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a5f6510902
Currently kernel prints out results of every single unpoison event, which i= s not necessary because unpoison is purely a testing feature and testers can = get little or no information from lots of lines of unpoison log storm. So this patch ratelimits printk in unpoison_memory(). This patch introduces a file local ratelimit_state, which adds 64 bytes to memory-failure.o. If we apply pr_info_ratelimited() for 8 callsite below, 2= 56 bytes is added, so it's a win. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1791 lines
49 KiB
C
1791 lines
49 KiB
C
/*
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* Copyright (C) 2008, 2009 Intel Corporation
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* Authors: Andi Kleen, Fengguang Wu
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*
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* This software may be redistributed and/or modified under the terms of
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* the GNU General Public License ("GPL") version 2 only as published by the
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* Free Software Foundation.
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*
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* High level machine check handler. Handles pages reported by the
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* hardware as being corrupted usually due to a multi-bit ECC memory or cache
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* failure.
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*
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* In addition there is a "soft offline" entry point that allows stop using
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* not-yet-corrupted-by-suspicious pages without killing anything.
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*
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* Handles page cache pages in various states. The tricky part
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* here is that we can access any page asynchronously in respect to
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* other VM users, because memory failures could happen anytime and
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* anywhere. This could violate some of their assumptions. This is why
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* this code has to be extremely careful. Generally it tries to use
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* normal locking rules, as in get the standard locks, even if that means
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* the error handling takes potentially a long time.
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*
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* It can be very tempting to add handling for obscure cases here.
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* In general any code for handling new cases should only be added iff:
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* - You know how to test it.
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* - You have a test that can be added to mce-test
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* https://git.kernel.org/cgit/utils/cpu/mce/mce-test.git/
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* - The case actually shows up as a frequent (top 10) page state in
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* tools/vm/page-types when running a real workload.
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*
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* There are several operations here with exponential complexity because
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* of unsuitable VM data structures. For example the operation to map back
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* from RMAP chains to processes has to walk the complete process list and
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* has non linear complexity with the number. But since memory corruptions
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* are rare we hope to get away with this. This avoids impacting the core
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* VM.
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*/
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/page-flags.h>
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#include <linux/kernel-page-flags.h>
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#include <linux/sched.h>
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#include <linux/ksm.h>
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#include <linux/rmap.h>
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#include <linux/export.h>
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#include <linux/pagemap.h>
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#include <linux/swap.h>
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#include <linux/backing-dev.h>
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#include <linux/migrate.h>
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#include <linux/page-isolation.h>
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#include <linux/suspend.h>
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#include <linux/slab.h>
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#include <linux/swapops.h>
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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/kfifo.h>
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#include <linux/ratelimit.h>
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#include "internal.h"
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#include "ras/ras_event.h"
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int sysctl_memory_failure_early_kill __read_mostly = 0;
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int sysctl_memory_failure_recovery __read_mostly = 1;
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atomic_long_t num_poisoned_pages __read_mostly = ATOMIC_LONG_INIT(0);
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#if defined(CONFIG_HWPOISON_INJECT) || defined(CONFIG_HWPOISON_INJECT_MODULE)
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u32 hwpoison_filter_enable = 0;
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u32 hwpoison_filter_dev_major = ~0U;
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u32 hwpoison_filter_dev_minor = ~0U;
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u64 hwpoison_filter_flags_mask;
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u64 hwpoison_filter_flags_value;
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EXPORT_SYMBOL_GPL(hwpoison_filter_enable);
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EXPORT_SYMBOL_GPL(hwpoison_filter_dev_major);
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EXPORT_SYMBOL_GPL(hwpoison_filter_dev_minor);
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EXPORT_SYMBOL_GPL(hwpoison_filter_flags_mask);
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EXPORT_SYMBOL_GPL(hwpoison_filter_flags_value);
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static int hwpoison_filter_dev(struct page *p)
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{
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struct address_space *mapping;
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dev_t dev;
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if (hwpoison_filter_dev_major == ~0U &&
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hwpoison_filter_dev_minor == ~0U)
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return 0;
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/*
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* page_mapping() does not accept slab pages.
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*/
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if (PageSlab(p))
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return -EINVAL;
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mapping = page_mapping(p);
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if (mapping == NULL || mapping->host == NULL)
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return -EINVAL;
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dev = mapping->host->i_sb->s_dev;
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if (hwpoison_filter_dev_major != ~0U &&
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hwpoison_filter_dev_major != MAJOR(dev))
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return -EINVAL;
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if (hwpoison_filter_dev_minor != ~0U &&
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hwpoison_filter_dev_minor != MINOR(dev))
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return -EINVAL;
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return 0;
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}
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static int hwpoison_filter_flags(struct page *p)
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{
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if (!hwpoison_filter_flags_mask)
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return 0;
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if ((stable_page_flags(p) & hwpoison_filter_flags_mask) ==
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hwpoison_filter_flags_value)
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return 0;
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else
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return -EINVAL;
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}
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/*
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* This allows stress tests to limit test scope to a collection of tasks
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* by putting them under some memcg. This prevents killing unrelated/important
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* processes such as /sbin/init. Note that the target task may share clean
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* pages with init (eg. libc text), which is harmless. If the target task
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* share _dirty_ pages with another task B, the test scheme must make sure B
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* is also included in the memcg. At last, due to race conditions this filter
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* can only guarantee that the page either belongs to the memcg tasks, or is
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* a freed page.
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*/
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#ifdef CONFIG_MEMCG
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u64 hwpoison_filter_memcg;
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EXPORT_SYMBOL_GPL(hwpoison_filter_memcg);
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static int hwpoison_filter_task(struct page *p)
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{
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if (!hwpoison_filter_memcg)
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return 0;
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if (page_cgroup_ino(p) != hwpoison_filter_memcg)
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return -EINVAL;
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return 0;
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}
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#else
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static int hwpoison_filter_task(struct page *p) { return 0; }
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#endif
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int hwpoison_filter(struct page *p)
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{
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if (!hwpoison_filter_enable)
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return 0;
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if (hwpoison_filter_dev(p))
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return -EINVAL;
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if (hwpoison_filter_flags(p))
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return -EINVAL;
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if (hwpoison_filter_task(p))
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return -EINVAL;
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return 0;
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}
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#else
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int hwpoison_filter(struct page *p)
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{
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return 0;
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}
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#endif
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EXPORT_SYMBOL_GPL(hwpoison_filter);
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/*
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* Send all the processes who have the page mapped a signal.
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* ``action optional'' if they are not immediately affected by the error
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* ``action required'' if error happened in current execution context
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*/
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static int kill_proc(struct task_struct *t, unsigned long addr, int trapno,
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unsigned long pfn, struct page *page, int flags)
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{
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struct siginfo si;
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int ret;
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printk(KERN_ERR
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"MCE %#lx: Killing %s:%d due to hardware memory corruption\n",
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pfn, t->comm, t->pid);
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si.si_signo = SIGBUS;
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si.si_errno = 0;
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si.si_addr = (void *)addr;
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#ifdef __ARCH_SI_TRAPNO
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si.si_trapno = trapno;
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#endif
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si.si_addr_lsb = compound_order(compound_head(page)) + PAGE_SHIFT;
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if ((flags & MF_ACTION_REQUIRED) && t->mm == current->mm) {
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si.si_code = BUS_MCEERR_AR;
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ret = force_sig_info(SIGBUS, &si, current);
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} else {
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/*
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* Don't use force here, it's convenient if the signal
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* can be temporarily blocked.
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* This could cause a loop when the user sets SIGBUS
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* to SIG_IGN, but hopefully no one will do that?
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*/
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si.si_code = BUS_MCEERR_AO;
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ret = send_sig_info(SIGBUS, &si, t); /* synchronous? */
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}
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if (ret < 0)
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printk(KERN_INFO "MCE: Error sending signal to %s:%d: %d\n",
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t->comm, t->pid, ret);
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return ret;
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}
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/*
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* When a unknown page type is encountered drain as many buffers as possible
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* in the hope to turn the page into a LRU or free page, which we can handle.
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*/
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void shake_page(struct page *p, int access)
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{
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if (!PageSlab(p)) {
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lru_add_drain_all();
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if (PageLRU(p))
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return;
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drain_all_pages(page_zone(p));
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if (PageLRU(p) || is_free_buddy_page(p))
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return;
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}
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/*
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* Only call shrink_node_slabs here (which would also shrink
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* other caches) if access is not potentially fatal.
