* [PATCH] mm: vmalloc: don't remove inexistent guard hole in remove_vm_area()
@ 2015-11-12 15:17 ` Jerome Marchand
0 siblings, 0 replies; 12+ messages in thread
From: Jerome Marchand @ 2015-11-12 15:17 UTC (permalink / raw)
To: linux-mm, Andrey Ryabinin; +Cc: linux-kernel
Commit 71394fe50146 ("mm: vmalloc: add flag preventing guard hole
allocation") missed a spot. Currently remove_vm_area() decreases
vm->size to remove the guard hole page, even when it isn't present.
This patch only decreases vm->size when VM_NO_GUARD isn't set.
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
---
mm/vmalloc.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index d045634..1388c3d 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1443,7 +1443,8 @@ struct vm_struct *remove_vm_area(const void *addr)
vmap_debug_free_range(va->va_start, va->va_end);
kasan_free_shadow(vm);
free_unmap_vmap_area(va);
- vm->size -= PAGE_SIZE;
+ if (!(vm->flags & VM_NO_GUARD))
+ vm->size -= PAGE_SIZE;
return vm;
}
--
2.4.3
^ permalink raw reply related [flat|nested] 12+ messages in thread
* [PATCH] mm: vmalloc: don't remove inexistent guard hole in remove_vm_area()
@ 2015-11-12 15:17 ` Jerome Marchand
0 siblings, 0 replies; 12+ messages in thread
From: Jerome Marchand @ 2015-11-12 15:17 UTC (permalink / raw)
To: linux-mm, Andrey Ryabinin; +Cc: linux-kernel
Commit 71394fe50146 ("mm: vmalloc: add flag preventing guard hole
allocation") missed a spot. Currently remove_vm_area() decreases
vm->size to remove the guard hole page, even when it isn't present.
This patch only decreases vm->size when VM_NO_GUARD isn't set.
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
---
mm/vmalloc.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index d045634..1388c3d 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1443,7 +1443,8 @@ struct vm_struct *remove_vm_area(const void *addr)
vmap_debug_free_range(va->va_start, va->va_end);
kasan_free_shadow(vm);
free_unmap_vmap_area(va);
- vm->size -= PAGE_SIZE;
+ if (!(vm->flags & VM_NO_GUARD))
+ vm->size -= PAGE_SIZE;
return vm;
}
--
2.4.3
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply related [flat|nested] 12+ messages in thread
* Re: [PATCH] mm: vmalloc: don't remove inexistent guard hole in remove_vm_area()
2015-11-12 15:17 ` Jerome Marchand
@ 2015-11-12 15:55 ` Andrey Ryabinin
-1 siblings, 0 replies; 12+ messages in thread
From: Andrey Ryabinin @ 2015-11-12 15:55 UTC (permalink / raw)
To: Jerome Marchand; +Cc: linux-mm, LKML, Andrew Morton
2015-11-12 18:17 GMT+03:00 Jerome Marchand <jmarchan@redhat.com>:
> Commit 71394fe50146 ("mm: vmalloc: add flag preventing guard hole
> allocation") missed a spot. Currently remove_vm_area() decreases
> vm->size to remove the guard hole page, even when it isn't present.
> This patch only decreases vm->size when VM_NO_GUARD isn't set.
>
> Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
> ---
> mm/vmalloc.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index d045634..1388c3d 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -1443,7 +1443,8 @@ struct vm_struct *remove_vm_area(const void *addr)
> vmap_debug_free_range(va->va_start, va->va_end);
> kasan_free_shadow(vm);
> free_unmap_vmap_area(va);
> - vm->size -= PAGE_SIZE;
> + if (!(vm->flags & VM_NO_GUARD))
> + vm->size -= PAGE_SIZE;
>
I'd fix this in another way. I think that remove_vm_area() shouldn't
change vm's size, IMO it doesn't make sense.
