Re: [RFC v9 PATCH 13/21] memory-hotplug: check page type in get_page_bootmem
On 10/01/2012 11:03 AM, Yasuaki Ishimatsu wrote:
Hi Chen,
2012/09/29 11:15, Ni zhan Chen wrote:
On 09/05/2012 05:25 PM, we...@cn.fujitsu.com wrote:
From: Yasuaki Ishimatsu
The function get_page_bootmem() may be called more than one time to
the same
page. There is no need to set page's type, private if the function
is not
the first time called to the page.
Note: the patch is just optimization and does not fix any problem.
Hi Yasuaki,
this patch is reasonable to me. I have another question associated to
get_page_bootmem(), the question is from another fujitsu guy's patch
changelog [commit : 04753278769f3], the changelog said that:
1) When the memmap of removing section is allocated on other
section by bootmem, it should/can be free.
2) When the memmap of removing section is allocated on the
same section, it shouldn't be freed. Because the section has to be
logical memory offlined already and all pages must be isolated
against
page allocater. If it is freed, page allocator may use it which
will
be removed physically soon.
but I don't see his patch guarantee 2), it means that his patch
doesn't guarantee the memmap of removing section which is allocated
on other section by bootmem doesn't be freed. Hopefully get your
explaination in details, thanks in advance. :-)
In my understanding, the patch does not guarantee it.
Please see [commit : 0c0a4a517a31e]. free_map_bootmem() in the commit
guarantees it.
Thanks Yasuaki, I have already seen the commit you mentioned. But the
changelog of the commit I point out 2), why it said that "If it is
freed, page allocator may use it which will be removed physically soon",
does it mean that use-after-free ? AFAK, the isolated pages will be free
if no users use it, so why not free the associated memmap?
Thanks,
Yasuaki Ishimatsu
CC: David Rientjes
CC: Jiang Liu
CC: Len Brown
CC: Benjamin Herrenschmidt
CC: Paul Mackerras
CC: Christoph Lameter
Cc: Minchan Kim
CC: Andrew Morton
CC: KOSAKI Motohiro
CC: Wen Congyang
Signed-off-by: Yasuaki Ishimatsu
---
mm/memory_hotplug.c | 15 +++
1 files changed, 11 insertions(+), 4 deletions(-)
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index d736df3..26a5012 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -95,10 +95,17 @@ static void release_memory_resource(struct
resource *res)
static void get_page_bootmem(unsigned long info, struct page *page,
unsigned long type)
{
-page->lru.next = (struct list_head *) type;
-SetPagePrivate(page);
-set_page_private(page, info);
-atomic_inc(>_count);
+unsigned long page_type;
+
+page_type = (unsigned long)page->lru.next;
+if (page_type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
+page_type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE){
+page->lru.next = (struct list_head *)type;
+SetPagePrivate(page);
+set_page_private(page, info);
+atomic_inc(>_count);
+} else
+atomic_inc(>_count);
}
/* reference to __meminit __free_pages_bootmem is valid
--
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Re: [RFC v9 PATCH 13/21] memory-hotplug: check page type in get_page_bootmem
On 10/01/2012 11:03 AM, Yasuaki Ishimatsu wrote:
Hi Chen,
2012/09/29 11:15, Ni zhan Chen wrote:
On 09/05/2012 05:25 PM, we...@cn.fujitsu.com wrote:
From: Yasuaki Ishimatsu isimatu.yasu...@jp.fujitsu.com
The function get_page_bootmem() may be called more than one time to
the same
page. There is no need to set page's type, private if the function
is not
the first time called to the page.
Note: the patch is just optimization and does not fix any problem.
Hi Yasuaki,
this patch is reasonable to me. I have another question associated to
get_page_bootmem(), the question is from another fujitsu guy's patch
changelog [commit : 04753278769f3], the changelog said that:
1) When the memmap of removing section is allocated on other
section by bootmem, it should/can be free.
