xref: /openbmc/linux/mm/mremap.c (revision b78412b8)
1 /*
2  *	mm/mremap.c
3  *
4  *	(C) Copyright 1996 Linus Torvalds
5  *
6  *	Address space accounting code	<alan@lxorguk.ukuu.org.uk>
7  *	(C) Copyright 2002 Red Hat Inc, All Rights Reserved
8  */
9 
10 #include <linux/mm.h>
11 #include <linux/hugetlb.h>
12 #include <linux/shm.h>
13 #include <linux/ksm.h>
14 #include <linux/mman.h>
15 #include <linux/swap.h>
16 #include <linux/capability.h>
17 #include <linux/fs.h>
18 #include <linux/swapops.h>
19 #include <linux/highmem.h>
20 #include <linux/security.h>
21 #include <linux/syscalls.h>
22 #include <linux/mmu_notifier.h>
23 #include <linux/uaccess.h>
24 #include <linux/mm-arch-hooks.h>
25 #include <linux/userfaultfd_k.h>
26 
27 #include <asm/cacheflush.h>
28 #include <asm/tlbflush.h>
29 
30 #include "internal.h"
31 
32 static pmd_t *get_old_pmd(struct mm_struct *mm, unsigned long addr)
33 {
34 	pgd_t *pgd;
35 	p4d_t *p4d;
36 	pud_t *pud;
37 	pmd_t *pmd;
38 
39 	pgd = pgd_offset(mm, addr);
40 	if (pgd_none_or_clear_bad(pgd))
41 		return NULL;
42 
43 	p4d = p4d_offset(pgd, addr);
44 	if (p4d_none_or_clear_bad(p4d))
45 		return NULL;
46 
47 	pud = pud_offset(p4d, addr);
48 	if (pud_none_or_clear_bad(pud))
49 		return NULL;
50 
51 	pmd = pmd_offset(pud, addr);
52 	if (pmd_none(*pmd))
53 		return NULL;
54 
55 	return pmd;
56 }
57 
58 static pmd_t *alloc_new_pmd(struct mm_struct *mm, struct vm_area_struct *vma,
59 			    unsigned long addr)
60 {
61 	pgd_t *pgd;
62 	p4d_t *p4d;
63 	pud_t *pud;
64 	pmd_t *pmd;
65 
66 	pgd = pgd_offset(mm, addr);
67 	p4d = p4d_alloc(mm, pgd, addr);
68 	if (!p4d)
69 		return NULL;
70 	pud = pud_alloc(mm, p4d, addr);
71 	if (!pud)
72 		return NULL;
73 
74 	pmd = pmd_alloc(mm, pud, addr);
75 	if (!pmd)
76 		return NULL;
77 
78 	VM_BUG_ON(pmd_trans_huge(*pmd));
79 
80 	return pmd;
81 }
82 
83 static void take_rmap_locks(struct vm_area_struct *vma)
84 {
85 	if (vma->vm_file)
86 		i_mmap_lock_write(vma->vm_file->f_mapping);
87 	if (vma->anon_vma)
88 		anon_vma_lock_write(vma->anon_vma);
89 }
90 
91 static void drop_rmap_locks(struct vm_area_struct *vma)
92 {
93 	if (vma->anon_vma)
94 		anon_vma_unlock_write(vma->anon_vma);
95 	if (vma->vm_file)
96 		i_mmap_unlock_write(vma->vm_file->f_mapping);
97 }
98 
99 static pte_t move_soft_dirty_pte(pte_t pte)
100 {
101 	/*
102 	 * Set soft dirty bit so we can notice
103 	 * in userspace the ptes were moved.
104 	 */
105 #ifdef CONFIG_MEM_SOFT_DIRTY
106 	if (pte_present(pte))
107 		pte = pte_mksoft_dirty(pte);
108 	else if (is_swap_pte(pte))
109 		pte = pte_swp_mksoft_dirty(pte);
110 #endif
111 	return pte;
112 }
113 
114 static void move_ptes(struct vm_area_struct *vma, pmd_t *old_pmd,
115 		unsigned long old_addr, unsigned long old_end,
116 		struct vm_area_struct *new_vma, pmd_t *new_pmd,
117 		unsigned long new_addr, bool need_rmap_locks, bool *need_flush)
118 {
119 	struct mm_struct *mm = vma->vm_mm;
120 	pte_t *old_pte, *new_pte, pte;
121 	spinlock_t *old_ptl, *new_ptl;
122 	bool force_flush = false;
123 	unsigned long len = old_end - old_addr;
124 
125 	/*
126 	 * When need_rmap_locks is true, we take the i_mmap_rwsem and anon_vma
127 	 * locks to ensure that rmap will always observe either the old or the
128 	 * new ptes. This is the easiest way to avoid races with
129 	 * truncate_pagecache(), page migration, etc...