The only caller who cares about vm's size after removing is __vunmap():
area = remove_vm_area(addr);
....
debug_check_no_locks_freed(addr, area->size);
debug_check_no_obj_freed(addr, area->size);
We already have proper get_vm_area_size() helper which takes
VM_NO_GUARD into account.
So I think we should use that helper for debug_check_no_*() and just
remove 'vm->size -= PAGE_SIZE;' line
from remove_vm_area()
> return vm;
> }
> --
> 2.4.3
>
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH] mm: vmalloc: don't remove inexistent guard hole in remove_vm_area()
@ 2015-11-12 15:55 ` Andrey Ryabinin
0 siblings, 0 replies; 12+ messages in thread
From: Andrey Ryabinin @ 2015-11-12 15:55 UTC (permalink / raw)
To: Jerome Marchand; +Cc: linux-mm, LKML, Andrew Morton
2015-11-12 18:17 GMT+03:00 Jerome Marchand <jmarchan@redhat.com>:
> Commit 71394fe50146 ("mm: vmalloc: add flag preventing guard hole
> allocation") missed a spot. Currently remove_vm_area() decreases
> vm->size to remove the guard hole page, even when it isn't present.
> This patch only decreases vm->size when VM_NO_GUARD isn't set.
>
> Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
> ---
> mm/vmalloc.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index d045634..1388c3d 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -1443,7 +1443,8 @@ struct vm_struct *remove_vm_area(const void *addr)
> vmap_debug_free_range(va->va_start, va->va_end);
> kasan_free_shadow(vm);
> free_unmap_vmap_area(va);
> - vm->size -= PAGE_SIZE;
> + if (!(vm->flags & VM_NO_GUARD))
> + vm->size -= PAGE_SIZE;
>
I'd fix this in another way. I think that remove_vm_area() shouldn't
change vm's size, IMO it doesn't make sense.
The only caller who cares about vm's size after removing is __vunmap():
area = remove_vm_area(addr);
....
debug_check_no_locks_freed(addr, area->size);
debug_check_no_obj_freed(addr, area->size);
We already have proper get_vm_area_size() helper which takes
VM_NO_GUARD into account.
So I think we should use that helper for debug_check_no_*() and just
remove 'vm->size -= PAGE_SIZE;' line
from remove_vm_area()
> return vm;
> }
> --
> 2.4.3
>
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH] mm: vmalloc: don't remove inexistent guard hole in remove_vm_area()
2015-11-12 15:55 ` Andrey Ryabinin
@ 2015-11-12 16:28 ` Jerome Marchand
-1 siblings, 0 replies; 12+ messages in thread
From: Jerome Marchand @ 2015-11-12 16:28 UTC (permalink / raw)
To: Andrey Ryabinin; +Cc: linux-mm, LKML, Andrew Morton, linux-sh
[-- Attachment #1: Type: text/plain, Size: 1937 bytes --]
On 11/12/2015 04:55 PM, Andrey Ryabinin wrote:
> 2015-11-12 18:17 GMT+03:00 Jerome Marchand <jmarchan@redhat.com>:
>> Commit 71394fe50146 ("mm: vmalloc: add flag preventing guard hole
>> allocation") missed a spot. Currently remove_vm_area() decreases
>> vm->size to remove the guard hole page, even when it isn't present.
>> This patch only decreases vm->size when VM_NO_GUARD isn't set.
>>
>> Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
>> ---
>> mm/vmalloc.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
>> index d045634..1388c3d 100644
>> --- a/mm/vmalloc.c
>> +++ b/mm/vmalloc.c
>> @@ -1443,7 +1443,8 @@ struct vm_struct *remove_vm_area(const void *addr)
>> vmap_debug_free_range(va->va_start, va->va_end);
>> kasan_free_shadow(vm);
>> free_unmap_vmap_area(va);
>> - vm->size -= PAGE_SIZE;
>> + if (!(vm->flags & VM_NO_GUARD))
>> + vm->size -= PAGE_SIZE;
>>
>
> I'd fix this in another way. I think that remove_vm_area() shouldn't
> change vm's size, IMO it doesn't make sense.
