On Thu, 4 Sep 2014 14:36:22 -0400 Sasha Levin <sasha.levin@xxxxxxxxxx> wrote:
> Make sure we actually see the output of validate_mm() and browse_rb()
> before triggering a BUG(). pr_info isn't shown by default so the reason
> for the BUG() isn't obvious.
>
yup, I'll scoot that into 3.17.
That code's actually pretty cruddy. How does this look?
From: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Subject: mm/mmap.c: clean up CONFIG_DEBUG_VM_RB checks
- be consistent in printing the test which failed
- one message was actually wrong (a<b != b>a)
- don't print second bogus warning if browse_rb() failed
Cc: Sasha Levin <sasha.levin@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mmap.c | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)
diff -puN mm/mmap.c~mm-mmapc-clean-up-config_debug_vm_rb-checks mm/mmap.c
--- a/mm/mmap.c~mm-mmapc-clean-up-config_debug_vm_rb-checks
+++ a/mm/mmap.c
@@ -369,16 +369,18 @@ static int browse_rb(struct rb_root *roo
struct vm_area_struct *vma;
vma = rb_entry(nd, struct vm_area_struct, vm_rb);
if (vma->vm_start < prev) {
- pr_emerg("vm_start %lx prev %lx\n", vma->vm_start, prev);
+ pr_emerg("vm_start %lx < prev %lx\n",
+ vma->vm_start, prev);
bug = 1;
}
if (vma->vm_start < pend) {
- pr_emerg("vm_start %lx pend %lx\n", vma->vm_start, pend);
+ pr_emerg("vm_start %lx < pend %lx\n",
+ vma->vm_start, pend);
bug = 1;
}
if (vma->vm_start > vma->vm_end) {
- pr_emerg("vm_end %lx < vm_start %lx\n",
- vma->vm_end, vma->vm_start);
+ pr_emerg("vm_start %lx > vm_end %lx\n",
+ vma->vm_start, vma->vm_end);
bug = 1;
}
if (vma->rb_subtree_gap != vma_compute_subtree_gap(vma)) {
@@ -420,8 +422,10 @@ static void validate_mm(struct mm_struct
int i = 0;
unsigned long highest_address = 0;
struct vm_area_struct *vma = mm->mmap;
+
while (vma) {
struct anon_vma_chain *avc;
+
vma_lock_anon_vma(vma);
list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
anon_vma_interval_tree_verify(avc);
@@ -436,12 +440,13 @@ static void validate_mm(struct mm_struct
}
if (highest_address != mm->highest_vm_end) {
pr_emerg("mm->highest_vm_end %lx, found %lx\n",
- mm->highest_vm_end, highest_address);
+ mm->highest_vm_end, highest_address);
bug = 1;
}
i = browse_rb(&mm->mm_rb);
if (i != mm->map_count) {
- pr_emerg("map_count %d rb %d\n", mm->map_count, i);
+ if (i != -1)
+ pr_emerg("map_count %d rb %d\n", mm->map_count, i);
bug = 1;
}
BUG_ON(bug);
_
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