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Commit 3a990a52 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'vm' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 

Pull munmap/truncate race fixes from Al Viro:
 "Fixes for racy use of unmap_vmas() on truncate-related codepaths"

* 'vm' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  VM: make zap_page_range() callers that act on a single VMA use separate helper
  VM: make unmap_vmas() return void
  VM: don't bother with feeding upper limit to tlb_finish_mmu() in exit_mmap()
  VM: make zap_page_range() return void
  VM: can't go through the inner loop in unmap_vmas() more than once...
  VM: unmap_page_range() can return void
parents 3556485f f5cc4eef

include/linux/mm.h

+2 −2
Original line number Diff line number Diff line
@@ -893,9 +893,9 @@ struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, 


int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,

		unsigned long size);

unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,

void zap_page_range(struct vm_area_struct *vma, unsigned long address,

		unsigned long size, struct zap_details *);

unsigned long unmap_vmas(struct mmu_gather *tlb,

void unmap_vmas(struct mmu_gather *tlb,

		struct vm_area_struct *start_vma, unsigned long start_addr,

		unsigned long end_addr, unsigned long *nr_accounted,

		struct zap_details *);

mm/memory.c

+80 −53
Original line number Diff line number Diff line
@@ -1282,7 +1282,7 @@ static inline unsigned long zap_pud_range(struct mmu_gather *tlb, 
	return addr;

}



static unsigned long unmap_page_range(struct mmu_gather *tlb,

static void unmap_page_range(struct mmu_gather *tlb,

			     struct vm_area_struct *vma,

			     unsigned long addr, unsigned long end,

			     struct zap_details *details)
@@ -1305,50 +1305,22 @@ static unsigned long unmap_page_range(struct mmu_gather *tlb, 
	} while (pgd++, addr = next, addr != end);

	tlb_end_vma(tlb, vma);

	mem_cgroup_uncharge_end();



	return addr;

}



/**

 * unmap_vmas - unmap a range of memory covered by a list of vma's

 * @tlb: address of the caller's struct mmu_gather

 * @vma: the starting vma

 * @start_addr: virtual address at which to start unmapping

 * @end_addr: virtual address at which to end unmapping

 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here

 * @details: details of nonlinear truncation or shared cache invalidation

 *

 * Returns the end address of the unmapping (restart addr if interrupted).

 *

 * Unmap all pages in the vma list.

 *

 * Only addresses between `start' and `end' will be unmapped.

 *

 * The VMA list must be sorted in ascending virtual address order.

 *

 * unmap_vmas() assumes that the caller will flush the whole unmapped address

 * range after unmap_vmas() returns.  So the only responsibility here is to

 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()

 * drops the lock and schedules.

 */

unsigned long unmap_vmas(struct mmu_gather *tlb,



static void unmap_single_vma(struct mmu_gather *tlb,

		struct vm_area_struct *vma, unsigned long start_addr,

		unsigned long end_addr, unsigned long *nr_accounted,

		struct zap_details *details)

{

	unsigned long start = start_addr;

	struct mm_struct *mm = vma->vm_mm;



	mmu_notifier_invalidate_range_start(mm, start_addr, end_addr);

	for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) {

	unsigned long start = max(vma->vm_start, start_addr);

	unsigned long end;



		start = max(vma->vm_start, start_addr);

	if (start >= vma->vm_end)

			continue;

		return;

	end = min(vma->vm_end, end_addr);

	if (end <= vma->vm_start)

			continue;

		return;



	if (vma->vm_flags & VM_ACCOUNT)

		*nr_accounted += (end - start) >> PAGE_SHIFT;
@@ -1356,7 +1328,7 @@ unsigned long unmap_vmas(struct mmu_gather *tlb, 
	if (unlikely(is_pfn_mapping(vma)))

		untrack_pfn_vma(vma, 0, 0);



		while (start != end) {

	if (start != end) {

		if (unlikely(is_vm_hugetlb_page(vma))) {

			/*

			 * It is undesirable to test vma->vm_file as it
@@ -1371,15 +1343,43 @@ unsigned long unmap_vmas(struct mmu_gather *tlb, 
			 */

			if (vma->vm_file)

				unmap_hugepage_range(vma, start, end, NULL);



				start = end;

		} else

				start = unmap_page_range(tlb, vma, start, end, details);

			unmap_page_range(tlb, vma, start, end, details);

	}

}



/**

 * unmap_vmas - unmap a range of memory covered by a list of vma's

 * @tlb: address of the caller's struct mmu_gather

 * @vma: the starting vma

 * @start_addr: virtual address at which to start unmapping

 * @end_addr: virtual address at which to end unmapping

 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here

 * @details: details of nonlinear truncation or shared cache invalidation

 *

 * Unmap all pages in the vma list.

