si.c-s.fr [172.26.127.67]) by localhost (Postfix) with ESMTP id 4L3xdR3DRQz9t0v; Thu, 19 May 2022 19:27:55 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from pegase2.c-s.fr ([172.26.127.65]) by localhost (pegase2.c-s.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id QInxpv6g3tR7; Thu, 19 May 2022 19:27:55 +0200 (CEST) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase2.c-s.fr (Postfix) with ESMTP id 4L3xdR23WNz9t0Q; Thu, 19 May 2022 19:27:55 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 360CC8B77E; Thu, 19 May 2022 19:27:55 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id xtWnll6ZhbEu; Thu, 19 May 2022 19:27:55 +0200 (CEST) Received: from [192.168.203.71] (unknown [192.168.203.71]) by messagerie.si.c-s.fr (Postfix) with ESMTP id BF5538B763; Thu, 19 May 2022 19:27:54 +0200 (CEST) Message-ID: <67938da3-07a6-3c51-e5b9-10b8047ff5b5@csgroup.eu> Date: Thu, 19 May 2022 19:27:54 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.0 Subject: Re: [PATCH v1 3/4] powerpc/code-patching: Use jump_label for testing freed initmem Content-Language: fr-FR From: Christophe Leroy To: Guenter Roeck References: <0aee964721cab7316cffde21a2ca223cee14d373.1647962456.git.christophe.leroy@csgroup.eu> <20220519021706.GA3526833@roeck-us.net>

In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "linuxppc-dev@lists.ozlabs.org" , Paul Mackerras , "linux-kernel@vger.kernel.org" Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Le 19/05/2022 à 08:53, Christophe Leroy a écrit : > > > Le 19/05/2022 à 08:27, Christophe Leroy a écrit : >> >> >> Le 19/05/2022 à 04:17, Guenter Roeck a écrit : >>> On Tue, Mar 22, 2022 at 04:40:20PM +0100, Christophe Leroy wrote: >>>> Once init is done, initmem is freed forever so no need to >>>> test system_state at every call to patch_instruction(). >>>> >>>> Use jump_label. >>>> >>>> This reduces by 2% the time needed to activate ftrace on an 8xx. >>>> >>> >>> It also causes the qemu mpc8544ds emulation to crash. >>> >>> BUG: Unable to handle kernel data access on write at 0xc122eb34 >>> Faulting instruction address: 0xc001b580 >>> Oops: Kernel access of bad area, sig: 11 [#1] >>> BE PAGE_SIZE=4K MPC8544 DS >>> Modules linked in: >>> CPU: 0 PID: 1 Comm: swapper Not tainted 5.18.0-rc7-next-20220518 #1 >>> NIP: c001b580 LR: c001b560 CTR: 00000003 >>> REGS: c5107dd0 TRAP: 0300 Not tainted (5.18.0-rc7-next-20220518) >>> MSR: 00009000 CR: 24000882 XER: 00000000 >>> DEAR: c122eb34 ESR: 00800000 >>> GPR00: c001b560 c5107ec0 c5120020 10000000 00000000 00000078 0c000000 >>> cfffffff >>> GPR08: c001e9ec 00000001 00000007 00000000 44000882 00000000 c0005178 >>> 00000000 >>> GPR16: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 >>> 00000000 >>> GPR24: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 >>> c1230000 >>> NIP [c001b580] free_initmem+0x48/0xa8 >>> LR [c001b560] free_initmem+0x28/0xa8 >>> Call Trace: >>> [c5107ec0] [c001b560] free_initmem+0x28/0xa8 (unreliable) >>> [c5107ee0] [c00051b0] kernel_init+0x38/0x150 >>> [c5107f00] [c001626c] ret_from_kernel_thread+0x5c/0x64 >>> Instruction dump: >>> 3fe0c123 912a00dc 90010024 48000665 3d20c218 8929fa65 2c090000 41820058 >>> 813feb34 2c090000 4082003c 39200001 <913feb34> 80010024 3cc0c114 >>> 83e1001c >>> >>> Reverting this patch fixes the problem. >>> >> >> That's strange. >> >> I was able to reproduce the problem. >> >> Removing the __ro_after_init in front of >> DEFINE_STATIC_KEY_FALSE(init_mem_is_free) fixes the problem. >> >> I can't understand why, mark_readonly() is called after free_initmem(). >> > > Moving static_branch_enable(&init_mem_is_free) before mark_initmem_nx() > also solves the problem. > > There must be something wrong with mark_initmem_nx(). > Fixing patch sent, see