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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7928DD35687 for ; Wed, 28 Jan 2026 07:13:09 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5453D6B0088; Wed, 28 Jan 2026 02:13:08 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 4F2F06B0089; Wed, 28 Jan 2026 02:13:08 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3CADC6B008A; Wed, 28 Jan 2026 02:13:08 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 2971D6B0088 for ; Wed, 28 Jan 2026 02:13:08 -0500 (EST) Received: from smtpin30.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 61241C1D96 for ; Wed, 28 Jan 2026 07:13:07 +0000 (UTC) X-FDA: 84380506014.30.92E7179 Received: from canpmsgout05.his.huawei.com (canpmsgout05.his.huawei.com [113.46.200.220]) by imf01.hostedemail.com (Postfix) with ESMTP id 100F840006 for ; Wed, 28 Jan 2026 07:13:03 +0000 (UTC) Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=huawei.com header.s=dkim header.b=GNnmKJXM; spf=pass (imf01.hostedemail.com: domain of tujinjiang@huawei.com designates 113.46.200.220 as permitted sender) smtp.mailfrom=tujinjiang@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1769584385; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=lDrDHaxzPUqDOGHtSAjw8UIOY7PPSYbUnoNgzHvr5I0=; b=DOU4pk43tW8XGwHdvmoZ4FNkBoMMN+1j9+toa1ux69qbMeNVt0JOdwEVj6vA+P/CDMsc0g HQ2lBgvGj0gbgyuMxtnci/O9XMTP52KDvfY0PESSo3BRD6aOWnKtlFQ2ODKAAb+m974avg MPSGNRxWGiOe81cxkJ2ItXMOq/ZNGxI= ARC-Authentication-Results: i=1; imf01.hostedemail.com; dkim=pass header.d=huawei.com header.s=dkim header.b=GNnmKJXM; spf=pass (imf01.hostedemail.com: domain of tujinjiang@huawei.com designates 113.46.200.220 as permitted sender) smtp.mailfrom=tujinjiang@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1769584385; a=rsa-sha256; cv=none; b=4/6HuKxyY91Cd7VcE3WVvbWDHhvU8v4HpVRGwxv+jCqapEWt8pofLS8v0owha3+4nAodpA 1qUQzJViHslxEwGF4rHZN8m2+/E8JQ5DtOn1n6zax3WfEUX7Sxh3NmwQUKH0TGWUYNZLKG aVcLE/PwLHhcEyYJFhwAQ5uZOgBYCL4= dkim-signature: v=1; a=rsa-sha256; d=huawei.com; s=dkim; c=relaxed/relaxed; q=dns/txt; h=From; bh=lDrDHaxzPUqDOGHtSAjw8UIOY7PPSYbUnoNgzHvr5I0=; b=GNnmKJXMOHfYxhNgVBD7aQXjjtZO1CwYmiFKicdhYA6iwUIQjplxkGPLDZ4VvWG0Au+0kgJ/6 3bLirJmYGft9AUlO4U5m2sXFWL3IYjb1AgWi1zrTFAJ+M5YnT1v5GjvmtbE3GozIddRJ9kXs2Vk cBVcPYqEiLnA567zo+XIgzo= Received: from mail.maildlp.com (unknown [172.19.162.144]) by canpmsgout05.his.huawei.com (SkyGuard) with ESMTPS id 4f1D0H4cJyz12LDP; Wed, 28 Jan 2026 15:09:03 +0800 (CST) Received: from kwepemr500001.china.huawei.com (unknown [7.202.194.229]) by mail.maildlp.com (Postfix) with ESMTPS id E85124056C; Wed, 28 Jan 2026 15:12:57 +0800 (CST) Received: from [10.174.179.179] (10.174.179.179) by kwepemr500001.china.huawei.com (7.202.194.229) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Wed, 28 Jan 2026 15:12:57 +0800 Message-ID: Date: Wed, 28 Jan 2026 15:12:56 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] arm64: mm: fix pass user prot to ioremap_prot in generic_access_phys To: , , , , , , , , , References: <20260127090129.412084-1-tujinjiang@huawei.com> From: Jinjiang Tu In-Reply-To: <20260127090129.412084-1-tujinjiang@huawei.