> The only caller who cares about vm's size after removing is __vunmap():
> area = remove_vm_area(addr);
> ....
> debug_check_no_locks_freed(addr, area->size);
> debug_check_no_obj_freed(addr, area->size);
>
> We already have proper get_vm_area_size() helper which takes
> VM_NO_GUARD into account.
> So I think we should use that helper for debug_check_no_*() and just
> remove 'vm->size -= PAGE_SIZE;' line
> from remove_vm_area()
Sure, that would be cleaner.
Btw, there might be a leak in sq_unmap() (arch/sh/kernel/cpu/sh4/sq.c)
as the vm_struct doesn't seem to be freed. CCed the SuperH folks.
Thanks,
Jerome
>
>
>
>> return vm;
>> }
>> --
>> 2.4.3
>>
[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 473 bytes --]
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH] mm: vmalloc: don't remove inexistent guard hole in remove_vm_area()
@ 2015-11-12 16:28 ` Jerome Marchand
0 siblings, 0 replies; 12+ messages in thread
From: Jerome Marchand @ 2015-11-12 16:28 UTC (permalink / raw)
To: Andrey Ryabinin; +Cc: linux-mm, LKML, Andrew Morton, linux-sh
[-- Attachment #1: Type: text/plain, Size: 1937 bytes --]
On 11/12/2015 04:55 PM, Andrey Ryabinin wrote:
> 2015-11-12 18:17 GMT+03:00 Jerome Marchand <jmarchan@redhat.com>:
>> Commit 71394fe50146 ("mm: vmalloc: add flag preventing guard hole
>> allocation") missed a spot. Currently remove_vm_area() decreases
>> vm->size to remove the guard hole page, even when it isn't present.
>> This patch only decreases vm->size when VM_NO_GUARD isn't set.
>>
>> Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
>> ---
>> mm/vmalloc.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
>> index d045634..1388c3d 100644
>> --- a/mm/vmalloc.c
>> +++ b/mm/vmalloc.c
>> @@ -1443,7 +1443,8 @@ struct vm_struct *remove_vm_area(const void *addr)
>> vmap_debug_free_range(va->va_start, va->va_end);
>> kasan_free_shadow(vm);
>> free_unmap_vmap_area(va);
>> - vm->size -= PAGE_SIZE;
>> + if (!(vm->flags & VM_NO_GUARD))
>> + vm->size -= PAGE_SIZE;
>>
>
> I'd fix this in another way. I think that remove_vm_area() shouldn't
> change vm's size, IMO it doesn't make sense.
> The only caller who cares about vm's size after removing is __vunmap():
> area = remove_vm_area(addr);
> ....
> debug_check_no_locks_freed(addr, area->size);
> debug_check_no_obj_freed(addr, area->size);
>
> We already have proper get_vm_area_size() helper which takes
> VM_NO_GUARD into account.
> So I think we should use that helper for debug_check_no_*() and just
> remove 'vm->size -= PAGE_SIZE;' line
> from remove_vm_area()
Sure, that would be cleaner.
Btw, there might be a leak in sq_unmap() (arch/sh/kernel/cpu/sh4/sq.c)
as the vm_struct doesn't seem to be freed. CCed the SuperH folks.
Thanks,
Jerome
>
>
>
>> return vm;
>> }
>> --
>> 2.4.3
>>
[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 473 bytes --]
^ permalink raw reply [flat|nested] 12+ messages in thread
* [PATCH V2] mm: vmalloc: don't remove inexistent guard hole in remove_vm_area()
2015-11-12 15:17 ` Jerome Marchand
@ 2015-11-12 16:37 ` Jerome Marchand
-1 siblings, 0 replies; 12+ messages in thread
From: Jerome Marchand @ 2015-11-12 16:37 UTC (permalink / raw)
To: linux-mm, Andrey Ryabinin, Andrew Morton; +Cc: linux-kernel
Commit 71394fe50146 ("mm: vmalloc: add flag preventing guard hole
allocation") missed a spot. Currently remove_vm_area() decreases
vm->size to "remove" the guard hole page, even when it isn't present.
