+ mm-hwpoison-avoid-the-impact-of-hwpoison_filter-return-value-on-mce-handler.patch added to -mm tree

+ mm-hwpoison-avoid-the-impact-of-hwpoison_filter-return-value-on-mce-handler.patch added to -mm tree

[Andrew Morton]

The patch titled
     Subject: mm/hwpoison: avoid the impact of hwpoison_filter() return value on mce handler
has been added to the -mm tree.  Its filename is
     mm-hwpoison-avoid-the-impact-of-hwpoison_filter-return-value-on-mce-handler.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-hwpoison-avoid-the-impact-of-hwpoison_filter-return-value-on-mce-handler.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-hwpoison-avoid-the-impact-of-hwpoison_filter-return-value-on-mce-handler.patch

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next and is updated
there every 3-4 working days

------------------------------------------------------
From: luofei <luofei@unicloud.com>
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 value(-EHWPOISON), 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 a new MF_MCE_HANDLE flag is introduced to identify the call from the
mce handler and instruct hwpoison_filter() to return -EHWPOISON, otherwise
return 0 for compatibility with the hwpoison injector.

Link: https://lkml.kernel.org/r/20220221021415.2328992-1-luofei@unicloud.com
Signed-off-by: luofei <luofei@unicloud.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Fei Luo <luofei@unicloud.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/x86/kernel/cpu/mce/core.c |   15 +++++++++------
 include/linux/mm.h             |    1 +
 mm/memory-failure.c            |   14 ++++++++++++--
 3 files changed, 22 insertions(+), 8 deletions(-)

--- 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
@@ -612,7 +612,7 @@ static int uc_decode_notifier(struct not
 		return NOTIFY_DONE;
 
 	pfn = mce->addr >> PAGE_SHIFT;
-	if (!memory_failure(pfn, 0)) {
+	if (!memory_failure(pfn, MF_MCE_HANDLE)) {
 		set_mce_nospec(pfn, whole_page(mce));
 		mce->kflags |= MCE_HANDLED_UC;
 	}
@@ -1286,7 +1286,7 @@ static void kill_me_now(struct callback_
 static void kill_me_maybe(struct callback_head *cb)
 {
 	struct task_struct *p = container_of(cb, struct task_struct, mce_kill_me);
-	int flags = MF_ACTION_REQUIRED;
+	int flags = MF_ACTION_REQUIRED | MF_MCE_HANDLE;
 	int ret;
 
 	p->mce_count = 0;
@@ -1303,9 +1303,12 @@ 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.
+	 * -EHWPOISON from memory_failure() means that memory_failure() did
+	 * not handle the error event for the following reason:
+	 *  - SIGBUS has already been sent to the current process with the
+	 *    proper error info, or
+	 *  - hwpoison_filter() filtered the event,
+	 * so no need to deal with it more.
 	 */
 	if (ret == -EHWPOISON)
 		return;
@@ -1320,7 +1323,7 @@ static void kill_me_never(struct callbac
 
 	p->mce_count = 0;
 	pr_err("Kernel accessed poison in user space at %llx\n", p->mce_addr);
-	if (!memory_failure(p->mce_addr >> PAGE_SHIFT, 0))
+	if (!memory_failure(p->mce_addr >> PAGE_SHIFT, MF_MCE_HANDLE))
 		set_mce_nospec(p->mce_addr >> PAGE_SHIFT, p->mce_whole_page);
 }
 
