When encountering any vma in the range with policy other than MPOL_BIND
or MPOL_PREFERRED_MANY, an error is returned without issuing a mpol_put
on the policy just allocated with mpol_dup().
This allows arbitrary users to leak kernel memory.
Fixes: c6018b4b2549 ("mm/mempolicy: add set_mempolicy_home_node syscall")
Signed-off-by: Mathieu Desnoyers <[email protected]>
Cc: Aneesh Kumar K.V <[email protected]>
Cc: Ben Widawsky <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Feng Tang <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Mike Kravetz <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: Huang Ying <[email protected]>
Cc: <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: [email protected] # 5.17+
---
mm/mempolicy.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 61aa9aedb728..02c8a712282f 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1540,6 +1540,7 @@ SYSCALL_DEFINE4(set_mempolicy_home_node, unsigned long, start, unsigned long, le
* the home node for vmas we already updated before.
*/
if (new->mode != MPOL_BIND && new->mode != MPOL_PREFERRED_MANY) {
+ mpol_put(new);
err = -EOPNOTSUPP;
break;
}
--
2.25.1
On 12/14/22 14:21, Mathieu Desnoyers wrote:
> When encountering any vma in the range with policy other than MPOL_BIND
> or MPOL_PREFERRED_MANY, an error is returned without issuing a mpol_put
> on the policy just allocated with mpol_dup().
>
> This allows arbitrary users to leak kernel memory.
>
> Fixes: c6018b4b2549 ("mm/mempolicy: add set_mempolicy_home_node syscall")
> Signed-off-by: Mathieu Desnoyers <[email protected]>
> Cc: Aneesh Kumar K.V <[email protected]>
> Cc: Ben Widawsky <[email protected]>
> Cc: Dave Hansen <[email protected]>
> Cc: Feng Tang <[email protected]>
> Cc: Michal Hocko <[email protected]>
> Cc: Andrea Arcangeli <[email protected]>
> Cc: Mel Gorman <[email protected]>
> Cc: Mike Kravetz <[email protected]>
> Cc: Randy Dunlap <[email protected]>
> Cc: Vlastimil Babka <[email protected]>
> Cc: Andi Kleen <[email protected]>
> Cc: Dan Williams <[email protected]>
> Cc: Huang Ying <[email protected]>
> Cc: <[email protected]>
> Cc: Andrew Morton <[email protected]>
> Cc: [email protected] # 5.17+
Reviewed-by: Randy Dunlap <[email protected]>
Thanks.
> ---
> mm/mempolicy.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> index 61aa9aedb728..02c8a712282f 100644
> --- a/mm/mempolicy.c
> +++ b/mm/mempolicy.c
> @@ -1540,6 +1540,7 @@ SYSCALL_DEFINE4(set_mempolicy_home_node, unsigned long, start, unsigned long, le
> * the home node for vmas we already updated before.
> */
> if (new->mode != MPOL_BIND && new->mode != MPOL_PREFERRED_MANY) {
> + mpol_put(new);
> err = -EOPNOTSUPP;
> break;
> }
--
~Randy
Mathieu Desnoyers <[email protected]> writes:
> When encountering any vma in the range with policy other than MPOL_BIND
> or MPOL_PREFERRED_MANY, an error is returned without issuing a mpol_put
> on the policy just allocated with mpol_dup().
>
> This allows arbitrary users to leak kernel memory.
>
> Fixes: c6018b4b2549 ("mm/mempolicy: add set_mempolicy_home_node syscall")
> Signed-off-by: Mathieu Desnoyers <[email protected]>
> Cc: Aneesh Kumar K.V <[email protected]>
> Cc: Ben Widawsky <[email protected]>
> Cc: Dave Hansen <[email protected]>
> Cc: Feng Tang <[email protected]>
> Cc: Michal Hocko <[email protected]>
> Cc: Andrea Arcangeli <[email protected]>
> Cc: Mel Gorman <[email protected]>
> Cc: Mike Kravetz <[email protected]>
> Cc: Randy Dunlap <[email protected]>
> Cc: Vlastimil Babka <[email protected]>
> Cc: Andi Kleen <[email protected]>
> Cc: Dan Williams <[email protected]>
> Cc: Huang Ying <[email protected]>
> Cc: <[email protected]>
> Cc: Andrew Morton <[email protected]>
> Cc: [email protected] # 5.17+
Reviewed-by: "Huang, Ying" <[email protected]>
Thanks!
