* [PATCH] mmap: fix loop when adjusting vma
@ 2011-11-11 12:53 ` Hillf Danton
0 siblings, 0 replies; 4+ messages in thread
From: Hillf Danton @ 2011-11-11 12:53 UTC (permalink / raw)
To: Andrew Morton
Cc: Andrea Arcangeli, Hugh Dickins, Johannes Weiner, LKML, linux-mm
If we have more work to do after one vma is removed, we have to reload @end in
case it is clobbered, then try again.
Thanks
Signed-off-by: Hillf Danton <dhillf@gmail.com>
---
--- a/mm/mmap.c Fri Nov 11 20:35:46 2011
+++ b/mm/mmap.c Fri Nov 11 20:41:32 2011
@@ -490,6 +490,7 @@ __vma_unlink(struct mm_struct *mm, struc
int vma_adjust(struct vm_area_struct *vma, unsigned long start,
unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert)
{
+ unsigned long saved_end = end;
struct mm_struct *mm = vma->vm_mm;
struct vm_area_struct *next = vma->vm_next;
struct vm_area_struct *importer = NULL;
@@ -634,7 +635,14 @@ again: remove_next = 1 + (end > next->
*/
if (remove_next == 2) {
next = vma->vm_next;
- goto again;
+ if (next) {
+ /*
+ * we have more work, reload @end in case
+ * it is clobbered.
+ */
+ end = saved_end;
+ goto again;
+ }
}
}
^ permalink raw reply [flat|nested] 4+ messages in thread* [PATCH] mmap: fix loop when adjusting vma
@ 2011-11-11 12:53 ` Hillf Danton
0 siblings, 0 replies; 4+ messages in thread
From: Hillf Danton @ 2011-11-11 12:53 UTC (permalink / raw)
To: Andrew Morton
Cc: Andrea Arcangeli, Hugh Dickins, Johannes Weiner, LKML, linux-mm
If we have more work to do after one vma is removed, we have to reload @end in
case it is clobbered, then try again.
Thanks
Signed-off-by: Hillf Danton <dhillf@gmail.com>
---
--- a/mm/mmap.c Fri Nov 11 20:35:46 2011
+++ b/mm/mmap.c Fri Nov 11 20:41:32 2011
@@ -490,6 +490,7 @@ __vma_unlink(struct mm_struct *mm, struc
int vma_adjust(struct vm_area_struct *vma, unsigned long start,
unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert)
{
+ unsigned long saved_end = end;
struct mm_struct *mm = vma->vm_mm;
struct vm_area_struct *next = vma->vm_next;
struct vm_area_struct *importer = NULL;
@@ -634,7 +635,14 @@ again: remove_next = 1 + (end > next->
*/
if (remove_next == 2) {
next = vma->vm_next;
- goto again;
+ if (next) {
+ /*
+ * we have more work, reload @end in case
+ * it is clobbered.
+ */
+ end = saved_end;
+ goto again;
+ }
}
}
--
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^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] mmap: fix loop when adjusting vma
2011-11-11 12:53 ` Hillf Danton
@ 2011-11-11 17:24 ` Andrea Arcangeli
-1 siblings, 0 replies; 4+ messages in thread
From: Andrea Arcangeli @ 2011-11-11 17:24 UTC (permalink / raw)
To: Hillf Danton; +Cc: Andrew Morton, Hugh Dickins, Johannes Weiner, LKML, linux-mm
On Fri, Nov 11, 2011 at 08:53:23PM +0800, Hillf Danton wrote:
> --- a/mm/mmap.c Fri Nov 11 20:35:46 2011
> +++ b/mm/mmap.c Fri Nov 11 20:41:32 2011
> @@ -490,6 +490,7 @@ __vma_unlink(struct mm_struct *mm, struc
> int vma_adjust(struct vm_area_struct *vma, unsigned long start,
> unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert)
> {
> + unsigned long saved_end = end;
> struct mm_struct *mm = vma->vm_mm;
> struct vm_area_struct *next = vma->vm_next;
> struct vm_area_struct *importer = NULL;
> @@ -634,7 +635,14 @@ again: remove_next = 1 + (end > next->
> */
> if (remove_next == 2) {
> next = vma->vm_next;
> - goto again;
> + if (next) {
> + /*
> + * we have more work, reload @end in case
> + * it is clobbered.
> + */
> + end = saved_end;
> + goto again;
> + }
> }
Doesn't matter if it's clobbered, remove_next will be set to 1 and
that's all we care about. Caller should use vma->vm_next->vm_end as
"end" anyway for case 6 so it wouldn't be set to 2. Also next can't be
NULL if remove_next == 2. So I don't think this is necessary.
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] mmap: fix loop when adjusting vma
@ 2011-11-11 17:24 ` Andrea Arcangeli
0 siblings, 0 replies; 4+ messages in thread
From: Andrea Arcangeli @ 2011-11-11 17:24 UTC (permalink / raw)
To: Hillf Danton; +Cc: Andrew Morton, Hugh Dickins, Johannes Weiner, LKML, linux-mm
On Fri, Nov 11, 2011 at 08:53:23PM +0800, Hillf Danton wrote:
> --- a/mm/mmap.c Fri Nov 11 20:35:46 2011
> +++ b/mm/mmap.c Fri Nov 11 20:41:32 2011
> @@ -490,6 +490,7 @@ __vma_unlink(struct mm_struct *mm, struc
> int vma_adjust(struct vm_area_struct *vma, unsigned long start,
> unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert)
> {
> + unsigned long saved_end = end;
> struct mm_struct *mm = vma->vm_mm;
> struct vm_area_struct *next = vma->vm_next;
> struct vm_area_struct *importer = NULL;
> @@ -634,7 +635,14 @@ again: remove_next = 1 + (end > next->
> */
> if (remove_next == 2) {
> next = vma->vm_next;
> - goto again;
> + if (next) {
> + /*
> + * we have more work, reload @end in case
> + * it is clobbered.
> + */
> + end = saved_end;
> + goto again;
> + }
> }
Doesn't matter if it's clobbered, remove_next will be set to 1 and
that's all we care about. Caller should use vma->vm_next->vm_end as
"end" anyway for case 6 so it wouldn't be set to 2. Also next can't be
NULL if remove_next == 2. So I don't think this is necessary.
--
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^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2011-11-11 17:25 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2011-11-11 12:53 [PATCH] mmap: fix loop when adjusting vma Hillf Danton
2011-11-11 12:53 ` Hillf Danton
2011-11-11 17:24 ` Andrea Arcangeli
2011-11-11 17:24 ` Andrea Arcangeli
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