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*/
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if (access)
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drop_slab_node(page_to_nid(p));
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}
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EXPORT_SYMBOL_GPL(shake_page);
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/*
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* Kill all processes that have a poisoned page mapped and then isolate
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* the page.
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*
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* General strategy:
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* Find all processes having the page mapped and kill them.
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* But we keep a page reference around so that the page is not
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* actually freed yet.
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* Then stash the page away
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*
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* There's no convenient way to get back to mapped processes
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* from the VMAs. So do a brute-force search over all
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* running processes.
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*
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* Remember that machine checks are not common (or rather
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* if they are common you have other problems), so this shouldn't
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* be a performance issue.
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*
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* Also there are some races possible while we get from the
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* error detection to actually handle it.
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*/
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struct to_kill {
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struct list_head nd;
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struct task_struct *tsk;
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unsigned long addr;
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char addr_valid;
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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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*/
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/*
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* Schedule a process for later kill.
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* Uses GFP_ATOMIC allocations to avoid potential recursions in the VM.
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* TBD would GFP_NOIO be enough?
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*/
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static void add_to_kill(struct task_struct *tsk, struct page *p,
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struct vm_area_struct *vma,
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struct list_head *to_kill,
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struct to_kill **tkc)
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{
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struct to_kill *tk;
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if (*tkc) {
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tk = *tkc;
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*tkc = NULL;
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} else {
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tk = kmalloc(sizeof(struct to_kill), GFP_ATOMIC);
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if (!tk) {
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printk(KERN_ERR
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"MCE: Out of memory while machine check handling\n");
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return;
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}
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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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/*
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* In theory we don't have to kill when the page was
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* munmaped. But it could be also a mremap. Since that's
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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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pr_info("MCE: 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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}
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get_task_struct(tsk);
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tk->tsk = tsk;
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list_add_tail(&tk->nd, to_kill);
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}
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/*
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* Kill the processes that have been collected earlier.
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*
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* Only do anything when DOIT is set, otherwise just free the list
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* (this is used for clean pages which do not need killing)
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* Also when FAIL is set do a force kill because something went
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* wrong earlier.
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*/
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static void kill_procs(struct list_head *to_kill, int forcekill, int trapno,
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int fail, struct page *page, unsigned long pfn,
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int flags)
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{
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struct to_kill *tk, *next;
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list_for_each_entry_safe (tk, next, to_kill, nd) {
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if (forcekill) {
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/*
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* In case something went wrong with munmapping
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* make sure the process doesn't catch the
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* signal and then access the memory. Just kill it.
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*/
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if (fail || tk->addr_valid == 0) {
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printk(KERN_ERR
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"MCE %#lx: forcibly killing %s:%d because of failure to unmap corrupted page\n",
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pfn, tk->tsk->comm, tk->tsk->pid);
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force_sig(SIGKILL, tk->tsk);
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}
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/*
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* In theory the process could have mapped
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* something else on the address in-between. We could
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* check for that, but we need to tell the
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* process anyways.
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*/
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else if (kill_proc(tk->tsk, tk->addr, trapno,
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pfn, page, flags) < 0)
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printk(KERN_ERR
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"MCE %#lx: Cannot send advisory machine check signal to %s:%d\n",
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pfn, tk->tsk->comm, tk->tsk->pid);
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}
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put_task_struct(tk->tsk);
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kfree(tk);
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}
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}
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/*
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* Find a dedicated thread which is supposed to handle SIGBUS(BUS_MCEERR_AO)
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* on behalf of the thread group. Return task_struct of the (first found)
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* dedicated thread if found, and return NULL otherwise.
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*
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* We already hold read_lock(&tasklist_lock) in the caller, so we don't
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* have to call rcu_read_lock/unlock() in this function.
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*/
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static struct task_struct *find_early_kill_thread(struct task_struct *tsk)
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{
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struct task_struct *t;
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for_each_thread(tsk, t)
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if ((t->flags & PF_MCE_PROCESS) && (t->flags & PF_MCE_EARLY))
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return t;
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return NULL;
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}
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/*
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* Determine whether a given process is "early kill" process which expects
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* to be signaled when some page under the process is hwpoisoned.
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* Return task_struct of the dedicated thread (main thread unless explicitly
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* specified) if the process is "early kill," and otherwise returns NULL.
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*/
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static struct task_struct *task_early_kill(struct task_struct *tsk,
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int force_early)
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{
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struct task_struct *t;
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if (!tsk->mm)
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return NULL;
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if (force_early)
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return tsk;
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t = find_early_kill_thread(tsk);
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if (t)
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return t;
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if (sysctl_memory_failure_early_kill)
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return tsk;
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return NULL;
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}
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/*
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* Collect processes when the error hit an anonymous page.
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*/
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static void collect_procs_anon(struct page *page, struct list_head *to_kill,
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struct to_kill **tkc, int force_early)
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{
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struct vm_area_struct *vma;
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struct task_struct *tsk;
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struct anon_vma *av;
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pgoff_t pgoff;
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av = page_lock_anon_vma_read(page);
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if (av == NULL) /* Not actually mapped anymore */
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return;
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pgoff = page_to_pgoff(page);
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read_lock(&tasklist_lock);
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for_each_process (tsk) {
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struct anon_vma_chain *vmac;
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struct task_struct *t = task_early_kill(tsk, force_early);
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if (!t)
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continue;
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anon_vma_interval_tree_foreach(vmac, &av->rb_root,
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pgoff, pgoff) {
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vma = vmac->vma;
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if (!page_mapped_in_vma(page, vma))
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continue;
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if (vma->vm_mm == t->mm)
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add_to_kill(t, page, vma, to_kill, tkc);
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}
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}
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read_unlock(&tasklist_lock);
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page_unlock_anon_vma_read(av);
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}
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|
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/*
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* Collect processes when the error hit a file mapped page.
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*/
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static void collect_procs_file(struct page *page, struct list_head *to_kill,
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struct to_kill **tkc, int force_early)
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{
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struct vm_area_struct *vma;
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struct task_struct *tsk;
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struct address_space *mapping = page->mapping;
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|
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i_mmap_lock_read(mapping);
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read_lock(&tasklist_lock);
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for_each_process(tsk) {
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pgoff_t pgoff = page_to_pgoff(page);
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struct task_struct *t = task_early_kill(tsk, force_early);
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|
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if (!t)
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continue;
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vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff,
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pgoff) {
|
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/*
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* Send early kill signal to tasks where a vma covers
|
|
* the page but the corrupted page is not necessarily
|
|
* mapped it in its pte.
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* Assume applications who requested early kill want
|
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* to be informed of all such data corruptions.
|
|
*/
|
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if (vma->vm_mm == t->mm)
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add_to_kill(t, page, vma, to_kill, tkc);
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}
|
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}
|
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read_unlock(&tasklist_lock);
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i_mmap_unlock_read(mapping);
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}
|
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|
|
/*
|
|
* Collect the processes who have the corrupted page mapped to kill.
|
|
* This is done in two steps for locking reasons.
|
|
* First preallocate one tokill structure outside the spin locks,
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* so that we can kill at least one process reasonably reliable.
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|
*/
|
|
static void collect_procs(struct page *page, struct list_head *tokill,
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int force_early)
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|
{
|
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struct to_kill *tk;
|
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|
|
if (!page->mapping)
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return;
|
|
|
|
tk = kmalloc(sizeof(struct to_kill), GFP_NOIO);
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|
if (!tk)
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return;
|
|
if (PageAnon(page))
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|
collect_procs_anon(page, tokill, &tk, force_early);
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|
else
|
|
collect_procs_file(page, tokill, &tk, force_early);
|
|
kfree(tk);
|
|
}
|
|
|
|
static const char *action_name[] = {
|
|
[MF_IGNORED] = "Ignored",
|
|
[MF_FAILED] = "Failed",
|
|
[MF_DELAYED] = "Delayed",
|
|
[MF_RECOVERED] = "Recovered",
|
|
};
|
|
|
|
static const char * const action_page_types[] = {
|
|
[MF_MSG_KERNEL] = "reserved kernel page",
|
|
[MF_MSG_KERNEL_HIGH_ORDER] = "high-order kernel page",
|
|
[MF_MSG_SLAB] = "kernel slab page",
|
|
[MF_MSG_DIFFERENT_COMPOUND] = "different compound page after locking",
|
|
[MF_MSG_POISONED_HUGE] = "huge page already hardware poisoned",
|
|
[MF_MSG_HUGE] = "huge page",
|
|
[MF_MSG_FREE_HUGE] = "free huge page",
|
|
[MF_MSG_UNMAP_FAILED] = "unmapping failed page",
|
|
[MF_MSG_DIRTY_SWAPCACHE] = "dirty swapcache page",
|
|
[MF_MSG_CLEAN_SWAPCACHE] = "clean swapcache page",
|
|
[MF_MSG_DIRTY_MLOCKED_LRU] = "dirty mlocked LRU page",
|
|
[MF_MSG_CLEAN_MLOCKED_LRU] = "clean mlocked LRU page",
|
|
[MF_MSG_DIRTY_UNEVICTABLE_LRU] = "dirty unevictable LRU page",
|
|
[MF_MSG_CLEAN_UNEVICTABLE_LRU] = "clean unevictable LRU page",
|
|
[MF_MSG_DIRTY_LRU] = "dirty LRU page",
|
|
[MF_MSG_CLEAN_LRU] = "clean LRU page",
|
|
[MF_MSG_TRUNCATED_LRU] = "already truncated LRU page",
|
|
[MF_MSG_BUDDY] = "free buddy page",
|
|
[MF_MSG_BUDDY_2ND] = "free buddy page (2nd try)",
|
|
[MF_MSG_UNKNOWN] = "unknown page",
|
|
};
|
|
|
|
/*
|
|
* XXX: It is possible that a page is isolated from LRU cache,
|
|
* and then kept in swap cache or failed to remove from page cache.
