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67f22ba775
Currently unpoison_memory(unsigned long pfn) is designed for soft poison(hwpoison-inject) only. Since17fae1294a, the KPTE gets cleared on a x86 platform once hardware memory corrupts. Unpoisoning a hardware corrupted page puts page back buddy only, the kernel has a chance to access the page with *NOT PRESENT* KPTE. This leads BUG during accessing on the corrupted KPTE. Suggested by David&Naoya, disable unpoison mechanism when a real HW error happens to avoid BUG like this: Unpoison: Software-unpoisoned page 0x61234 BUG: unable to handle page fault for address: ffff888061234000 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 2c01067 P4D 2c01067 PUD 107267063 PMD 10382b063 PTE 800fffff9edcb062 Oops: 0002 [#1] PREEMPT SMP NOPTI CPU: 4 PID: 26551 Comm: stress Kdump: loaded Tainted: G M OE 5.18.0.bm.1-amd64 #7 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) ... RIP: 0010:clear_page_erms+0x7/0x10 Code: ... RSP: 0000:ffffc90001107bc8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000901 RCX: 0000000000001000 RDX: ffffea0001848d00 RSI: ffffea0001848d40 RDI: ffff888061234000 RBP: ffffea0001848d00 R08: 0000000000000901 R09: 0000000000001276 R10: 0000000000000003 R11: 0000000000000000 R12: 0000000000000001 R13: 0000000000000000 R14: 0000000000140dca R15: 0000000000000001 FS: 00007fd8b2333740(0000) GS:ffff88813fd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff888061234000 CR3: 00000001023d2005 CR4: 0000000000770ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: <TASK> prep_new_page+0x151/0x170 get_page_from_freelist+0xca0/0xe20 ? sysvec_apic_timer_interrupt+0xab/0xc0 ? asm_sysvec_apic_timer_interrupt+0x1b/0x20 __alloc_pages+0x17e/0x340 __folio_alloc+0x17/0x40 vma_alloc_folio+0x84/0x280 __handle_mm_fault+0x8d4/0xeb0 handle_mm_fault+0xd5/0x2a0 do_user_addr_fault+0x1d0/0x680 ? kvm_read_and_reset_apf_flags+0x3b/0x50 exc_page_fault+0x78/0x170 asm_exc_page_fault+0x27/0x30 Link: https://lkml.kernel.org/r/20220615093209.259374-2-pizhenwei@bytedance.com Fixes:847ce401df("HWPOISON: Add unpoisoning support") Fixes:17fae1294a("x86/{mce,mm}: Unmap the entire page if the whole page is affected and poisoned") Signed-off-by: zhenwei pi <pizhenwei@bytedance.com> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: <stable@vger.kernel.org> [5.8+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
113 lines
2.7 KiB
C
113 lines
2.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/* Inject a hwpoison memory failure on a arbitrary pfn */
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#include <linux/module.h>
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#include <linux/debugfs.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/swap.h>
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#include <linux/pagemap.h>
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#include <linux/hugetlb.h>
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#include "internal.h"
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static struct dentry *hwpoison_dir;
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static int hwpoison_inject(void *data, u64 val)
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{
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unsigned long pfn = val;
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struct page *p;
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struct page *hpage;
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int err;
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if (!capable(CAP_SYS_ADMIN))
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return -EPERM;
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if (!pfn_valid(pfn))
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return -ENXIO;
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p = pfn_to_page(pfn);
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hpage = compound_head(p);
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if (!hwpoison_filter_enable)
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goto inject;
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shake_page(hpage);
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/*
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* This implies unable to support non-LRU pages except free page.
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*/
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if (!PageLRU(hpage) && !PageHuge(p) && !is_free_buddy_page(p))
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return 0;
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/*
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* do a racy check to make sure PG_hwpoison will only be set for
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* the targeted owner (or on a free page).
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* memory_failure() will redo the check reliably inside page lock.
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*/
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err = hwpoison_filter(hpage);
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if (err)
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return 0;
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inject:
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pr_info("Injecting memory failure at pfn %#lx\n", pfn);
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err = memory_failure(pfn, MF_SW_SIMULATED);
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return (err == -EOPNOTSUPP) ? 0 : err;
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}
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static int hwpoison_unpoison(void *data, u64 val)
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{
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if (!capable(CAP_SYS_ADMIN))
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return -EPERM;
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return unpoison_memory(val);
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}
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DEFINE_DEBUGFS_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n");
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DEFINE_DEBUGFS_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n");
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static void pfn_inject_exit(void)
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{
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hwpoison_filter_enable = 0;
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debugfs_remove_recursive(hwpoison_dir);
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}
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static int pfn_inject_init(void)
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{
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hwpoison_dir = debugfs_create_dir("hwpoison", NULL);
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/*
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* Note that the below poison/unpoison interfaces do not involve
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* hardware status change, hence do not require hardware support.
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* They are mainly for testing hwpoison in software level.
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*/
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debugfs_create_file("corrupt-pfn", 0200, hwpoison_dir, NULL,
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&hwpoison_fops);
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debugfs_create_file("unpoison-pfn", 0200, hwpoison_dir, NULL,
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&unpoison_fops);
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debugfs_create_u32("corrupt-filter-enable", 0600, hwpoison_dir,
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&hwpoison_filter_enable);
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debugfs_create_u32("corrupt-filter-dev-major", 0600, hwpoison_dir,
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&hwpoison_filter_dev_major);
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debugfs_create_u32("corrupt-filter-dev-minor", 0600, hwpoison_dir,
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&hwpoison_filter_dev_minor);
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debugfs_create_u64("corrupt-filter-flags-mask", 0600, hwpoison_dir,
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&hwpoison_filter_flags_mask);
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debugfs_create_u64("corrupt-filter-flags-value", 0600, hwpoison_dir,
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&hwpoison_filter_flags_value);
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#ifdef CONFIG_MEMCG
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debugfs_create_u64("corrupt-filter-memcg", 0600, hwpoison_dir,
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&hwpoison_filter_memcg);
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#endif
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return 0;
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}
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module_init(pfn_inject_init);
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module_exit(pfn_inject_exit);
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MODULE_LICENSE("GPL");
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