From 68bc521f08d5a2baeacb85318e393ac84afc7861 Mon Sep 17 00:00:00 2001 From: Michel Lespinasse Date: Thu, 29 Nov 2012 14:17:14 +1100 Subject: [PATCH] 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. Signed-off-by: Michel Lespinasse Reviewed-by: Rik van Riel Cc: Hugh Dickins Cc: Russell King Cc: Ralf Baechle Cc: Paul Mundt Cc: "David S. Miller" Cc: Chris Metcalf Cc: Ingo Molnar Cc: Thomas Gleixner Cc: "H. Peter Anvin" Signed-off-by: Andrew Morton --- mm/mmap.c | 24 ++++++++++++++++-------- 1 file changed, 16 insertions(+), 8 deletions(-) diff --git a/mm/mmap.c b/mm/mmap.c index e8cd2b7deb66..bd56e8ee41a2 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -336,7 +336,7 @@ 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; @@ -344,23 +344,26 @@ 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; } static void validate_mm_rb(struct rb_root *root, struct vm_area_struct *ignore) @@ -379,6 +382,7 @@ 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; @@ -386,11 +390,15 @@ void validate_mm(struct mm_struct *mm) list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) anon_vma_interval_tree_verify(avc); 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 (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; -- 2.39.5