|
|
* The page count will stop it from being freed by unpoison.
|
|
* Stress tests should be aware of this memory leak problem.
|
|
*/
|
|
static int delete_from_lru_cache(struct page *p)
|
|
{
|
|
if (!isolate_lru_page(p)) {
|
|
/*
|
|
* Clear sensible page flags, so that the buddy system won't
|
|
* complain when the page is unpoison-and-freed.
|
|
*/
|
|
ClearPageActive(p);
|
|
ClearPageUnevictable(p);
|
|
/*
|
|
* drop the page count elevated by isolate_lru_page()
|
|
*/
|
|
page_cache_release(p);
|
|
return 0;
|
|
}
|
|
return -EIO;
|
|
}
|
|
|
|
/*
|
|
* Error hit kernel page.
|
|
* Do nothing, try to be lucky and not touch this instead. For a few cases we
|
|
* could be more sophisticated.
|
|
*/
|
|
static int me_kernel(struct page *p, unsigned long pfn)
|
|
{
|
|
return MF_IGNORED;
|
|
}
|
|
|
|
/*
|
|
* Page in unknown state. Do nothing.
|
|
*/
|
|
static int me_unknown(struct page *p, unsigned long pfn)
|
|
{
|
|
printk(KERN_ERR "MCE %#lx: Unknown page state\n", pfn);
|
|
return MF_FAILED;
|
|
}
|
|
|
|
/*
|
|
* Clean (or cleaned) page cache page.
|
|
*/
|
|
static int me_pagecache_clean(struct page *p, unsigned long pfn)
|
|
{
|
|
int err;
|
|
int ret = MF_FAILED;
|
|
struct address_space *mapping;
|
|
|
|
delete_from_lru_cache(p);
|
|
|
|
/*
|
|
* For anonymous pages we're done the only reference left
|
|
* should be the one m_f() holds.
|
|
*/
|
|
if (PageAnon(p))
|
|
return MF_RECOVERED;
|
|
|
|
/*
|
|
* Now truncate the page in the page cache. This is really
|
|
* more like a "temporary hole punch"
|
|
* Don't do this for block devices when someone else
|
|
* has a reference, because it could be file system metadata
|
|
* and that's not safe to truncate.
|
|
*/
|
|
mapping = page_mapping(p);
|
|
if (!mapping) {
|
|
/*
|
|
* Page has been teared down in the meanwhile
|
|
*/
|
|
return MF_FAILED;
|
|
}
|
|
|
|
/*
|
|
* Truncation is a bit tricky. Enable it per file system for now.
|
|
*
|
|
* Open: to take i_mutex or not for this? Right now we don't.
|
|
*/
|
|
if (mapping->a_ops->error_remove_page) {
|
|
err = mapping->a_ops->error_remove_page(mapping, p);
|
|
if (err != 0) {
|
|
printk(KERN_INFO "MCE %#lx: Failed to punch page: %d\n",
|
|
pfn, err);
|
|
} else if (page_has_private(p) &&
|
|
!try_to_release_page(p, GFP_NOIO)) {
|
|
pr_info("MCE %#lx: failed to release buffers\n", pfn);
|
|
} else {
|
|
ret = MF_RECOVERED;
|
|
}
|
|
} else {
|
|
/*
|
|
* If the file system doesn't support it just invalidate
|
|
* This fails on dirty or anything with private pages
|
|
*/
|
|
if (invalidate_inode_page(p))
|
|
ret = MF_RECOVERED;
|
|
else
|
|
printk(KERN_INFO "MCE %#lx: Failed to invalidate\n",
|
|
pfn);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Dirty pagecache page
|
|
* Issues: when the error hit a hole page the error is not properly
|
|
* propagated.
|
|
*/
|
|
static int me_pagecache_dirty(struct page *p, unsigned long pfn)
|
|
{
|
|
struct address_space *mapping = page_mapping(p);
|
|
|
|
SetPageError(p);
|
|
/* TBD: print more information about the file. */
|
|
if (mapping) {
|
|
/*
|
|
* IO error will be reported by write(), fsync(), etc.
|
|
* who check the mapping.
|
|
* This way the application knows that something went
|
|
* wrong with its dirty file data.
|
|
*
|
|
* There's one open issue:
|
|
*
|
|
* The EIO will be only reported on the next IO
|
|
* operation and then cleared through the IO map.
|
|
* Normally Linux has two mechanisms to pass IO error
|
|
* first through the AS_EIO flag in the address space
|
|
* and then through the PageError flag in the page.
|
|
* Since we drop pages on memory failure handling the
|
|
* only mechanism open to use is through AS_AIO.
|
|
*
|
|
* This has the disadvantage that it gets cleared on
|
|
* the first operation that returns an error, while
|
|
* the PageError bit is more sticky and only cleared
|
|
* when the page is reread or dropped. If an
|
|
* application assumes it will always get error on
|
|
* fsync, but does other operations on the fd before
|
|
* and the page is dropped between then the error
|
|
* will not be properly reported.
|
|
*
|
|
* This can already happen even without hwpoisoned
|
|
* pages: first on metadata IO errors (which only
|
|
* report through AS_EIO) or when the page is dropped
|
|
* at the wrong time.
|
|
*
|
|
* So right now we assume that the application DTRT on
|
|
* the first EIO, but we're not worse than other parts
|
|
* of the kernel.
|
|
*/
|
|
mapping_set_error(mapping, EIO);
|
|
}
|
|
|
|
return me_pagecache_clean(p, pfn);
|
|
}
|
|
|
|
/*
|
|
* Clean and dirty swap cache.
|
|
*
|
|
* Dirty swap cache page is tricky to handle. The page could live both in page
|
|
* cache and swap cache(ie. page is freshly swapped in). So it could be
|
|
* referenced concurrently by 2 types of PTEs:
|
|
* normal PTEs and swap PTEs. We try to handle them consistently by calling
|
|
* try_to_unmap(TTU_IGNORE_HWPOISON) to convert the normal PTEs to swap PTEs,
|
|
* and then
|
|
* - clear dirty bit to prevent IO
|
|
* - remove from LRU
|
|
* - but keep in the swap cache, so that when we return to it on
|
|
* a later page fault, we know the application is accessing
|
|
* corrupted data and shall be killed (we installed simple
|
|
* interception code in do_swap_page to catch it).
|
|
*
|
|
* Clean swap cache pages can be directly isolated. A later page fault will
|
|
* bring in the known good data from disk.
|
|
*/
|
|
static int me_swapcache_dirty(struct page *p, unsigned long pfn)
|
|
{
|
|
ClearPageDirty(p);
|
|
/* Trigger EIO in shmem: */
|
|
ClearPageUptodate(p);
|
|
|
|
if (!delete_from_lru_cache(p))
|
|
return MF_DELAYED;
|
|
else
|
|
return MF_FAILED;
|
|
}
|
|
|
|
static int me_swapcache_clean(struct page *p, unsigned long pfn)
|
|
{
|
|
delete_from_swap_cache(p);
|
|
|
|
if (!delete_from_lru_cache(p))
|
|
return MF_RECOVERED;
|
|
else
|
|
return MF_FAILED;
|
|
}
|
|
|
|
/*
|
|
* Huge pages. Needs work.
