mm: make mm->flags a bitmap and 64-bit on all arches

[PATCH 07/10] mm: correct sign-extension issue in MMF_* flag masks

Posted by Lorenzo Stoakes 1 month, 3 weeks ago

There is an issue with the mask declarations in linux/mm_types.h, which
naively do (1 << bit) operations. Unfortunately this results in the 1 being
defaulted as a signed (32-bit) integer.

When the compiler expands the MMF_INIT_MASK bitmask it comes up with:

(((1 << 2) - 1) | (((1 << 9) - 1) << 2) | (1 << 24) | (1 << 28) | (1 << 30)
| (1 << 31))

Which overflows the signed integer to -788,527,105. Implicitly casting this
to an unsigned integer results in sign-expansion, and thus this value
becomes 0xffffffffd10007ff, rather than the intended 0xd10007ff.

While we're limited to a maximum of 32 bits in mm->flags, this isn't an
issue as the remaining bits being masked will always be zero.

However, now we are moving towards having more bits in this flag, this
becomes an issue.

Simply resolve this by using the _BITUL() helper to cast the shifted value
to an unsigned long.

Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
---
 include/linux/mm_types.h | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 46d3fb8935c7..38b3fa927997 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -1756,7 +1756,7 @@ enum {
  * the modes are SUID_DUMP_* defined in linux/sched/coredump.h
  */
 #define MMF_DUMPABLE_BITS 2
-#define MMF_DUMPABLE_MASK ((1 << MMF_DUMPABLE_BITS) - 1)
+#define MMF_DUMPABLE_MASK (_BITUL(MMF_DUMPABLE_BITS) - 1)
 /* coredump filter bits */
 #define MMF_DUMP_ANON_PRIVATE	2
 #define MMF_DUMP_ANON_SHARED	3
@@ -1771,13 +1771,13 @@ enum {
 #define MMF_DUMP_FILTER_SHIFT	MMF_DUMPABLE_BITS
 #define MMF_DUMP_FILTER_BITS	9
 #define MMF_DUMP_FILTER_MASK \
-	(((1 << MMF_DUMP_FILTER_BITS) - 1) << MMF_DUMP_FILTER_SHIFT)
+	((_BITUL(MMF_DUMP_FILTER_BITS) - 1) << MMF_DUMP_FILTER_SHIFT)
 #define MMF_DUMP_FILTER_DEFAULT \
-	((1 << MMF_DUMP_ANON_PRIVATE) |	(1 << MMF_DUMP_ANON_SHARED) |\
-	 (1 << MMF_DUMP_HUGETLB_PRIVATE) | MMF_DUMP_MASK_DEFAULT_ELF)
+	(_BITUL(MMF_DUMP_ANON_PRIVATE) | _BITUL(MMF_DUMP_ANON_SHARED) | \
+	 _BITUL(MMF_DUMP_HUGETLB_PRIVATE) | MMF_DUMP_MASK_DEFAULT_ELF)
 
 #ifdef CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS
-# define MMF_DUMP_MASK_DEFAULT_ELF	(1 << MMF_DUMP_ELF_HEADERS)
+# define MMF_DUMP_MASK_DEFAULT_ELF	_BITUL(MMF_DUMP_ELF_HEADERS)
 #else
 # define MMF_DUMP_MASK_DEFAULT_ELF	0
 #endif
@@ -1797,7 +1797,7 @@ enum {
 #define MMF_UNSTABLE		22	/* mm is unstable for copy_from_user */
 #define MMF_HUGE_ZERO_FOLIO	23      /* mm has ever used the global huge zero folio */
 #define MMF_DISABLE_THP		24	/* disable THP for all VMAs */
-#define MMF_DISABLE_THP_MASK	(1 << MMF_DISABLE_THP)
+#define MMF_DISABLE_THP_MASK	_BITUL(MMF_DISABLE_THP)
 #define MMF_OOM_REAP_QUEUED	25	/* mm was queued for oom_reaper */
 #define MMF_MULTIPROCESS	26	/* mm is shared between processes */
 /*
@@ -1810,16 +1810,15 @@ enum {
 #define MMF_HAS_PINNED		27	/* FOLL_PIN has run, never cleared */
 
 #define MMF_HAS_MDWE		28
-#define MMF_HAS_MDWE_MASK	(1 << MMF_HAS_MDWE)
-
+#define MMF_HAS_MDWE_MASK	_BITUL(MMF_HAS_MDWE)
 
