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[23.128.96.18]) by mx.google.com with ESMTP id l6si459500ejd.115.2021.03.04.17.37.31; Thu, 04 Mar 2021 17:37:54 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229494AbhCEBhA (ORCPT + 99 others); Thu, 4 Mar 2021 20:37:00 -0500 Received: from mail.kingsoft.com ([114.255.44.145]:13246 "EHLO mail.kingsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229436AbhCEBg7 (ORCPT ); Thu, 4 Mar 2021 20:36:59 -0500 X-AuditID: 0a580157-f21ff7000005df43-f7-604184ba87cd Received: from mail.kingsoft.com (localhost [10.88.1.32]) (using TLS with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client did not present a certificate) by mail.kingsoft.com (SMG-1-NODE-87) with SMTP id 82.28.57155.AB481406; Fri, 5 Mar 2021 09:09:14 +0800 (HKT) Received: from alex-virtual-machine (172.16.253.254) by KSBJMAIL2.kingsoft.cn (10.88.1.32) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Fri, 5 Mar 2021 09:36:57 +0800 Date: Fri, 5 Mar 2021 09:36:56 +0800 From: Aili Yao To: "Luck, Tony" CC: "HORIGUCHI =?UTF-8?B?TkFPWUE=?=(=?UTF-8?B?5aCA5Y+j44CA55u05Lmf?=)" , Oscar Salvador , "david@redhat.com" , "akpm@linux-foundation.org" , "bp@alien8.de" , "tglx@linutronix.de" , "mingo@redhat.com" , "hpa@zytor.com" , "x86@kernel.org" , "linux-edac@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "yangfeng1@kingsoft.com" , Subject: Re: [PATCH] mm,hwpoison: return -EBUSY when page already poisoned Message-ID: <20210305093656.6c262b19@alex-virtual-machine> In-Reply-To: <20210305093016.40c87375@alex-virtual-machine> References: <20210225181542.GA178925@agluck-desk2.amr.corp.intel.com> <20210226021907.GA27861@hori.linux.bs1.fc.nec.co.jp> <20210226105915.6cf7d2b8@alex-virtual-machine> <20210303033953.GA205389@agluck-desk2.amr.corp.intel.com> <20210303115710.2e9f8e23@alex-virtual-machine> <20210303163912.3d508e0f@alex-virtual-machine> <1a78e9abdc134e35a5efcbf6b2fd2263@intel.com> <20210304101653.546a9da1@alex-virtual-machine> <20210304121941.667047c3@alex-virtual-machine> <20210304144524.795872d7@alex-virtual-machine> <20210304235720.GA215567@agluck-desk2.amr.corp.intel.com> <20210305093016.40c87375@alex-virtual-machine> Organization: kingsoft X-Mailer: Claws Mail 3.17.5 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [172.16.253.254] X-ClientProxiedBy: KSBJMAIL1.kingsoft.cn (10.88.1.31) To KSBJMAIL2.kingsoft.cn (10.88.1.32) X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFprDIsWRmVeSWpSXmKPExsXCFcGooLurxTHBoHcJv8Wc9WvYLD5v+Mdm 8XX9L2aLaRvFLS6camCyuLxrDpvFvTX/WS0uHVjAZHGx8QCjxZlpRRabN01ltnhz4R6LxY8N j1kdeD2+t/axeCze85LJY9OqTjaPTZ8msXu8O3eO3ePEjN8sHi+ubmTxeL/vKpvH5tPVHp83 yXmcaPnCGsAdxWWTkpqTWZZapG+XwJUx5e9LpoIZSRUL/z9kaWCc4N3FyMkhIWAi8WjlP7Yu Ri4OIYHpTBKr3r1ngXBeMkrMu3uMGaSKRUBF4tPEEywgNpuAqsSue7NYQWwRATWJS4sfMIM0 MAvMZpU4NfksWIOwgJfEl/trGbsYOTh4BawkzryxBwlzClhL9M1/A7XgF4vEpFtLwIbyC4hJ 9F75zwRxkr1E25ZFjCA2r4CgxMmZT8BqmAV0JE6sgjiIWUBeYvvbOWC2kICixOElv9ghepUk jnTPYIOwYyWWzXvFOoFReBaSUbOQjJqFZNQCRuZVjCzFuemGmxghERi+g3Fe00e9Q4xMHIyH GCU4mJVEeMVf2iYI8aYkVlalFuXHF5XmpBYfYpTmYFES521xsk8QEkhPLEnNTk0tSC2CyTJx cEo1MM36ejjB+FPqOa+uO4IBF943LzPY3sl/c0d46GJnprB5y3d17vl9X3eF+VGv7ZreGjpP NJ2u8vdc+88eFP+geVJXQvypzOXOS89/nDipojwjQG3Hji2fV71QZlom9T5hz1qfilmX0oO7 kjgXF/ocLVKTK+Sv0Dm6RabSYubCuWmGU39p3b7zuuracQ3nE06ixp5qD96Jmkf1CB8yNBBQ mZy1cJFsh/scNr0a3xd32ToPT5q2OLrjecyNKVGPDdRu1kjXzei7mRy53XuBmnnguWuTngtm rIy7qHzUP5KNX+Hqdp8VsjnCjKHKeRe+Fgaujvdn7Li/bHrApmtOdi/WsWlEqWm+8ha98TfU +52ZhRJLcUaioRZzUXEiAOsMPRwvAwAA Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 5 Mar 2021 09:30:16 +0800 Aili Yao wrote: > On Thu, 4 Mar 2021 15:57:20 -0800 > "Luck, Tony" wrote: > > > On Thu, Mar 04, 2021 at 02:45:24PM +0800, Aili Yao wrote: > > > > > if your methods works, should it be like this? > > > > > > > > > > 1582 pteval = swp_entry_to_pte(make_hwpoison_entry(subpage)); > > > > > 1583 if (PageHuge(page)) { > > > > > 1584 hugetlb_count_sub(compound_nr(page), mm); > > > > > 1585 set_huge_swap_pte_at(mm, address, > > > > > 1586 pvmw.pte, pteval, > > > > > 1587 vma_mmu_pagesize(vma)); > > > > > 1588 } else { > > > > > 1589 dec_mm_counter(mm, mm_counter(page)); > > > > > 1590 set_pte_at(mm, address, pvmw.pte, pteval); > > > > > 1591 } > > > > > > > > > > the page fault check if it's a poison page using is_hwpoison_entry(), > > > > > > > > > > > > > And if it works, does we need some locking mechanism before we call walk_page_range(); > > > > if we lock, does we need to process the blocking interrupted error as other places will do? > > > > > > > > > > And another thing: > > > Do we need a call to flush_tlb_page(vma, address) to make the pte changes into effect? > > > > Thanks for all the pointers. I added them to the patch (see below). > > [The pmd/pud cases may need some tweaking ... but just trying to get > > the 4K page case working first] > > > > I tried testing by skipping the call to memory_failure() and just > > using this new code to search the page tables for current page and > > marking it hwpoison (to simulate the case where 2nd process gets the > > early return from memory_failure(). Something is still missing because I get: > > > > [ 481.911298] mce: pte_entry: matched pfn - mark poison & zap pte > > [ 481.917935] MCE: Killing einj_mem_uc:5555 due to hardware memory corruption fault at 7fe64b33b400 > > [ 482.933775] BUG: Bad page cache in process einj_mem_uc pfn:408b6d6 > > [ 482.940777] page:0000000013ea6e96 refcount:3 mapcount:1 mapping:00000000e3a069d9 index:0x0 pfn:0x408b6d6 > > [ 482.951355] memcg:ffff94a809834000 > > [ 482.955153] aops:shmem_aops ino:3c04 > > [ 482.959142] flags: 0x97ffffc0880015(locked|uptodate|lru|swapbacked|hwpoison) > > [ 482.967018] raw: 0097ffffc0880015 ffff94c80e93ec00 ffff94c80e93ec00 ffff94c80a9b25a8 > > [ 482.975666] raw: 0000000000000000 0000000000000000 0000000300000000 ffff94a809834000 > > [ 482.984310] page dumped because: still mapped when deleted > > From the walk, it seems we have got the virtual address, can we just send a SIGBUS with it? Does this walk proper for other memory-failure error cases, can it be applied to if (p->mce_vaddr != (void __user *)-1l) branch in kill_me_maybe()? > > commit e5de44560b33e2d407704243566253a70f858a59 > > Author: Tony Luck > > Date: Tue Mar 2 15:06:33 2021 -0800 > > > > x86/mce: Handle races between machine checks > > > > When multiple CPUs hit the same poison memory there is a race. The > > first CPU into memory_failure() atomically marks the page as poison > > and continues processing to hunt down all the tasks that map this page > > so that the virtual addresses can be marked not-present and SIGBUS > > sent to the task that did the access. > > > > Later CPUs get an early return from memory_failure() and may return > > to user mode and access the poison again. > > > > Add a new argument to memory_failure() so that it can indicate when > > the race has been lost. Fix kill_me_maybe() to scan page tables in > > this case to unmap pages. > > > > diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c > > index 7962355436da..a52c6a772de2 100644 > > --- a/arch/x86/kernel/cpu/mce/core.c > > +++ b/arch/x86/kernel/cpu/mce/core.c > > @@ -28,8 +28,12 @@ > > #include > > #include > > #include > > +#include > > +#include > > +#include > > #include > > #include > > +#include > > #include > > #include > > #include > > @@ -637,6 +641,7 @@ static int uc_decode_notifier(struct notifier_block *nb, unsigned long val, > > { > > struct mce *mce = (struct mce *)data; > > unsigned long pfn; > > + int already = 0; > > > > if (!mce || !mce_usable_address(mce)) > > return NOTIFY_DONE; > > @@ -646,8 +651,9 @@ static int uc_decode_notifier(struct notifier_block *nb, unsigned long val, > > return NOTIFY_DONE; > > > > pfn = mce->addr >> PAGE_SHIFT; > > - if (!memory_failure(pfn, 0)) { > > - set_mce_nospec(pfn, whole_page(mce)); > > + if (!memory_failure(pfn, 0, &already)) { > > + if (!already) > > + set_mce_nospec(pfn, whole_page(mce)); > > mce->kflags |= MCE_HANDLED_UC; > > } > > > > @@ -1248,6 +1254,79 @@ static void __mc_scan_banks(struct mce *m, struct pt_regs *regs, struct mce *fin > > *m = *final; > > } > > > > +static int pte_entry(pte_t *pte, unsigned long addr, unsigned long next, struct mm_walk *walk) > > +{ > > + u64 pfn = (u64)walk->private; > > + struct page *page; > > + pte_t pteval; > > + > > + if (pte_pfn(*pte) == pfn) { > > +pr_info("pte_entry: matched pfn - mark poison & zap pte\n"); > > + page = pfn_to_page(pfn); > > + lock_page(page); > > +SetPageHWPoison(page); > > + pteval = swp_entry_to_pte(make_hwpoison_entry(page)); > > + dec_mm_counter(walk->mm, mm_counter(page)); > > + set_pte_at(current->mm, addr, pte, pteval); > > + unlock_page(page); > > + flush_tlb_page(walk->vma, addr); > > + } > > + > > + return 0; > > +} > > + > > +static int pmd_entry(pmd_t *pmd, unsigned long addr, unsigned long next, struct mm_walk *walk) > > +{ > > + int shift = PMD_SHIFT - PAGE_SHIFT; > > + u64 pfn = (u64)walk->private; > > + struct page *page; > > + pte_t pteval; > > + > > + if (!pmd_large(*pmd)) > > + return 0; > > + > > + if (pmd_pfn(*pmd) >> shift == pfn >> shift) { > > + page = pfn_to_page(pfn); > > + lock_page(page); > > + pteval = swp_entry_to_pte(make_hwpoison_entry(page)); > > + hugetlb_count_sub(compound_nr(page), walk->mm); > > + set_huge_swap_pte_at(walk->mm, addr, (pte_t *)pmd, pteval, vma_mmu_pagesize(walk->vma)); > > + unlock_page(page); > > + flush_tlb_page(walk->vma, addr); > > + } > > + > > + return 0; > > +} > > + > > +static int pud_entry(pud_t *pud, unsigned long addr, unsigned long next, struct mm_walk *walk) > > +{ > > + int shift = PUD_SHIFT - PAGE_SHIFT; > > + u64 pfn = (u64)walk->private; > > + struct page *page; > > + pte_t pteval; > > + > > + if (!pud_large(*pud)) > > + return 0; > > + > > + if (pud_pfn(*pud) >> shift == pfn >> shift) { > > + page = pfn_to_page(pfn); > > + lock_page(page); > > + pteval = swp_entry_to_pte(make_hwpoison_entry(page)); > > + hugetlb_count_sub(compound_nr(page), walk->mm); > > + set_huge_swap_pte_at(walk->mm, addr, (pte_t *)pud, pteval, vma_mmu_pagesize(walk->vma)); > > + unlock_page(page); > > + flush_tlb_page(walk->vma, addr); > > + } > > + > > + return 0; > > +} > > + > > +static struct mm_walk_ops walk = { > > + .pte_entry = pte_entry, > > + .pmd_entry = pmd_entry, > > + .pud_entry = pud_entry > > +}; > > + > > static void kill_me_now(struct callback_head *ch) > > { > > force_sig(SIGBUS); > > @@ -1257,15 +1336,22 @@ static void kill_me_maybe(struct callback_head *cb) > > { > > struct task_struct *p = container_of(cb, struct task_struct, mce_kill_me); > > int flags = MF_ACTION_REQUIRED; > > + int already = 0; > > > > pr_err("Uncorrected hardware memory error in user-access at %llx", p->mce_addr); > > > > if (!p->mce_ripv) > > flags |= MF_MUST_KILL; > > > > - if (!memory_failure(p->mce_addr >> PAGE_SHIFT, flags) && > > + if (!memory_failure(p->mce_addr >> PAGE_SHIFT, flags, &already) && > > !