|
|
* Issues:
|
|
* - Error on hugepage is contained in hugepage unit (not in raw page unit.)
|
|
* To narrow down kill region to one page, we need to break up pmd.
|
|
*/
|
|
static int me_huge_page(struct page *p, unsigned long pfn)
|
|
{
|
|
int res = 0;
|
|
struct page *hpage = compound_head(p);
|
|
|
|
if (!PageHuge(hpage))
|
|
return MF_DELAYED;
|
|
|
|
/*
|
|
* We can safely recover from error on free or reserved (i.e.
|
|
* not in-use) hugepage by dequeuing it from freelist.
|
|
* To check whether a hugepage is in-use or not, we can't use
|
|
* page->lru because it can be used in other hugepage operations,
|
|
* such as __unmap_hugepage_range() and gather_surplus_pages().
|
|
* So instead we use page_mapping() and PageAnon().
|
|
* We assume that this function is called with page lock held,
|
|
* so there is no race between isolation and mapping/unmapping.
|
|
*/
|
|
if (!(page_mapping(hpage) || PageAnon(hpage))) {
|
|
res = dequeue_hwpoisoned_huge_page(hpage);
|
|
if (!res)
|
|
return MF_RECOVERED;
|
|
}
|
|
return MF_DELAYED;
|
|
}
|
|
|
|
/*
|
|
* Various page states we can handle.
|
|
*
|
|
* A page state is defined by its current page->flags bits.
|
|
* The table matches them in order and calls the right handler.
|
|
*
|
|
* This is quite tricky because we can access page at any time
|
|
* in its live cycle, so all accesses have to be extremely careful.
|
|
*
|
|
* This is not complete. More states could be added.
|
|
* For any missing state don't attempt recovery.
|
|
*/
|
|
|
|
#define dirty (1UL << PG_dirty)
|
|
#define sc (1UL << PG_swapcache)
|
|
#define unevict (1UL << PG_unevictable)
|
|
#define mlock (1UL << PG_mlocked)
|
|
#define writeback (1UL << PG_writeback)
|
|
#define lru (1UL << PG_lru)
|
|
#define swapbacked (1UL << PG_swapbacked)
|
|
#define head (1UL << PG_head)
|
|
#define tail (1UL << PG_tail)
|
|
#define compound (1UL << PG_compound)
|
|
#define slab (1UL << PG_slab)
|
|
#define reserved (1UL << PG_reserved)
|
|
|
|
static struct page_state {
|
|
unsigned long mask;
|
|
unsigned long res;
|
|
enum mf_action_page_type type;
|
|
int (*action)(struct page *p, unsigned long pfn);
|
|
} error_states[] = {
|
|
{ reserved, reserved, MF_MSG_KERNEL, me_kernel },
|
|
/*
|
|
* free pages are specially detected outside this table:
|
|
* PG_buddy pages only make a small fraction of all free pages.
|
|
*/
|
|
|
|
/*
|
|
* Could in theory check if slab page is free or if we can drop
|
|
* currently unused objects without touching them. But just
|
|
* treat it as standard kernel for now.
|
|
*/
|
|
{ slab, slab, MF_MSG_SLAB, me_kernel },
|
|
|
|
#ifdef CONFIG_PAGEFLAGS_EXTENDED
|
|
{ head, head, MF_MSG_HUGE, me_huge_page },
|
|
{ tail, tail, MF_MSG_HUGE, me_huge_page },
|
|
#else
|
|
{ compound, compound, MF_MSG_HUGE, me_huge_page },
|
|
#endif
|
|
|
|
{ sc|dirty, sc|dirty, MF_MSG_DIRTY_SWAPCACHE, me_swapcache_dirty },
|
|
{ sc|dirty, sc, MF_MSG_CLEAN_SWAPCACHE, me_swapcache_clean },
|
|
|
|
{ mlock|dirty, mlock|dirty, MF_MSG_DIRTY_MLOCKED_LRU, me_pagecache_dirty },
|
|
{ mlock|dirty, mlock, MF_MSG_CLEAN_MLOCKED_LRU, me_pagecache_clean },
|
|
|
|
{ unevict|dirty, unevict|dirty, MF_MSG_DIRTY_UNEVICTABLE_LRU, me_pagecache_dirty },
|
|
{ unevict|dirty, unevict, MF_MSG_CLEAN_UNEVICTABLE_LRU, me_pagecache_clean },
|
|
|
|
{ lru|dirty, lru|dirty, MF_MSG_DIRTY_LRU, me_pagecache_dirty },
|
|
{ lru|dirty, lru, MF_MSG_CLEAN_LRU, me_pagecache_clean },
|
|
|
|
/*
|
|
* Catchall entry: must be at end.
|
|
*/
|
|
{ 0, 0, MF_MSG_UNKNOWN, me_unknown },
|
|
};
|
|
|
|
#undef dirty
|
|
#undef sc
|
|
#undef unevict
|
|
#undef mlock
|
|
#undef writeback
|
|
#undef lru
|
|
#undef swapbacked
|
|
#undef head
|
|
#undef tail
|
|
#undef compound
|
|
#undef slab
|
|
#undef reserved
|
|
|
|
/*
|
|
* "Dirty/Clean" indication is not 100% accurate due to the possibility of
|
|
* setting PG_dirty outside page lock. See also comment above set_page_dirty().
|
|
*/
|
|
static void action_result(unsigned long pfn, enum mf_action_page_type type,
|
|
enum mf_result result)
|
|
{
|
|
trace_memory_failure_event(pfn, type, result);
|
|
|
|
pr_err("MCE %#lx: recovery action for %s: %s\n",
|
|
pfn, action_page_types[type], action_name[result]);
|
|
}
|
|
|
|
static int page_action(struct page_state *ps, struct page *p,
|
|
unsigned long pfn)
|
|
{
|
|
int result;
|
|
int count;
|
|
|
|
result = ps->action(p, pfn);
|
|
|
|
count = page_count(p) - 1;
|
|
if (ps->action == me_swapcache_dirty && result == MF_DELAYED)
|
|
count--;
|
|
if (count != 0) {
|
|
printk(KERN_ERR
|
|
"MCE %#lx: %s still referenced by %d users\n",
|
|
pfn, action_page_types[ps->type], count);
|
|
result = MF_FAILED;
|
|
}
|
|
action_result(pfn, ps->type, result);
|
|
|
|
/* Could do more checks here if page looks ok */
|
|
/*
|
|
* Could adjust zone counters here to correct for the missing page.
|
|
*/
|
|
|
|
return (result == MF_RECOVERED || result == MF_DELAYED) ? 0 : -EBUSY;
|
|
}
|
|
|
|
/**
|
|
* get_hwpoison_page() - Get refcount for memory error handling:
|
|
* @page: raw error page (hit by memory error)
|
|
*
|
|
* Return: return 0 if failed to grab the refcount, otherwise true (some
|
|
* non-zero value.)
|
|
*/
|
|
int get_hwpoison_page(struct page *page)
|
|
{
|
|
struct page *head = compound_head(page);
|
|
|
|
if (PageHuge(head))
|
|
return get_page_unless_zero(head);
|
|
|
|
/*
|
|
* Thp tail page has special refcounting rule (refcount of tail pages
|
|
* is stored in ->_mapcount,) so we can't call get_page_unless_zero()
|
|
* directly for tail pages.
|
|
*/
|
|
if (PageTransHuge(head)) {
|
|
/*
|
|
* Non anonymous thp exists only in allocation/free time. We
|
|
* can't handle such a case correctly, so let's give it up.
|
|
* This should be better than triggering BUG_ON when kernel
|
|
* tries to touch the "partially handled" page.
|
|
*/
|
|
if (!PageAnon(head)) {
|
|
pr_err("MCE: %#lx: non anonymous thp\n",
|
|
page_to_pfn(page));
|
|
return 0;
|
|
}
|
|
|
|
if (get_page_unless_zero(head)) {
|
|
if (PageTail(page))
|
|
get_page(page);
|
|
return 1;
|
|
} else {
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
return get_page_unless_zero(page);
|
|
}
|
|
EXPORT_SYMBOL_GPL(get_hwpoison_page);
|
|
|
|
/**
|
|
* put_hwpoison_page() - Put refcount for memory error handling:
|
|
* @page: raw error page (hit by memory error)
|
|
*/
|
|
void put_hwpoison_page(struct page *page)
|
|
{
|
|
struct page *head = compound_head(page);
|
|
|
|
if (PageHuge(head)) {
|
|
put_page(head);
|
|
return;
|
|
}
|
|
|
|
if (PageTransHuge(head))
|
|
if (page != head)
|
|
put_page(head);
|
|
|
|
put_page(page);
|
|
}
|
|
EXPORT_SYMBOL_GPL(put_hwpoison_page);
|
|
|
|
/*
|
|
* Do all that is necessary to remove user space mappings. Unmap
|
|
* the pages and send SIGBUS to the processes if the data was dirty.
