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]) by smtp.lore.kernel.org (Postfix) with ESMTP id B1189C433EF for ; Tue, 7 Jun 2022 12:08:19 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 04E636B0074; Tue, 7 Jun 2022 08:08:19 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id F404B6B0075; Tue, 7 Jun 2022 08:08:18 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E2F0F6B0078; Tue, 7 Jun 2022 08:08:18 -0400 (EDT) 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 CE3F16B0074 for ; Tue, 7 Jun 2022 08:08:18 -0400 (EDT) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 9A8E920506 for ; Tue, 7 Jun 2022 12:08:18 +0000 (UTC) X-FDA: 79551317076.06.FB85190 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by imf25.hostedemail.com (Postfix) with ESMTP id 7F15AA0071 for ; Tue, 7 Jun 2022 12:07:37 +0000 (UTC) Received: from canpemm500002.china.huawei.com (unknown [172.30.72.55]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4LHTD51PDBzjXQ1; Tue, 7 Jun 2022 19:49:25 +0800 (CST) Received: from [10.174.177.76] (10.174.177.76) by canpemm500002.china.huawei.com (7.192.104.244) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Tue, 7 Jun 2022 19:50:43 +0800 Subject: Re: [PATCH] mm/memory-failure: don't allow to unpoison hw corrupted page To: zhenwei pi , HORIGUCHI NAOYA CC: , , Andrew Morton References: <20220604103229.3378591-1-pizhenwei@bytedance.com> From: Miaohe Lin Message-ID: Date: Tue, 7 Jun 2022 19:50:43 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: <20220604103229.3378591-1-pizhenwei@bytedance.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.177.76] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To canpemm500002.china.huawei.com (7.192.104.244) X-CFilter-Loop: Reflected X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 7F15AA0071 X-Stat-Signature: u3go7wxkhpkhauhtwweeffb79k8gk3po Authentication-Results: imf25.hostedemail.com; dkim=none; dmarc=pass (policy=quarantine) header.from=huawei.com; spf=pass (imf25.hostedemail.com: domain of linmiaohe@huawei.com designates 45.249.212.188 as permitted sender) smtp.mailfrom=linmiaohe@huawei.com X-HE-Tag: 1654603657-941326 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: On 2022/6/4 18:32, zhenwei pi wrote: > Currently unpoison_memory(unsigned long pfn) is designed for soft > poison(hwpoison-inject) only. Unpoisoning a hardware corrupted page > puts page back buddy only, this leads BUG during accessing on the > corrupted KPTE. > > Do not allow to unpoison hardware corrupted page in unpoison_memory() > to avoid BUG like this: > > Unpoison: Software-unpoisoned page 0x61234 > BUG: unable to handle page fault for address: ffff888061234000 > #PF: supervisor write access in kernel mode > #PF: error_code(0x0002) - not-present page > PGD 2c01067 P4D 2c01067 PUD 107267063 PMD 10382b063 PTE 800fffff9edcb062 > Oops: 0002 [#1] PREEMPT SMP NOPTI > CPU: 4 PID: 26551 Comm: stress Kdump: loaded Tainted: G M OE 5.18.0.bm.1-amd64 #7 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) ... > RIP: 0010:clear_page_erms+0x7/0x10 > Code: ... > RSP: 0000:ffffc90001107bc8 EFLAGS: 00010246 > RAX: 0000000000000000 RBX: 0000000000000901 RCX: 0000000000001000 > RDX: ffffea0001848d00 RSI: ffffea0001848d40 RDI: ffff888061234000 > RBP: ffffea0001848d00 R08: 0000000000000901 R09: 0000000000001276 > R10: 0000000000000003 R11: 0000000000000000 R12: 0000000000000001 > R13: 0000000000000000 R14: 0000000000140dca R15: 0000000000000001 > FS: 00007fd8b2333740(0000) GS:ffff88813fd00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: ffff888061234000 CR3: 00000001023d2005 CR4: 0000000000770ee0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > PKRU: 55555554 > Call Trace: > > prep_new_page+0x151/0x170 > get_page_from_freelist+0xca0/0xe20 > ? sysvec_apic_timer_interrupt+0xab/0xc0 > ? asm_sysvec_apic_timer_interrupt+0x1b/0x20 > __alloc_pages+0x17e/0x340 > __folio_alloc+0x17/0x40 > vma_alloc_folio+0x84/0x280 > __handle_mm_fault+0x8d4/0xeb0 > handle_mm_fault+0xd5/0x2a0 > do_user_addr_fault+0x1d0/0x680 > ? kvm_read_and_reset_apf_flags+0x3b/0x50 > exc_page_fault+0x78/0x170 > asm_exc_page_fault+0x27/0x30 > Thanks for fixing this issue. > Signed-off-by: zhenwei pi > --- > mm/memory-failure.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index b85661cbdc4a..ec49571924f4 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -2090,6 +2090,7 @@ int unpoison_memory(unsigned long pfn) > { > struct page *page; > struct page *p; > + pte_t *kpte; > int ret = -EBUSY; > int freeit = 0; > static DEFINE_RATELIMIT_STATE(unpoison_rs, DEFAULT_RATELIMIT_INTERVAL, > @@ -2101,6 +2102,13 @@ int unpoison_memory(unsigned long pfn) > p = pfn_to_page(pfn); > page = compound_head(p); > > + kpte = virt_to_kpte((unsigned long)page_to_virt(p)); > + if (kpte && !pte_present(*kpte)) { It seems this bug is specified to x86? IIUC, not all arch will unmap the entire page if the whole page is affected and poisoned. So the above virt_to_kpte + !pte_present check could not detect the hardware corrupted page reliably, i.e. if page is not *whole* unmapped, e.g. *possible* hugetlb page, we will still unpoison a hardware corrupted page. Or am I miss something? > + unpoison_pr_info("Unpoison: Page was hardware poisoned %#lx\n", > + pfn, &unpoison_rs); > + return -EPERM; > + } > + I think -EOPNOTSUPP might be a better error code too as Naoya pointed out. > mutex_lock(&mf_mutex); > > if (!PageHWPoison(p)) { > Thanks!