--- a/include/linux/mm.h~mm-hwpoison-avoid-the-impact-of-hwpoison_filter-return-value-on-mce-handler
+++ a/include/linux/mm.h
@@ -3173,6 +3173,7 @@ enum mf_flags {
 	MF_MUST_KILL = 1 << 2,
 	MF_SOFT_OFFLINE = 1 << 3,
 	MF_UNPOISON = 1 << 4,
+	MF_MCE_HANDLE = 1 << 5,
 };
 extern int memory_failure(unsigned long pfn, int flags);
 extern void memory_failure_queue(unsigned long pfn, int flags);
--- 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 +1515,10 @@ static int memory_failure_hugetlb(unsign
 				if (TestClearPageHWPoison(head))
 					num_poisoned_pages_dec();
 				unlock_page(head);
-				return 0;
+				if (flags & MF_MCE_HANDLE)
+					return -EHWPOISON;
+				else
+					return 0;
 			}
 			unlock_page(head);
 			res = MF_FAILED;
@@ -1602,7 +1605,10 @@ static int memory_failure_dev_pagemap(un
 		goto out;
 
 	if (hwpoison_filter(page)) {
-		rc = 0;
+		if (flags & MF_MCE_HANDLE)
+			rc = -EHWPOISON;
+		else
+			rc = 0;
 		goto unlock;
 	}
 
@@ -1830,6 +1836,10 @@ try_again:
 			num_poisoned_pages_dec();
 		unlock_page(p);
 		put_page(p);
+		if (flags & MF_MCE_HANDLE)
+			res = -EHWPOISON;
+		else
+			res = 0;
 		goto unlock_mutex;
 	}
 
_

Patches currently in -mm which might be from luofei@unicloud.com are

mm-hwpoison-avoid-the-impact-of-hwpoison_filter-return-value-on-mce-handler.patch
mm-hwpoison-add-in-use-hugepage-hwpoison-filter-judgement.patch

Re: + mm-hwpoison-avoid-the-impact-of-hwpoison_filter-return-value-on-mce-handler.patch added to -mm tree

[Borislav Petkov]

On Mon, Feb 21, 2022 at 07:48:20PM -0800, Andrew Morton wrote:
> The patch titled
>      Subject: mm/hwpoison: avoid the impact of hwpoison_filter() return value on mce handler
> has been added to the -mm tree.  Its filename is
>      mm-hwpoison-avoid-the-impact-of-hwpoison_filter-return-value-on-mce-handler.patch

Andrew, please drop this patch from your queue. Review below:

> From: luofei <luofei@unicloud.com>
> 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 value(-EHWPOISON), 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 a new MF_MCE_HANDLE flag is introduced to identify the call from the
> mce handler and instruct hwpoison_filter() to return -EHWPOISON, otherwise
> return 0 for compatibility with the hwpoison injector.
> 
> Link: https://lkml.kernel.org/r/20220221021415.2328992-1-luofei@unicloud.com
> Signed-off-by: luofei <luofei@unicloud.com>
> Cc: Tony Luck <tony.luck@intel.com>
> Cc: Borislav Petkov <bp@alien8.de>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Dave Hansen <dave.hansen@linux.intel.com>
> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
> Cc: H. Peter Anvin <hpa@zytor.com>
> Cc: Fei Luo <luofei@unicloud.com>
> Cc: Miaohe Lin <linmiaohe@huawei.com>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
> 
>  arch/x86/kernel/cpu/mce/core.c |   15 +++++++++------
>  include/linux/mm.h             |    1 +
>  mm/memory-failure.c            |   14 ++++++++++++--
>  3 files changed, 22 insertions(+), 8 deletions(-)
> 
> --- 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
> @@ -612,7 +612,7 @@ static int uc_decode_notifier(struct not
>  		return NOTIFY_DONE;
>  
>  	pfn = mce->addr >> PAGE_SHIFT;
> -	if (!memory_failure(pfn, 0)) {
> +	if (!memory_failure(pfn, MF_MCE_HANDLE)) {
>  		set_mce_nospec(pfn, whole_page(mce));
>  		mce->kflags |= MCE_HANDLED_UC;
>  	}
> @@ -1286,7 +1286,7 @@ static void kill_me_now(struct callback_
>  static void kill_me_maybe(struct callback_head *cb)
>  {
>  	struct task_struct *p = container_of(cb, struct task_struct, mce_kill_me);
> -	int flags = MF_ACTION_REQUIRED;
> +	int flags = MF_ACTION_REQUIRED | MF_MCE_HANDLE;
>  	int ret;
>  
>  	p->mce_count = 0;
> @@ -1303,9 +1303,12 @@ 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.
> +	 * -EHWPOISON from memory_failure() means that memory_failure() did
> +	 * not handle the error event for the following reason:
> +	 *  - SIGBUS has already been sent to the current process with the
> +	 *    proper error info, or
> +	 *  - hwpoison_filter() filtered the event,
> +	 * so no need to deal with it more.