https://patchwork.ozlabs.org/project/linuxppc-dev/patch/2e35f0fd649c83c5add17a99514ac040767be93a.1652981047.git.christophe.leroy@csgroup.eu/ Christophe 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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 70B72C433F5 for ; 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Thu, 19 May 2022 19:27:55 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 360CC8B77E; Thu, 19 May 2022 19:27:55 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id xtWnll6ZhbEu; Thu, 19 May 2022 19:27:55 +0200 (CEST) Received: from [192.168.203.71] (unknown [192.168.203.71]) by messagerie.si.c-s.fr (Postfix) with ESMTP id BF5538B763; Thu, 19 May 2022 19:27:54 +0200 (CEST) Message-ID: <67938da3-07a6-3c51-e5b9-10b8047ff5b5@csgroup.eu> Date: Thu, 19 May 2022 19:27:54 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.0 Subject: Re: [PATCH v1 3/4] powerpc/code-patching: Use jump_label for testing freed initmem Content-Language: fr-FR From: Christophe Leroy To: Guenter Roeck Cc: Paul Mackerras , "linuxppc-dev@lists.ozlabs.org" , "linux-kernel@vger.kernel.org" References: <0aee964721cab7316cffde21a2ca223cee14d373.1647962456.git.christophe.leroy@csgroup.eu> <20220519021706.GA3526833@roeck-us.net>

In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Le 19/05/2022 à 08:53, Christophe Leroy a écrit : > > > Le 19/05/2022 à 08:27, Christophe Leroy a écrit : >> >> >> Le 19/05/2022 à 04:17, Guenter Roeck a écrit : >>> On Tue, Mar 22, 2022 at 04:40:20PM +0100, Christophe Leroy wrote: >>>> Once init is done, initmem is freed forever so no need to >>>> test system_state at every call to patch_instruction(). >>>> >>>> Use jump_label. >>>> >>>> This reduces by 2% the time needed to activate ftrace on an 8xx. >>>> >>> >>> It also causes the qemu mpc8544ds emulation to crash. >>> >>> BUG: Unable to handle kernel data access on write at 0xc122eb34 >>> Faulting instruction address: 0xc001b580 >>> Oops: Kernel access of bad area, sig: 11 [#1] >>> BE PAGE_SIZE=4K MPC8544 DS >>> Modules linked in: >>> CPU: 0 PID: 1 Comm: swapper Not tainted 5.18.0-rc7-next-20220518 #1 >>> NIP: c001b580 LR: c001b560 CTR: 00000003 >>> REGS: c5107dd0 TRAP: 0300 Not tainted (5.18.0-rc7-next-20220518) >>> MSR: 00009000 CR: 24000882 XER: 00000000 >>> DEAR: c122eb34 ESR: 00800000 >>> GPR00: c001b560 c5107ec0 c5120020 10000000 00000000 00000078 0c000000 >>> cfffffff >>> GPR08: c001e9ec 00000001 00000007 00000000 44000882 00000000 c0005178 >>> 00000000 >>> GPR16: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 >>> 00000000 >>> GPR24: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 >>> c1230000 >>> NIP [c001b580] free_initmem+0x48/0xa8 >>> LR [c001b560] free_initmem+0x28/0xa8 >>> Call Trace: >>> [c5107ec0] [c001b560] free_initmem+0x28/0xa8 (unreliable) >>> [c5107ee0] [c00051b0] kernel_init+0x38/0x150 >>> [c5107f00] [c001626c] ret_from_kernel_thread+0x5c/0x64 >>> Instruction dump: >>> 3fe0c123 912a00dc 90010024 48000665 3d20c218 8929fa65 2c090000 41820058 >>> 813feb34 2c090000 4082003c 39200001 <913feb34> 80010024 3cc0c114 >>> 83e1001c >>> >>> Reverting this patch fixes the problem. >>> >> >> That's strange. >> >> I was able to reproduce the problem. >> >> Removing the __ro_after_init in front of >> DEFINE_STATIC_KEY_FALSE(init_mem_is_free) fixes the problem. >> >> I can't understand why, mark_readonly() is called after free_initmem(). >> > > Moving static_branch_enable(&init_mem_is_free) before mark_initmem_nx() > also solves the problem. > > There must be something wrong with mark_initmem_nx(). > Fixing patch sent, see https://patchwork.ozlabs.org/project/linuxppc-dev/patch/2e35f0fd649c83c5add17a99514ac040767be93a.1652981047.git.christophe.leroy@csgroup.eu/ Christophe