*/
int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
{
- unsigned long free, allowed;
+ long free, allowed;
vm_acct_memory(pages);
unsigned long rlim, retval;
unsigned long newbrk, oldbrk;
struct mm_struct *mm = current->mm;
+ struct vm_area_struct *next;
unsigned long min_brk;
down_write(&mm->mmap_sem);
}
/* Check against existing mmap mappings. */
- if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE))
+ next = find_vma(mm, oldbrk);
+ if (next && newbrk + PAGE_SIZE > vm_start_gap(next))
goto out;
/* Ok, looks good - let it rip. */
importer->anon_vma = exporter->anon_vma;
error = anon_vma_clone(importer, exporter);
- if (error) {
- importer->anon_vma = NULL;
+ if (error)
return error;
- }
}
}
unsigned long len, unsigned long pgoff, unsigned long flags)
{
struct mm_struct *mm = current->mm;
- struct vm_area_struct *vma;
- unsigned long start_addr;
+ struct vm_area_struct *vma, *prev;
+ unsigned long start_addr, vm_start, prev_end;
if (len > TASK_SIZE - mmap_min_addr)
return -ENOMEM;
if (addr) {
addr = PAGE_ALIGN(addr);
- vma = find_vma(mm, addr);
+ vma = find_vma_prev(mm, addr, &prev);
if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
- (!vma || addr + len <= vma->vm_start))
+ (!vma || addr + len <= vm_start_gap(vma)) &&
+ (!prev || addr >= vm_end_gap(prev)))
return addr;
}
if (len > mm->cached_hole_size) {
}
full_search:
- for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
+ for (vma = find_vma_prev(mm, addr, &prev); ; prev = vma,
+ vma = vma->vm_next) {
+ if (prev) {
+ prev_end = vm_end_gap(prev);
+ if (addr < prev_end) {
+ addr = prev_end;
+ /* If vma already violates gap, forget it */
+ if (vma && addr > vma->vm_start)
+ addr = vma->vm_start;
+ }
+ }
/* At this point: (!vma || addr < vma->vm_end). */
if (TASK_SIZE - len < addr) {
/*
}
return -ENOMEM;
}
- if (!vma || addr + len <= vma->vm_start) {
+ vm_start = vma ? vm_start_gap(vma) : TASK_SIZE;
+ if (addr + len <= vm_start) {
/*
* Remember the place where we stopped the search:
*/
mm->free_area_cache = addr + len;
return addr;
}
- if (addr + mm->cached_hole_size < vma->vm_start)
- mm->cached_hole_size = vma->vm_start - addr;
- addr = vma->vm_end;
+ if (addr + mm->cached_hole_size < vm_start)
+ mm->cached_hole_size = vm_start - addr;
}
}
#endif
const unsigned long len, const unsigned long pgoff,
const unsigned long flags)
{
- struct vm_area_struct *vma;
+ struct vm_area_struct *vma, *prev;
struct mm_struct *mm = current->mm;
unsigned long addr = addr0;
+ unsigned long vm_start, prev_end;
unsigned long low_limit = max(PAGE_SIZE, mmap_min_addr);
/* requested length too big for entire address space */
/* requesting a specific address */
if (addr) {
addr = PAGE_ALIGN(addr);
- vma = find_vma(mm, addr);
+ vma = find_vma_prev(mm, addr, &prev);
if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
- (!vma || addr + len <= vma->vm_start))
+ (!vma || addr + len <= vm_start_gap(vma)) &&
+ (!prev || addr >= vm_end_gap(prev)))
return addr;
}
/* make sure it can fit in the remaining address space */
if (addr >= low_limit + len) {
- vma = find_vma(mm, addr-len);
- if (!vma || addr <= vma->vm_start)
+ vma = find_vma_prev(mm, addr-len, &prev);
+ if ((!vma || addr <= vm_start_gap(vma)) &&
+ (!prev || addr-len >= vm_end_gap(prev)))
/* remember the address as a hint for next time */
return (mm->free_area_cache = addr-len);
}
* else if new region fits below vma->vm_start,
* return with success:
*/
- vma = find_vma(mm, addr);
- if (!vma || addr+len <= vma->vm_start)
+ vma = find_vma_prev(mm, addr, &prev);
+ vm_start = vma ? vm_start_gap(vma) : mm->mmap_base;
+ prev_end = prev ? vm_end_gap(prev) : low_limit;
+
+ if (addr + len <= vm_start && addr >= prev_end)
/* remember the address as a hint for next time */
return (mm->free_area_cache = addr);
/* remember the largest hole we saw so far */
- if (addr + mm->cached_hole_size < vma->vm_start)
- mm->cached_hole_size = vma->vm_start - addr;
+ if (addr + mm->cached_hole_size < vm_start)
+ mm->cached_hole_size = vm_start - addr;
/* try just below the current vma->vm_start */
- addr = vma->vm_start-len;
- } while (vma->vm_start >= low_limit + len);
+ addr = vm_start - len;
+ } while (vm_start >= low_limit + len);
bottomup:
/*
EXPORT_SYMBOL(find_vma);
-/* Same as find_vma, but also return a pointer to the previous VMA in *pprev. */
+/*
+ * Same as find_vma, but also return a pointer to the previous VMA in *pprev.
+ * Note: pprev is set to NULL when return value is NULL.