130 	 *
131 	 * When need_rmap_locks is false, we use other ways to avoid
132 	 * such races:
133 	 *
134 	 * - During exec() shift_arg_pages(), we use a specially tagged vma
135 	 *   which rmap call sites look for using is_vma_temporary_stack().
136 	 *
137 	 * - During mremap(), new_vma is often known to be placed after vma
138 	 *   in rmap traversal order. This ensures rmap will always observe
139 	 *   either the old pte, or the new pte, or both (the page table locks
140 	 *   serialize access to individual ptes, but only rmap traversal
141 	 *   order guarantees that we won't miss both the old and new ptes).
142 	 */
143 	if (need_rmap_locks)
144 		take_rmap_locks(vma);
145 
146 	/*
147 	 * We don't have to worry about the ordering of src and dst
148 	 * pte locks because exclusive mmap_sem prevents deadlock.
149 	 */
150 	old_pte = pte_offset_map_lock(mm, old_pmd, old_addr, &old_ptl);
151 	new_pte = pte_offset_map(new_pmd, new_addr);
152 	new_ptl = pte_lockptr(mm, new_pmd);
153 	if (new_ptl != old_ptl)
154 		spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING);
155 	flush_tlb_batched_pending(vma->vm_mm);
156 	arch_enter_lazy_mmu_mode();
157 
158 	for (; old_addr < old_end; old_pte++, old_addr += PAGE_SIZE,
159 				   new_pte++, new_addr += PAGE_SIZE) {
160 		if (pte_none(*old_pte))
161 			continue;
162 
163 		pte = ptep_get_and_clear(mm, old_addr, old_pte);
164 		/*
165 		 * If we are remapping a dirty PTE, make sure
166 		 * to flush TLB before we drop the PTL for the
167 		 * old PTE or we may race with page_mkclean().
168 		 *
169 		 * This check has to be done after we removed the
170 		 * old PTE from page tables or another thread may
171 		 * dirty it after the check and before the removal.
172 		 */
173 		if (pte_present(pte) && pte_dirty(pte))
174 			force_flush = true;
175 		pte = move_pte(pte, new_vma->vm_page_prot, old_addr, new_addr);
176 		pte = move_soft_dirty_pte(pte);
177 		set_pte_at(mm, new_addr, new_pte, pte);
178 	}
179 
180 	arch_leave_lazy_mmu_mode();
181 	if (new_ptl != old_ptl)
182 		spin_unlock(new_ptl);
183 	pte_unmap(new_pte - 1);
184 	if (force_flush)
185 		flush_tlb_range(vma, old_end - len, old_end);
186 	else
187 		*need_flush = true;
188 	pte_unmap_unlock(old_pte - 1, old_ptl);
189 	if (need_rmap_locks)
190 		drop_rmap_locks(vma);
191 }
192 
193 #define LATENCY_LIMIT	(64 * PAGE_SIZE)
194 
195 unsigned long move_page_tables(struct vm_area_struct *vma,
196 		unsigned long old_addr, struct vm_area_struct *new_vma,
197 		unsigned long new_addr, unsigned long len,
198 		bool need_rmap_locks)
199 {
200 	unsigned long extent, next, old_end;
201 	pmd_t *old_pmd, *new_pmd;
202 	bool need_flush = false;
203 	unsigned long mmun_start;	/* For mmu_notifiers */
204 	unsigned long mmun_end;		/* For mmu_notifiers */
205 
206 	old_end = old_addr + len;
207 	flush_cache_range(vma, old_addr, old_end);
208 
209 	mmun_start = old_addr;
210 	mmun_end   = old_end;
211 	mmu_notifier_invalidate_range_start(vma->vm_mm, mmun_start, mmun_end);
212 
213 	for (; old_addr < old_end; old_addr += extent, new_addr += extent) {
214 		cond_resched();
215 		next = (old_addr + PMD_SIZE) & PMD_MASK;
216 		/* even if next overflowed, extent below will be ok */
217 		extent = next - old_addr;
218 		if (extent > old_end - old_addr)
219 			extent = old_end - old_addr;