> ---
> mm/mempolicy.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> index 61aa9aedb728..02c8a712282f 100644
> --- a/mm/mempolicy.c
> +++ b/mm/mempolicy.c
> @@ -1540,6 +1540,7 @@ SYSCALL_DEFINE4(set_mempolicy_home_node, unsigned long, start, unsigned long, le
> * the home node for vmas we already updated before.
> */
> if (new->mode != MPOL_BIND && new->mode != MPOL_PREFERRED_MANY) {
> + mpol_put(new);
> err = -EOPNOTSUPP;
> break;
> }
On Wed 14-12-22 17:21:10, Mathieu Desnoyers wrote:
> When encountering any vma in the range with policy other than MPOL_BIND
> or MPOL_PREFERRED_MANY, an error is returned without issuing a mpol_put
> on the policy just allocated with mpol_dup().
>
> This allows arbitrary users to leak kernel memory.
>
> Fixes: c6018b4b2549 ("mm/mempolicy: add set_mempolicy_home_node syscall")
> Signed-off-by: Mathieu Desnoyers <[email protected]>
> Cc: Aneesh Kumar K.V <[email protected]>
> Cc: Ben Widawsky <[email protected]>
> Cc: Dave Hansen <[email protected]>
> Cc: Feng Tang <[email protected]>
> Cc: Michal Hocko <[email protected]>
> Cc: Andrea Arcangeli <[email protected]>
> Cc: Mel Gorman <[email protected]>
> Cc: Mike Kravetz <[email protected]>
> Cc: Randy Dunlap <[email protected]>
> Cc: Vlastimil Babka <[email protected]>
> Cc: Andi Kleen <[email protected]>
> Cc: Dan Williams <[email protected]>
> Cc: Huang Ying <[email protected]>
> Cc: <[email protected]>
> Cc: Andrew Morton <[email protected]>
> Cc: [email protected] # 5.17+
Acked-by: Michal Hocko <[email protected]>
Thanks for catching this!
Btw. looking at the code again it seems rather pointless to duplicate
the policy just to throw it away anyway. A slightly bigger diff but this
looks more reasonable to me. What do you think? I can also send it as a
clean up on top of your fix.
---
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 61aa9aedb728..918cdc8a7f0c 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1489,7 +1489,7 @@ SYSCALL_DEFINE4(set_mempolicy_home_node, unsigned long, start, unsigned long, le
{
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
- struct mempolicy *new;
+ struct mempolicy *new. *old;
unsigned long vmstart;
unsigned long vmend;
unsigned long end;
@@ -1521,30 +1521,28 @@ SYSCALL_DEFINE4(set_mempolicy_home_node, unsigned long, start, unsigned long, le
return 0;
mmap_write_lock(mm);
for_each_vma_range(vmi, vma, end) {
- vmstart = max(start, vma->vm_start);
- vmend = min(end, vma->vm_end);
- new = mpol_dup(vma_policy(vma));
- if (IS_ERR(new)) {
- err = PTR_ERR(new);
- break;
- }
- /*
- * Only update home node if there is an existing vma policy
- */
- if (!new)
- continue;
-
/*
* If any vma in the range got policy other than MPOL_BIND
* or MPOL_PREFERRED_MANY we return error. We don't reset
* the home node for vmas we already updated before.
*/
- if (new->mode != MPOL_BIND && new->mode != MPOL_PREFERRED_MANY) {
+ old = vma_policy(vma);
+ if (!old)
+ continue;
+ if (old->mode != MPOL_BIND && old->mode != MPOL_PREFERRED_MANY) {
err = -EOPNOTSUPP;
break;
}
+ new = mpol_dup(vma_policy(vma));
+ if (IS_ERR(new)) {
+ err = PTR_ERR(new);
+ break;
+ }
+
new->home_node = home_node;
+ vmstart = max(start, vma->vm_start);
+ vmend = min(end, vma->vm_end);
err = mbind_range(mm, vmstart, vmend, new);
mpol_put(new);
if (err)
--
Michal Hocko
SUSE Labs
Michal Hocko <[email protected]> writes:
> On Wed 14-12-22 17:21:10, Mathieu Desnoyers wrote:
>> When encountering any vma in the range with policy other than MPOL_BIND
>> or MPOL_PREFERRED_MANY, an error is returned without issuing a mpol_put
>> on the policy just allocated with mpol_dup().