So you're overloading what we do for -EHWPOISON because it is just fits?

The right way to do this is to return a *distinct* error value which
means "ignore this error" and the MCE code can then ignore it.

> --- a/include/linux/mm.h~mm-hwpoison-avoid-the-impact-of-hwpoison_filter-return-value-on-mce-handler
> +++ a/include/linux/mm.h
> @@ -3173,6 +3173,7 @@ enum mf_flags {
>  	MF_MUST_KILL = 1 << 2,
>  	MF_SOFT_OFFLINE = 1 << 3,
>  	MF_UNPOISON = 1 << 4,
> +	MF_MCE_HANDLE = 1 << 5,

This thing is too x86-specific and means nothing for other arches which
use memory_failure().

And I don't like this jumping through hoops one bit:

MCE code sets MF_MCE_HANDLE to tell the memory failure code to return a
special error which it does and then the MCE code again looks looks at
that special error. That's just nuts.

As said above, all you wanna do is have memory_failure() return a
distinct error value which says "ignore this error and don't do any
further processing". Without a new MF flag.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

+ mm-hwpoison-avoid-the-impact-of-hwpoison_filter-return-value-on-mce-handler.patch added to -mm tree

[Andrew Morton]

The patch titled
     Subject: mm/hwpoison: avoid the impact of hwpoison_filter() return value on mce handler
has been added to the -mm tree.  Its filename is
     mm-hwpoison-avoid-the-impact-of-hwpoison_filter-return-value-on-mce-handler.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-hwpoison-avoid-the-impact-of-hwpoison_filter-return-value-on-mce-handler.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-hwpoison-avoid-the-impact-of-hwpoison_filter-return-value-on-mce-handler.patch

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next and is updated
there every 3-4 working days

------------------------------------------------------
From: luofei <luofei@unicloud.com>
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 value(-EHWPOISON), 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 a new MF_MCE_HANDLE flag is introduced to identify the call from the
mce handler and instruct hwpoison_filter() to return -EHWPOISON, otherwise
return 0 for compatibility with the hwpoison injector.

Link: https://lkml.kernel.org/r/20220221021415.2328992-1-luofei@unicloud.com
Signed-off-by: luofei <luofei@unicloud.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/x86/kernel/cpu/mce/core.c |   15 +++++++++------
 include/linux/mm.h             |    1 +
 mm/memory-failure.c            |   14 ++++++++++++--
 3 files changed, 22 insertions(+), 8 deletions(-)

--- 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
@@ -612,7 +612,7 @@ static int uc_decode_notifier(struct not
 		return NOTIFY_DONE;
 
 	pfn = mce->addr >> PAGE_SHIFT;
-	if (!memory_failure(pfn, 0)) {
+	if (!memory_failure(pfn, MF_MCE_HANDLE)) {
 		set_mce_nospec(pfn, whole_page(mce));
 		mce->kflags |= MCE_HANDLED_UC;
 	}
@@ -1286,7 +1286,7 @@ static void kill_me_now(struct callback_
 static void kill_me_maybe(struct callback_head *cb)
 {
 	struct task_struct *p = container_of(cb, struct task_struct, mce_kill_me);
-	int flags = MF_ACTION_REQUIRED;
+	int flags = MF_ACTION_REQUIRED | MF_MCE_HANDLE;
 	int ret;
 
