[PATCH 4.17 300/324] mm: make vm_area_alloc() initialize core fields

Greg Kroah-Hartman
2018-08-23T09:08:54Z

From: Linus Torvalds <torvalds@linux-foundation.org>

[ Upstream commit 490fc053865c9cc40f1085ef8a5504f5341f79d2 ]

Like vm_area_dup(), it initializes the anon_vma_chain head, and the
basic mm pointer.

The rest of the fields end up being different for different users,
although the plan is to also initialize the 'vm_ops' field to a dummy
entry.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/ia64/kernel/perfmon.c | 4 +---
arch/ia64/mm/init.c | 8 ++------
fs/exec.c | 4 +---
include/linux/mm.h | 2 +-
kernel/fork.c | 10 ++++++++--
mm/mmap.c | 12 +++---------
mm/nommu.c | 3 +--
7 files changed, 17 insertions(+), 26 deletions(-)

--- a/arch/ia64/kernel/perfmon.c
+++ b/arch/ia64/kernel/perfmon.c
@@ -2278,17 +2278,15 @@ pfm_smpl_buffer_alloc(struct task_struct
DPRINT(("smpl_buf @%p\n", smpl_buf));

/* allocate vma */
- vma = vm_area_alloc();
+ vma = vm_area_alloc(mm);
if (!vma) {
DPRINT(("Cannot allocate vma\n"));
goto error_kmem;
}
- INIT_LIST_HEAD(&vma->anon_vma_chain);

/*
* partially initialize the vma for the sampling buffer
*/
- vma->vm_mm = mm;
vma->vm_file = get_file(filp);
vma->vm_flags = VM_READ|VM_MAYREAD|VM_DONTEXPAND|VM_DONTDUMP;
vma->vm_page_prot = PAGE_READONLY; /* XXX may need to change */
--- a/arch/ia64/mm/init.c
+++ b/arch/ia64/mm/init.c
@@ -114,10 +114,8 @@ ia64_init_addr_space (void)
* the problem. When the process attempts to write to the register backing store
* for the first time, it will get a SEGFAULT in this case.
*/
- vma = vm_area_alloc();
+ vma = vm_area_alloc(current->mm);
if (vma) {
- INIT_LIST_HEAD(&vma->anon_vma_chain);
- vma->vm_mm = current->mm;
vma->vm_start = current->thread.rbs_bot & PAGE_MASK;
vma->vm_end = vma->vm_start + PAGE_SIZE;
vma->vm_flags = VM_DATA_DEFAULT_FLAGS|VM_GROWSUP|VM_ACCOUNT;
@@ -133,10 +131,8 @@ ia64_init_addr_space (void)

/* map NaT-page at address zero to speed up speculative dereferencing of NULL: */
if (!(current->personality & MMAP_PAGE_ZERO)) {
- vma = vm_area_alloc();
+ vma = vm_area_alloc(current->mm);
if (vma) {
- INIT_LIST_HEAD(&vma->anon_vma_chain);
- vma->vm_mm = current->mm;
vma->vm_end = PAGE_SIZE;
vma->vm_page_prot = __pgprot(pgprot_val(PAGE_READONLY) | _PAGE_MA_NAT);
vma->vm_flags = VM_READ | VM_MAYREAD | VM_IO |
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -290,7 +290,7 @@ static int __bprm_mm_init(struct linux_b
struct vm_area_struct *vma = NULL;
struct mm_struct *mm = bprm->mm;

- bprm->vma = vma = vm_area_alloc();
+ bprm->vma = vma = vm_area_alloc(mm);
if (!vma)
return -ENOMEM;

@@ -298,7 +298,6 @@ static int __bprm_mm_init(struct linux_b
err = -EINTR;
goto err_free;
}
- vma->vm_mm = mm;

/*
* Place the stack at the largest stack address the architecture
@@ -311,7 +310,6 @@ static int __bprm_mm_init(struct linux_b
vma->vm_start = vma->vm_end - PAGE_SIZE;
vma->vm_flags = VM_SOFTDIRTY | VM_STACK_FLAGS | VM_STACK_INCOMPLETE_SETUP;
vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
- INIT_LIST_HEAD(&vma->anon_vma_chain);

err = insert_vm_struct(mm, vma);
if (err)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -154,7 +154,7 @@ extern int overcommit_kbytes_handler(str
* mmap() functions).
*/

-struct vm_area_struct *vm_area_alloc(void);
+struct vm_area_struct *vm_area_alloc(struct mm_struct *);
struct vm_area_struct *vm_area_dup(struct vm_area_struct *);
void vm_area_free(struct vm_area_struct *);

--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -308,9 +308,15 @@ static struct kmem_cache *vm_area_cachep
/* SLAB cache for mm_struct structures (tsk->mm) */
static struct kmem_cache *mm_cachep;

-struct vm_area_struct *vm_area_alloc(void)
+struct vm_area_struct *vm_area_alloc(struct mm_struct *mm)
{
- return kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
+ struct vm_area_struct *vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
+
+ if (vma) {
+ vma->vm_mm = mm;
+ INIT_LIST_HEAD(&vma->anon_vma_chain);
+ }
+ return vma;
}

struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1729,19 +1729,17 @@ unsigned long mmap_region(struct file *f
* specific mapper. the address has already been validated, but
* not unmapped, but the maps are removed from the list.
*/
- vma = vm_area_alloc();
+ vma = vm_area_alloc(mm);
if (!vma) {
error = -ENOMEM;
goto unacct_error;
}

- vma->vm_mm = mm;
vma->vm_start = addr;
vma->vm_end = addr + len;
vma->vm_flags = vm_flags;
vma->vm_page_prot = vm_get_page_prot(vm_flags);
vma->vm_pgoff = pgoff;
- INIT_LIST_HEAD(&vma->anon_vma_chain);

if (file) {
if (vm_flags & VM_DENYWRITE) {
@@ -2979,14 +2977,12 @@ static int do_brk_flags(unsigned long ad
/*
* create a vma struct for an anonymous mapping
*/
- vma = vm_area_alloc();
+ vma = vm_area_alloc(mm);
if (!vma) {
vm_unacct_memory(len >> PAGE_SHIFT);
return -ENOMEM;
}

- INIT_LIST_HEAD(&vma->anon_vma_chain);
- vma->vm_mm = mm;
vma->vm_start = addr;
vma->vm_end = addr + len;
vma->vm_pgoff = pgoff;
@@ -3343,12 +3339,10 @@ static struct vm_area_struct *__install_
int ret;
struct vm_area_struct *vma;

- vma = vm_area_alloc();
+ vma = vm_area_alloc(mm);
if (unlikely(vma == NULL))
return ERR_PTR(-ENOMEM);

- INIT_LIST_HEAD(&vma->anon_vma_chain);
- vma->vm_mm = mm;
vma->vm_start = addr;
vma->vm_end = addr + len;

--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1204,7 +1204,7 @@ unsigned long do_mmap(struct file *file,
if (!region)
goto error_getting_region;

- vma = vm_area_alloc();
+ vma = vm_area_alloc(current->mm);
if (!vma)
goto error_getting_vma;

@@ -1212,7 +1212,6 @@ unsigned long do_mmap(struct file *file,
region->vm_flags = vm_flags;
region->vm_pgoff = pgoff;

- INIT_LIST_HEAD(&vma->anon_vma_chain);
vma->vm_flags = vm_flags;
vma->vm_pgoff = pgoff;