From a670468f5e0b5fad4db6e4d195f15915dc2a35c1 Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Tue, 21 Aug 2018 21:53:06 -0700 Subject: [PATCH] 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 Cc: Russell King Cc: Dmitry Vyukov Cc: Oleg Nesterov Cc: Andrea Arcangeli Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/arm/kernel/process.c | 9 ++++----- fs/hugetlbfs/inode.c | 2 -- include/linux/mm.h | 1 + kernel/fork.c | 3 ++- mm/mempolicy.c | 1 - mm/shmem.c | 1 - 6 files changed, 7 insertions(+), 10 deletions(-) diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c index d9c29913311116..82ab015bf42b7b 100644 --- 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//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 346a146c7617d1..32920a10100e23 100644 --- 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 a3cae495f9ce95..3a4b87d1a59abc 100644 --- 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 5ee74c113381b1..8c760effa42ea8 100644 --- 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 01f1a14facc461..4861ba738d6fc6 100644 --- 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 c48c79018a7c0c..fb04baacc9fa28 100644 --- 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;