All but one users just free the vm_struct rigth away and never access
vm->size anyway.
Don't touch the size in remove_vm_area() and have __vunmap() use the
proper get_vm_area_size() helper.
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
---
mm/vmalloc.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index d045634..8e3c9c5 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1443,7 +1443,6 @@ struct vm_struct *remove_vm_area(const void *addr)
vmap_debug_free_range(va->va_start, va->va_end);
kasan_free_shadow(vm);
free_unmap_vmap_area(va);
- vm->size -= PAGE_SIZE;
return vm;
}
@@ -1468,8 +1467,8 @@ static void __vunmap(const void *addr, int deallocate_pages)
return;
}
- debug_check_no_locks_freed(addr, area->size);
- debug_check_no_obj_freed(addr, area->size);
+ debug_check_no_locks_freed(addr, get_vm_area_size(area));
+ debug_check_no_obj_freed(addr, get_vm_area_size(area));
if (deallocate_pages) {
int i;
--
2.4.3
^ permalink raw reply related [flat|nested] 12+ messages in thread
* [PATCH V2] mm: vmalloc: don't remove inexistent guard hole in remove_vm_area()
@ 2015-11-12 16:37 ` Jerome Marchand
0 siblings, 0 replies; 12+ messages in thread
From: Jerome Marchand @ 2015-11-12 16:37 UTC (permalink / raw)
To: linux-mm, Andrey Ryabinin, Andrew Morton; +Cc: linux-kernel
Commit 71394fe50146 ("mm: vmalloc: add flag preventing guard hole
allocation") missed a spot. Currently remove_vm_area() decreases
vm->size to "remove" the guard hole page, even when it isn't present.
All but one users just free the vm_struct rigth away and never access
vm->size anyway.
Don't touch the size in remove_vm_area() and have __vunmap() use the
proper get_vm_area_size() helper.
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
---
mm/vmalloc.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index d045634..8e3c9c5 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1443,7 +1443,6 @@ struct vm_struct *remove_vm_area(const void *addr)
vmap_debug_free_range(va->va_start, va->va_end);
kasan_free_shadow(vm);
free_unmap_vmap_area(va);
- vm->size -= PAGE_SIZE;
return vm;
}
@@ -1468,8 +1467,8 @@ static void __vunmap(const void *addr, int deallocate_pages)
return;
}
- debug_check_no_locks_freed(addr, area->size);
- debug_check_no_obj_freed(addr, area->size);
+ debug_check_no_locks_freed(addr, get_vm_area_size(area));
+ debug_check_no_obj_freed(addr, get_vm_area_size(area));
if (deallocate_pages) {
int i;
--
2.4.3
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply related [flat|nested] 12+ messages in thread
* Re: [PATCH V2] mm: vmalloc: don't remove inexistent guard hole in remove_vm_area()
2015-11-12 16:37 ` Jerome Marchand
@ 2015-11-12 18:48 ` Andrey Ryabinin
-1 siblings, 0 replies; 12+ messages in thread
From: Andrey Ryabinin @ 2015-11-12 18:48 UTC (permalink / raw)
To: Jerome Marchand; +Cc: linux-mm, Andrew Morton, LKML
2015-11-12 19:37 GMT+03:00 Jerome Marchand <jmarchan@redhat.com>:
> Commit 71394fe50146 ("mm: vmalloc: add flag preventing guard hole
> allocation") missed a spot. Currently remove_vm_area() decreases
> vm->size to "remove" the guard hole page, even when it isn't present.