+ */
struct vm_area_struct *
find_vma_prev(struct mm_struct *mm, unsigned long addr,
struct vm_area_struct **pprev)
{
- struct vm_area_struct *vma = NULL, *prev = NULL;
- struct rb_node *rb_node;
- if (!mm)
- goto out;
-
- /* Guard against addr being lower than the first VMA */
- vma = mm->mmap;
-
- /* Go through the RB tree quickly. */
- rb_node = mm->mm_rb.rb_node;
-
- while (rb_node) {
- struct vm_area_struct *vma_tmp;
- vma_tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb);
-
- if (addr < vma_tmp->vm_end) {
- rb_node = rb_node->rb_left;
- } else {
- prev = vma_tmp;
- if (!prev->vm_next || (addr < prev->vm_next->vm_end))
- break;
- rb_node = rb_node->rb_right;
- }
- }
+ struct vm_area_struct *vma;
-out:
- *pprev = prev;
- return prev ? prev->vm_next : vma;
+ vma = find_vma(mm, addr);
+ *pprev = vma ? vma->vm_prev : NULL;
+ return vma;
}
/*
* update accounting. This is shared with both the
* grow-up and grow-down cases.
*/
-static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, unsigned long grow)
+static int acct_stack_growth(struct vm_area_struct *vma,
+ unsigned long size, unsigned long grow)
{
struct mm_struct *mm = vma->vm_mm;
struct rlimit *rlim = current->signal->rlim;
- unsigned long new_start, actual_size;
+ unsigned long new_start;
/* address space limit tests */
if (!may_expand_vm(mm, grow))
return -ENOMEM;
/* Stack limit test */
- actual_size = size;
- if (size && (vma->vm_flags & (VM_GROWSUP | VM_GROWSDOWN)))
- actual_size -= PAGE_SIZE;
- if (actual_size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur))
+ if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur))
return -ENOMEM;
/* mlock limit tests */
*/
int expand_upwards(struct vm_area_struct *vma, unsigned long address)
{
- int error;
+ struct vm_area_struct *next;
+ unsigned long gap_addr;
+ int error = 0;
if (!(vma->vm_flags & VM_GROWSUP))
return -EFAULT;
- /*
- * We must make sure the anon_vma is allocated
- * so that the anon_vma locking is not a noop.
- */
+ /* Guard against exceeding limits of the address space. */
+ address &= PAGE_MASK;
+ if (address >= TASK_SIZE)
+ return -ENOMEM;
+ address += PAGE_SIZE;
+
+ /* Enforce stack_guard_gap */
+ gap_addr = address + stack_guard_gap;
+
+ /* Guard against overflow */
+ if (gap_addr < address || gap_addr > TASK_SIZE)
+ gap_addr = TASK_SIZE;
+
+ next = vma->vm_next;
+ if (next && next->vm_start < gap_addr) {
+ if (!(next->vm_flags & VM_GROWSUP))
+ return -ENOMEM;
+ /* Check that both stack segments have the same anon_vma? */
+ }
+
+ /* We must make sure the anon_vma is allocated. */
if (unlikely(anon_vma_prepare(vma)))
return -ENOMEM;
- vma_lock_anon_vma(vma);
/*
* vma->vm_start/vm_end cannot change under us because the caller
* is required to hold the mmap_sem in read mode. We need the
* anon_vma lock to serialize against concurrent expand_stacks.
- * Also guard against wrapping around to address 0.
*/
- if (address < PAGE_ALIGN(address+4))
- address = PAGE_ALIGN(address+4);
- else {
- vma_unlock_anon_vma(vma);
- return -ENOMEM;
- }
- error = 0;
+ vma_lock_anon_vma(vma);
/* Somebody else might have raced and expanded it already */
if (address > vma->vm_end) {
int expand_downwards(struct vm_area_struct *vma,
unsigned long address)
{
+ struct vm_area_struct *prev;
+ unsigned long gap_addr;
int error;
- /*
- * We must make sure the anon_vma is allocated
- * so that the anon_vma locking is not a noop.
- */
- if (unlikely(anon_vma_prepare(vma)))
- return -ENOMEM;
-
address &= PAGE_MASK;
error = security_file_mmap(NULL, 0, 0, 0, address, 1);
if (error)
return error;
- vma_lock_anon_vma(vma);
+ /* Enforce stack_guard_gap */
+ gap_addr = address - stack_guard_gap;
+ if (gap_addr > address)
+ return -ENOMEM;
+ prev = vma->vm_prev;
+ if (prev && prev->vm_end > gap_addr) {
+ if (!(prev->vm_flags & VM_GROWSDOWN))
+ return -ENOMEM;
+ /* Check that both stack segments have the same anon_vma? */
+ }
+
+ /* We must make sure the anon_vma is allocated. */
+ if (unlikely(anon_vma_prepare(vma)))
+ return -ENOMEM;
/*
* vma->vm_start/vm_end cannot change under us because the caller
* is required to hold the mmap_sem in read mode. We need the
* anon_vma lock to serialize against concurrent expand_stacks.
*/
+ vma_lock_anon_vma(vma);
/* Somebody else might have raced and expanded it already */
if (address < vma->vm_start) {
return error;
}
+/* enforced gap between the expanding stack and other mappings. */
+unsigned long stack_guard_gap = 256UL<<PAGE_SHIFT;
+
+static int __init cmdline_parse_stack_guard_gap(char *p)
+{
+ unsigned long val;
+ char *endptr;
+
+ val = simple_strtoul(p, &endptr, 10);
+ if (!*endptr)
+ stack_guard_gap = val << PAGE_SHIFT;
+
+ return 0;
+}
+__setup("stack_guard_gap=", cmdline_parse_stack_guard_gap);
+
#ifdef CONFIG_STACK_GROWSUP
int expand_stack(struct vm_area_struct *vma, unsigned long address)
{
git.openpandora.org / pandora-kernel.git / blobdiff