 #define MMF_HAS_MDWE_NO_INHERIT	29
 
 #define MMF_VM_MERGE_ANY	30
-#define MMF_VM_MERGE_ANY_MASK	(1 << MMF_VM_MERGE_ANY)
+#define MMF_VM_MERGE_ANY_MASK	_BITUL(MMF_VM_MERGE_ANY)
 
 #define MMF_TOPDOWN		31	/* mm searches top down by default */
-#define MMF_TOPDOWN_MASK	(1 << MMF_TOPDOWN)
+#define MMF_TOPDOWN_MASK	_BITUL(MMF_TOPDOWN)
 
 #define MMF_INIT_MASK		(MMF_DUMPABLE_MASK | MMF_DUMP_FILTER_MASK |\
 				 MMF_DISABLE_THP_MASK | MMF_HAS_MDWE_MASK |\
-- 
2.50.1

Re: [PATCH 07/10] mm: correct sign-extension issue in MMF_* flag masks

Posted by Lorenzo Stoakes 1 month, 1 week ago

Hi Andrew,

Quick fix-patch to use BIT() in favour of _BITUL() as requested by David,
since this is a far more sensible way of generating a bitmask.

Thanks, Lorenzo

----8<----
From 83a10e3fe7dbbc7ab7c04312fff32b28787acf9b Mon Sep 17 00:00:00 2001
From: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Date: Tue, 26 Aug 2025 15:01:18 +0100
Subject: [PATCH] mm: prefer BIT() to _BITUL()

BIT() does the same thing, and is defined in actual linux headers rather
than a uapi header.

Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
---
 include/linux/mm_types.h | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 3affc6a9e279..c3d40fddfb60 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -1755,7 +1755,7 @@ enum {
  * the modes are SUID_DUMP_* defined in linux/sched/coredump.h
  */
 #define MMF_DUMPABLE_BITS 2
-#define MMF_DUMPABLE_MASK (_BITUL(MMF_DUMPABLE_BITS) - 1)
+#define MMF_DUMPABLE_MASK (BIT(MMF_DUMPABLE_BITS) - 1)
 /* coredump filter bits */
 #define MMF_DUMP_ANON_PRIVATE	2
 #define MMF_DUMP_ANON_SHARED	3
@@ -1770,13 +1770,13 @@ enum {
 #define MMF_DUMP_FILTER_SHIFT	MMF_DUMPABLE_BITS
 #define MMF_DUMP_FILTER_BITS	9
 #define MMF_DUMP_FILTER_MASK \
-	((_BITUL(MMF_DUMP_FILTER_BITS) - 1) << MMF_DUMP_FILTER_SHIFT)
+	((BIT(MMF_DUMP_FILTER_BITS) - 1) << MMF_DUMP_FILTER_SHIFT)
 #define MMF_DUMP_FILTER_DEFAULT \
-	(_BITUL(MMF_DUMP_ANON_PRIVATE) | _BITUL(MMF_DUMP_ANON_SHARED) | \
-	 _BITUL(MMF_DUMP_HUGETLB_PRIVATE) | MMF_DUMP_MASK_DEFAULT_ELF)
+	(BIT(MMF_DUMP_ANON_PRIVATE) | BIT(MMF_DUMP_ANON_SHARED) | \
+	 BIT(MMF_DUMP_HUGETLB_PRIVATE) | MMF_DUMP_MASK_DEFAULT_ELF)

 #ifdef CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS
-# define MMF_DUMP_MASK_DEFAULT_ELF	_BITUL(MMF_DUMP_ELF_HEADERS)
+# define MMF_DUMP_MASK_DEFAULT_ELF	BIT(MMF_DUMP_ELF_HEADERS)
 #else
 # define MMF_DUMP_MASK_DEFAULT_ELF	0
 #endif
@@ -1796,7 +1796,7 @@ enum {
 #define MMF_UNSTABLE		22	/* mm is unstable for copy_from_user */
 #define MMF_HUGE_ZERO_FOLIO	23      /* mm has ever used the global huge zero folio */
 #define MMF_DISABLE_THP		24	/* disable THP for all VMAs */
-#define MMF_DISABLE_THP_MASK	_BITUL(MMF_DISABLE_THP)
+#define MMF_DISABLE_THP_MASK	BIT(MMF_DISABLE_THP)
 #define MMF_OOM_REAP_QUEUED	25	/* mm was queued for oom_reaper */
 #define MMF_MULTIPROCESS	26	/* mm is shared between processes */
 /*
@@ -1809,15 +1809,15 @@ enum {
 #define MMF_HAS_PINNED		27	/* FOLL_PIN has run, never cleared */

