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[2003:cb:c705:1f00:4727:6420:1d4d:ca23]) by smtp.gmail.com with ESMTPSA id j3-20020a5d4643000000b002103a7c5c91sm26337436wrs.43.2022.06.10.05.12.00 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 10 Jun 2022 05:12:01 -0700 (PDT) Message-ID: <0fedf6f3-3ab3-e1d2-fd6e-3dbe8e92f06d@redhat.com> Date: Fri, 10 Jun 2022 14:12:00 +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 v3 1/1] mm/memory-failure: don't allow to unpoison hw corrupted page To: zhenwei pi , naoya.horiguchi@nec.com, akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20220610114646.162764-1-pizhenwei@bytedance.com> <20220610114646.162764-2-pizhenwei@bytedance.com> From: David Hildenbrand Organization: Red Hat In-Reply-To: <20220610114646.162764-2-pizhenwei@bytedance.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1654863127; a=rsa-sha256; cv=none; b=YaGvBGrsE9T5XD/Z+3d/Nu6aEZMoocDuItD+5j9OvHOb41yz7x+hNBZadXBbeP+XS7cihF jMYVvQziUNGLVFUQrQvqynKKm5JxMJoijfvQAWd4yETapj6phyChGPa36knEW7ExwP+sbK +k5JFa+3fG9QKWAVcDk1xRnc50OG9GQ= ARC-Authentication-Results: i=1; imf18.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b="Z3aLcew/"; spf=none (imf18.hostedemail.com: domain of david@redhat.com has no SPF policy when checking 170.10.129.124) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1654863127; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc: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=yWrigY09pHnr8+XLazEvyTbDnwfdwYvMh735UfA4r58=; b=pZSdxBbm+k7xuMVn8TOvDcHidxp9TKY/UoRD624R+qEAUg5/Il/hLZBNXUDg30AKTscxeP 4NP9zB+KP00WXRV28cWW9lUvxsQU10A8f9UiL1gtLHw0Q9x4x9GEYWsyhDD8uMQn+EULpP 49Y9X3QOb1ZyFLic67PcJHHZxS9jCC0= X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 2B87A1C0074 X-Rspam-User: Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b="Z3aLcew/"; spf=none (imf18.hostedemail.com: domain of david@redhat.com has no SPF policy when checking 170.10.129.124) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com X-Stat-Signature: dnsmoe75qng6wfgq9sduu1w6ow8giifh X-HE-Tag: 1654863126-837013 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 10.06.22 13:46, zhenwei pi wrote: > Currently unpoison_memory(unsigned long pfn) is designed for soft > poison(hwpoison-inject) only. Since 17fae1294ad9d, the KPTE gets > cleared on a x86 platform once hardware memory corrupts. > > Unpoisoning a hardware corrupted page puts page back buddy only, > the kernel has a chance to access the page with *NOT PRESENT* KPTE. > 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 > > Fixes: 847ce401df392 ("HWPOISON: Add unpoisoning support") > Fixes: 17fae1294ad9d ("x86/{mce,mm}: Unmap the entire page if the whole page is affected and poisoned") > Cc: Naoya Horiguchi > Cc: David Hildenbrand > Signed-off-by: zhenwei pi > --- > mm/memory-failure.c | 59 +++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 59 insertions(+) > > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index b85661cbdc4a..3124f428302c 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -2068,6 +2068,58 @@ static int __init memory_failure_init(void) > } > core_initcall(memory_failure_init); > > +/* > + * Unpoisoning a hardware corrupted page with *NOT PRESENT* KPTE leads panic. > + * Test a page is valid in the kernel mapping. > + */ > +static bool kmap_valid(struct page *page) > +{ > + unsigned long addr = (unsigned long)page_to_virt(page); > + pgd_t *pgd; > + p4d_t *p4d; > + pud_t *pud; > + pmd_t *pmd; > + pte_t *pte; > + > + pgd = pgd_offset_k(addr); > + if (pgd_none(*pgd)) > + return false; > + if (pgd_leaf(*pgd)) > + return true; > + if (pgd_bad(*pgd)) > + return false; > + > + p4d = p4d_offset(pgd, addr); > + if (p4d_none(*p4d)) > + return false; > + if (p4d_leaf(*p4d)) > + return true; > + if (p4d_bad(*p4d)) > + return false; > + > + pud = pud_offset(p4d, addr); > + if (pud_none(*pud)) > + return false; > + if (pud_leaf(*pud)) > + return true; > + if (pud_bad(*pud)) > + return false; > + > + pmd = pmd_offset(pud, addr); > + if (pmd_none(*pmd)) > + return false; > + if (pmd_leaf(*pmd)) > + return true; > + if (pmd_bad(*pmd)) > + return false; > + > + pte = pte_offset_map(pmd, addr); > + if (pte_none(*pte) || !pte_present(*pte)) > + return false; > + > + return true; > +} > + > #define unpoison_pr_info(fmt, pfn, rs) \ > ({ \ > if (__ratelimit(rs)) \ > @@ -2109,6 +2161,13 @@ int unpoison_memory(unsigned long pfn) > goto unlock_mutex; > } > > + if (!kmap_valid(page)) { > + unpoison_pr_info("Unpoison: Page was hardware poisoned %#lx\n", > + pfn, &unpoison_rs); > + ret = -EOPNOTSUPP; > + goto unlock_mutex; > + } > + > if (page_count(page) > 1) { > unpoison_pr_info("Unpoison: Someone grabs the hwpoison page %#lx\n", > pfn, &unpoison_rs); I really prefer just disabling the unpoisioning mechanism in case there is a real hw injected error. -- Thanks, David / dhildenb