|
|
*/
|
|
static int hwpoison_user_mappings(struct page *p, unsigned long pfn,
|
|
int trapno, int flags, struct page **hpagep)
|
|
{
|
|
enum ttu_flags ttu = TTU_UNMAP | TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS;
|
|
struct address_space *mapping;
|
|
LIST_HEAD(tokill);
|
|
int ret;
|
|
int kill = 1, forcekill;
|
|
struct page *hpage = *hpagep;
|
|
|
|
/*
|
|
* Here we are interested only in user-mapped pages, so skip any
|
|
* other types of pages.
|
|
*/
|
|
if (PageReserved(p) || PageSlab(p))
|
|
return SWAP_SUCCESS;
|
|
if (!(PageLRU(hpage) || PageHuge(p)))
|
|
return SWAP_SUCCESS;
|
|
|
|
/*
|
|
* This check implies we don't kill processes if their pages
|
|
* are in the swap cache early. Those are always late kills.
|
|
*/
|
|
if (!page_mapped(hpage))
|
|
return SWAP_SUCCESS;
|
|
|
|
if (PageKsm(p)) {
|
|
pr_err("MCE %#lx: can't handle KSM pages.\n", pfn);
|
|
return SWAP_FAIL;
|
|
}
|
|
|
|
if (PageSwapCache(p)) {
|
|
printk(KERN_ERR
|
|
"MCE %#lx: keeping poisoned page in swap cache\n", pfn);
|
|
ttu |= TTU_IGNORE_HWPOISON;
|
|
}
|
|
|
|
/*
|
|
* Propagate the dirty bit from PTEs to struct page first, because we
|
|
* need this to decide if we should kill or just drop the page.
|
|
* XXX: the dirty test could be racy: set_page_dirty() may not always
|
|
* be called inside page lock (it's recommended but not enforced).
|
|
*/
|
|
mapping = page_mapping(hpage);
|
|
if (!(flags & MF_MUST_KILL) && !PageDirty(hpage) && mapping &&
|
|
mapping_cap_writeback_dirty(mapping)) {
|
|
if (page_mkclean(hpage)) {
|
|
SetPageDirty(hpage);
|
|
} else {
|
|
kill = 0;
|
|
ttu |= TTU_IGNORE_HWPOISON;
|
|
printk(KERN_INFO
|
|
"MCE %#lx: corrupted page was clean: dropped without side effects\n",
|
|
pfn);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* First collect all the processes that have the page
|
|
* mapped in dirty form. This has to be done before try_to_unmap,
|
|
* because ttu takes the rmap data structures down.
|
|
*
|
|
* Error handling: We ignore errors here because
|
|
* there's nothing that can be done.
|
|
*/
|
|
if (kill)
|
|
collect_procs(hpage, &tokill, flags & MF_ACTION_REQUIRED);
|
|
|
|
ret = try_to_unmap(hpage, ttu);
|
|
if (ret != SWAP_SUCCESS)
|
|
printk(KERN_ERR "MCE %#lx: failed to unmap page (mapcount=%d)\n",
|
|
pfn, page_mapcount(hpage));
|
|
|
|
/*
|
|
* Now that the dirty bit has been propagated to the
|
|
* struct page and all unmaps done we can decide if
|
|
* killing is needed or not. Only kill when the page
|
|
* was dirty or the process is not restartable,
|
|
* otherwise the tokill list is merely
|
|
* freed. When there was a problem unmapping earlier
|
|
* use a more force-full uncatchable kill to prevent
|
|
* any accesses to the poisoned memory.
|
|
*/
|
|
forcekill = PageDirty(hpage) || (flags & MF_MUST_KILL);
|
|
kill_procs(&tokill, forcekill, trapno,
|
|
ret != SWAP_SUCCESS, p, pfn, flags);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static void set_page_hwpoison_huge_page(struct page *hpage)
|
|
{
|
|
int i;
|
|
int nr_pages = 1 << compound_order(hpage);
|
|
for (i = 0; i < nr_pages; i++)
|
|
SetPageHWPoison(hpage + i);
|
|
}
|
|
|
|
static void clear_page_hwpoison_huge_page(struct page *hpage)
|
|
{
|
|
int i;
|
|
int nr_pages = 1 << compound_order(hpage);
|
|
for (i = 0; i < nr_pages; i++)
|
|
ClearPageHWPoison(hpage + i);
|
|
}
|
|
|
|
/**
|
|
* memory_failure - Handle memory failure of a page.
|
|
* @pfn: Page Number of the corrupted page
|
|
* @trapno: Trap number reported in the signal to user space.
|
|
* @flags: fine tune action taken
|
|
*
|
|
* This function is called by the low level machine check code
|
|
* of an architecture when it detects hardware memory corruption
|
|
* of a page. It tries its best to recover, which includes
|
|
* dropping pages, killing processes etc.
|
|
*
|
|
* The function is primarily of use for corruptions that
|
|
* happen outside the current execution context (e.g. when
|
|
* detected by a background scrubber)
|
|
*
|
|
* Must run in process context (e.g. a work queue) with interrupts
|
|
* enabled and no spinlocks hold.
|
|
*/
|
|
int memory_failure(unsigned long pfn, int trapno, int flags)
|
|
{
|
|
struct page_state *ps;
|
|
struct page *p;
|
|
struct page *hpage;
|
|
struct page *orig_head;
|
|
int res;
|
|
unsigned int nr_pages;
|
|
unsigned long page_flags;
|
|
|
|
if (!sysctl_memory_failure_recovery)
|
|
panic("Memory failure from trap %d on page %lx", trapno, pfn);
|
|
|
|
if (!pfn_valid(pfn)) {
|
|
printk(KERN_ERR
|
|
"MCE %#lx: memory outside kernel control\n",
|
|
pfn);
|
|
return -ENXIO;
|
|
}
|
|
|
|
p = pfn_to_page(pfn);
|
|
orig_head = hpage = compound_head(p);
|
|
if (TestSetPageHWPoison(p)) {
|
|
printk(KERN_ERR "MCE %#lx: already hardware poisoned\n", pfn);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Currently errors on hugetlbfs pages are measured in hugepage units,
|
|
* so nr_pages should be 1 << compound_order. OTOH when errors are on
|
|
* transparent hugepages, they are supposed to be split and error
|
|
* measurement is done in normal page units. So nr_pages should be one
|
|
* in this case.
|
|
*/
|
|
if (PageHuge(p))
|
|
nr_pages = 1 << compound_order(hpage);
|
|
else /* normal page or thp */
|
|
nr_pages = 1;
|
|
num_poisoned_pages_add(nr_pages);
|
|
|
|
/*
|
|
* We need/can do nothing about count=0 pages.
|
|
* 1) it's a free page, and therefore in safe hand:
|
|
* prep_new_page() will be the gate keeper.
|
|
* 2) it's a free hugepage, which is also safe:
|
|
* an affected hugepage will be dequeued from hugepage freelist,
|
|
* so there's no concern about reusing it ever after.
|
|
* 3) it's part of a non-compound high order page.
|
|
* Implies some kernel user: cannot stop them from
|
|
* R/W the page; let's pray that the page has been
|
|
* used and will be freed some time later.
|
|
* In fact it's dangerous to directly bump up page count from 0,
|
|
* that may make page_freeze_refs()/page_unfreeze_refs() mismatch.
|
|
*/
|
|
if (!(flags & MF_COUNT_INCREASED) && !get_hwpoison_page(p)) {
|
|
if (is_free_buddy_page(p)) {
|
|
action_result(pfn, MF_MSG_BUDDY, MF_DELAYED);
|
|
return 0;
|
|
} else if (PageHuge(hpage)) {
|
|
/*
|
|
* Check "filter hit" and "race with other subpage."