(p->mce_kflags & MCE_IN_KERNEL_COPYIN)) { > > - set_mce_nospec(p->mce_addr >> PAGE_SHIFT, p->mce_whole_page); > > + if (already) { > > + mmap_read_lock(current->mm); > > + walk_page_range(current->mm, 0, TASK_SIZE_MAX, &walk, (void *)(p->mce_addr >> PAGE_SHIFT)); > > + mmap_read_unlock(current->mm); > > + } else { > > + set_mce_nospec(p->mce_addr >> PAGE_SHIFT, p->mce_whole_page); > > + } > > sync_core(); > > return; > > } > > @@ -1452,7 +1538,7 @@ noinstr void do_machine_check(struct pt_regs *regs) > > EXPORT_SYMBOL_GPL(do_machine_check); > > > > #ifndef CONFIG_MEMORY_FAILURE > > -int memory_failure(unsigned long pfn, int flags) > > +int memory_failure(unsigned long pfn, int flags, int *already) > > { > > /* mce_severity() should not hand us an ACTION_REQUIRED error */ > > BUG_ON(flags & MF_ACTION_REQUIRED); > > diff --git a/drivers/base/memory.c b/drivers/base/memory.c > > index f35298425575..144500983656 100644 > > --- a/drivers/base/memory.c > > +++ b/drivers/base/memory.c > > @@ -480,7 +480,7 @@ 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, 0, NULL); > > return ret ? ret : count; > > } > > > > diff --git a/include/linux/mm.h b/include/linux/mm.h > > index 77e64e3eac80..beaa6e871cbe 100644 > > --- a/include/linux/mm.h > > +++ b/include/linux/mm.h > > @@ -3003,7 +3003,7 @@ enum mf_flags { > > MF_MUST_KILL = 1 << 2, > > MF_SOFT_OFFLINE = 1 << 3, > > }; > > -extern int memory_failure(unsigned long pfn, int flags); > > +extern int memory_failure(unsigned long pfn, int flags, int *already); > > extern void memory_failure_queue(unsigned long pfn, int flags); > > extern void memory_failure_queue_kick(int cpu); > > extern int unpoison_memory(unsigned long pfn); > > diff --git a/mm/hwpoison-inject.c b/mm/hwpoison-inject.c > > index 1ae1ebc2b9b1..bfd5151dcd3f 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); > > - return memory_failure(pfn, 0); > > + return memory_failure(pfn, 0, NULL); > > } > > > > static int hwpoison_unpoison(void *data, u64 val) > > diff --git a/mm/madvise.c b/mm/madvise.c > > index df692d2e35d4..09f569fed68d 100644 > > --- a/mm/madvise.c > > +++ b/mm/madvise.c > > @@ -908,7 +908,7 @@ 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, NULL); > > } > > > > if (ret) > > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > > index 24210c9bd843..9a8911aa5fc9 100644 > > --- a/mm/memory-failure.c > > +++ b/mm/memory-failure.c > > @@ -1398,7 +1398,7 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags, > > * Must run in process context (e.g. a work queue) with interrupts > > * enabled and no spinlocks hold. > > */ > > -int memory_failure(unsigned long pfn, int flags) > > +int memory_failure(unsigned long pfn, int flags, int *already) > > { > > struct page *p; > > struct page *hpage; > > @@ -1428,6 +1428,8 @@ int memory_failure(unsigned long pfn, int flags) > > if (PageHuge(p)) > > return memory_failure_hugetlb(pfn, flags); > > if (TestSetPageHWPoison(p)) { > > + if (already) > > + *already = 1; > > pr_err("Memory failure: %#lx: already hardware poisoned\n", > > pfn); > > return 0; > > @@ -1634,7 +1636,7 @@ static void memory_failure_work_func(struct work_struct *work) > > if (entry.flags & MF_SOFT_OFFLINE) > > soft_offline_page(entry.pfn, entry.flags); > > else > > - memory_failure(entry.pfn, entry.flags); > > + memory_failure(entry.pfn, entry.flags, NULL); > > } > > } > > > -- Thanks! Aili Yao