[linux-next:master 5085/5845] fs/userfaultfd.c:337:13: error: implicit declaration of function 'pte_none_mostly'

[linux-next:master 5085/5845] fs/userfaultfd.c:337:13: error: implicit declaration of function 'pte_none_mostly'

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
head:   e7d6987e09a328d4a949701db40ef63fbb970670
commit: 70a8da53f7cb7368776f9d2790ecbb4f8bc53ba5 [5085/5845] mm: teach core mm about pte markers
config: x86_64-randconfig-a002-20210928 (https://download.01.org/0day-ci/archive/20220424/202204240320.TGDuGcsL-lkp@intel.com/config)
compiler: gcc-11 (Debian 11.2.0-20) 11.2.0
reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=70a8da53f7cb7368776f9d2790ecbb4f8bc53ba5
        git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
        git fetch --no-tags linux-next master
        git checkout 70a8da53f7cb7368776f9d2790ecbb4f8bc53ba5
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

Note: the linux-next/master HEAD e7d6987e09a328d4a949701db40ef63fbb970670 builds fine.
      It may have been fixed somewhere.

All errors (new ones prefixed by >>):

   fs/userfaultfd.c: In function 'userfaultfd_must_wait':
>> fs/userfaultfd.c:337:13: error: implicit declaration of function 'pte_none_mostly' [-Werror=implicit-function-declaration]
     337 |         if (pte_none_mostly(*pte))
         |             ^~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors


vim +/pte_none_mostly +337 fs/userfaultfd.c

   272	
   273	/*
   274	 * Verify the pagetables are still not ok after having reigstered into
   275	 * the fault_pending_wqh to avoid userland having to UFFDIO_WAKE any
   276	 * userfault that has already been resolved, if userfaultfd_read and
   277	 * UFFDIO_COPY|ZEROPAGE are being run simultaneously on two different
   278	 * threads.
   279	 */
   280	static inline bool userfaultfd_must_wait(struct userfaultfd_ctx *ctx,
   281						 unsigned long address,
   282						 unsigned long flags,
   283						 unsigned long reason)
   284	{
   285		struct mm_struct *mm = ctx->mm;
   286		pgd_t *pgd;
   287		p4d_t *p4d;
   288		pud_t *pud;
   289		pmd_t *pmd, _pmd;
   290		pte_t *pte;
   291		bool ret = true;
   292	
   293		mmap_assert_locked(mm);
   294	
   295		pgd = pgd_offset(mm, address);
   296		if (!pgd_present(*pgd))
   297			goto out;
   298		p4d = p4d_offset(pgd, address);
   299		if (!p4d_present(*p4d))
   300			goto out;
   301		pud = pud_offset(p4d, address);
   302		if (!pud_present(*pud))
   303			goto out;
   304		pmd = pmd_offset(pud, address);
   305		/*
   306		 * READ_ONCE must function as a barrier with narrower scope
   307		 * and it must be equivalent to:
   308		 *	_pmd = *pmd; barrier();
   309		 *
   310		 * This is to deal with the instability (as in
   311		 * pmd_trans_unstable) of the pmd.
   312		 */
   313		_pmd = READ_ONCE(*pmd);
   314		if (pmd_none(_pmd))
   315			goto out;
   316	
   317		ret = false;
   318		if (!pmd_present(_pmd))
   319			goto out;
   320	
   321		if (pmd_trans_huge(_pmd)) {
   322			if (!pmd_write(_pmd) && (reason & VM_UFFD_WP))
   323				ret = true;
   324			goto out;
   325		}
   326	
   327		/*
   328		 * the pmd is stable (as in !pmd_trans_unstable) so we can re-read it
   329		 * and use the standard pte_offset_map() instead of parsing _pmd.
   330		 */
   331		pte = pte_offset_map(pmd, address);
   332		/*
   333		 * Lockless access: we're in a wait_event so it's ok if it
   334		 * changes under us.  PTE markers should be handled the same as none
   335		 * ptes here.
   336		 */
 > 337		if (pte_none_mostly(*pte))
   338			ret = true;
   339		if (!pte_write(*pte) && (reason & VM_UFFD_WP))
   340			ret = true;
   341		pte_unmap(pte);
   342	
   343	out:
   344		return ret;
   345	}
   346	

-- 
0-DAY CI Kernel Test Service
https://01.org/lkp

Re: [linux-next:master 5085/5845] fs/userfaultfd.c:337:13: error: implicit declaration of function 'pte_none_mostly'

[Peter Xu]

[-- Attachment #1: Type: text/plain, Size: 1817 bytes --]

On Sun, Apr 24, 2022 at 03:23:23AM +0800, kernel test robot wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> head:   e7d6987e09a328d4a949701db40ef63fbb970670
> commit: 70a8da53f7cb7368776f9d2790ecbb4f8bc53ba5 [5085/5845] mm: teach core mm about pte markers
> config: x86_64-randconfig-a002-20210928 (https://download.01.org/0day-ci/archive/20220424/202204240320.TGDuGcsL-lkp@intel.com/config)
> compiler: gcc-11 (Debian 11.2.0-20) 11.2.0
> reproduce (this is a W=1 build):
>         # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=70a8da53f7cb7368776f9d2790ecbb4f8bc53ba5
>         git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
>         git fetch --no-tags linux-next master
>         git checkout 70a8da53f7cb7368776f9d2790ecbb4f8bc53ba5
>         # save the config file
>         mkdir build_dir && cp config build_dir/.config
>         make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash
> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
> 
> Note: the linux-next/master HEAD e7d6987e09a328d4a949701db40ef63fbb970670 builds fine.
>       It may have been fixed somewhere.
> 
> All errors (new ones prefixed by >>):
> 
>    fs/userfaultfd.c: In function 'userfaultfd_must_wait':
> >> fs/userfaultfd.c:337:13: error: implicit declaration of function 'pte_none_mostly' [-Werror=implicit-function-declaration]
>      337 |         if (pte_none_mostly(*pte))
>          |             ^~~~~~~~~~~~~~~
>    cc1: some warnings being treated as errors

Ah, userfaultfd.c may need explicit inclusion for swapops.h now..  Expected
fix attached to be squashed into "mm: Teach core mm about pte markers", I think.

Thanks,

-- 
Peter Xu

[-- Attachment #2: 0001-fixup-mm-Teach-core-mm-about-pte-markers.patch --]
[-- Type: text/plain, Size: 667 bytes --]

From 009572e59f7d72c5085676b0506f0b269f9ef334 Mon Sep 17 00:00:00 2001
From: Peter Xu <peterx@redhat.com>
Date: Sat, 23 Apr 2022 16:39:15 -0400
Subject: [PATCH] fixup! mm: Teach core mm about pte markers
Content-type: text/plain

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 fs/userfaultfd.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index fb45522a2b44..e943370107d0 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -29,6 +29,7 @@
 #include <linux/ioctl.h>
 #include <linux/security.h>
 #include <linux/hugetlb.h>
+#include <linux/swapops.h>
 
 int sysctl_unprivileged_userfaultfd __read_mostly;
 
-- 
2.32.0