2) When the memmap of removing section is allocated on the
same section, it shouldn't be freed. Because the section has to be
logical memory offlined already and all pages must be isolated
against
page allocater. If it is freed, page allocator may use it which
will
be removed physically soon.
but I don't see his patch guarantee 2), it means that his patch
doesn't guarantee the memmap of removing section which is allocated
on other section by bootmem doesn't be freed. Hopefully get your
explaination in details, thanks in advance. :-)
In my understanding, the patch does not guarantee it.
Please see [commit : 0c0a4a517a31e]. free_map_bootmem() in the commit
guarantees it.
Thanks Yasuaki, I have already seen the commit you mentioned. But the
changelog of the commit I point out 2), why it said that If it is
freed, page allocator may use it which will be removed physically soon,
does it mean that use-after-free ? AFAK, the isolated pages will be free
if no users use it, so why not free the associated memmap?
Thanks,
Yasuaki Ishimatsu
CC: David Rientjes rient...@google.com
CC: Jiang Liu liu...@gmail.com
CC: Len Brown len.br...@intel.com
CC: Benjamin Herrenschmidt b...@kernel.crashing.org
CC: Paul Mackerras pau...@samba.org
CC: Christoph Lameter c...@linux.com
Cc: Minchan Kim minchan@gmail.com
CC: Andrew Morton a...@linux-foundation.org
CC: KOSAKI Motohiro kosaki.motoh...@jp.fujitsu.com
CC: Wen Congyang we...@cn.fujitsu.com
Signed-off-by: Yasuaki Ishimatsu isimatu.yasu...@jp.fujitsu.com
---
mm/memory_hotplug.c | 15 +++
1 files changed, 11 insertions(+), 4 deletions(-)
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index d736df3..26a5012 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -95,10 +95,17 @@ static void release_memory_resource(struct
resource *res)
static void get_page_bootmem(unsigned long info, struct page *page,
unsigned long type)
{
-page-lru.next = (struct list_head *) type;
-SetPagePrivate(page);
-set_page_private(page, info);
-atomic_inc(page-_count);
+unsigned long page_type;
+
+page_type = (unsigned long)page-lru.next;
+if (page_type MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
+page_type MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE){
+page-lru.next = (struct list_head *)type;
+SetPagePrivate(page);
+set_page_private(page, info);
+atomic_inc(page-_count);
+} else
+atomic_inc(page-_count);
}
/* reference to __meminit __free_pages_bootmem is valid
--
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the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [RFC v9 PATCH 13/21] memory-hotplug: check page type in get_page_bootmem
Hi Chen,
2012/09/29 11:15, Ni zhan Chen wrote:
On 09/05/2012 05:25 PM, we...@cn.fujitsu.com wrote:
From: Yasuaki Ishimatsu
The function get_page_bootmem() may be called more than one time to the same
page. There is no need to set page's type, private if the function is not
the first time called to the page.
Note: the patch is just optimization and does not fix any problem.
Hi Yasuaki,
this patch is reasonable to me. I have another question associated to
get_page_bootmem(), the question is from another fujitsu guy's patch changelog
[commit : 04753278769f3], the changelog said that:
1) When the memmap of removing section is allocated on other
section by bootmem, it should/can be free.
2) When the memmap of removing section is allocated on the
same section, it shouldn't be freed. Because the section has to be
logical memory offlined already and all pages must be isolated against
page allocater. If it is freed, page allocator may use it which will
be removed physically soon.
but I don't see his patch guarantee 2), it means that his patch doesn't
guarantee the memmap of removing section which is allocated on other section by
bootmem doesn't be freed. Hopefully get your explaination in details, thanks in
advance. :-)
In my understanding, the patch does not guarantee it.
Please see [commit : 0c0a4a517a31e]. free_map_bootmem() in the commit
guarantees it.