 	p->mce_count = 0;
@@ -1303,9 +1303,12 @@ 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.
+	 * -EHWPOISON from memory_failure() means that memory_failure() did
+	 * not handle the error event for the following reason:
+	 *  - SIGBUS has already been sent to the current process with the
+	 *    proper error info, or
+	 *  - hwpoison_filter() filtered the event,
+	 * so no need to deal with it more.
 	 */
 	if (ret == -EHWPOISON)
 		return;
@@ -1320,7 +1323,7 @@ static void kill_me_never(struct callbac
 
 	p->mce_count = 0;
 	pr_err("Kernel accessed poison in user space at %llx\n", p->mce_addr);
-	if (!memory_failure(p->mce_addr >> PAGE_SHIFT, 0))
+	if (!memory_failure(p->mce_addr >> PAGE_SHIFT, MF_MCE_HANDLE))
 		set_mce_nospec(p->mce_addr >> PAGE_SHIFT, p->mce_whole_page);
 }
 
--- a/include/linux/mm.h~mm-hwpoison-avoid-the-impact-of-hwpoison_filter-return-value-on-mce-handler
+++ a/include/linux/mm.h
@@ -3177,6 +3177,7 @@ enum mf_flags {
 	MF_MUST_KILL = 1 << 2,
 	MF_SOFT_OFFLINE = 1 << 3,
 	MF_UNPOISON = 1 << 4,
+	MF_MCE_HANDLE = 1 << 5,
 };
 extern int memory_failure(unsigned long pfn, int flags);
 extern void memory_failure_queue(unsigned long pfn, int flags);
--- 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 +1515,10 @@ static int memory_failure_hugetlb(unsign
 				if (TestClearPageHWPoison(head))
 					num_poisoned_pages_dec();
 				unlock_page(head);
-				return 0;
+				if (flags & MF_MCE_HANDLE)
+					return -EHWPOISON;
+				else
+					return 0;
 			}
 			unlock_page(head);
 			res = MF_FAILED;
@@ -1602,7 +1605,10 @@ static int memory_failure_dev_pagemap(un
 		goto out;
 
 	if (hwpoison_filter(page)) {
-		rc = 0;
+		if (flags & MF_MCE_HANDLE)
+			rc = -EHWPOISON;
+		else
+			rc = 0;
 		goto unlock;
 	}
 
@@ -1836,6 +1842,10 @@ try_again:
 			num_poisoned_pages_dec();
 		unlock_page(p);
 		put_page(p);
+		if (flags & MF_MCE_HANDLE)
+			res = -EHWPOISON;
+		else
+			res = 0;
 		goto unlock_mutex;
 	}
 
_

Patches currently in -mm which might be from luofei@unicloud.com are

mm-hwpoison-avoid-the-impact-of-hwpoison_filter-return-value-on-mce-handler.patch
mm-hwpoison-add-in-use-hugepage-hwpoison-filter-judgement.patch

+ mm-hwpoison-avoid-the-impact-of-hwpoison_filter-return-value-on-mce-handler.patch added to -mm tree

[Andrew Morton]

The patch titled
     Subject: mm/hwpoison: avoid the impact of hwpoison_filter() return value on mce handler
has been added to the -mm tree.  Its filename is
     mm-hwpoison-avoid-the-impact-of-hwpoison_filter-return-value-on-mce-handler.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-hwpoison-avoid-the-impact-of-hwpoison_filter-return-value-on-mce-handler.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-hwpoison-avoid-the-impact-of-hwpoison_filter-return-value-on-mce-handler.patch

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next and is updated
there every 3-4 working days

------------------------------------------------------
From: luofei <luofei@unicloud.com>
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/20220223082135.2769649-1-luofei@unicloud.com
Signed-off-by: luofei <luofei@unicloud.com>
Acked-by: Borislav Petkov <bp@suse.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 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(-)

--- 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;
 	}
 
_

Patches currently in -mm which might be from luofei@unicloud.com are

mm-hwpoison-avoid-the-impact-of-hwpoison_filter-return-value-on-mce-handler.patch
mm-hwpoison-add-in-use-hugepage-hwpoison-filter-judgement.patch