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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>
This commit is contained in:
Michel Lespinasse 2012-12-11 16:01:42 -08:00 committed by Linus Torvalds
parent d37371870c
commit 5a0768f641
1 changed files with 39 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

53
mm/mmap.c
View File

@ -322,31 +322,45 @@ static long vma_compute_subtree_gap(struct vm_area_struct *vma)
#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 @@ 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;
@ -372,14 +387,24 @@ void validate_mm(struct mm_struct *mm)
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