When CONFIG_DEBUG_VM_RB is enabled, check that rb_subtree_gap is
correctly set for every vma and that mm->highest_vm_end is also correct.
Also add an explicit 'bug' variable to track if browse_rb() detected any
invalid condition.
Signed-off-by: Michel Lespinasse <walken@xxxxxxxxxx>
Reviewed-by: Rik van Riel <riel@xxxxxxxxxx>
---
mm/mmap.c | 24 ++++++++++++++++--------
1 files changed, 16 insertions(+), 8 deletions(-)
diff --git a/mm/mmap.c b/mm/mmap.c
index 2de8bcfe859d..769a09cc71af 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -365,7 +365,7 @@ static void vma_rb_erase(struct vm_area_struct *vma, struct rb_root *root)
#ifdef CONFIG_DEBUG_VM_RB
static int browse_rb(struct rb_root *root)
{
- int i = 0, j;
+ int i = 0, j, bug = 0;
struct rb_node *nd, *pn = NULL;
unsigned long prev = 0, pend = 0;
@@ -373,29 +373,33 @@ static int browse_rb(struct rb_root *root)
struct vm_area_struct *vma;
vma = rb_entry(nd, struct vm_area_struct, vm_rb);
if (vma->vm_start < prev)
- printk("vm_start %lx prev %lx\n", vma->vm_start, prev), i = -1;
+ printk("vm_start %lx prev %lx\n", vma->vm_start, prev), bug = 1;
if (vma->vm_start < pend)
- printk("vm_start %lx pend %lx\n", vma->vm_start, pend);
+ printk("vm_start %lx pend %lx\n", vma->vm_start, pend), bug = 1;
if (vma->vm_start > vma->vm_end)
- printk("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start);
+ printk("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start), bug = 1;
+ if (vma->rb_subtree_gap != vma_compute_subtree_gap(vma))
+ printk("free gap %lx, correct %lx\n",
+ vma->rb_subtree_gap,
+ vma_compute_subtree_gap(vma)), bug = 1;
i++;
pn = nd;
prev = vma->vm_start;
pend = vma->vm_end;
}
j = 0;
- for (nd = pn; nd; nd = rb_prev(nd)) {
+ for (nd = pn; nd; nd = rb_prev(nd))
j++;
- }
if (i != j)
- printk("backwards %d, forwards %d\n", j, i), i = 0;
- return i;
+ printk("backwards %d, forwards %d\n", j, i), bug = 1;
+ return bug ? -1 : i;
}
void validate_mm(struct mm_struct *mm)
{
int bug = 0;
int i = 0;
+ unsigned long highest_address = 0;
struct vm_area_struct *vma = mm->mmap;
while (vma) {
struct anon_vma_chain *avc;
@@ -403,11 +407,15 @@ void validate_mm(struct mm_struct *mm)
list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
anon_vma_interval_tree_verify(avc);
anon_vma_unlock(vma->anon_vma);
+ highest_address = vma->vm_end;
vma = vma->vm_next;
i++;
}
if (i != mm->map_count)
printk("map_count %d vm_next %d\n", mm->map_count, i), bug = 1;
+ if (highest_address != mm->highest_vm_end)
+ printk("mm->highest_vm_end %lx, found %lx\n",
+ mm->highest_vm_end, highest_address), bug = 1;
i = browse_rb(&mm->mm_rb);
if (i != mm->map_count)
printk("map_count %d rb %d\n", mm->map_count, i), bug = 1;
--
1.7.7.3
