[android-common:android12-5.10 13859/13862] mm/memory.c:4724:9: error: implicit declaration of function 'mmu_notifier_trylock'; did you mean 'mmu_notifier_unlock'?

[android-common:android12-5.10 13859/13862] mm/memory.c:4724:9: error: implicit declaration of function 'mmu_notifier_trylock'; did you mean 'mmu_notifier_unlock'?

[kernel test robot]

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tree:   https://android.googlesource.com/kernel/common android12-5.10
head:   70c9301d9c4be76630901189cc7376eb22115a3b
commit: 6971350406a366f4565bdc6b17c08ddd577f27f3 [13859/13862] ANDROID: fix mmu_notifier race caused by not taking mmap_lock during SPF
config: x86_64-randconfig-r033-20211214 (https://download.01.org/0day-ci/archive/20211216/202112161632.kQZI4tAz-lkp(a)intel.com/config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
        git remote add android-common https://android.googlesource.com/kernel/common
        git fetch --no-tags android-common android12-5.10
        git checkout 6971350406a366f4565bdc6b17c08ddd577f27f3
        # save the config file to linux build tree
        mkdir build_dir
        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>

All errors (new ones prefixed by >>):

   mm/memory.c: In function 'handle_pte_fault':
>> mm/memory.c:4724:9: error: implicit declaration of function 'mmu_notifier_trylock'; did you mean 'mmu_notifier_unlock'? [-Werror=implicit-function-declaration]
    4724 |    if (!mmu_notifier_trylock(vmf->vma->vm_mm)) {
         |         ^~~~~~~~~~~~~~~~~~~~
         |         mmu_notifier_unlock
   cc1: some warnings being treated as errors


