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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9101DC433F5 for ; Tue, 12 Oct 2021 01:43:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6BA4A6109E for ; Tue, 12 Oct 2021 01:43:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229913AbhJLBpc (ORCPT ); Mon, 11 Oct 2021 21:45:32 -0400 Received: from szxga03-in.huawei.com ([45.249.212.189]:24243 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229565AbhJLBpb (ORCPT ); Mon, 11 Oct 2021 21:45:31 -0400 Received: from dggemv711-chm.china.huawei.com (unknown [172.30.72.56]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4HSz1W0phzz8tZh; Tue, 12 Oct 2021 09:42:23 +0800 (CST) Received: from dggpemm100009.china.huawei.com (7.185.36.113) by dggemv711-chm.china.huawei.com (10.1.198.66) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.8; Tue, 12 Oct 2021 09:43:28 +0800 Received: from [10.174.179.24] (10.174.179.24) by dggpemm100009.china.huawei.com (7.185.36.113) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.8; Tue, 12 Oct 2021 09:43:28 +0800 Subject: Re: [PATCH] powerpc: don't select KFENCE on platform PPC_FSL_BOOK3E To: Marco Elver , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras References: <20210924063927.1341241-1-liushixin2@huawei.com> CC: , From: Liu Shixin Message-ID: <77ce95e4-1af1-6536-5f0c-a573c648801a@huawei.com> Date: Tue, 12 Oct 2021 09:43:21 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.7.1 MIME-Version: 1.0 In-Reply-To: <20210924063927.1341241-1-liushixin2@huawei.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.179.24] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggpemm100009.china.huawei.com (7.185.36.113) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org kindly ping. On 2021/9/24 14:39, Liu Shixin wrote: > On platform PPC_FSL_BOOK3E, all lowmem is managed by tlbcam. That means > we didn't really map the kfence pool with page granularity. Therefore, > if KFENCE is enabled, the system will hit the following panic: > > BUG: Kernel NULL pointer dereference on read at 0x00000000 > Faulting instruction address: 0xc01de598 > Oops: Kernel access of bad area, sig: 11 [#1] > BE PAGE_SIZE=4K SMP NR_CPUS=4 MPC8544 DS > Dumping ftrace buffer: > (ftrace buffer empty) > Modules linked in: > CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.12.0-rc3+ #298 > NIP: c01de598 LR: c08ae9c4 CTR: 00000000 > REGS: c0b4bea0 TRAP: 0300 Not tainted (5.12.0-rc3+) > MSR: 00021000 CR: 24000228 XER: 20000000 > DEAR: 00000000 ESR: 00000000 > GPR00: c08ae9c4 c0b4bf60 c0ad64e0 ef720000 00021000 00000000 00000000 00000200 > GPR08: c0ad5000 00000000 00000000 00000004 00000000 008fbb30 00000000 00000000 > GPR16: 00000000 00000000 00000000 00000000 c0000000 00000000 00000000 00000000 > GPR24: c08ca004 c08ca004 c0b6a0e0 c0b60000 c0b58f00 c0850000 c08ca000 ef720000 > NIP [c01de598] kfence_protect+0x44/0x6c > LR [c08ae9c4] kfence_init+0xfc/0x2a4 > Call Trace: > [c0b4bf60] [efffe160] 0xefffe160 (unreliable) > [c0b4bf70] [c08ae9c4] kfence_init+0xfc/0x2a4 > [c0b4bfb0] [c0894d3c] start_kernel+0x3bc/0x574 > [c0b4bff0] [c0000470] set_ivor+0x14c/0x188 > Instruction dump: > 7c0802a6 8109d594 546a653a 90010014 54630026 39200000 7d48502e 2c0a0000 > 41820010 554a0026 5469b53a 7d295214 <81490000> 38831000 554a003c 91490000 > random: get_random_bytes called from print_oops_end_marker+0x40/0x78 with crng_init=0 > ---[ end trace 0000000000000000 ]--- > > Signed-off-by: Liu Shixin > --- > arch/powerpc/Kconfig | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig > index d46db0bfb998..cffd57bcb5e4 100644 > --- a/arch/powerpc/Kconfig > +++ b/arch/powerpc/Kconfig > @@ -185,7 +185,7 @@ config PPC > select HAVE_ARCH_KASAN if PPC32 && PPC_PAGE_SHIFT <= 14 > select HAVE_ARCH_KASAN_VMALLOC if PPC32 && PPC_PAGE_SHIFT <= 14 > select HAVE_ARCH_KGDB > - select HAVE_ARCH_KFENCE if PPC32 > + select HAVE_ARCH_KFENCE if PPC32 && !PPC_FSL_BOOK3E > select HAVE_ARCH_MMAP_RND_BITS > select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT > select HAVE_ARCH_NVRAM_OPS