Thanks,
Yasuaki Ishimatsu
CC: David Rientjes
CC: Jiang Liu
CC: Len Brown
CC: Benjamin Herrenschmidt
CC: Paul Mackerras
CC: Christoph Lameter
Cc: Minchan Kim
CC: Andrew Morton
CC: KOSAKI Motohiro
CC: Wen Congyang
Signed-off-by: Yasuaki Ishimatsu
---
mm/memory_hotplug.c | 15 +++
1 files changed, 11 insertions(+), 4 deletions(-)
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index d736df3..26a5012 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -95,10 +95,17 @@ static void release_memory_resource(struct resource *res)
static void get_page_bootmem(unsigned long info, struct page *page,
unsigned long type)
{
-page->lru.next = (struct list_head *) type;
-SetPagePrivate(page);
-set_page_private(page, info);
-atomic_inc(>_count);
+unsigned long page_type;
+
+page_type = (unsigned long)page->lru.next;
+if (page_type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
+page_type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE){
+page->lru.next = (struct list_head *)type;
+SetPagePrivate(page);
+set_page_private(page, info);
+atomic_inc(>_count);
+} else
+atomic_inc(>_count);
}
/* reference to __meminit __free_pages_bootmem is valid
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [RFC v9 PATCH 13/21] memory-hotplug: check page type in get_page_bootmem
Hi Chen,
2012/09/29 11:15, Ni zhan Chen wrote:
On 09/05/2012 05:25 PM, we...@cn.fujitsu.com wrote:
From: Yasuaki Ishimatsu isimatu.yasu...@jp.fujitsu.com
The function get_page_bootmem() may be called more than one time to the same
page. There is no need to set page's type, private if the function is not
the first time called to the page.
Note: the patch is just optimization and does not fix any problem.
Hi Yasuaki,
this patch is reasonable to me. I have another question associated to
get_page_bootmem(), the question is from another fujitsu guy's patch changelog
[commit : 04753278769f3], the changelog said that:
1) When the memmap of removing section is allocated on other
section by bootmem, it should/can be free.
2) When the memmap of removing section is allocated on the
same section, it shouldn't be freed. Because the section has to be
logical memory offlined already and all pages must be isolated against
page allocater. If it is freed, page allocator may use it which will
be removed physically soon.
but I don't see his patch guarantee 2), it means that his patch doesn't
guarantee the memmap of removing section which is allocated on other section by
bootmem doesn't be freed. Hopefully get your explaination in details, thanks in
advance. :-)
In my understanding, the patch does not guarantee it.
Please see [commit : 0c0a4a517a31e]. free_map_bootmem() in the commit
guarantees it.
Thanks,
Yasuaki Ishimatsu
CC: David Rientjes rient...@google.com
CC: Jiang Liu liu...@gmail.com
CC: Len Brown len.br...@intel.com
CC: Benjamin Herrenschmidt b...@kernel.crashing.org
CC: Paul Mackerras pau...@samba.org
CC: Christoph Lameter c...@linux.com
Cc: Minchan Kim minchan@gmail.com
CC: Andrew Morton a...@linux-foundation.org
CC: KOSAKI Motohiro kosaki.motoh...@jp.fujitsu.com
CC: Wen Congyang we...@cn.fujitsu.com
Signed-off-by: Yasuaki Ishimatsu isimatu.yasu...@jp.fujitsu.com
---
mm/memory_hotplug.c | 15 +++
1 files changed, 11 insertions(+), 4 deletions(-)
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index d736df3..26a5012 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -95,10 +95,17 @@ static void release_memory_resource(struct resource *res)
static void get_page_bootmem(unsigned long info, struct page *page,
unsigned long type)
{
-page-lru.next = (struct list_head *) type;
-SetPagePrivate(page);
-set_page_private(page, info);
-atomic_inc(page-_count);
+unsigned long page_type;
+
+page_type = (unsigned long)page-lru.next;
+if (page_type MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
+page_type MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE){
+page-lru.next = (struct list_head *)type;
+SetPagePrivate(page);
+set_page_private(page, info);
+atomic_inc(page-_count);
+} else
+atomic_inc(page-_count);
}
/* reference to __meminit __free_pages_bootmem is valid
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [RFC v9 PATCH 13/21] memory-hotplug: check page type in get_page_bootmem
On 09/05/2012 05:25 PM, we...@cn.fujitsu.com wrote:
From: Yasuaki Ishimatsu
The function get_page_bootmem() may be called more than one time to the same
page. There is no need to set page's type, private if the function is not
the first time called to the page.