 *

 * Only addresses between `start' and `end' will be unmapped.

 *

 * The VMA list must be sorted in ascending virtual address order.

 *

 * unmap_vmas() assumes that the caller will flush the whole unmapped address

 * range after unmap_vmas() returns.  So the only responsibility here is to

 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()

 * drops the lock and schedules.

 */

void unmap_vmas(struct mmu_gather *tlb,

		struct vm_area_struct *vma, unsigned long start_addr,

		unsigned long end_addr, unsigned long *nr_accounted,

		struct zap_details *details)

{

	struct mm_struct *mm = vma->vm_mm;



	mmu_notifier_invalidate_range_start(mm, start_addr, end_addr);

	for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next)

		unmap_single_vma(tlb, vma, start_addr, end_addr, nr_accounted,

				 details);

	mmu_notifier_invalidate_range_end(mm, start_addr, end_addr);

	return start;	/* which is now the end (or restart) address */

}



/**
@@ -1388,8 +1388,34 @@ unsigned long unmap_vmas(struct mmu_gather *tlb, 
 * @address: starting address of pages to zap

 * @size: number of bytes to zap

 * @details: details of nonlinear truncation or shared cache invalidation

 *

 * Caller must protect the VMA list

 */

void zap_page_range(struct vm_area_struct *vma, unsigned long address,

		unsigned long size, struct zap_details *details)

{

	struct mm_struct *mm = vma->vm_mm;

	struct mmu_gather tlb;

	unsigned long end = address + size;

	unsigned long nr_accounted = 0;



	lru_add_drain();

	tlb_gather_mmu(&tlb, mm, 0);

	update_hiwater_rss(mm);

	unmap_vmas(&tlb, vma, address, end, &nr_accounted, details);

	tlb_finish_mmu(&tlb, address, end);

}



/**

 * zap_page_range_single - remove user pages in a given range

 * @vma: vm_area_struct holding the applicable pages

 * @address: starting address of pages to zap

 * @size: number of bytes to zap

 * @details: details of nonlinear truncation or shared cache invalidation

 *

 * The range must fit into one VMA.

 */

unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,

static void zap_page_range_single(struct vm_area_struct *vma, unsigned long address,

		unsigned long size, struct zap_details *details)

{

	struct mm_struct *mm = vma->vm_mm;
@@ -1400,9 +1426,10 @@ unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address, 
	lru_add_drain();

	tlb_gather_mmu(&tlb, mm, 0);

	update_hiwater_rss(mm);

	end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details);

	mmu_notifier_invalidate_range_start(mm, address, end);

	unmap_single_vma(&tlb, vma, address, end, &nr_accounted, details);

	mmu_notifier_invalidate_range_end(mm, address, end);

	tlb_finish_mmu(&tlb, address, end);

	return end;

}



/**
@@ -1423,7 +1450,7 @@ int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address, 
	if (address < vma->vm_start || address + size > vma->vm_end ||

	    		!(vma->vm_flags & VM_PFNMAP))

		return -1;

	zap_page_range(vma, address, size, NULL);

	zap_page_range_single(vma, address, size, NULL);

	return 0;

}

EXPORT_SYMBOL_GPL(zap_vma_ptes);
@@ -2770,7 +2797,7 @@ static void unmap_mapping_range_vma(struct vm_area_struct *vma, 
		unsigned long start_addr, unsigned long end_addr,

		struct zap_details *details)

{

	zap_page_range(vma, start_addr, end_addr - start_addr, details);

	zap_page_range_single(vma, start_addr, end_addr - start_addr, details);

}



static inline void unmap_mapping_range_tree(struct prio_tree_root *root,

mm/mmap.c

+2 −3
Original line number Diff line number Diff line
@@ -2237,7 +2237,6 @@ void exit_mmap(struct mm_struct *mm) 
	struct mmu_gather tlb;

	struct vm_area_struct *vma;

	unsigned long nr_accounted = 0;

	unsigned long end;



	/* mm's last user has gone, and its about to be pulled down */

	mmu_notifier_release(mm);
@@ -2262,11 +2261,11 @@ void exit_mmap(struct mm_struct *mm) 
	tlb_gather_mmu(&tlb, mm, 1);

	/* update_hiwater_rss(mm) here? but nobody should be looking */

	/* Use -1 here to ensure all VMAs in the mm are unmapped */

	end = unmap_vmas(&tlb, vma, 0, -1, &nr_accounted, NULL);

	unmap_vmas(&tlb, vma, 0, -1, &nr_accounted, NULL);

	vm_unacct_memory(nr_accounted);



	free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0);

	tlb_finish_mmu(&tlb, 0, end);

	tlb_finish_mmu(&tlb, 0, -1);



	/*

	 * Walk the list again, actually closing and freeing it,