Merge "BACKPORT: FROMLIST: mm: protect free_pgtables with mmap_lock write lock in exit_mmap" (d6b9900a) · Commits · e / devices / android_kernel_oneplus_sm7250

mm/mmap.c

+7 −7

Original line number	Diff line number	Diff line
		@@ -3178,10 +3178,9 @@ void exit_mmap(struct mm_struct *mm)
		(void)__oom_reap_task_mm(mm);

		set_bit(MMF_OOM_SKIP, &mm->flags);
		down_write(&mm->mmap_sem);
		up_write(&mm->mmap_sem);
		}

		down_write(&mm->mmap_sem);
		if (mm->locked_vm) {
		vma = mm->mmap;
		while (vma) {
		@@ -3194,8 +3193,11 @@ void exit_mmap(struct mm_struct *mm)
		arch_exit_mmap(mm);

		vma = mm->mmap;
		if (!vma) /* Can happen if dup_mmap() received an OOM */
		if (!vma) {
		/* Can happen if dup_mmap() received an OOM */
		up_write(&mm->mmap_sem);;
		return;
		}

		lru_add_drain();
		flush_cache_mm(mm);
		@@ -3206,16 +3208,14 @@ void exit_mmap(struct mm_struct *mm)
		free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, USER_PGTABLES_CEILING);
		tlb_finish_mmu(&tlb, 0, -1);

		/*
		* Walk the list again, actually closing and freeing it,
		* with preemption enabled, without holding any MM locks.
		*/
		/* Walk the list again, actually closing and freeing it. */
		while (vma) {
		if (vma->vm_flags & VM_ACCOUNT)
		nr_accounted += vma_pages(vma);
		vma = remove_vma(vma);
		cond_resched();
		}
		up_write(&mm->mmap_sem);
		vm_unacct_memory(nr_accounted);
		}