vim +4724 mm/memory.c

  4616	
  4617	/*
  4618	 * These routines also need to handle stuff like marking pages dirty
  4619	 * and/or accessed for architectures that don't do it in hardware (most
  4620	 * RISC architectures).  The early dirtying is also good on the i386.
  4621	 *
  4622	 * There is also a hook called "update_mmu_cache()" that architectures
  4623	 * with external mmu caches can use to update those (ie the Sparc or
  4624	 * PowerPC hashed page tables that act as extended TLBs).
  4625	 *
  4626	 * We enter with non-exclusive mmap_lock (to exclude vma changes, but allow
  4627	 * concurrent faults).
  4628	 *
  4629	 * The mmap_lock may have been released depending on flags and our return value.
  4630	 * See filemap_fault() and __lock_page_or_retry().
  4631	 */
  4632	static vm_fault_t handle_pte_fault(struct vm_fault *vmf)
  4633	{
  4634		pte_t entry;
  4635		vm_fault_t ret = 0;
  4636	
  4637		if (unlikely(pmd_none(*vmf->pmd))) {
  4638			/*
  4639			 * In the case of the speculative page fault handler we abort
  4640			 * the speculative path immediately as the pmd is probably
  4641			 * in the way to be converted in a huge one. We will try
  4642			 * again holding the mmap_sem (which implies that the collapse
  4643			 * operation is done).
  4644			 */
  4645			if (vmf->flags & FAULT_FLAG_SPECULATIVE)
  4646				return VM_FAULT_RETRY;
  4647			/*
  4648			 * Leave __pte_alloc() until later: because vm_ops->fault may
  4649			 * want to allocate huge page, and if we expose page table
  4650			 * for an instant, it will be difficult to retract from
  4651			 * concurrent faults and from rmap lookups.
  4652			 */
  4653			vmf->pte = NULL;
  4654		} else if (!(vmf->flags & FAULT_FLAG_SPECULATIVE)) {
  4655			/*
  4656			 * If a huge pmd materialized under us just retry later.  Use
  4657			 * pmd_trans_unstable() via pmd_devmap_trans_unstable() instead
  4658			 * of pmd_trans_huge() to ensure the pmd didn't become
  4659			 * pmd_trans_huge under us and then back to pmd_none, as a
  4660			 * result of MADV_DONTNEED running immediately after a huge pmd
  4661			 * fault in a different thread of this mm, in turn leading to a
  4662			 * misleading pmd_trans_huge() retval. All we have to ensure is
  4663			 * that it is a regular pmd that we can walk with
  4664			 * pte_offset_map() and we can do that through an atomic read
  4665			 * in C, which is what pmd_trans_unstable() provides.
  4666			 */
  4667			if (pmd_devmap_trans_unstable(vmf->pmd))
  4668				return 0;
  4669			/*
  4670			 * A regular pmd is established and it can't morph into a huge
  4671			 * pmd from under us anymore at this point because we hold the
  4672			 * mmap_lock read mode and khugepaged takes it in write mode.
  4673			 * So now it's safe to run pte_offset_map().
  4674			 * This is not applicable to the speculative page fault handler
  4675			 * but in that case, the pte is fetched earlier in
  4676			 * handle_speculative_fault().
  4677			 */
  4678			vmf->pte = pte_offset_map(vmf->pmd, vmf->address);
  4679			vmf->orig_pte = *vmf->pte;
  4680	
  4681			/*
  4682			 * some architectures can have larger ptes than wordsize,
  4683			 * e.g.ppc44x-defconfig has CONFIG_PTE_64BIT=y and
  4684			 * CONFIG_32BIT=y, so READ_ONCE cannot guarantee atomic
  4685			 * accesses.  The code below just needs a consistent view
  4686			 * for the ifs and we later double check anyway with the
  4687			 * ptl lock held. So here a barrier will do.
  4688			 */
  4689			barrier();
  4690			if (pte_none(vmf->orig_pte)) {
  4691				pte_unmap(vmf->pte);
  4692				vmf->pte = NULL;
  4693			}
  4694		}
  4695	
  4696		if (!vmf->pte) {
  4697			if (vma_is_anonymous(vmf->vma))
  4698				return do_anonymous_page(vmf);
  4699			else if ((vmf->flags & FAULT_FLAG_SPECULATIVE) &&
  4700					!vmf_allows_speculation(vmf))
  4701				return VM_FAULT_RETRY;
  4702			else
  4703				return do_fault(vmf);
  4704		}
  4705	
  4706		if (!pte_present(vmf->orig_pte))
  4707			return do_swap_page(vmf);
  4708	
  4709		if (pte_protnone(vmf->orig_pte) && vma_is_accessible(vmf->vma))
  4710			return do_numa_page(vmf);
  4711	
  4712		if (!pte_spinlock(vmf))
  4713			return VM_FAULT_RETRY;
  4714		entry = vmf->orig_pte;
  4715		if (unlikely(!pte_same(*vmf->pte, entry))) {
  4716			update_mmu_tlb(vmf->vma, vmf->address, vmf->pte);
  4717			goto unlock;
  4718		}
  4719		if (vmf->flags & FAULT_FLAG_WRITE) {
  4720			if (!pte_write(entry)) {
  4721				if (!(vmf->flags & FAULT_FLAG_SPECULATIVE))
  4722					return do_wp_page(vmf);
  4723	
> 4724				if (!mmu_notifier_trylock(vmf->vma->vm_mm)) {
  4725					ret = VM_FAULT_RETRY;
  4726					goto unlock;
  4727				}
  4728	
  4729				ret = do_wp_page(vmf);
  4730				mmu_notifier_unlock(vmf->vma->vm_mm);
  4731				return ret;
  4732			}
  4733			entry = pte_mkdirty(entry);
  4734		}
  4735		entry = pte_mkyoung(entry);
  4736		if (ptep_set_access_flags(vmf->vma, vmf->address, vmf->pte, entry,
  4737					vmf->flags & FAULT_FLAG_WRITE)) {
  4738			update_mmu_cache(vmf->vma, vmf->address, vmf->pte);
  4739		} else {
  4740			/* Skip spurious TLB flush for retried page fault */
  4741			if (vmf->flags & FAULT_FLAG_TRIED)
  4742				goto unlock;
  4743			if (vmf->flags & FAULT_FLAG_SPECULATIVE)
  4744				ret = VM_FAULT_RETRY;
  4745			/*
  4746			 * This is needed only for protection faults but the arch code
  4747			 * is not yet telling us if this is a protection fault or not.
  4748			 * This still avoids useless tlb flushes for .text page faults
  4749			 * with threads.
  4750			 */
  4751			if (vmf->flags & FAULT_FLAG_WRITE)
  4752				flush_tlb_fix_spurious_fault(vmf->vma, vmf->address);
  4753		}
  4754	unlock:
  4755		pte_unmap_unlock(vmf->pte, vmf->ptl);
  4756		return ret;
  4757	}
  4758	

---
0-DAY CI Kernel Test Service, Intel Corporation
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