|
|
*/
|
|
lock_page(hpage);
|
|
if (PageHWPoison(hpage)) {
|
|
if ((hwpoison_filter(p) && TestClearPageHWPoison(p))
|
|
|| (p != hpage && TestSetPageHWPoison(hpage))) {
|
|
num_poisoned_pages_sub(nr_pages);
|
|
unlock_page(hpage);
|
|
return 0;
|
|
}
|
|
}
|
|
set_page_hwpoison_huge_page(hpage);
|
|
res = dequeue_hwpoisoned_huge_page(hpage);
|
|
action_result(pfn, MF_MSG_FREE_HUGE,
|
|
res ? MF_IGNORED : MF_DELAYED);
|
|
unlock_page(hpage);
|
|
return res;
|
|
} else {
|
|
action_result(pfn, MF_MSG_KERNEL_HIGH_ORDER, MF_IGNORED);
|
|
return -EBUSY;
|
|
}
|
|
}
|
|
|
|
if (!PageHuge(p) && PageTransHuge(hpage)) {
|
|
if (!PageAnon(hpage) || unlikely(split_huge_page(hpage))) {
|
|
if (!PageAnon(hpage))
|
|
pr_err("MCE: %#lx: non anonymous thp\n", pfn);
|
|
else
|
|
pr_err("MCE: %#lx: thp split failed\n", pfn);
|
|
if (TestClearPageHWPoison(p))
|
|
num_poisoned_pages_sub(nr_pages);
|
|
put_hwpoison_page(p);
|
|
return -EBUSY;
|
|
}
|
|
VM_BUG_ON_PAGE(!page_count(p), p);
|
|
hpage = compound_head(p);
|
|
}
|
|
|
|
/*
|
|
* We ignore non-LRU pages for good reasons.
|
|
* - PG_locked is only well defined for LRU pages and a few others
|
|
* - to avoid races with __set_page_locked()
|
|
* - to avoid races with __SetPageSlab*() (and more non-atomic ops)
|
|
* The check (unnecessarily) ignores LRU pages being isolated and
|
|
* walked by the page reclaim code, however that's not a big loss.
|
|
*/
|
|
if (!PageHuge(p)) {
|
|
if (!PageLRU(p))
|
|
shake_page(p, 0);
|
|
if (!PageLRU(p)) {
|
|
/*
|
|
* shake_page could have turned it free.
|
|
*/
|
|
if (is_free_buddy_page(p)) {
|
|
if (flags & MF_COUNT_INCREASED)
|
|
action_result(pfn, MF_MSG_BUDDY, MF_DELAYED);
|
|
else
|
|
action_result(pfn, MF_MSG_BUDDY_2ND,
|
|
MF_DELAYED);
|
|
return 0;
|
|
}
|
|
}
|
|
}
|
|
|
|
lock_page(hpage);
|
|
|
|
/*
|
|
* The page could have changed compound pages during the locking.
|
|
* If this happens just bail out.
|
|
*/
|
|
if (PageCompound(p) && compound_head(p) != orig_head) {
|
|
action_result(pfn, MF_MSG_DIFFERENT_COMPOUND, MF_IGNORED);
|
|
res = -EBUSY;
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* We use page flags to determine what action should be taken, but
|
|
* the flags can be modified by the error containment action. One
|
|
* example is an mlocked page, where PG_mlocked is cleared by
|
|
* page_remove_rmap() in try_to_unmap_one(). So to determine page status
|
|
* correctly, we save a copy of the page flags at this time.
|
|
*/
|
|
page_flags = p->flags;
|
|
|
|
/*
|
|
* unpoison always clear PG_hwpoison inside page lock
|
|
*/
|
|
if (!PageHWPoison(p)) {
|
|
printk(KERN_ERR "MCE %#lx: just unpoisoned\n", pfn);
|
|
num_poisoned_pages_sub(nr_pages);
|
|
unlock_page(hpage);
|
|
put_hwpoison_page(hpage);
|
|
return 0;
|
|
}
|
|
if (hwpoison_filter(p)) {
|
|
if (TestClearPageHWPoison(p))
|
|
num_poisoned_pages_sub(nr_pages);
|
|
unlock_page(hpage);
|
|
put_hwpoison_page(hpage);
|
|
return 0;
|
|
}
|
|
|
|
if (!PageHuge(p) && !PageTransTail(p) && !PageLRU(p))
|
|
goto identify_page_state;
|
|
|
|
/*
|
|
* For error on the tail page, we should set PG_hwpoison
|
|
* on the head page to show that the hugepage is hwpoisoned
|
|
*/
|
|
if (PageHuge(p) && PageTail(p) && TestSetPageHWPoison(hpage)) {
|
|
action_result(pfn, MF_MSG_POISONED_HUGE, MF_IGNORED);
|
|
unlock_page(hpage);
|
|
put_hwpoison_page(hpage);
|
|
return 0;
|
|
}
|
|
/*
|
|
* Set PG_hwpoison on all pages in an error hugepage,
|
|
* because containment is done in hugepage unit for now.
|
|
* Since we have done TestSetPageHWPoison() for the head page with
|
|
* page lock held, we can safely set PG_hwpoison bits on tail pages.
|
|
*/
|
|
if (PageHuge(p))
|
|
set_page_hwpoison_huge_page(hpage);
|
|
|
|
/*
|
|
* It's very difficult to mess with pages currently under IO
|
|
* and in many cases impossible, so we just avoid it here.
|
|
*/
|
|
wait_on_page_writeback(p);
|
|
|
|
/*
|
|
* Now take care of user space mappings.
|
|
* Abort on fail: __delete_from_page_cache() assumes unmapped page.
|
|
*
|
|
* When the raw error page is thp tail page, hpage points to the raw
|
|
* page after thp split.
|
|
*/
|
|
if (hwpoison_user_mappings(p, pfn, trapno, flags, &hpage)
|
|
!= SWAP_SUCCESS) {
|
|
action_result(pfn, MF_MSG_UNMAP_FAILED, MF_IGNORED);
|
|
res = -EBUSY;
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* Torn down by someone else?
|
|
*/
|
|
if (PageLRU(p) && !PageSwapCache(p) && p->mapping == NULL) {
|
|
action_result(pfn, MF_MSG_TRUNCATED_LRU, MF_IGNORED);
|
|
res = -EBUSY;
|
|
goto out;
|
|
}
|
|
|
|
identify_page_state:
|
|
res = -EBUSY;
|
|
/*
|
|
* The first check uses the current page flags which may not have any
|
|
* relevant information. The second check with the saved page flagss is
|
|
* carried out only if the first check can't determine the page status.
|
|
*/
|
|
for (ps = error_states;; ps++)
|
|
if ((p->flags & ps->mask) == ps->res)
|
|
break;
|
|
|
|
page_flags |= (p->flags & (1UL << PG_dirty));
|
|
|
|
if (!ps->mask)
|
|
for (ps = error_states;; ps++)
|
|
if ((page_flags & ps->mask) == ps->res)
|
|
break;
|
|
res = page_action(ps, p, pfn);
|
|
out:
|
|
unlock_page(hpage);
|
|
return res;
|
|
}
|
|
EXPORT_SYMBOL_GPL(memory_failure);
|
|
|
|
#define MEMORY_FAILURE_FIFO_ORDER 4
|
|
#define MEMORY_FAILURE_FIFO_SIZE (1 << MEMORY_FAILURE_FIFO_ORDER)
|
|
|
|
struct memory_failure_entry {
|
|
unsigned long pfn;
|
|
int trapno;
|
|
int flags;
|
|
};
|
|
|
|
struct memory_failure_cpu {
|
|
DECLARE_KFIFO(fifo, struct memory_failure_entry,
|
|
MEMORY_FAILURE_FIFO_SIZE);
|
|
spinlock_t lock;
|
|
struct work_struct work;
|
|
};
|
|
|
|
static DEFINE_PER_CPU(struct memory_failure_cpu, memory_failure_cpu);
|
|
|
|
/**
|
|
* memory_failure_queue - Schedule handling memory failure of a page.
|
|
* @pfn: Page Number of the corrupted page
|
|
* @trapno: Trap number reported in the signal to user space.
|
|
* @flags: Flags for memory failure handling
|
|
*
|
|
* This function is called by the low level hardware error handler
|
|
* when it detects hardware memory corruption of a page. It schedules
|
|
* the recovering of error page, including dropping pages, killing
|
|
* processes etc.
|
|
*
|
|
* The function is primarily of use for corruptions that
|
|
* happen outside the current execution context (e.g. when
|
|
* detected by a background scrubber)
|
|
*
|
|
* Can run in IRQ context.