> All but one users just free the vm_struct rigth away and never access
> vm->size anyway.
> Don't touch the size in remove_vm_area() and have __vunmap() use the
> proper get_vm_area_size() helper.
>
> Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH V2] mm: vmalloc: don't remove inexistent guard hole in remove_vm_area()
@ 2015-11-12 18:48 ` Andrey Ryabinin
0 siblings, 0 replies; 12+ messages in thread
From: Andrey Ryabinin @ 2015-11-12 18:48 UTC (permalink / raw)
To: Jerome Marchand; +Cc: linux-mm, Andrew Morton, LKML
2015-11-12 19:37 GMT+03:00 Jerome Marchand <jmarchan@redhat.com>:
> Commit 71394fe50146 ("mm: vmalloc: add flag preventing guard hole
> allocation") missed a spot. Currently remove_vm_area() decreases
> vm->size to "remove" the guard hole page, even when it isn't present.
> All but one users just free the vm_struct rigth away and never access
> vm->size anyway.
> Don't touch the size in remove_vm_area() and have __vunmap() use the
> proper get_vm_area_size() helper.
>
> Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH V2] mm: vmalloc: don't remove inexistent guard hole in remove_vm_area()
2015-11-12 16:37 ` Jerome Marchand
@ 2015-11-12 20:55 ` David Rientjes
-1 siblings, 0 replies; 12+ messages in thread
From: David Rientjes @ 2015-11-12 20:55 UTC (permalink / raw)
To: Jerome Marchand; +Cc: linux-mm, Andrey Ryabinin, Andrew Morton, linux-kernel
On Thu, 12 Nov 2015, Jerome Marchand wrote:
> Commit 71394fe50146 ("mm: vmalloc: add flag preventing guard hole
> allocation") missed a spot. Currently remove_vm_area() decreases
> vm->size to "remove" the guard hole page, even when it isn't present.
> All but one users just free the vm_struct rigth away and never access
> vm->size anyway.
> Don't touch the size in remove_vm_area() and have __vunmap() use the
> proper get_vm_area_size() helper.
>
> Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH V2] mm: vmalloc: don't remove inexistent guard hole in remove_vm_area()
@ 2015-11-12 20:55 ` David Rientjes
0 siblings, 0 replies; 12+ messages in thread
From: David Rientjes @ 2015-11-12 20:55 UTC (permalink / raw)
To: Jerome Marchand; +Cc: linux-mm, Andrey Ryabinin, Andrew Morton, linux-kernel
On Thu, 12 Nov 2015, Jerome Marchand wrote:
> Commit 71394fe50146 ("mm: vmalloc: add flag preventing guard hole
> allocation") missed a spot. Currently remove_vm_area() decreases
> vm->size to "remove" the guard hole page, even when it isn't present.
> All but one users just free the vm_struct rigth away and never access
> vm->size anyway.
> Don't touch the size in remove_vm_area() and have __vunmap() use the
> proper get_vm_area_size() helper.
>
> Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 12+ messages in thread
end of thread, other threads:[~2015-11-12 20:56 UTC | newest]
Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-11-12 15:17 [PATCH] mm: vmalloc: don't remove inexistent guard hole in remove_vm_area() Jerome Marchand
2015-11-12 15:17 ` Jerome Marchand
2015-11-12 15:55 ` Andrey Ryabinin
2015-11-12 15:55 ` Andrey Ryabinin
2015-11-12 16:28 ` Jerome Marchand
2015-11-12 16:28 ` Jerome Marchand
2015-11-12 16:37 ` [PATCH V2] " Jerome Marchand
2015-11-12 16:37 ` Jerome Marchand
2015-11-12 18:48 ` Andrey Ryabinin
2015-11-12 18:48 ` Andrey Ryabinin
2015-11-12 20:55 ` David Rientjes
2015-11-12 20:55 ` David Rientjes
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.