diff options
| author | Michel Lespinasse <walken@google.com> | 2012-12-11 16:01:42 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-12-11 17:22:25 -0800 |
| commit | 5a0768f641a5bad844860e67250baf0d1aa5e03c (patch) | |
| tree | 3bb26ec05c4aede8ff37474dc27b5af49892c95e | |
| parent | d37371870ceb1d2165397dc36114725b6dca946c (diff) | |
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>
| -rw-r--r-- | mm/mmap.c | 53 |
1 files changed, 39 insertions, 14 deletions
diff --git a/mm/mmap.c b/mm/mmap.c index bdcea6310fff..ff93f6c8436c 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -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 |