mm/memory-failure: disable unpoison once hw error happens

Currently unpoison_memory(unsigned long pfn) is designed for soft
poison(hwpoison-inject) only.  Since 17fae1294ad9d, the KPTE gets cleared
on a x86 platform once hardware memory corrupts.

Unpoisoning a hardware corrupted page puts page back buddy only, the
kernel has a chance to access the page with *NOT PRESENT* KPTE.  This
leads BUG during accessing on the corrupted KPTE.

Suggested by David&Naoya, disable unpoison mechanism when a real HW error
happens to avoid BUG like this:

 Unpoison: Software-unpoisoned page 0x61234
 BUG: unable to handle page fault for address: ffff888061234000
 #PF: supervisor write access in kernel mode
 #PF: error_code(0x0002) - not-present page
 PGD 2c01067 P4D 2c01067 PUD 107267063 PMD 10382b063 PTE 800fffff9edcb062
 Oops: 0002 [#1] PREEMPT SMP NOPTI
 CPU: 4 PID: 26551 Comm: stress Kdump: loaded Tainted: G   M       OE     5.18.0.bm.1-amd64 #7
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) ...
 RIP: 0010:clear_page_erms+0x7/0x10
 Code: ...
 RSP: 0000:ffffc90001107bc8 EFLAGS: 00010246
 RAX: 0000000000000000 RBX: 0000000000000901 RCX: 0000000000001000
 RDX: ffffea0001848d00 RSI: ffffea0001848d40 RDI: ffff888061234000
 RBP: ffffea0001848d00 R08: 0000000000000901 R09: 0000000000001276
 R10: 0000000000000003 R11: 0000000000000000 R12: 0000000000000001
 R13: 0000000000000000 R14: 0000000000140dca R15: 0000000000000001
 FS:  00007fd8b2333740(0000) GS:ffff88813fd00000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: ffff888061234000 CR3: 00000001023d2005 CR4: 0000000000770ee0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
 PKRU: 55555554
 Call Trace:
  <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: 847ce401df392 ("HWPOISON: Add unpoisoning support")
Fixes: 17fae1294ad9d ("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>

diff --git a/Documentation/vm/hwpoison.rst b/Documentation/vm/hwpoison.rst
index c742de1..b9d5253 100644 (file)
--- a/Documentation/vm/hwpoison.rst
+++ b/Documentation/vm/hwpoison.rst
@@ -120,7 +120,8 @@ Testing
   unpoison-pfn
        Software-unpoison page at PFN echoed into this file. This way
        a page can be reused again.  This only works for Linux
-       injected failures, not for real memory failures.
+       injected failures, not for real memory failures. Once any hardware
+       memory failure happens, this feature is disabled.
 
   Note these injection interfaces are not stable and might change between
   kernel versions

diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 084d67f..bc60c9c 100644 (file)
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -558,7 +558,7 @@ static ssize_t hard_offline_page_store(struct device *dev,
        if (kstrtoull(buf, 0, &pfn) < 0)
                return -EINVAL;
        pfn >>= PAGE_SHIFT;
-       ret = memory_failure(pfn, 0);
+       ret = memory_failure(pfn, MF_SW_SIMULATED);
        if (ret == -EOPNOTSUPP)
                ret = 0;
        return ret ? ret : count;

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 781fae1..cf3d0d6 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3232,6 +3232,7 @@ enum mf_flags {
        MF_MUST_KILL = 1 << 2,
        MF_SOFT_OFFLINE = 1 << 3,
        MF_UNPOISON = 1 << 4,
+       MF_SW_SIMULATED = 1 << 5,
 };
 extern int memory_failure(unsigned long pfn, int flags);
 extern void memory_failure_queue(unsigned long pfn, int flags);

diff --git a/mm/hwpoison-inject.c b/mm/hwpoison-inject.c
index 5c0cddd..65e242b 100644 (file)
--- a/mm/hwpoison-inject.c
+++ b/mm/hwpoison-inject.c
@@ -48,7 +48,7 @@ static int hwpoison_inject(void *data, u64 val)
 
 inject:
        pr_info("Injecting memory failure at pfn %#lx\n", pfn);
-       err = memory_failure(pfn, 0);
+       err = memory_failure(pfn, MF_SW_SIMULATED);
        return (err == -EOPNOTSUPP) ? 0 : err;
 }
 

diff --git a/mm/madvise.c b/mm/madvise.c
index d7b4f26..0316bbc 100644 (file)
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -1112,7 +1112,7 @@ static int madvise_inject_error(int behavior,
                } else {
                        pr_info("Injecting memory failure for pfn %#lx at process virtual address %#lx\n",
                                 pfn, start);
-                       ret = memory_failure(pfn, MF_COUNT_INCREASED);
+                       ret = memory_failure(pfn, MF_COUNT_INCREASED | MF_SW_SIMULATED);
                        if (ret == -EOPNOTSUPP)
                                ret = 0;
                }

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index b85661c..da39ec8 100644 (file)
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -69,6 +69,8 @@ int sysctl_memory_failure_recovery __read_mostly = 1;
 
 atomic_long_t num_poisoned_pages __read_mostly = ATOMIC_LONG_INIT(0);
 
+static bool hw_memory_failure __read_mostly = false;
+
 static bool __page_handle_poison(struct page *page)
 {
        int ret;
@@ -1768,6 +1770,9 @@ int memory_failure(unsigned long pfn, int flags)
 
        mutex_lock(&mf_mutex);
 
+       if (!(flags & MF_SW_SIMULATED))
+               hw_memory_failure = true;
+
        p = pfn_to_online_page(pfn);
        if (!p) {
                res = arch_memory_failure(pfn, flags);
@@ -2103,6 +2108,13 @@ int unpoison_memory(unsigned long pfn)
 
        mutex_lock(&mf_mutex);
 
+       if (hw_memory_failure) {
+               unpoison_pr_info("Unpoison: Disabled after HW memory failure %#lx\n",
+                                pfn, &unpoison_rs);
+               ret = -EOPNOTSUPP;
+               goto unlock_mutex;
+       }
+
        if (!PageHWPoison(p)) {
                unpoison_pr_info("Unpoison: Page was already unpoisoned %#lx\n",
                                 pfn, &unpoison_rs);