220 		old_pmd = get_old_pmd(vma->vm_mm, old_addr);
221 		if (!old_pmd)
222 			continue;
223 		new_pmd = alloc_new_pmd(vma->vm_mm, vma, new_addr);
224 		if (!new_pmd)
225 			break;
226 		if (is_swap_pmd(*old_pmd) || pmd_trans_huge(*old_pmd)) {
227 			if (extent == HPAGE_PMD_SIZE) {
228 				bool moved;
229 				/* See comment in move_ptes() */
230 				if (need_rmap_locks)
231 					take_rmap_locks(vma);
232 				moved = move_huge_pmd(vma, old_addr, new_addr,
233 						    old_end, old_pmd, new_pmd,
234 						    &need_flush);
235 				if (need_rmap_locks)
236 					drop_rmap_locks(vma);
237 				if (moved)
238 					continue;
239 			}
240 			split_huge_pmd(vma, old_pmd, old_addr);
241 			if (pmd_trans_unstable(old_pmd))
242 				continue;
243 		}
244 		if (pte_alloc(new_vma->vm_mm, new_pmd, new_addr))
245 			break;
246 		next = (new_addr + PMD_SIZE) & PMD_MASK;
247 		if (extent > next - new_addr)
248 			extent = next - new_addr;
249 		if (extent > LATENCY_LIMIT)
250 			extent = LATENCY_LIMIT;
251 		move_ptes(vma, old_pmd, old_addr, old_addr + extent, new_vma,
252 			  new_pmd, new_addr, need_rmap_locks, &need_flush);
253 	}
254 	if (need_flush)
255 		flush_tlb_range(vma, old_end-len, old_addr);
256 
257 	mmu_notifier_invalidate_range_end(vma->vm_mm, mmun_start, mmun_end);
258 
259 	return len + old_addr - old_end;	/* how much done */
260 }
261 
262 static unsigned long move_vma(struct vm_area_struct *vma,
263 		unsigned long old_addr, unsigned long old_len,
264 		unsigned long new_len, unsigned long new_addr,
265 		bool *locked, struct vm_userfaultfd_ctx *uf,
266 		struct list_head *uf_unmap)
267 {
268 	struct mm_struct *mm = vma->vm_mm;
269 	struct vm_area_struct *new_vma;
270 	unsigned long vm_flags = vma->vm_flags;
271 	unsigned long new_pgoff;
272 	unsigned long moved_len;
273 	unsigned long excess = 0;
274 	unsigned long hiwater_vm;
275 	int split = 0;
276 	int err;
277 	bool need_rmap_locks;
278 
279 	/*
280 	 * We'd prefer to avoid failure later on in do_munmap:
281 	 * which may split one vma into three before unmapping.
282 	 */
283 	if (mm->map_count >= sysctl_max_map_count - 3)
284 		return -ENOMEM;
285 
286 	/*
287 	 * Advise KSM to break any KSM pages in the area to be moved:
288 	 * it would be confusing if they were to turn up at the new
289 	 * location, where they happen to coincide with different KSM
290 	 * pages recently unmapped.  But leave vma->vm_flags as it was,
291 	 * so KSM can come around to merge on vma and new_vma afterwards.
292 	 */
293 	err = ksm_madvise(vma, old_addr, old_addr + old_len,
294 						MADV_UNMERGEABLE, &vm_flags);
295 	if (err)
296 		return err;
297 
298 	new_pgoff = vma->vm_pgoff + ((old_addr - vma->vm_start) >> PAGE_SHIFT);
299 	new_vma = copy_vma(&vma, new_addr, new_len, new_pgoff,
300 			   &need_rmap_locks);
301 	if (!new_vma)
302 		return -ENOMEM;
303 
304 	moved_len = move_page_tables(vma, old_addr, new_vma, new_addr, old_len,
305 				     need_rmap_locks);
306 	if (moved_len < old_len) {
307 		err = -ENOMEM;
308 	} else if (vma->vm_ops && vma->vm_ops->mremap) {
309 		err = vma->vm_ops->mremap(new_vma);
310 	}
311 
312 	if (unlikely(err)) {
313 		/*
314 		 * On error, move entries back from new area to old,
315 		 * which will succeed since page tables still there,
316 		 * and then proceed to unmap new area instead of old.