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.179.179] X-ClientProxiedBy: kwepems100002.china.huawei.com (7.221.188.206) To kwepemr500001.china.huawei.com (7.202.194.229) X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 100F840006 X-Stat-Signature: 1dw9aksaty5agf1mx3i6wb9pznbzmskz X-Rspam-User: X-HE-Tag: 1769584383-41772 X-HE-Meta: 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 ggpbfgaC W0Wd2Sw8aHwF3hE1nJtqX42osQpf2GcH8DtUHafC184JPcax94b7HoESXaKFtNH2900rssMs6K+w+TZvcEYAYGCLD6P3aah4qLdBQROV2CkPvmguyelYIPmBNTbCO0PZcZyJJgjPQBT5yW+pW0aF9yIvdyuAGvk5aAAmOrMlz9tT8cNuHVSwj8qTgWnOUw6O61MJW4tDLlGWOFgxK9OBlH5L+cytKv6m0ahp0dlBNYyyyLPrFXrcS2FSTp0FOoUCrZLIiluFNOnW9M6DHILnHSFR6YQgpziwwpd/qj7CzAGG3CgF/dNaDOUs4l24MQpx75+ryD+1IyC+jThA5G9quJCzOaaUkk8JqhFZRPpf4IJ0otU8BhP6BYXVN/vG9Fr9345hREMVUMXHRZ85ibiuS9qs/yPJz02lo3L5/ X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 在 2026/1/27 17:01, Jinjiang Tu 写道: > Here is a syzkaller error log: > [0000000020ffc000] pgd=080000010598d403, p4d=080000010598d403, pud=0800000125ddb403, > pmd=080000007833c403, pte=01608000007fcfcf > Unable to handle kernel read from unreadable memory at virtual address ffff80008ea89000 > KASAN: probably user-memory-access in range [0x0000000475448000-0x0000000475448007] > Mem abort info: > ESR = 0x000000009600000f > EC = 0x25: DABT (current EL), IL = 32 bits > SET = 0, FnV = 0 > EA = 0, S1PTW = 0 > FSC = 0x0f: level 3 permission fault > Data abort info: > ISV = 0, ISS = 0x0000000f, ISS2 = 0x00000000 > CM = 0, WnR = 0, TnD = 0, TagAccess = 0 > GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 > swapper pgtable: 4k pages, 48-bit VAs, pgdp=00000001244aa000 > [ffff80008ea89000] pgd=100000013ffff403, p4d=100000013ffff403, pud=100000013fffe403, > pmd=100000010a453403, pte=01608000007fcfcf > Internal error: Oops: 000000009600000f [#1] SMP > Modules linked in: team > CPU: 1 PID: 10840 Comm: syz.9.83 Kdump: loaded Tainted: G > Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 > pstate: 20400005 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) > pc : __memcpy_fromio+0x80/0xf8 > lr : generic_access_phys+0x20c/0x2b8 > sp : ffff8000a0507960 > x29: ffff8000a0507960 x28: 1ffff000140a0f44 x27: ffff00003833cfe0 > x26: 0000000000000000 x25: 0000000000001000 x24: 0010000000000001 > x23: ffff80008ea89000 x22: ffff00004ea63000 x21: 0000000000001000 > x20: ffff80008ea89000 x19: ffff00004ea62000 x18: 0000000000000000 > x17: 0000000000000000 x16: 0000000000000000 x15: ffff8000806f1e3c > x14: ffff8000806f1d44 x13: 0000000041b58ab3 x12: ffff7000140a0f23 > x11: 1ffff000140a0f22 x10: ffff7000140a0f22 x9 : ffff800080579d24 > x8 : 0000000000000004 x7 : 0000000000000003 x6 : 0000000000000001 > x5 : ffff8000a0507910 x4 : ffff7000140a0f22 x3 : dfff800000000000 > x2 : 0000000000001000 x1 : ffff80008ea89000 x0 : ffff00004ea62000 > Call trace: > __memcpy_fromio+0x80/0xf8 > generic_access_phys+0x20c/0x2b8 > __access_remote_vm+0x46c/0x5b8 > access_remote_vm+0x18/0x30 > environ_read+0x238/0x3e8 > vfs_read+0xe4/0x2b0 > ksys_read+0xcc/0x178 > __arm64_sys_read+0x4c/0x68 > invoke_syscall+0x68/0x1a0 > el0_svc_common.constprop.0+0x11c/0x150 > do_el0_svc+0x38/0x50 > el0_svc+0x50/0x258 > el0t_64_sync_handler+0xc0/0xc8 > el0t_64_sync+0x1a4/0x1a8 > Code: 91002339 aa1403f7 8b190276 d503201f (f94002f8) > > The local syzkaller first maps I/O address from /dev/mem to userspace, > overiding the stack vma with MAP_FIXED flag. As a result, when reading > /proc/$pid/environ, generic_access_phys() is called to access the region, > which triggers a PAN permission-check fault and causes a kernel access > fault. > > The root cause is that generic_access_phys() passes a user pte to > ioremap_prot(), the user pte sets PTE_USER and PTE_NG bits. Consequently, > any subsequent kernel-mode access to the remapped address raises a fault. > > To fix it, define arch_mk_kernel_prot() to convert user prot to kernel > prot for arm64, and call arch_mk_kernel_prot() in generic_access_phys(), > so that a user prot is passed to ioremap_prot(). > > Fixes: 893dea9ccd08 ("arm64: Add HAVE_IOREMAP_PROT support") > Signed-off-by: Zeng Heng > Signed-off-by: Jinjiang Tu > --- > Change since v1: > * fix in ther caller generic_access_phys(), suggested by Catalin Marinas. > > arch/arm64/include/asm/io.h | 11 +++++++++++ > mm/memory.c | 12 +++++++++++- > 2 files changed, 22 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h > index 83e03abbb2ca..fe8607eafab6 100644 > --- a/arch/arm64/include/asm/io.h > +++ b/arch/arm64/include/asm/io.h > @@ -267,6 +267,17 @@ int arm64_ioremap_prot_hook_register(const ioremap_prot_hook_t hook); > > #define ioremap_prot ioremap_prot > > +#define arch_mk_kernel_prot arch_mk_kernel_prot > +static inline pgprot_t arch_mk_kernel_prot(pgprot_t user_prot) > +{ > + unsigned long kernel_prot_val; > + > + kernel_prot_val = _PAGE_KERNEL & ~(PTE_WRITE | PTE_ATTRINDX_MASK); > + kernel_prot_val |= pgprot_val(user_prot) & (PTE_WRITE | PTE_ATTRINDX_MASK); > + > + return __pgprot(kernel_prot_val); > +} I found I misunderstand the READ/WRITE permisson here. If the pte is writeale, the PTE_WRITE is 1, and PTE_RDONLY means dirty or not (With DBM). If the pte is read-only, the PTE_WRITE is 0, and PTE_RDONLY is 1. Since generic_access_phys() have checked if the user can write with: if ((write & FOLL_WRITE) && !pte_write(pte)) return -EINVAL; So, maybe we could always grant writable permission, just as x86's ioremap() does? Thanks. > + > #define _PAGE_IOREMAP PROT_DEVICE_nGnRE > > #define ioremap_wc(addr, size) \ > diff --git a/mm/memory.c b/mm/memory.c > index da360a6eb8a4..68fcfc3bbad8 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -6836,6 +6836,14 @@ void follow_pfnmap_end(struct follow_pfnmap_args *args) > EXPORT_SYMBOL_GPL(follow_pfnmap_end); > > #ifdef CONFIG_HAVE_IOREMAP_PROT > +#ifndef arch_mk_kernel_prot > +#define arch_mk_kernel_prot arch_mk_kernel_prot > +static inline pgprot_t arch_mk_kernel_prot(pgprot_t user_prot) > +{ > + return user_prot; > +} > +#endif > + > /** > * generic_access_phys - generic implementation for iomem mmap access > * @vma: the vma to access > @@ -6853,6 +6861,7 @@ int generic_access_phys(struct vm_area_struct *vma, unsigned long addr, > { > resource_size_t phys_addr; > pgprot_t prot = __pgprot(0); > + pgprot_t kernel_prot; > void __iomem *maddr; > int offset = offset_in_page(addr); > int ret = -EINVAL; > @@ -6870,7 +6879,8 @@ int generic_access_phys(struct vm_area_struct *vma, unsigned long addr, > if ((write & FOLL_WRITE) && !writable) > return -EINVAL; > > - maddr = ioremap_prot(phys_addr, PAGE_ALIGN(len + offset), prot); > + kernel_prot = arch_mk_kernel_prot(prot); > + maddr = ioremap_prot(phys_addr, PAGE_ALIGN(len + offset), kernel_prot); > if (!maddr) > return -ENOMEM; >