>>
>> This allows arbitrary users to leak kernel memory.
>>
>> Fixes: c6018b4b2549 ("mm/mempolicy: add set_mempolicy_home_node syscall")
>> Signed-off-by: Mathieu Desnoyers <[email protected]>
>> Cc: Aneesh Kumar K.V <[email protected]>
>> Cc: Ben Widawsky <[email protected]>
>> Cc: Dave Hansen <[email protected]>
>> Cc: Feng Tang <[email protected]>
>> Cc: Michal Hocko <[email protected]>
>> Cc: Andrea Arcangeli <[email protected]>
>> Cc: Mel Gorman <[email protected]>
>> Cc: Mike Kravetz <[email protected]>
>> Cc: Randy Dunlap <[email protected]>
>> Cc: Vlastimil Babka <[email protected]>
>> Cc: Andi Kleen <[email protected]>
>> Cc: Dan Williams <[email protected]>
>> Cc: Huang Ying <[email protected]>
>> Cc: <[email protected]>
>> Cc: Andrew Morton <[email protected]>
>> Cc: [email protected] # 5.17+
>
> Acked-by: Michal Hocko <[email protected]>
> Thanks for catching this!
>
> Btw. looking at the code again it seems rather pointless to duplicate
> the policy just to throw it away anyway. A slightly bigger diff but this
> looks more reasonable to me. What do you think? I can also send it as a
> clean up on top of your fix.
> ---
> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> index 61aa9aedb728..918cdc8a7f0c 100644
> --- a/mm/mempolicy.c
> +++ b/mm/mempolicy.c
> @@ -1489,7 +1489,7 @@ SYSCALL_DEFINE4(set_mempolicy_home_node, unsigned long, start, unsigned long, le
> {
> struct mm_struct *mm = current->mm;
> struct vm_area_struct *vma;
> - struct mempolicy *new;
> + struct mempolicy *new. *old;
> unsigned long vmstart;
> unsigned long vmend;
> unsigned long end;
> @@ -1521,30 +1521,28 @@ SYSCALL_DEFINE4(set_mempolicy_home_node, unsigned long, start, unsigned long, le
> return 0;
> mmap_write_lock(mm);
> for_each_vma_range(vmi, vma, end) {
> - vmstart = max(start, vma->vm_start);
> - vmend = min(end, vma->vm_end);
> - new = mpol_dup(vma_policy(vma));
> - if (IS_ERR(new)) {
> - err = PTR_ERR(new);
> - break;
> - }
> - /*
> - * Only update home node if there is an existing vma policy
> - */
> - if (!new)
> - continue;
> -
> /*
> * If any vma in the range got policy other than MPOL_BIND
> * or MPOL_PREFERRED_MANY we return error. We don't reset
> * the home node for vmas we already updated before.
> */
> - if (new->mode != MPOL_BIND && new->mode != MPOL_PREFERRED_MANY) {
> + old = vma_policy(vma);
> + if (!old)
> + continue;
> + if (old->mode != MPOL_BIND && old->mode != MPOL_PREFERRED_MANY) {
> err = -EOPNOTSUPP;
> break;
> }
>
> + new = mpol_dup(vma_policy(vma));
new = mpol_dup(old);
> + if (IS_ERR(new)) {
> + err = PTR_ERR(new);
> + break;
> + }
> +
> new->home_node = home_node;
> + vmstart = max(start, vma->vm_start);
> + vmend = min(end, vma->vm_end);
> err = mbind_range(mm, vmstart, vmend, new);
> mpol_put(new);
> if (err)
> --
> Michal Hocko
> SUSE Labs
Mathieu Desnoyers <[email protected]> writes:
> When encountering any vma in the range with policy other than MPOL_BIND
> or MPOL_PREFERRED_MANY, an error is returned without issuing a mpol_put
> on the policy just allocated with mpol_dup().
>
> This allows arbitrary users to leak kernel memory.