317 		 */
318 		move_page_tables(new_vma, new_addr, vma, old_addr, moved_len,
319 				 true);
320 		vma = new_vma;
321 		old_len = new_len;
322 		old_addr = new_addr;
323 		new_addr = err;
324 	} else {
325 		mremap_userfaultfd_prep(new_vma, uf);
326 		arch_remap(mm, old_addr, old_addr + old_len,
327 			   new_addr, new_addr + new_len);
328 	}
329 
330 	/* Conceal VM_ACCOUNT so old reservation is not undone */
331 	if (vm_flags & VM_ACCOUNT) {
332 		vma->vm_flags &= ~VM_ACCOUNT;
333 		excess = vma->vm_end - vma->vm_start - old_len;
334 		if (old_addr > vma->vm_start &&
335 		    old_addr + old_len < vma->vm_end)
336 			split = 1;
337 	}
338 
339 	/*
340 	 * If we failed to move page tables we still do total_vm increment
341 	 * since do_munmap() will decrement it by old_len == new_len.
342 	 *
343 	 * Since total_vm is about to be raised artificially high for a
344 	 * moment, we need to restore high watermark afterwards: if stats
345 	 * are taken meanwhile, total_vm and hiwater_vm appear too high.
346 	 * If this were a serious issue, we'd add a flag to do_munmap().
347 	 */
348 	hiwater_vm = mm->hiwater_vm;
349 	vm_stat_account(mm, vma->vm_flags, new_len >> PAGE_SHIFT);
350 
351 	/* Tell pfnmap has moved from this vma */
352 	if (unlikely(vma->vm_flags & VM_PFNMAP))
353 		untrack_pfn_moved(vma);
354 
355 	if (do_munmap(mm, old_addr, old_len, uf_unmap) < 0) {
356 		/* OOM: unable to split vma, just get accounts right */
357 		vm_unacct_memory(excess >> PAGE_SHIFT);
358 		excess = 0;
359 	}
360 	mm->hiwater_vm = hiwater_vm;
361 
362 	/* Restore VM_ACCOUNT if one or two pieces of vma left */
363 	if (excess) {
364 		vma->vm_flags |= VM_ACCOUNT;
365 		if (split)
366 			vma->vm_next->vm_flags |= VM_ACCOUNT;
367 	}
368 
369 	if (vm_flags & VM_LOCKED) {
370 		mm->locked_vm += new_len >> PAGE_SHIFT;
371 		*locked = true;
372 	}
373 
374 	return new_addr;
375 }
376 
377 static struct vm_area_struct *vma_to_resize(unsigned long addr,
378 	unsigned long old_len, unsigned long new_len, unsigned long *p)
379 {
380 	struct mm_struct *mm = current->mm;
381 	struct vm_area_struct *vma = find_vma(mm, addr);
382 	unsigned long pgoff;
383 
384 	if (!vma || vma->vm_start > addr)
385 		return ERR_PTR(-EFAULT);
386 
387 	/*
388 	 * !old_len is a special case where an attempt is made to 'duplicate'
389 	 * a mapping.  This makes no sense for private mappings as it will
390 	 * instead create a fresh/new mapping unrelated to the original.  This
391 	 * is contrary to the basic idea of mremap which creates new mappings
392 	 * based on the original.  There are no known use cases for this
393 	 * behavior.  As a result, fail such attempts.
