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mm, memory_failure: Teach memory_failure() about dev_pagemap pages
mce: Uncorrected hardware memory error in user-access at af34214200 {1}[Hardware Error]: It has been corrected by h/w and requires no further action mce: [Hardware Error]: Machine check events logged {1}[Hardware Error]: event severity: corrected Memory failure: 0xaf34214: reserved kernel page still referenced by 1 users [..] Memory failure: 0xaf34214: recovery action for reserved kernel page: Failed mce: Memory error not recovered In contrast to typical memory, dev_pagemap pages may be dax mapped. With dax there is no possibility to map in another page dynamically since dax establishes 1:1 physical address to file offset associations. Also dev_pagemap pages associated with NVDIMM / persistent memory devices can internal remap/repair addresses with poison. While memory_failure() assumes that it can discard typical poisoned pages and keep them unmapped indefinitely, dev_pagemap pages may be returned to service after the error is cleared. Teach memory_failure() to detect and handle MEMORY_DEVICE_HOST dev_pagemap pages that have poison consumed by userspace. Mark the memory as UC instead of unmapping it completely to allow ongoing access via the device driver (nd_pmem). Later, nd_pmem will grow support for marking the page back to WB when the error is cleared. Cc: Jan Kara <jack@suse.cz> Cc: Christoph Hellwig <hch@lst.de> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
This commit is contained in:
parent
c2a7d2a115
commit
6100e34b25
2 changed files with 124 additions and 2 deletions
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@ -2725,6 +2725,7 @@ enum mf_action_page_type {
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MF_MSG_TRUNCATED_LRU,
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MF_MSG_BUDDY,
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MF_MSG_BUDDY_2ND,
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MF_MSG_DAX,
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MF_MSG_UNKNOWN,
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};
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@ -55,6 +55,7 @@
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#include <linux/hugetlb.h>
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#include <linux/memory_hotplug.h>
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#include <linux/mm_inline.h>
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#include <linux/memremap.h>
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#include <linux/kfifo.h>
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#include <linux/ratelimit.h>
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#include "internal.h"
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@ -263,6 +264,40 @@ void shake_page(struct page *p, int access)
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}
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EXPORT_SYMBOL_GPL(shake_page);
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static unsigned long dev_pagemap_mapping_shift(struct page *page,
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struct vm_area_struct *vma)
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{
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unsigned long address = vma_address(page, vma);
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pgd_t *pgd;
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p4d_t *p4d;
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pud_t *pud;
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pmd_t *pmd;
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pte_t *pte;
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pgd = pgd_offset(vma->vm_mm, address);
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if (!pgd_present(*pgd))
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return 0;
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p4d = p4d_offset(pgd, address);
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if (!p4d_present(*p4d))
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return 0;
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pud = pud_offset(p4d, address);
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if (!pud_present(*pud))
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return 0;
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if (pud_devmap(*pud))
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return PUD_SHIFT;
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pmd = pmd_offset(pud, address);
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if (!pmd_present(*pmd))
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return 0;
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if (pmd_devmap(*pmd))
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return PMD_SHIFT;
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pte = pte_offset_map(pmd, address);
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if (!pte_present(*pte))
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return 0;
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if (pte_devmap(*pte))
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return PAGE_SHIFT;
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return 0;
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}
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/*
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* Failure handling: if we can't find or can't kill a process there's
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* not much we can do. We just print a message and ignore otherwise.
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@ -292,7 +327,10 @@ static void add_to_kill(struct task_struct *tsk, struct page *p,
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}
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tk->addr = page_address_in_vma(p, vma);
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tk->addr_valid = 1;
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tk->size_shift = compound_order(compound_head(p)) + PAGE_SHIFT;
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if (is_zone_device_page(p))
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tk->size_shift = dev_pagemap_mapping_shift(p, vma);
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else
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tk->size_shift = compound_order(compound_head(p)) + PAGE_SHIFT;
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/*
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* In theory we don't have to kill when the page was
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@ -300,7 +338,7 @@ static void add_to_kill(struct task_struct *tsk, struct page *p,
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* likely very rare kill anyways just out of paranoia, but use
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* a SIGKILL because the error is not contained anymore.