|
|
*/
|
|
void memory_failure_queue(unsigned long pfn, int trapno, int flags)
|
|
{
|
|
struct memory_failure_cpu *mf_cpu;
|
|
unsigned long proc_flags;
|
|
struct memory_failure_entry entry = {
|
|
.pfn = pfn,
|
|
.trapno = trapno,
|
|
.flags = flags,
|
|
};
|
|
|
|
mf_cpu = &get_cpu_var(memory_failure_cpu);
|
|
spin_lock_irqsave(&mf_cpu->lock, proc_flags);
|
|
if (kfifo_put(&mf_cpu->fifo, entry))
|
|
schedule_work_on(smp_processor_id(), &mf_cpu->work);
|
|
else
|
|
pr_err("Memory failure: buffer overflow when queuing memory failure at %#lx\n",
|
|
pfn);
|
|
spin_unlock_irqrestore(&mf_cpu->lock, proc_flags);
|
|
put_cpu_var(memory_failure_cpu);
|
|
}
|
|
EXPORT_SYMBOL_GPL(memory_failure_queue);
|
|
|
|
static void memory_failure_work_func(struct work_struct *work)
|
|
{
|
|
struct memory_failure_cpu *mf_cpu;
|
|
struct memory_failure_entry entry = { 0, };
|
|
unsigned long proc_flags;
|
|
int gotten;
|
|
|
|
mf_cpu = this_cpu_ptr(&memory_failure_cpu);
|
|
for (;;) {
|
|
spin_lock_irqsave(&mf_cpu->lock, proc_flags);
|
|
gotten = kfifo_get(&mf_cpu->fifo, &entry);
|
|
spin_unlock_irqrestore(&mf_cpu->lock, proc_flags);
|
|
if (!gotten)
|
|
break;
|
|
if (entry.flags & MF_SOFT_OFFLINE)
|
|
soft_offline_page(pfn_to_page(entry.pfn), entry.flags);
|
|
else
|
|
memory_failure(entry.pfn, entry.trapno, entry.flags);
|
|
}
|
|
}
|
|
|
|
static int __init memory_failure_init(void)
|
|
{
|
|
struct memory_failure_cpu *mf_cpu;
|
|
int cpu;
|
|
|
|
for_each_possible_cpu(cpu) {
|
|
mf_cpu = &per_cpu(memory_failure_cpu, cpu);
|
|
spin_lock_init(&mf_cpu->lock);
|
|
INIT_KFIFO(mf_cpu->fifo);
|
|
INIT_WORK(&mf_cpu->work, memory_failure_work_func);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
core_initcall(memory_failure_init);
|
|
|
|
#define unpoison_pr_info(fmt, pfn, rs) \
|
|
({ \
|
|
if (__ratelimit(rs)) \
|
|
pr_info(fmt, pfn); \
|
|
})
|
|
|
|
/**
|
|
* unpoison_memory - Unpoison a previously poisoned page
|
|
* @pfn: Page number of the to be unpoisoned page
|
|
*
|
|
* Software-unpoison a page that has been poisoned by
|
|
* memory_failure() earlier.
|
|
*
|
|
* This is only done on the software-level, so it only works
|
|
* for linux injected failures, not real hardware failures
|
|
*
|
|
* Returns 0 for success, otherwise -errno.
|
|
*/
|
|
int unpoison_memory(unsigned long pfn)
|
|
{
|
|
struct page *page;
|
|
struct page *p;
|
|
int freeit = 0;
|
|
unsigned int nr_pages;
|
|
static DEFINE_RATELIMIT_STATE(unpoison_rs, DEFAULT_RATELIMIT_INTERVAL,
|
|
DEFAULT_RATELIMIT_BURST);
|
|
|
|
if (!pfn_valid(pfn))
|
|
return -ENXIO;
|
|
|
|
p = pfn_to_page(pfn);
|
|
page = compound_head(p);
|
|
|
|
if (!PageHWPoison(p)) {
|
|
unpoison_pr_info("MCE: Page was already unpoisoned %#lx\n",
|
|
pfn, &unpoison_rs);
|
|
return 0;
|
|
}
|
|
|
|
if (page_count(page) > 1) {
|
|
unpoison_pr_info("MCE: Someone grabs the hwpoison page %#lx\n",
|
|
pfn, &unpoison_rs);
|
|
return 0;
|
|
}
|
|
|
|
if (page_mapped(page)) {
|
|
unpoison_pr_info("MCE: Someone maps the hwpoison page %#lx\n",
|
|
pfn, &unpoison_rs);
|
|
return 0;
|
|
}
|
|
|
|
if (page_mapping(page)) {
|
|
unpoison_pr_info("MCE: the hwpoison page has non-NULL mapping %#lx\n",
|
|
pfn, &unpoison_rs);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* unpoison_memory() can encounter thp only when the thp is being
|
|
* worked by memory_failure() and the page lock is not held yet.
|
|
* In such case, we yield to memory_failure() and make unpoison fail.
|
|
*/
|
|
if (!PageHuge(page) && PageTransHuge(page)) {
|
|
unpoison_pr_info("MCE: Memory failure is now running on %#lx\n",
|
|
pfn, &unpoison_rs);
|
|
return 0;
|
|
}
|
|
|
|
nr_pages = 1 << compound_order(page);
|
|
|
|
if (!get_hwpoison_page(p)) {
|
|
/*
|
|
* Since HWPoisoned hugepage should have non-zero refcount,
|
|
* race between memory failure and unpoison seems to happen.
|
|
* In such case unpoison fails and memory failure runs
|
|
* to the end.
|
|
*/
|
|
if (PageHuge(page)) {
|
|
unpoison_pr_info("MCE: Memory failure is now running on free hugepage %#lx\n",
|
|
pfn, &unpoison_rs);
|
|
return 0;
|
|
}
|
|
if (TestClearPageHWPoison(p))
|
|
num_poisoned_pages_dec();
|
|
unpoison_pr_info("MCE: Software-unpoisoned free page %#lx\n",
|
|
pfn, &unpoison_rs);
|
|
return 0;
|
|
}
|
|
|
|
lock_page(page);
|
|
/*
|
|
* This test is racy because PG_hwpoison is set outside of page lock.
|
|
* That's acceptable because that won't trigger kernel panic. Instead,
|
|
* the PG_hwpoison page will be caught and isolated on the entrance to
|
|
* the free buddy page pool.
|
|
*/
|
|
if (TestClearPageHWPoison(page)) {
|
|
unpoison_pr_info("MCE: Software-unpoisoned page %#lx\n",
|
|
pfn, &unpoison_rs);
|
|
num_poisoned_pages_sub(nr_pages);
|
|
freeit = 1;
|
|
if (PageHuge(page))
|
|
clear_page_hwpoison_huge_page(page);
|
|
}
|
|
unlock_page(page);
|
|
|
|
put_hwpoison_page(page);
|
|
if (freeit && !(pfn == my_zero_pfn(0) && page_count(p) == 1))
|
|
put_hwpoison_page(page);
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(unpoison_memory);
|
|
|
|
static struct page *new_page(struct page *p, unsigned long private, int **x)
|
|
{
|
|
int nid = page_to_nid(p);
|
|
if (PageHuge(p))
|
|
return alloc_huge_page_node(page_hstate(compound_head(p)),
|
|
nid);
|
|
else
|
|
return __alloc_pages_node(nid, GFP_HIGHUSER_MOVABLE, 0);
|
|
}
|
|
|
|
/*
|
|
* Safely get reference count of an arbitrary page.
|
|
* Returns 0 for a free page, -EIO for a zero refcount page
|
|
* that is not free, and 1 for any other page type.
|
|
* For 1 the page is returned with increased page count, otherwise not.
|
|
*/
|
|
static int __get_any_page(struct page *p, unsigned long pfn, int flags)
|
|
{
|
|
int ret;
|
|
|
|
if (flags & MF_COUNT_INCREASED)
|
|
return 1;
|
|
|
|
/*
|
|
* When the target page is a free hugepage, just remove it
|
|
* from free hugepage list.
|
|
*/
|
|
if (!get_hwpoison_page(p)) {
|
|
if (PageHuge(p)) {
|
|
pr_info("%s: %#lx free huge page\n", __func__, pfn);
|
|
ret = 0;
|
|
} else if (is_free_buddy_page(p)) {
|
|
pr_info("%s: %#lx free buddy page\n", __func__, pfn);
|
|
ret = 0;
|
|
} else {
|
|
pr_info("%s: %#lx: unknown zero refcount page type %lx\n",
|
|
__func__, pfn, p->flags);
|
|
ret = -EIO;
|
|
}
|
|
} else {
|
|
/* Not a free page */
|
|
ret = 1;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static int get_any_page(struct page *page, unsigned long pfn, int flags)
|
|
{
|
|
int ret = __get_any_page(page, pfn, flags);
|
|
|
|
if (ret == 1 && !PageHuge(page) && !PageLRU(page)) {
|
|
/*
|
|
* Try to free it.
