From: Andrew Morton <akpm@linux-foundation.org>
To: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>, Hugh Dickins <hughd@google.com>,
linux-kernel@vger.kernel.org,
Russell King <linux@arm.linux.org.uk>,
Ralf Baechle <ralf@linux-mips.org>,
Paul Mundt <lethal@linux-sh.org>,
"David S. Miller" <davem@davemloft.net>,
Chris Metcalf <cmetcalf@tilera.com>,
x86@kernel.org, William Irwin <wli@holomorphy.com>,
linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org,
linux-mips@linux-mips.org, linux-sh@vger.kernel.org,
sparclinux@vger.kernel.org
Subject: Re: [PATCH 03/16] mm: check rb_subtree_gap correctness
Date: Tue, 6 Nov 2012 14:38:15 -0800 [thread overview]
Message-ID: <20121106143815.2d311383.akpm@linux-foundation.org> (raw)
In-Reply-To: <1352155633-8648-4-git-send-email-walken@google.com>
On Mon, 5 Nov 2012 14:47:00 -0800
Michel Lespinasse <walken@google.com> wrote:
> 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.
>
> ...
>
> @@ -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;
OK, now who did that. Whoever it was: stop it or you'll have your
kernel license revoked!
--- a/mm/mmap.c~mm-check-rb_subtree_gap-correctness-fix
+++ a/mm/mmap.c
@@ -372,16 +372,25 @@ static int browse_rb(struct rb_root *roo
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), bug = 1;
- if (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), bug = 1;
- if (vma->rb_subtree_gap != vma_compute_subtree_gap(vma))
+ 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);
+ 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;
+ vma_compute_subtree_gap(vma));
+ bug = 1;
+ }
i++;
pn = nd;
prev = vma->vm_start;
@@ -390,8 +399,10 @@ static int browse_rb(struct rb_root *roo
j = 0;
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);
+ bug = 1;
+ }
return bug ? -1 : i;
}
@@ -411,14 +422,20 @@ void validate_mm(struct mm_struct *mm)
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)
+ 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;
+ 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
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next prev parent reply other threads:[~2012-11-06 22:38 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-05 22:46 [PATCH 00/16] mm: use augmented rbtrees for finding unmapped areas Michel Lespinasse
2012-11-05 22:46 ` [PATCH 01/16] mm: add anon_vma_lock to validate_mm() Michel Lespinasse
2012-11-05 23:06 ` Rik van Riel
2012-11-06 8:00 ` Michel Lespinasse
2012-11-05 22:46 ` [PATCH 02/16] mm: augment vma rbtree with rb_subtree_gap Michel Lespinasse
2012-11-05 22:47 ` [PATCH 03/16] mm: check rb_subtree_gap correctness Michel Lespinasse
2012-11-06 22:38 ` Andrew Morton [this message]
2012-11-09 14:13 ` Sasha Levin
2012-11-09 20:06 ` Hugh Dickins
2012-11-12 11:55 ` Michel Lespinasse
2012-11-05 22:47 ` [PATCH 04/16] mm: rearrange vm_area_struct for fewer cache misses Michel Lespinasse
2012-11-05 22:47 ` [PATCH 05/16] mm: vm_unmapped_area() lookup function Michel Lespinasse
2012-11-05 22:47 ` [PATCH 06/16] mm: use vm_unmapped_area() on x86_64 architecture Michel Lespinasse
2012-11-05 22:47 ` [PATCH 07/16] mm: fix cache coloring " Michel Lespinasse
2012-11-06 22:38 ` Andrew Morton
2012-11-05 22:47 ` [PATCH 08/16] mm: use vm_unmapped_area() in hugetlbfs Michel Lespinasse
2012-11-05 23:33 ` Rik van Riel
2012-11-05 22:47 ` [PATCH 09/16] mm: use vm_unmapped_area() in hugetlbfs on i386 architecture Michel Lespinasse
2012-11-05 23:07 ` Rik van Riel
2012-11-06 22:38 ` Andrew Morton
2012-11-06 22:48 ` Rik van Riel
2012-11-05 22:47 ` [PATCH 10/16] mm: use vm_unmapped_area() on mips architecture Michel Lespinasse
2012-11-05 23:34 ` Rik van Riel
2012-11-06 22:38 ` Andrew Morton
2012-11-05 22:47 ` [PATCH 11/16] mm: use vm_unmapped_area() on arm architecture Michel Lespinasse
2012-11-05 23:35 ` Rik van Riel
2012-11-06 22:38 ` Andrew Morton
2012-11-05 22:47 ` [PATCH 12/16] mm: use vm_unmapped_area() on sh architecture Michel Lespinasse
2012-11-05 23:35 ` Rik van Riel
2012-11-05 22:47 ` [PATCH 13/16] mm: use vm_unmapped_area() on sparc64 architecture Michel Lespinasse
2012-11-05 23:36 ` Rik van Riel
2012-11-05 22:47 ` [PATCH 14/16] mm: use vm_unmapped_area() in hugetlbfs " Michel Lespinasse
2012-11-05 23:36 ` Rik van Riel
2012-11-05 22:47 ` [PATCH 15/16] mm: use vm_unmapped_area() on sparc32 architecture Michel Lespinasse
2012-11-05 23:37 ` Rik van Riel
2012-11-06 1:25 ` David Miller
2012-11-06 3:13 ` Michel Lespinasse
2012-11-06 7:30 ` Rik van Riel
2012-11-06 17:41 ` David Miller
2012-11-05 22:47 ` [PATCH 16/16] mm: use vm_unmapped_area() in hugetlbfs on tile architecture Michel Lespinasse
2012-11-05 23:37 ` Rik van Riel
2012-11-06 22:11 ` [PATCH 00/16] mm: use augmented rbtrees for finding unmapped areas Andrew Morton
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