Note: the patch is just optimization and does not fix any problem.
Hi Yasuaki,
this patch is reasonable to me. I have another question associated to
get_page_bootmem(), the question is from another fujitsu guy's patch
changelog [commit : 04753278769f3], the changelog said that:
1) When the memmap of removing section is allocated on other
section by bootmem, it should/can be free.
2) When the memmap of removing section is allocated on the
same section, it shouldn't be freed. Because the section has to be
logical memory offlined already and all pages must be isolated against
page allocater. If it is freed, page allocator may use it which will
be removed physically soon.
but I don't see his patch guarantee 2), it means that his patch doesn't
guarantee the memmap of removing section which is allocated on other
section by bootmem doesn't be freed. Hopefully get your explaination in
details, thanks in advance. :-)
CC: David Rientjes
CC: Jiang Liu
CC: Len Brown
CC: Benjamin Herrenschmidt
CC: Paul Mackerras
CC: Christoph Lameter
Cc: Minchan Kim
CC: Andrew Morton
CC: KOSAKI Motohiro
CC: Wen Congyang
Signed-off-by: Yasuaki Ishimatsu
---
mm/memory_hotplug.c | 15 +++
1 files changed, 11 insertions(+), 4 deletions(-)
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index d736df3..26a5012 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -95,10 +95,17 @@ static void release_memory_resource(struct resource *res)
static void get_page_bootmem(unsigned long info, struct page *page,
unsigned long type)
{
- page->lru.next = (struct list_head *) type;
- SetPagePrivate(page);
- set_page_private(page, info);
- atomic_inc(>_count);
+ unsigned long page_type;
+
+ page_type = (unsigned long)page->lru.next;
+ if (page_type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
+ page_type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE){
+ page->lru.next = (struct list_head *)type;
+ SetPagePrivate(page);
+ set_page_private(page, info);
+ atomic_inc(>_count);
+ } else
+ atomic_inc(>_count);
}
/* reference to __meminit __free_pages_bootmem is valid
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [RFC v9 PATCH 13/21] memory-hotplug: check page type in get_page_bootmem
On 09/05/2012 05:25 PM, we...@cn.fujitsu.com wrote:
From: Yasuaki Ishimatsu isimatu.yasu...@jp.fujitsu.com
The function get_page_bootmem() may be called more than one time to the same
page. There is no need to set page's type, private if the function is not
the first time called to the page.
Note: the patch is just optimization and does not fix any problem.
Hi Yasuaki,
this patch is reasonable to me. I have another question associated to
get_page_bootmem(), the question is from another fujitsu guy's patch
changelog [commit : 04753278769f3], the changelog said that:
1) When the memmap of removing section is allocated on other
section by bootmem, it should/can be free.
2) When the memmap of removing section is allocated on the
same section, it shouldn't be freed. Because the section has to be
logical memory offlined already and all pages must be isolated against
page allocater. If it is freed, page allocator may use it which will
be removed physically soon.
but I don't see his patch guarantee 2), it means that his patch doesn't
guarantee the memmap of removing section which is allocated on other
section by bootmem doesn't be freed. Hopefully get your explaination in
details, thanks in advance. :-)
CC: David Rientjes rient...@google.com
CC: Jiang Liu liu...@gmail.com
CC: Len Brown len.br...@intel.com
CC: Benjamin Herrenschmidt b...@kernel.crashing.org
CC: Paul Mackerras pau...@samba.org
CC: Christoph Lameter c...@linux.com
Cc: Minchan Kim minchan@gmail.com
CC: Andrew Morton a...@linux-foundation.org
CC: KOSAKI Motohiro kosaki.motoh...@jp.fujitsu.com
CC: Wen Congyang we...@cn.fujitsu.com
Signed-off-by: Yasuaki Ishimatsu isimatu.yasu...@jp.fujitsu.com
---
mm/memory_hotplug.c | 15 +++
1 files changed, 11 insertions(+), 4 deletions(-)
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index d736df3..26a5012 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -95,10 +95,17 @@ static void release_memory_resource(struct resource *res)
static void get_page_bootmem(unsigned long info, struct page *page,
unsigned long type)
{
- page-lru.next = (struct list_head *) type;
- SetPagePrivate(page);
- set_page_private(page, info);
- atomic_inc(page-_count);
+ unsigned long page_type;
+
+ page_type = (unsigned long)page-lru.next;
+ if (page_type MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
+ page_type MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE){
+ page-lru.next = (struct list_head *)type;
+ SetPagePrivate(page);
+ set_page_private(page, info);
+ atomic_inc(page-_count);
+ } else
+ atomic_inc(page-_count);
}
/* reference to __meminit __free_pages_bootmem is valid
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[RFC v9 PATCH 13/21] memory-hotplug: check page type in get_page_bootmem
From: Yasuaki Ishimatsu
The function get_page_bootmem() may be called more than one time to the same
page. There is no need to set page's type, private if the function is not
the first time called to the page.
