[121/227] mm/hwpoison: avoid the impact of hwpoison_filter() return value on mce handler

Commit Message

Andrew Morton March 22, 2022, 9:44 p.m. UTC

From: luofei <[e-mail]>
Subject: mm/hwpoison: avoid the impact of hwpoison_filter() return value on mce handler

When the hwpoison page meets the filter conditions, it should not be
regarded as successful memory_failure() processing for mce handler, but
should return a distinct value, otherwise mce handler regards the error
page has been identified and isolated, which may lead to calling
set_mce_nospec() to change page attribute, etc.

Here memory_failure() return -EOPNOTSUPP to indicate that the error event
is filtered, mce handler should not take any action for this situation and
hwpoison injector should treat as correct.

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: luofei <[e-mail]>
Acked-by: Borislav Petkov <[e-mail]>
Cc: Dave Hansen <[e-mail]>
Cc: H. Peter Anvin <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Miaohe Lin <[e-mail]>
Cc: Naoya Horiguchi <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: Tony Luck <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 arch/x86/kernel/cpu/mce/core.c |    8 +++++---
 drivers/base/memory.c          |    2 ++
 mm/hwpoison-inject.c           |    3 ++-
 mm/madvise.c                   |    2 ++
 mm/memory-failure.c            |    9 +++++++--
 5 files changed, 18 insertions(+), 6 deletions(-)

Patch

--- a/arch/x86/kernel/cpu/mce/core.c~mm-hwpoison-avoid-the-impact-of-hwpoison_filter-return-value-on-mce-handler
+++ a/arch/x86/kernel/cpu/mce/core.c
@@ -1304,10 +1304,12 @@  static void kill_me_maybe(struct callbac
 
 	/*
 	 * -EHWPOISON from memory_failure() means that it already sent SIGBUS
-	 * to the current process with the proper error info, so no need to
-	 * send SIGBUS here again.
+	 * to the current process with the proper error info,
+	 * -EOPNOTSUPP means hwpoison_filter() filtered the error event,
+	 *
+	 * In both cases, no further processing is required.
 	 */
-	if (ret == -EHWPOISON)
+	if (ret == -EHWPOISON || ret == -EOPNOTSUPP)
 		return;
 
 	pr_err("Memory error not recovered");
--- a/drivers/base/memory.c~mm-hwpoison-avoid-the-impact-of-hwpoison_filter-return-value-on-mce-handler
+++ a/drivers/base/memory.c
@@ -555,6 +555,8 @@  static ssize_t hard_offline_page_store(s
 		return -EINVAL;
 	pfn >>= PAGE_SHIFT;
 	ret = memory_failure(pfn, 0);
+	if (ret == -EOPNOTSUPP)
+		ret = 0;
 	return ret ? ret : count;
 }
 
--- a/mm/hwpoison-inject.c~mm-hwpoison-avoid-the-impact-of-hwpoison_filter-return-value-on-mce-handler
+++ a/mm/hwpoison-inject.c
@@ -48,7 +48,8 @@  static int hwpoison_inject(void *data, u
 
 inject:
 	pr_info("Injecting memory failure at pfn %#lx\n", pfn);
-	return memory_failure(pfn, 0);
+	err = memory_failure(pfn, 0);
+	return (err == -EOPNOTSUPP) ? 0 : err;
 }
 
 static int hwpoison_unpoison(void *data, u64 val)
--- a/mm/madvise.c~mm-hwpoison-avoid-the-impact-of-hwpoison_filter-return-value-on-mce-handler
+++ a/mm/madvise.c
@@ -1067,6 +1067,8 @@  static int madvise_inject_error(int beha
 			pr_info("Injecting memory failure for pfn %#lx at process virtual address %#lx\n",
 				 pfn, start);
 			ret = memory_failure(pfn, MF_COUNT_INCREASED);
+			if (ret == -EOPNOTSUPP)
+				ret = 0;
 		}
 
 		if (ret)
--- a/mm/memory-failure.c~mm-hwpoison-avoid-the-impact-of-hwpoison_filter-return-value-on-mce-handler
+++ a/mm/memory-failure.c
@@ -1515,7 +1515,7 @@  static int memory_failure_hugetlb(unsign
 				if (TestClearPageHWPoison(head))
 					num_poisoned_pages_dec();
 				unlock_page(head);
-				return 0;
+				return -EOPNOTSUPP;
 			}
 			unlock_page(head);
 			res = MF_FAILED;
@@ -1602,7 +1602,7 @@  static int memory_failure_dev_pagemap(un
 		goto out;
 
 	if (hwpoison_filter(page)) {
-		rc = 0;
+		rc = -EOPNOTSUPP;
 		goto unlock;
 	}
 
@@ -1671,6 +1671,10 @@  static DEFINE_MUTEX(mf_mutex);
  *
  * Must run in process context (e.g. a work queue) with interrupts
  * enabled and no spinlocks hold.
+ *
+ * Return: 0 for successfully handled the memory error,
+ *         -EOPNOTSUPP for memory_filter() filtered the error event,
+ *         < 0(except -EOPNOTSUPP) on failure.
  */
 int memory_failure(unsigned long pfn, int flags)
 {
@@ -1836,6 +1840,7 @@  try_again:
 			num_poisoned_pages_dec();
 		unlock_page(p);
 		put_page(p);
+		res = -EOPNOTSUPP;
 		goto unlock_mutex;
 	}