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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2833AC43334 for ; Thu, 16 Jun 2022 08:30:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230468AbiFPIas (ORCPT ); Thu, 16 Jun 2022 04:30:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49872 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229531AbiFPIar (ORCPT ); Thu, 16 Jun 2022 04:30:47 -0400 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 532075DA3A for ; Thu, 16 Jun 2022 01:30:46 -0700 (PDT) Received: from canpemm500002.china.huawei.com (unknown [172.30.72.55]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4LNwN82MwNzDqqF; Thu, 16 Jun 2022 16:30:16 +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; Thu, 16 Jun 2022 16:30:42 +0800 Subject: Re: [PATCH v6 1/1] mm/memory-failure: disable unpoison once hw error happens To: zhenwei pi , CC: , , , , Oscar Salvador , Andrew Morton References: <20220615093209.259374-1-pizhenwei@bytedance.com> <20220615093209.259374-2-pizhenwei@bytedance.com> From: Miaohe Lin Message-ID: <61092273-ea3f-449a-8993-a917837e1cf0@huawei.com> Date: Thu, 16 Jun 2022 16:30:42 +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: <20220615093209.259374-2-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: dggems703-chm.china.huawei.com (10.3.19.180) To canpemm500002.china.huawei.com (7.192.104.244) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022/6/15 17:32, 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. > > Suggested by David&Naoya, disable unpoison mechanism when a real HW error > happens 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 > Cc: Oscar Salvador > Cc: Greg Kroah-Hartman > Acked-by: David Hildenbrand > Signed-off-by: zhenwei pi > --- > Documentation/vm/hwpoison.rst | 3 ++- > drivers/base/memory.c | 2 +- > include/linux/mm.h | 1 + > mm/hwpoison-inject.c | 2 +- > mm/madvise.c | 2 +- > mm/memory-failure.c | 12 ++++++++++++ > 6 files changed, 18 insertions(+), 4 deletions(-) > > diff --git a/Documentation/vm/hwpoison.rst b/Documentation/vm/hwpoison.rst > index c742de1769d1..b9d5253c1305 100644 > --- a/Documentation/vm/hwpoison.rst > +++ b/Documentation/vm/hwpoison.rst > @@ -120,7 +120,8 @@ Testing > unpoison-pfn > Software-unpoison page at PFN echoed into this file. This way > a page can be reused again. This only works for Linux > - injected failures, not for real memory failures. > + injected failures, not for real memory failures. Once any hardware > + memory failure happens, this feature is disabled. > > Note these injection interfaces are not stable and might change between > kernel versions > diff --git a/drivers/base/memory.c b/drivers/base/memory.c > index 084d67fd55cc..bc60c9cd3230 100644 > --- a/drivers/base/memory.c > +++ b/drivers/base/memory.c > @@ -558,7 +558,7 @@ static ssize_t hard_offline_page_store(struct device *dev, > if (kstrtoull(buf, 0, &pfn) < 0) > return -EINVAL; > pfn >>= PAGE_SHIFT; > - ret = memory_failure(pfn, 0); > + ret = memory_failure(pfn, MF_SW_SIMULATED); > if (ret == -EOPNOTSUPP) > ret = 0; > return ret ? ret : count; > diff --git a/include/linux/mm.h b/include/linux/mm.h > index bc8f326be0ce..4346e51484ba 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -3232,6 +3232,7 @@ enum mf_flags { > MF_MUST_KILL = 1 << 2, > MF_SOFT_OFFLINE = 1 << 3, > MF_UNPOISON = 1 << 4, > + MF_SW_SIMULATED = 1 << 5, > }; > extern int memory_failure(unsigned long pfn, int flags); > extern void memory_failure_queue(unsigned long pfn, int flags); > diff --git a/mm/hwpoison-inject.c b/mm/hwpoison-inject.c > index 5c0cddd81505..65e242b5a432 100644 > --- a/mm/hwpoison-inject.c > +++ b/mm/hwpoison-inject.c > @@ -48,7 +48,7 @@ static int hwpoison_inject(void *data, u64 val) > > inject: > pr_info("Injecting memory failure at pfn %#lx\n", pfn); > - err = memory_failure(pfn, 0); > + err = memory_failure(pfn, MF_SW_SIMULATED); > return (err == -EOPNOTSUPP) ? 0 : err; > } > > diff --git a/mm/madvise.c b/mm/madvise.c > index d7b4f2602949..0316bbc6441b 100644 > --- a/mm/madvise.c > +++ b/mm/madvise.c > @@ -1112,7 +1112,7 @@ static int madvise_inject_error(int behavior, > } else { > pr_info("Injecting memory failure for pfn %#lx at process virtual address %#lx\n", > pfn, start); > - ret = memory_failure(pfn, MF_COUNT_INCREASED); > + ret = memory_failure(pfn, MF_COUNT_INCREASED | MF_SW_SIMULATED); > if (ret == -EOPNOTSUPP) > ret = 0; > } > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index b85661cbdc4a..da39ec8afca8 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -69,6 +69,8 @@ int sysctl_memory_failure_recovery __read_mostly = 1; > > atomic_long_t num_poisoned_pages __read_mostly = ATOMIC_LONG_INIT(0); > > +static bool hw_memory_failure __read_mostly = false; IIUC, this variable is updated every time when hardware memory corrupt happens. So adding __read_mostly macro here doesn't look very appropriate. But when compared to soft unpoison, this should be much rare. So __read_mostly should make sense from this point of view. No strong opinion. Anyway, the patch looks good to me. Thanks! Reviewed-by: Miaohe Lin > + > static bool __page_handle_poison(struct page *page) > { > int ret; > @@ -1768,6 +1770,9 @@ int memory_failure(unsigned long pfn, int flags) > > mutex_lock(&mf_mutex); > > + if (!(flags & MF_SW_SIMULATED)) > + hw_memory_failure = true; > + > p = pfn_to_online_page(pfn); > if (!p) { > res = arch_memory_failure(pfn, flags); > @@ -2103,6 +2108,13 @@ int unpoison_memory(unsigned long pfn) > > mutex_lock(&mf_mutex); > > + if (hw_memory_failure) { > + unpoison_pr_info("Unpoison: Disabled after HW memory failure %#lx\n", > + pfn, &unpoison_rs); > + ret = -EOPNOTSUPP; > + goto unlock_mutex; > + } > + > if (!PageHWPoison(p)) { > unpoison_pr_info("Unpoison: Page was already unpoisoned %#lx\n", > pfn, &unpoison_rs); >