Note: the patch is just optimization and does not fix any problem.
CC: David Rientjes
CC: Jiang Liu
CC: Len Brown
CC: Benjamin Herrenschmidt
CC: Paul Mackerras
CC: Christoph Lameter
Cc: Minchan Kim
CC: Andrew Morton
CC: KOSAKI Motohiro
CC: Wen Congyang
Signed-off-by: Yasuaki Ishimatsu
---
mm/memory_hotplug.c | 15 +++
1 files changed, 11 insertions(+), 4 deletions(-)
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index d736df3..26a5012 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -95,10 +95,17 @@ static void release_memory_resource(struct resource *res)
static void get_page_bootmem(unsigned long info, struct page *page,
unsigned long type)
{
- page->lru.next = (struct list_head *) type;
- SetPagePrivate(page);
- set_page_private(page, info);
- atomic_inc(>_count);
+ unsigned long page_type;
+
+ page_type = (unsigned long)page->lru.next;
+ if (page_type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
+ page_type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE){
+ page->lru.next = (struct list_head *)type;
+ SetPagePrivate(page);
+ set_page_private(page, info);
+ atomic_inc(>_count);
+ } else
+ atomic_inc(>_count);
}
/* reference to __meminit __free_pages_bootmem is valid
--
1.7.1
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[RFC v9 PATCH 13/21] memory-hotplug: check page type in get_page_bootmem
From: Yasuaki Ishimatsu isimatu.yasu...@jp.fujitsu.com
The function get_page_bootmem() may be called more than one time to the same
page. There is no need to set page's type, private if the function is not
the first time called to the page.
Note: the patch is just optimization and does not fix any problem.
CC: David Rientjes rient...@google.com
CC: Jiang Liu liu...@gmail.com
CC: Len Brown len.br...@intel.com
CC: Benjamin Herrenschmidt b...@kernel.crashing.org
CC: Paul Mackerras pau...@samba.org
CC: Christoph Lameter c...@linux.com
Cc: Minchan Kim minchan@gmail.com
CC: Andrew Morton a...@linux-foundation.org
CC: KOSAKI Motohiro kosaki.motoh...@jp.fujitsu.com
CC: Wen Congyang we...@cn.fujitsu.com
Signed-off-by: Yasuaki Ishimatsu isimatu.yasu...@jp.fujitsu.com
---
mm/memory_hotplug.c | 15 +++
1 files changed, 11 insertions(+), 4 deletions(-)
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index d736df3..26a5012 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -95,10 +95,17 @@ static void release_memory_resource(struct resource *res)
static void get_page_bootmem(unsigned long info, struct page *page,
unsigned long type)
{
- page-lru.next = (struct list_head *) type;
- SetPagePrivate(page);
- set_page_private(page, info);
- atomic_inc(page-_count);
+ unsigned long page_type;
+
+ page_type = (unsigned long)page-lru.next;
+ if (page_type MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
+ page_type MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE){
+ page-lru.next = (struct list_head *)type;
+ SetPagePrivate(page);
+ set_page_private(page, info);
+ atomic_inc(page-_count);
+ } else
+ atomic_inc(page-_count);
}
/* reference to __meminit __free_pages_bootmem is valid
--
1.7.1
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