>
Reviewed-by: Aneesh Kumar K.V <[email protected]>
> Fixes: c6018b4b2549 ("mm/mempolicy: add set_mempolicy_home_node syscall")
> Signed-off-by: Mathieu Desnoyers <[email protected]>
> Cc: Aneesh Kumar K.V <[email protected]>
> Cc: Ben Widawsky <[email protected]>
> Cc: Dave Hansen <[email protected]>
> Cc: Feng Tang <[email protected]>
> Cc: Michal Hocko <[email protected]>
> Cc: Andrea Arcangeli <[email protected]>
> Cc: Mel Gorman <[email protected]>
> Cc: Mike Kravetz <[email protected]>
> Cc: Randy Dunlap <[email protected]>
> Cc: Vlastimil Babka <[email protected]>
> Cc: Andi Kleen <[email protected]>
> Cc: Dan Williams <[email protected]>
> Cc: Huang Ying <[email protected]>
> Cc: <[email protected]>
> Cc: Andrew Morton <[email protected]>
> Cc: [email protected] # 5.17+
> ---
> mm/mempolicy.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> index 61aa9aedb728..02c8a712282f 100644
> --- a/mm/mempolicy.c
> +++ b/mm/mempolicy.c
> @@ -1540,6 +1540,7 @@ SYSCALL_DEFINE4(set_mempolicy_home_node, unsigned long, start, unsigned long, le
> * the home node for vmas we already updated before.
> */
> if (new->mode != MPOL_BIND && new->mode != MPOL_PREFERRED_MANY) {
> + mpol_put(new);
> err = -EOPNOTSUPP;
> break;
> }
> --
> 2.25.1
On 2022-12-15 02:51, Michal Hocko wrote:
> On Wed 14-12-22 17:21:10, Mathieu Desnoyers wrote:
>> When encountering any vma in the range with policy other than MPOL_BIND
>> or MPOL_PREFERRED_MANY, an error is returned without issuing a mpol_put
>> on the policy just allocated with mpol_dup().
>>
>> This allows arbitrary users to leak kernel memory.
>>
>> Fixes: c6018b4b2549 ("mm/mempolicy: add set_mempolicy_home_node syscall")
>> Signed-off-by: Mathieu Desnoyers <[email protected]>
>> Cc: Aneesh Kumar K.V <[email protected]>
>> Cc: Ben Widawsky <[email protected]>
>> Cc: Dave Hansen <[email protected]>
>> Cc: Feng Tang <[email protected]>
>> Cc: Michal Hocko <[email protected]>
>> Cc: Andrea Arcangeli <[email protected]>
>> Cc: Mel Gorman <[email protected]>
>> Cc: Mike Kravetz <[email protected]>
>> Cc: Randy Dunlap <[email protected]>
>> Cc: Vlastimil Babka <[email protected]>
>> Cc: Andi Kleen <[email protected]>
>> Cc: Dan Williams <[email protected]>
>> Cc: Huang Ying <[email protected]>
>> Cc: <[email protected]>
>> Cc: Andrew Morton <[email protected]>
>> Cc: [email protected] # 5.17+
>
> Acked-by: Michal Hocko <[email protected]>
> Thanks for catching this!
>
> Btw. looking at the code again it seems rather pointless to duplicate
> the policy just to throw it away anyway. A slightly bigger diff but this
> looks more reasonable to me. What do you think? I can also send it as a
> clean up on top of your fix.
I think it would be best if this comes as a cleanup on top of my fix.
The diff is larger than the minimal change needed to fix the leak in
stable branches.
Your approach looks fine, except for the vma_policy(vma) -> old change
already spotted by Aneesh.
Thanks,
Mathieu
> ---
> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> index 61aa9aedb728..918cdc8a7f0c 100644
> --- a/mm/mempolicy.c
> +++ b/mm/mempolicy.c
> @@ -1489,7 +1489,7 @@ SYSCALL_DEFINE4(set_mempolicy_home_node, unsigned long, start, unsigned long, le
> {
> struct mm_struct *mm = current->mm;
> struct vm_area_struct *vma;
> - struct mempolicy *new;
> + struct mempolicy *new. *old;
> unsigned long vmstart;
> unsigned long vmend;
> unsigned long end;
> @@ -1521,30 +1521,28 @@ SYSCALL_DEFINE4(set_mempolicy_home_node, unsigned long, start, unsigned long, le
> return 0;
> mmap_write_lock(mm);
> for_each_vma_range(vmi, vma, end) {
> - vmstart = max(start, vma->vm_start);
> - vmend = min(end, vma->vm_end);
> - new = mpol_dup(vma_policy(vma));
> - if (IS_ERR(new)) {
> - err = PTR_ERR(new);
> - break;
> - }
> - /*
> - * Only update home node if there is an existing vma policy
> - */
> - if (!new)
> - continue;
> -
> /*
> * If any vma in the range got policy other than MPOL_BIND
> * or MPOL_PREFERRED_MANY we return error. We don't reset
> * the home node for vmas we already updated before.