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*/
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if (tk->addr == -EFAULT) {
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if (tk->addr == -EFAULT || tk->size_shift == 0) {
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pr_info("Memory failure: Unable to find user space address %lx in %s\n",
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page_to_pfn(p), tsk->comm);
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tk->addr_valid = 0;
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@ -514,6 +552,7 @@ static const char * const action_page_types[] = {
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[MF_MSG_TRUNCATED_LRU] = "already truncated LRU page",
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[MF_MSG_BUDDY] = "free buddy page",
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[MF_MSG_BUDDY_2ND] = "free buddy page (2nd try)",
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[MF_MSG_DAX] = "dax page",
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[MF_MSG_UNKNOWN] = "unknown page",
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};
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@ -1111,6 +1150,83 @@ static int memory_failure_hugetlb(unsigned long pfn, int flags)
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return res;
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}
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static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
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struct dev_pagemap *pgmap)
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{
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struct page *page = pfn_to_page(pfn);
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const bool unmap_success = true;
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unsigned long size = 0;
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struct to_kill *tk;
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LIST_HEAD(tokill);
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int rc = -EBUSY;
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loff_t start;
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/*
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* Prevent the inode from being freed while we are interrogating
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* the address_space, typically this would be handled by
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* lock_page(), but dax pages do not use the page lock. This
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* also prevents changes to the mapping of this pfn until
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* poison signaling is complete.
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*/
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if (!dax_lock_mapping_entry(page))
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goto out;
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if (hwpoison_filter(page)) {
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rc = 0;
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goto unlock;
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}
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switch (pgmap->type) {
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case MEMORY_DEVICE_PRIVATE:
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case MEMORY_DEVICE_PUBLIC:
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/*
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* TODO: Handle HMM pages which may need coordination
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* with device-side memory.
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*/
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goto unlock;
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default:
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break;
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}
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/*
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* Use this flag as an indication that the dax page has been
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* remapped UC to prevent speculative consumption of poison.
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*/
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SetPageHWPoison(page);
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/*
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* Unlike System-RAM there is no possibility to swap in a
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* different physical page at a given virtual address, so all
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* userspace consumption of ZONE_DEVICE memory necessitates
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* SIGBUS (i.e. MF_MUST_KILL)
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*/
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flags |= MF_ACTION_REQUIRED | MF_MUST_KILL;
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collect_procs(page, &tokill, flags & MF_ACTION_REQUIRED);
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list_for_each_entry(tk, &tokill, nd)
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if (tk->size_shift)
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size = max(size, 1UL << tk->size_shift);
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if (size) {
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/*
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* Unmap the largest mapping to avoid breaking up
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* device-dax mappings which are constant size. The
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* actual size of the mapping being torn down is
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* communicated in siginfo, see kill_proc()
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*/
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start = (page->index << PAGE_SHIFT) & ~(size - 1);
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unmap_mapping_range(page->mapping, start, start + size, 0);
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}
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kill_procs(&tokill, flags & MF_MUST_KILL, !unmap_success, pfn, flags);
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rc = 0;
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unlock:
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dax_unlock_mapping_entry(page);
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out:
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/* drop pgmap ref acquired in caller */
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put_dev_pagemap(pgmap);
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action_result(pfn, MF_MSG_DAX, rc ? MF_FAILED : MF_RECOVERED);
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return rc;
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}
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/**
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* memory_failure - Handle memory failure of a page.
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* @pfn: Page Number of the corrupted page
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@ -1133,6 +1249,7 @@ int memory_failure(unsigned long pfn, int flags)
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struct page *p;
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struct page *hpage;
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struct page *orig_head;
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struct dev_pagemap *pgmap;
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int res;
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unsigned long page_flags;
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@ -1145,6 +1262,10 @@ int memory_failure(unsigned long pfn, int flags)
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return -ENXIO;
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}
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pgmap = get_dev_pagemap(pfn, NULL);
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if (pgmap)
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return memory_failure_dev_pagemap(pfn, flags, pgmap);
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p = pfn_to_page(pfn);
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if (PageHuge(p))
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return memory_failure_hugetlb(pfn, flags);
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