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 848F4C433F5 for ; Tue, 12 Oct 2021 06:25:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5CBBF60EFE for ; Tue, 12 Oct 2021 06:25:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233005AbhJLG1D (ORCPT ); Tue, 12 Oct 2021 02:27:03 -0400 Received: from gandalf.ozlabs.org ([150.107.74.76]:32895 "EHLO gandalf.ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232690AbhJLG1A (ORCPT ); Tue, 12 Oct 2021 02:27:00 -0400 Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 4HT5HY6fjyz4xb9; Tue, 12 Oct 2021 17:24:57 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ellerman.id.au; s=201909; t=1634019898; bh=347ctPqhsS5IaLblCKv5phu1n7PGnyVqN5oJsZcxlUk=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=f2eZZN4KOw1R8VYJk3QQTbeucJ85RyFTJUp0z6fgRGJ79Lh9XtSaWtvnaepFCN58N vCUggjmFvl+wjyv5vrn2LpJwXNyvDbDbSKryldqVZBZhlh5z9afWW5flVS8ZP9RUML Ev7MOS73ZC2hEada1xEXpEFU7cmt1W85gY2fKQ7ZSYT86xe0yX/vPtb6xBPB0YyKgt c6uR+Qb5EIwUoFecb/fZMw0+07ZqL9pPXht+PyHu3k7pP411bvcDRFXH99FtuVcF9c RsXKaAh/Q1tPGu0i4N72GL/R5QHyq21Dv2BtZ3jVzdOYs+aARERXnqILMmfK7xh6do Ra6CiM/fzOoYQ== From: Michael Ellerman To: Liu Shixin , Marco Elver , Benjamin Herrenschmidt , Paul Mackerras Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] powerpc: don't select KFENCE on platform PPC_FSL_BOOK3E In-Reply-To: <77ce95e4-1af1-6536-5f0c-a573c648801a@huawei.com> References: <20210924063927.1341241-1-liushixin2@huawei.com> <77ce95e4-1af1-6536-5f0c-a573c648801a@huawei.com> Date: Tue, 12 Oct 2021 17:24:53 +1100 Message-ID: <87bl3u7oay.fsf@mpe.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Liu Shixin writes: > kindly ping. I was under the impression you were trying to debug why it wasn't working with Christophe. cheers > 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