394 	 */
395 	if (!old_len && !(vma->vm_flags & (VM_SHARED | VM_MAYSHARE))) {
396 		pr_warn_once("%s (%d): attempted to duplicate a private mapping with mremap.  This is not supported.\n", current->comm, current->pid);
397 		return ERR_PTR(-EINVAL);
398 	}
399 
400 	if (is_vm_hugetlb_page(vma))
401 		return ERR_PTR(-EINVAL);
402 
403 	/* We can't remap across vm area boundaries */
404 	if (old_len > vma->vm_end - addr)
405 		return ERR_PTR(-EFAULT);
406 
407 	if (new_len == old_len)
408 		return vma;
409 
410 	/* Need to be careful about a growing mapping */
411 	pgoff = (addr - vma->vm_start) >> PAGE_SHIFT;
412 	pgoff += vma->vm_pgoff;
413 	if (pgoff + (new_len >> PAGE_SHIFT) < pgoff)
414 		return ERR_PTR(-EINVAL);
415 
416 	if (vma->vm_flags & (VM_DONTEXPAND | VM_PFNMAP))
417 		return ERR_PTR(-EFAULT);
418 
419 	if (vma->vm_flags & VM_LOCKED) {
420 		unsigned long locked, lock_limit;
421 		locked = mm->locked_vm << PAGE_SHIFT;
422 		lock_limit = rlimit(RLIMIT_MEMLOCK);
423 		locked += new_len - old_len;
424 		if (locked > lock_limit && !capable(CAP_IPC_LOCK))
425 			return ERR_PTR(-EAGAIN);
426 	}
427 
428 	if (!may_expand_vm(mm, vma->vm_flags,
429 				(new_len - old_len) >> PAGE_SHIFT))
430 		return ERR_PTR(-ENOMEM);
431 
432 	if (vma->vm_flags & VM_ACCOUNT) {
433 		unsigned long charged = (new_len - old_len) >> PAGE_SHIFT;
434 		if (security_vm_enough_memory_mm(mm, charged))
435 			return ERR_PTR(-ENOMEM);
436 		*p = charged;
437 	}
438 
439 	return vma;
440 }
441 
442 static unsigned long mremap_to(unsigned long addr, unsigned long old_len,
443 		unsigned long new_addr, unsigned long new_len, bool *locked,
444 		struct vm_userfaultfd_ctx *uf,
445 		struct list_head *uf_unmap_early,
446 		struct list_head *uf_unmap)
447 {
448 	struct mm_struct *mm = current->mm;
449 	struct vm_area_struct *vma;
450 	unsigned long ret = -EINVAL;
451 	unsigned long charged = 0;
452 	unsigned long map_flags;
453 
454 	if (offset_in_page(new_addr))
455 		goto out;
456 
457 	if (new_len > TASK_SIZE || new_addr > TASK_SIZE - new_len)
458 		goto out;
459 
460 	/* Ensure the old/new locations do not overlap */
461 	if (addr + old_len > new_addr && new_addr + new_len > addr)
462 		goto out;
463 
464 	ret = do_munmap(mm, new_addr, new_len, uf_unmap_early);
465 	if (ret)
466 		goto out;
467 
468 	if (old_len >= new_len) {
469 		ret = do_munmap(mm, addr+new_len, old_len - new_len, uf_unmap);
470 		if (ret && old_len != new_len)
471 			goto out;
472 		old_len = new_len;
473 	}
474 
475 	vma = vma_to_resize(addr, old_len, new_len, &charged);
476 	if (IS_ERR(vma)) {
477 		ret = PTR_ERR(vma);
478 		goto out;
479 	}
480 
481 	map_flags = MAP_FIXED;
482 	if (vma->vm_flags & VM_MAYSHARE)
483 		map_flags |= MAP_SHARED;
484 
485 	ret = get_unmapped_area(vma->vm_file, new_addr, new_len, vma->vm_pgoff +
486 				((addr - vma->vm_start) >> PAGE_SHIFT),
487 				map_flags);
488 	if (offset_in_page(ret))
489 		goto out1;
490 
491 	ret = move_vma(vma, addr, old_len, new_len, new_addr, locked, uf,
492 		       uf_unmap);
493 	if (!(offset_in_page(ret)))
494 		goto out;
495 out1:
496 	vm_unacct_memory(charged);
497 
498 out:
499 	return ret;
500 }
501 
502 static int vma_expandable(struct vm_area_struct *vma, unsigned long delta)
503 {
504 	unsigned long end = vma->vm_end + delta;
505 	if (end < vma->vm_end) /* overflow */
506 		return 0;
507 	if (vma->vm_next && vma->vm_next->vm_start < end) /* intersection */
508 		return 0;
509 	if (get_unmapped_area(NULL, vma->vm_start, end - vma->vm_start,
510 			      0, MAP_FIXED) & ~PAGE_MASK)
511 		return 0;
512 	return 1;
513 }
514 
515 /*
516  * Expand (or shrink) an existing mapping, potentially moving it at the
517  * same time (controlled by the MREMAP_MAYMOVE flag and available VM space)
518  *
519  * MREMAP_FIXED option added 5-Dec-1999 by Benjamin LaHaise
520  * This option implies MREMAP_MAYMOVE.