 #define MMF_HAS_MDWE		28
-#define MMF_HAS_MDWE_MASK	_BITUL(MMF_HAS_MDWE)
+#define MMF_HAS_MDWE_MASK	BIT(MMF_HAS_MDWE)

 #define MMF_HAS_MDWE_NO_INHERIT	29

 #define MMF_VM_MERGE_ANY	30
-#define MMF_VM_MERGE_ANY_MASK	_BITUL(MMF_VM_MERGE_ANY)
+#define MMF_VM_MERGE_ANY_MASK	BIT(MMF_VM_MERGE_ANY)

 #define MMF_TOPDOWN		31	/* mm searches top down by default */
-#define MMF_TOPDOWN_MASK	_BITUL(MMF_TOPDOWN)
+#define MMF_TOPDOWN_MASK	BIT(MMF_TOPDOWN)

 #define MMF_INIT_MASK		(MMF_DUMPABLE_MASK | MMF_DUMP_FILTER_MASK |\
 				 MMF_DISABLE_THP_MASK | MMF_HAS_MDWE_MASK |\
--
2.50.1

Re: [PATCH 07/10] mm: correct sign-extension issue in MMF_* flag masks

Posted by David Hildenbrand 1 month, 1 week ago

On 12.08.25 17:44, Lorenzo Stoakes wrote:
> There is an issue with the mask declarations in linux/mm_types.h, which
> naively do (1 << bit) operations. Unfortunately this results in the 1 being
> defaulted as a signed (32-bit) integer.
> 
> When the compiler expands the MMF_INIT_MASK bitmask it comes up with:
> 
> (((1 << 2) - 1) | (((1 << 9) - 1) << 2) | (1 << 24) | (1 << 28) | (1 << 30)
> | (1 << 31))
> 
> Which overflows the signed integer to -788,527,105. Implicitly casting this
> to an unsigned integer results in sign-expansion, and thus this value
> becomes 0xffffffffd10007ff, rather than the intended 0xd10007ff.
> 
> While we're limited to a maximum of 32 bits in mm->flags, this isn't an
> issue as the remaining bits being masked will always be zero.
> 
> However, now we are moving towards having more bits in this flag, this
> becomes an issue.
> 
> Simply resolve this by using the _BITUL() helper to cast the shifted value
> to an unsigned long.

Hmm, I thought BIT() should be used and would just fine?

include/linux/bits.h includes <vdso/bits.h> where we have

#define BIT(nr)			(UL(1) << (nr))

In contrast, _BITUL is a uapi thingy from include/uapi/linux/const.h ...
as it seems.

$ git grep "_BITUL" -- include/linux/
include/linux/mm_types.h:#define MMF_DUMPABLE_MASK (_BITUL(MMF_DUMPABLE_BITS) - 1)
include/linux/mm_types.h:       ((_BITUL(MMF_DUMP_FILTER_BITS) - 1) << MMF_DUMP_FILTER_SHIFT)
include/linux/mm_types.h:       (_BITUL(MMF_DUMP_ANON_PRIVATE) | _BITUL(MMF_DUMP_ANON_SHARED) | \
include/linux/mm_types.h:        _BITUL(MMF_DUMP_HUGETLB_PRIVATE) | MMF_DUMP_MASK_DEFAULT_ELF)
include/linux/mm_types.h:# define MMF_DUMP_MASK_DEFAULT_ELF     _BITUL(MMF_DUMP_ELF_HEADERS)
include/linux/mm_types.h:#define MMF_DISABLE_THP_MASK   (_BITUL(MMF_DISABLE_THP_COMPLETELY) | \
include/linux/mm_types.h:                                _BITUL(MMF_DISABLE_THP_EXCEPT_ADVISED))
include/linux/mm_types.h:#define MMF_HAS_MDWE_MASK      _BITUL(MMF_HAS_MDWE)
include/linux/mm_types.h:#define MMF_VM_MERGE_ANY_MASK  _BITUL(MMF_VM_MERGE_ANY)
include/linux/mm_types.h:#define MMF_TOPDOWN_MASK       _BITUL(MMF_TOPDOWN)

Oh, hey, it's only your changes :P

We should better just be using BIT().

