mm: zero out the vma in vma_init()

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>

diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index d9c2991..82ab015 100644 (file)
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -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);

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 346a146..32920a1 100644 (file)
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -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;

diff --git a/include/linux/mm.h b/include/linux/mm.h
index a3cae49..3a4b87d 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -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);

diff --git a/kernel/fork.c b/kernel/fork.c
index 5ee74c1..8c760ef 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -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;

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 01f1a14..4861ba7 100644 (file)
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -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 */

diff --git a/mm/shmem.c b/mm/shmem.c
index c48c790..fb04baa 100644 (file)
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -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;