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mm: zero out the vma in vma_init()

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Rather than in vm_area_alloc().  To ensure that the various oddball
stack-based vmas are in a good state.  Some of the callers were zeroing
them out, others were not.

Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Andrew Morton 2018-08-21 21:53:06 -07:00 committed by Linus Torvalds
parent a3bf6ce366
commit a670468f5e
6 changed files with 7 additions and 10 deletions
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9
arch/arm/kernel/process.c
View file

@ -330,16 +330,15 @@ unsigned long arch_randomize_brk(struct mm_struct *mm)
* atomic helpers. Insert it into the gate_vma so that it is visible
* through ptrace and /proc/<pid>/mem.
*/
static struct vm_area_struct gate_vma = {
.vm_start = 0xffff0000,
.vm_end = 0xffff0000 + PAGE_SIZE,
.vm_flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC,
};
static struct vm_area_struct gate_vma;
static int __init gate_vma_init(void)
{
vma_init(&gate_vma, NULL);
gate_vma.vm_page_prot = PAGE_READONLY_EXEC;
gate_vma.vm_start = 0xffff0000;
gate_vma.vm_end = 0xffff0000 + PAGE_SIZE;
gate_vma.vm_flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC;
return 0;
}
arch_initcall(gate_vma_init);

2
fs/hugetlbfs/inode.c
View file

@ -410,7 +410,6 @@ static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
int i, freed = 0;
bool truncate_op = (lend == LLONG_MAX);
memset(&pseudo_vma, 0, sizeof(struct vm_area_struct));
vma_init(&pseudo_vma, current->mm);
pseudo_vma.vm_flags = (VM_HUGETLB | VM_MAYSHARE | VM_SHARED);
pagevec_init(&pvec);
@ -595,7 +594,6 @@ static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
* allocation routines. If NUMA is configured, use page index
* as input to create an allocation policy.
*/
memset(&pseudo_vma, 0, sizeof(struct vm_area_struct));
vma_init(&pseudo_vma, mm);
pseudo_vma.vm_flags = (VM_HUGETLB | VM_MAYSHARE | VM_SHARED);
pseudo_vma.vm_file = file;

1
include/linux/mm.h
View file

@ -456,6 +456,7 @@ static inline void vma_init(struct vm_area_struct *vma, struct mm_struct *mm)
{
static const struct vm_operations_struct dummy_vm_ops = {};
memset(vma, 0, sizeof(*vma));
vma->vm_mm = mm;
vma->vm_ops = &dummy_vm_ops;
INIT_LIST_HEAD(&vma->anon_vma_chain);

3
kernel/fork.c
View file

@ -310,8 +310,9 @@ static struct kmem_cache *mm_cachep;
struct vm_area_struct *vm_area_alloc(struct mm_struct *mm)
{
struct vm_area_struct *vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
struct vm_area_struct *vma;
vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
if (vma)
vma_init(vma, mm);
return vma;

1
mm/mempolicy.c
View file

@ -2504,7 +2504,6 @@ void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol)
goto put_new;
/* Create pseudo-vma that contains just the policy */
memset(&pvma, 0, sizeof(struct vm_area_struct));
vma_init(&pvma, NULL);
pvma.vm_end = TASK_SIZE; /* policy covers entire file */
mpol_set_shared_policy(sp, &pvma, new); /* adds ref */

1
mm/shmem.c
View file

@ -1421,7 +1421,6 @@ static void shmem_pseudo_vma_init(struct vm_area_struct *vma,
struct shmem_inode_info *info, pgoff_t index)
{
/* Create a pseudo vma that just contains the policy */
memset(vma, 0, sizeof(*vma));
vma_init(vma, NULL);
/* Bias interleave by inode number to distribute better across nodes */
vma->vm_pgoff = index + info->vfs_inode.i_ino;