-- 
Cheers

David / dhildenb

Re: [PATCH 07/10] mm: correct sign-extension issue in MMF_* flag masks

Posted by Lorenzo Stoakes 1 month, 1 week ago

On Tue, Aug 26, 2025 at 03:05:27PM +0200, David Hildenbrand wrote:
> On 12.08.25 17:44, Lorenzo Stoakes wrote:
> > There is an issue with the mask declarations in linux/mm_types.h, which
> > naively do (1 << bit) operations. Unfortunately this results in the 1 being
> > defaulted as a signed (32-bit) integer.
> >
> > When the compiler expands the MMF_INIT_MASK bitmask it comes up with:
> >
> > (((1 << 2) - 1) | (((1 << 9) - 1) << 2) | (1 << 24) | (1 << 28) | (1 << 30)
> > | (1 << 31))
> >
> > Which overflows the signed integer to -788,527,105. Implicitly casting this
> > to an unsigned integer results in sign-expansion, and thus this value
> > becomes 0xffffffffd10007ff, rather than the intended 0xd10007ff.
> >
> > While we're limited to a maximum of 32 bits in mm->flags, this isn't an
> > issue as the remaining bits being masked will always be zero.
> >
> > However, now we are moving towards having more bits in this flag, this
> > becomes an issue.
> >
> > Simply resolve this by using the _BITUL() helper to cast the shifted value
> > to an unsigned long.
>
> Hmm, I thought BIT() should be used and would just fine?

Sure.

Re: [PATCH 07/10] mm: correct sign-extension issue in MMF_* flag masks

Posted by Mike Rapoport 1 month, 3 weeks ago

On Tue, Aug 12, 2025 at 04:44:16PM +0100, Lorenzo Stoakes wrote:
> There is an issue with the mask declarations in linux/mm_types.h, which
> naively do (1 << bit) operations. Unfortunately this results in the 1 being
> defaulted as a signed (32-bit) integer.
> 
> When the compiler expands the MMF_INIT_MASK bitmask it comes up with:
> 
> (((1 << 2) - 1) | (((1 << 9) - 1) << 2) | (1 << 24) | (1 << 28) | (1 << 30)
> | (1 << 31))
> 
> Which overflows the signed integer to -788,527,105. Implicitly casting this
> to an unsigned integer results in sign-expansion, and thus this value
> becomes 0xffffffffd10007ff, rather than the intended 0xd10007ff.
> 
> While we're limited to a maximum of 32 bits in mm->flags, this isn't an
> issue as the remaining bits being masked will always be zero.
> 
> However, now we are moving towards having more bits in this flag, this
> becomes an issue.
> 
> Simply resolve this by using the _BITUL() helper to cast the shifted value
> to an unsigned long.
> 
> Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>

Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

> ---
>  include/linux/mm_types.h | 19 +++++++++----------
>  1 file changed, 9 insertions(+), 10 deletions(-)
> 
> diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
> index 46d3fb8935c7..38b3fa927997 100644
> --- a/include/linux/mm_types.h
> +++ b/include/linux/mm_types.h
> @@ -1756,7 +1756,7 @@ enum {
>   * the modes are SUID_DUMP_* defined in linux/sched/coredump.h
>   */
>  #define MMF_DUMPABLE_BITS 2
> -#define MMF_DUMPABLE_MASK ((1 << MMF_DUMPABLE_BITS) - 1)
> +#define MMF_DUMPABLE_MASK (_BITUL(MMF_DUMPABLE_BITS) - 1)
>  /* coredump filter bits */
>  #define MMF_DUMP_ANON_PRIVATE	2
>  #define MMF_DUMP_ANON_SHARED	3
> @@ -1771,13 +1771,13 @@ enum {
>  #define MMF_DUMP_FILTER_SHIFT	MMF_DUMPABLE_BITS
>  #define MMF_DUMP_FILTER_BITS	9
>  #define MMF_DUMP_FILTER_MASK \
> -	(((1 << MMF_DUMP_FILTER_BITS) - 1) << MMF_DUMP_FILTER_SHIFT)
> +	((_BITUL(MMF_DUMP_FILTER_BITS) - 1) << MMF_DUMP_FILTER_SHIFT)
>  #define MMF_DUMP_FILTER_DEFAULT \
> -	((1 << MMF_DUMP_ANON_PRIVATE) |	(1 << MMF_DUMP_ANON_SHARED) |\
> -	 (1 << MMF_DUMP_HUGETLB_PRIVATE) | MMF_DUMP_MASK_DEFAULT_ELF)
> +	(_BITUL(MMF_DUMP_ANON_PRIVATE) | _BITUL(MMF_DUMP_ANON_SHARED) | \
> +	 _BITUL(MMF_DUMP_HUGETLB_PRIVATE) | MMF_DUMP_MASK_DEFAULT_ELF)
>  
>  #ifdef CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS
> -# define MMF_DUMP_MASK_DEFAULT_ELF	(1 << MMF_DUMP_ELF_HEADERS)
> +# define MMF_DUMP_MASK_DEFAULT_ELF	_BITUL(MMF_DUMP_ELF_HEADERS)
>  #else
>  # define MMF_DUMP_MASK_DEFAULT_ELF	0
>  #endif
> @@ -1797,7 +1797,7 @@ enum {
>  #define MMF_UNSTABLE		22	/* mm is unstable for copy_from_user */
>  #define MMF_HUGE_ZERO_FOLIO	23      /* mm has ever used the global huge zero folio */
>  #define MMF_DISABLE_THP		24	/* disable THP for all VMAs */
> -#define MMF_DISABLE_THP_MASK	(1 << MMF_DISABLE_THP)
> +#define MMF_DISABLE_THP_MASK	_BITUL(MMF_DISABLE_THP)
>  #define MMF_OOM_REAP_QUEUED	25	/* mm was queued for oom_reaper */
>  #define MMF_MULTIPROCESS	26	/* mm is shared between processes */
>  /*
> @@ -1810,16 +1810,15 @@ enum {
>  #define MMF_HAS_PINNED		27	/* FOLL_PIN has run, never cleared */
>  
>  #define MMF_HAS_MDWE		28
> -#define MMF_HAS_MDWE_MASK	(1 << MMF_HAS_MDWE)
> -
> +#define MMF_HAS_MDWE_MASK	_BITUL(MMF_HAS_MDWE)
>  
>  #define MMF_HAS_MDWE_NO_INHERIT	29
>  
>  #define MMF_VM_MERGE_ANY	30
> -#define MMF_VM_MERGE_ANY_MASK	(1 << MMF_VM_MERGE_ANY)
> +#define MMF_VM_MERGE_ANY_MASK	_BITUL(MMF_VM_MERGE_ANY)
>  
>  #define MMF_TOPDOWN		31	/* mm searches top down by default */
> -#define MMF_TOPDOWN_MASK	(1 << MMF_TOPDOWN)
> +#define MMF_TOPDOWN_MASK	_BITUL(MMF_TOPDOWN)
>  
>  #define MMF_INIT_MASK		(MMF_DUMPABLE_MASK | MMF_DUMP_FILTER_MASK |\
>  				 MMF_DISABLE_THP_MASK | MMF_HAS_MDWE_MASK |\
> -- 
> 2.50.1
> 

-- 
Sincerely yours,
Mike.

Re: [PATCH 07/10] mm: correct sign-extension issue in MMF_* flag masks

Posted by Liam R. Howlett 1 month, 3 weeks ago

* Lorenzo Stoakes <lorenzo.stoakes@oracle.com> [250812 11:47]:
> There is an issue with the mask declarations in linux/mm_types.h, which
> naively do (1 << bit) operations. Unfortunately this results in the 1 being
> defaulted as a signed (32-bit) integer.
> 
> When the compiler expands the MMF_INIT_MASK bitmask it comes up with:
> 
> (((1 << 2) - 1) | (((1 << 9) - 1) << 2) | (1 << 24) | (1 << 28) | (1 << 30)
> | (1 << 31))
> 
> Which overflows the signed integer to -788,527,105. Implicitly casting this
> to an unsigned integer results in sign-expansion, and thus this value
> becomes 0xffffffffd10007ff, rather than the intended 0xd10007ff.
> 
> While we're limited to a maximum of 32 bits in mm->flags, this isn't an
> issue as the remaining bits being masked will always be zero.
> 
> However, now we are moving towards having more bits in this flag, this
> becomes an issue.
> 
> Simply resolve this by using the _BITUL() helper to cast the shifted value
> to an unsigned long.
> 
> Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>

Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>

> ---
>  include/linux/mm_types.h | 19 +++++++++----------
>  1 file changed, 9 insertions(+), 10 deletions(-)
> 
> diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
> index 46d3fb8935c7..38b3fa927997 100644
> --- a/include/linux/mm_types.h
> +++ b/include/linux/mm_types.h
> @@ -1756,7 +1756,7 @@ enum {
>   * the modes are SUID_DUMP_* defined in linux/sched/coredump.h
>   */
>  #define MMF_DUMPABLE_BITS 2
> -#define MMF_DUMPABLE_MASK ((1 << MMF_DUMPABLE_BITS) - 1)
> +#define MMF_DUMPABLE_MASK (_BITUL(MMF_DUMPABLE_BITS) - 1)
>  /* coredump filter bits */
>  #define MMF_DUMP_ANON_PRIVATE	2
>  #define MMF_DUMP_ANON_SHARED	3
> @@ -1771,13 +1771,13 @@ enum {
>  #define MMF_DUMP_FILTER_SHIFT	MMF_DUMPABLE_BITS
>  #define MMF_DUMP_FILTER_BITS	9
>  #define MMF_DUMP_FILTER_MASK \
> -	(((1 << MMF_DUMP_FILTER_BITS) - 1) << MMF_DUMP_FILTER_SHIFT)
> +	((_BITUL(MMF_DUMP_FILTER_BITS) - 1) << MMF_DUMP_FILTER_SHIFT)
>  #define MMF_DUMP_FILTER_DEFAULT \
> -	((1 << MMF_DUMP_ANON_PRIVATE) |	(1 << MMF_DUMP_ANON_SHARED) |\
> -	 (1 << MMF_DUMP_HUGETLB_PRIVATE) | MMF_DUMP_MASK_DEFAULT_ELF)
> +	(_BITUL(MMF_DUMP_ANON_PRIVATE) | _BITUL(MMF_DUMP_ANON_SHARED) | \
> +	 _BITUL(MMF_DUMP_HUGETLB_PRIVATE) | MMF_DUMP_MASK_DEFAULT_ELF)
>  
>  #ifdef CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS
> -# define MMF_DUMP_MASK_DEFAULT_ELF	(1 << MMF_DUMP_ELF_HEADERS)
> +# define MMF_DUMP_MASK_DEFAULT_ELF	_BITUL(MMF_DUMP_ELF_HEADERS)
>  #else
>  # define MMF_DUMP_MASK_DEFAULT_ELF	0
>  #endif
> @@ -1797,7 +1797,7 @@ enum {
>  #define MMF_UNSTABLE		22	/* mm is unstable for copy_from_user */
>  #define MMF_HUGE_ZERO_FOLIO	23      /* mm has ever used the global huge zero folio */
>  #define MMF_DISABLE_THP		24	/* disable THP for all VMAs */
> -#define MMF_DISABLE_THP_MASK	(1 << MMF_DISABLE_THP)
> +#define MMF_DISABLE_THP_MASK	_BITUL(MMF_DISABLE_THP)
>  #define MMF_OOM_REAP_QUEUED	25	/* mm was queued for oom_reaper */
>  #define MMF_MULTIPROCESS	26	/* mm is shared between processes */
>  /*
> @@ -1810,16 +1810,15 @@ enum {
>  #define MMF_HAS_PINNED		27	/* FOLL_PIN has run, never cleared */
>  
>  #define MMF_HAS_MDWE		28
> -#define MMF_HAS_MDWE_MASK	(1 << MMF_HAS_MDWE)
> -
> +#define MMF_HAS_MDWE_MASK	_BITUL(MMF_HAS_MDWE)
>  
>  #define MMF_HAS_MDWE_NO_INHERIT	29
>  
>  #define MMF_VM_MERGE_ANY	30
> -#define MMF_VM_MERGE_ANY_MASK	(1 << MMF_VM_MERGE_ANY)
> +#define MMF_VM_MERGE_ANY_MASK	_BITUL(MMF_VM_MERGE_ANY)
>  
>  #define MMF_TOPDOWN		31	/* mm searches top down by default */
> -#define MMF_TOPDOWN_MASK	(1 << MMF_TOPDOWN)
> +#define MMF_TOPDOWN_MASK	_BITUL(MMF_TOPDOWN)
>  
>  #define MMF_INIT_MASK		(MMF_DUMPABLE_MASK | MMF_DUMP_FILTER_MASK |\
>  				 MMF_DISABLE_THP_MASK | MMF_HAS_MDWE_MASK |\
> -- 
> 2.50.1
>