521  */
522 SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
523 		unsigned long, new_len, unsigned long, flags,
524 		unsigned long, new_addr)
525 {
526 	struct mm_struct *mm = current->mm;
527 	struct vm_area_struct *vma;
528 	unsigned long ret = -EINVAL;
529 	unsigned long charged = 0;
530 	bool locked = false;
531 	struct vm_userfaultfd_ctx uf = NULL_VM_UFFD_CTX;
532 	LIST_HEAD(uf_unmap_early);
533 	LIST_HEAD(uf_unmap);
534 
535 	if (flags & ~(MREMAP_FIXED | MREMAP_MAYMOVE))
536 		return ret;
537 
538 	if (flags & MREMAP_FIXED && !(flags & MREMAP_MAYMOVE))
539 		return ret;
540 
541 	if (offset_in_page(addr))
542 		return ret;
543 
544 	old_len = PAGE_ALIGN(old_len);
545 	new_len = PAGE_ALIGN(new_len);
546 
547 	/*
548 	 * We allow a zero old-len as a special case
549 	 * for DOS-emu "duplicate shm area" thing. But
550 	 * a zero new-len is nonsensical.
551 	 */
552 	if (!new_len)
553 		return ret;
554 
555 	if (down_write_killable(&current->mm->mmap_sem))
556 		return -EINTR;
557 
558 	if (flags & MREMAP_FIXED) {
559 		ret = mremap_to(addr, old_len, new_addr, new_len,
560 				&locked, &uf, &uf_unmap_early, &uf_unmap);
561 		goto out;
562 	}
563 
564 	/*
565 	 * Always allow a shrinking remap: that just unmaps
566 	 * the unnecessary pages..
567 	 * do_munmap does all the needed commit accounting
568 	 */
569 	if (old_len >= new_len) {
570 		ret = do_munmap(mm, addr+new_len, old_len - new_len, &uf_unmap);
571 		if (ret && old_len != new_len)
572 			goto out;
573 		ret = addr;
574 		goto out;
575 	}
576 
577 	/*
578 	 * Ok, we need to grow..
579 	 */
580 	vma = vma_to_resize(addr, old_len, new_len, &charged);
581 	if (IS_ERR(vma)) {
582 		ret = PTR_ERR(vma);
583 		goto out;
584 	}
585 
586 	/* old_len exactly to the end of the area..
587 	 */
588 	if (old_len == vma->vm_end - addr) {
589 		/* can we just expand the current mapping? */
590 		if (vma_expandable(vma, new_len - old_len)) {
591 			int pages = (new_len - old_len) >> PAGE_SHIFT;
592 
593 			if (vma_adjust(vma, vma->vm_start, addr + new_len,
594 				       vma->vm_pgoff, NULL)) {
595 				ret = -ENOMEM;
596 				goto out;
597 			}
598 
599 			vm_stat_account(mm, vma->vm_flags, pages);
600 			if (vma->vm_flags & VM_LOCKED) {
601 				mm->locked_vm += pages;
602 				locked = true;
603 				new_addr = addr;
604 			}
605 			ret = addr;
606 			goto out;
607 		}
608 	}
609 
610 	/*
611 	 * We weren't able to just expand or shrink the area,
612 	 * we need to create a new one and move it..
613 	 */
614 	ret = -ENOMEM;
615 	if (flags & MREMAP_MAYMOVE) {
616 		unsigned long map_flags = 0;
617 		if (vma->vm_flags & VM_MAYSHARE)
618 			map_flags |= MAP_SHARED;
619 
620 		new_addr = get_unmapped_area(vma->vm_file, 0, new_len,
621 					vma->vm_pgoff +
622 					((addr - vma->vm_start) >> PAGE_SHIFT),
623 					map_flags);
624 		if (offset_in_page(new_addr)) {
625 			ret = new_addr;
626 			goto out;
627 		}
628 
629 		ret = move_vma(vma, addr, old_len, new_len, new_addr,
630 			       &locked, &uf, &uf_unmap);
631 	}
632 out:
633 	if (offset_in_page(ret)) {
634 		vm_unacct_memory(charged);
635 		locked = 0;
636 	}
637 	up_write(&current->mm->mmap_sem);
638 	if (locked && new_len > old_len)
639 		mm_populate(new_addr + old_len, new_len - old_len);
640 	userfaultfd_unmap_complete(mm, &uf_unmap_early);
641 	mremap_userfaultfd_complete(&uf, addr, new_addr, old_len);
642 	userfaultfd_unmap_complete(mm, &uf_unmap);
643 	return ret;
644 }
645