|
|
*/
|
|
put_hwpoison_page(page);
|
|
shake_page(page, 1);
|
|
|
|
/*
|
|
* Did it turn free?
|
|
*/
|
|
ret = __get_any_page(page, pfn, 0);
|
|
if (!PageLRU(page)) {
|
|
/* Drop page reference which is from __get_any_page() */
|
|
put_hwpoison_page(page);
|
|
pr_info("soft_offline: %#lx: unknown non LRU page type %lx\n",
|
|
pfn, page->flags);
|
|
return -EIO;
|
|
}
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static int soft_offline_huge_page(struct page *page, int flags)
|
|
{
|
|
int ret;
|
|
unsigned long pfn = page_to_pfn(page);
|
|
struct page *hpage = compound_head(page);
|
|
LIST_HEAD(pagelist);
|
|
|
|
/*
|
|
* This double-check of PageHWPoison is to avoid the race with
|
|
* memory_failure(). See also comment in __soft_offline_page().
|
|
*/
|
|
lock_page(hpage);
|
|
if (PageHWPoison(hpage)) {
|
|
unlock_page(hpage);
|
|
put_hwpoison_page(hpage);
|
|
pr_info("soft offline: %#lx hugepage already poisoned\n", pfn);
|
|
return -EBUSY;
|
|
}
|
|
unlock_page(hpage);
|
|
|
|
ret = isolate_huge_page(hpage, &pagelist);
|
|
/*
|
|
* get_any_page() and isolate_huge_page() takes a refcount each,
|
|
* so need to drop one here.
|
|
*/
|
|
put_hwpoison_page(hpage);
|
|
if (!ret) {
|
|
pr_info("soft offline: %#lx hugepage failed to isolate\n", pfn);
|
|
return -EBUSY;
|
|
}
|
|
|
|
ret = migrate_pages(&pagelist, new_page, NULL, MPOL_MF_MOVE_ALL,
|
|
MIGRATE_SYNC, MR_MEMORY_FAILURE);
|
|
if (ret) {
|
|
pr_info("soft offline: %#lx: migration failed %d, type %lx\n",
|
|
pfn, ret, page->flags);
|
|
/*
|
|
* We know that soft_offline_huge_page() tries to migrate
|
|
* only one hugepage pointed to by hpage, so we need not
|
|
* run through the pagelist here.
|
|
*/
|
|
putback_active_hugepage(hpage);
|
|
if (ret > 0)
|
|
ret = -EIO;
|
|
} else {
|
|
/* overcommit hugetlb page will be freed to buddy */
|
|
if (PageHuge(page)) {
|
|
set_page_hwpoison_huge_page(hpage);
|
|
dequeue_hwpoisoned_huge_page(hpage);
|
|
num_poisoned_pages_add(1 << compound_order(hpage));
|
|
} else {
|
|
SetPageHWPoison(page);
|
|
num_poisoned_pages_inc();
|
|
}
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static int __soft_offline_page(struct page *page, int flags)
|
|
{
|
|
int ret;
|
|
unsigned long pfn = page_to_pfn(page);
|
|
|
|
/*
|
|
* Check PageHWPoison again inside page lock because PageHWPoison
|
|
* is set by memory_failure() outside page lock. Note that
|
|
* memory_failure() also double-checks PageHWPoison inside page lock,
|
|
* so there's no race between soft_offline_page() and memory_failure().
|
|
*/
|
|
lock_page(page);
|
|
wait_on_page_writeback(page);
|
|
if (PageHWPoison(page)) {
|
|
unlock_page(page);
|
|
put_hwpoison_page(page);
|
|
pr_info("soft offline: %#lx page already poisoned\n", pfn);
|
|
return -EBUSY;
|
|
}
|
|
/*
|
|
* Try to invalidate first. This should work for
|
|
* non dirty unmapped page cache pages.
|
|
*/
|
|
ret = invalidate_inode_page(page);
|
|
unlock_page(page);
|
|
/*
|
|
* RED-PEN would be better to keep it isolated here, but we
|
|
* would need to fix isolation locking first.
|
|
*/
|
|
if (ret == 1) {
|
|
put_hwpoison_page(page);
|
|
pr_info("soft_offline: %#lx: invalidated\n", pfn);
|
|
SetPageHWPoison(page);
|
|
num_poisoned_pages_inc();
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Simple invalidation didn't work.
|
|
* Try to migrate to a new page instead. migrate.c
|
|
* handles a large number of cases for us.
|
|
*/
|
|
ret = isolate_lru_page(page);
|
|
/*
|
|
* Drop page reference which is came from get_any_page()
|
|
* successful isolate_lru_page() already took another one.
|
|
*/
|
|
put_hwpoison_page(page);
|
|
if (!ret) {
|
|
LIST_HEAD(pagelist);
|
|
inc_zone_page_state(page, NR_ISOLATED_ANON +
|
|
page_is_file_cache(page));
|
|
list_add(&page->lru, &pagelist);
|
|
ret = migrate_pages(&pagelist, new_page, NULL, MPOL_MF_MOVE_ALL,
|
|
MIGRATE_SYNC, MR_MEMORY_FAILURE);
|
|
if (ret) {
|
|
if (!list_empty(&pagelist)) {
|
|
list_del(&page->lru);
|
|
dec_zone_page_state(page, NR_ISOLATED_ANON +
|
|
page_is_file_cache(page));
|
|
putback_lru_page(page);
|
|
}
|
|
|
|
pr_info("soft offline: %#lx: migration failed %d, type %lx\n",
|
|
pfn, ret, page->flags);
|
|
if (ret > 0)
|
|
ret = -EIO;
|
|
}
|
|
} else {
|
|
pr_info("soft offline: %#lx: isolation failed: %d, page count %d, type %lx\n",
|
|
pfn, ret, page_count(page), page->flags);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* soft_offline_page - Soft offline a page.
|
|
* @page: page to offline
|
|
* @flags: flags. Same as memory_failure().
|
|
*
|
|
* Returns 0 on success, otherwise negated errno.
|
|
*
|
|
* Soft offline a page, by migration or invalidation,
|
|
* without killing anything. This is for the case when
|
|
* a page is not corrupted yet (so it's still valid to access),
|
|
* but has had a number of corrected errors and is better taken
|
|
* out.
|
|
*
|
|
* The actual policy on when to do that is maintained by
|
|
* user space.
|
|
*
|
|
* This should never impact any application or cause data loss,
|
|
* however it might take some time.
|
|
*
|
|
* This is not a 100% solution for all memory, but tries to be
|
|
* ``good enough'' for the majority of memory.
|
|
*/
|
|
int soft_offline_page(struct page *page, int flags)
|
|
{
|
|
int ret;
|
|
unsigned long pfn = page_to_pfn(page);
|
|
struct page *hpage = compound_head(page);
|
|
|
|
if (PageHWPoison(page)) {
|
|
pr_info("soft offline: %#lx page already poisoned\n", pfn);
|
|
if (flags & MF_COUNT_INCREASED)
|
|
put_hwpoison_page(page);
|
|
return -EBUSY;
|
|
}
|
|
if (!PageHuge(page) && PageTransHuge(hpage)) {
|
|
if (PageAnon(hpage) && unlikely(split_huge_page(hpage))) {
|
|
pr_info("soft offline: %#lx: failed to split THP\n",
|
|
pfn);
|
|
if (flags & MF_COUNT_INCREASED)
|
|
put_hwpoison_page(page);
|
|
return -EBUSY;
|
|
}
|
|
}
|
|
|
|
get_online_mems();
|
|
|
|
ret = get_any_page(page, pfn, flags);
|
|
put_online_mems();
|
|
if (ret > 0) { /* for in-use pages */
|
|
if (PageHuge(page))
|
|
ret = soft_offline_huge_page(page, flags);
|
|
else
|
|
ret = __soft_offline_page(page, flags);
|
|
} else if (ret == 0) { /* for free pages */
|
|
if (PageHuge(page)) {
|
|
set_page_hwpoison_huge_page(hpage);
|
|
if (!dequeue_hwpoisoned_huge_page(hpage))
|
|
num_poisoned_pages_add(1 << compound_order(hpage));
|
|
} else {
|
|
if (!TestSetPageHWPoison(page))
|
|
num_poisoned_pages_inc();
|
|
}
|
|
}
|
|
return ret;
|
|
}
|