mm: check rb_subtree_gap correctness
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.
[akpm@linux-foundation.org: repair innovative coding-style inventions]
Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/mmap.c b/mm/mmap.c
index bdcea63..ff93f6c 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -322,31 +322,45 @@
#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;
for (nd = rb_first(root); nd; nd = rb_next(nd)) {
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;
- if (vma->vm_start < pend)
+ if (vma->vm_start < prev) {
+ 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);
- if (vma->vm_start > vma->vm_end)
- printk("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start);
+ bug = 1;
+ }
+ if (vma->vm_start > vma->vm_end) {
+ 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);
+ bug = 1;
}
- if (i != j)
- printk("backwards %d, forwards %d\n", j, i), i = 0;
- return i;
+ return bug ? -1 : i;
}
static void validate_mm_rb(struct rb_root *root, struct vm_area_struct *ignore)
@@ -365,6 +379,7 @@
{
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;
@@ -372,14 +387,24 @@
list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
anon_vma_interval_tree_verify(avc);
vma_unlock_anon_vma(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 (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;
+ if (i != mm->map_count) {
+ printk("map_count %d rb %d\n", mm->map_count, i);
+ bug = 1;
+ }
BUG_ON(bug);
}
#else