> */
> - if (new->mode != MPOL_BIND && new->mode != MPOL_PREFERRED_MANY) {
> + old = vma_policy(vma);
> + if (!old)
> + continue;
> + if (old->mode != MPOL_BIND && old->mode != MPOL_PREFERRED_MANY) {
> err = -EOPNOTSUPP;
> break;
> }
>
> + new = mpol_dup(vma_policy(vma));
> + if (IS_ERR(new)) {
> + err = PTR_ERR(new);
> + break;
> + }
> +
> new->home_node = home_node;
> + vmstart = max(start, vma->vm_start);
> + vmend = min(end, vma->vm_end);
> err = mbind_range(mm, vmstart, vmend, new);
> mpol_put(new);
> if (err)
--
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com
On Thu 15-12-22 09:33:54, Mathieu Desnoyers wrote:
> On 2022-12-15 02:51, Michal Hocko wrote:
[...]
> > Btw. looking at the code again it seems rather pointless to duplicate
> > the policy just to throw it away anyway. A slightly bigger diff but this
> > looks more reasonable to me. What do you think? I can also send it as a
> > clean up on top of your fix.
>
> I think it would be best if this comes as a cleanup on top of my fix. The
> diff is larger than the minimal change needed to fix the leak in stable
> branches.
>
> Your approach looks fine, except for the vma_policy(vma) -> old change
> already spotted by Aneesh.
This shouldn't have any real effect on the functionality. Anyway, here
is a follow up cleanup:
---
From f3fdb6f65fa3977aab13378b8e299b168719577c Mon Sep 17 00:00:00 2001
From: Michal Hocko <[email protected]>
Date: Thu, 15 Dec 2022 15:41:27 +0100
Subject: [PATCH] mm/mempolicy: do not duplicate policy if it is not applicable
for set_mempolicy_home_node
set_mempolicy_home_node tries to duplicate a memory policy before
checking it whether it is applicable for the operation. There is
no real reason for doing that and it might actually be a pointless
memory allocation and deallocation exercise for MPOL_INTERLEAVE.
Not a big problem but we can do better. Simply check the policy before
acting on it.
Signed-off-by: Michal Hocko <[email protected]>
---
mm/mempolicy.c | 28 ++++++++++++----------------
1 file changed, 12 insertions(+), 16 deletions(-)
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 02c8a712282f..becf41e10076 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1489,7 +1489,7 @@ SYSCALL_DEFINE4(set_mempolicy_home_node, unsigned long, start, unsigned long, le
{
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
- struct mempolicy *new;
+ struct mempolicy *new, *old;
unsigned long vmstart;
unsigned long vmend;
unsigned long end;
@@ -1521,31 +1521,27 @@ SYSCALL_DEFINE4(set_mempolicy_home_node, unsigned long, start, unsigned long, le
return 0;
mmap_write_lock(mm);
for_each_vma_range(vmi, vma, end) {
- vmstart = max(start, vma->vm_start);
- vmend = min(end, vma->vm_end);
- new = mpol_dup(vma_policy(vma));
- if (IS_ERR(new)) {
- err = PTR_ERR(new);
- break;
- }
- /*
- * Only update home node if there is an existing vma policy
- */
- if (!new)
- continue;
-
/*
* If any vma in the range got policy other than MPOL_BIND
* or MPOL_PREFERRED_MANY we return error. We don't reset
* the home node for vmas we already updated before.
*/
- if (new->mode != MPOL_BIND && new->mode != MPOL_PREFERRED_MANY) {
- mpol_put(new);
+ old = vma_policy(vma);
+ if (!old)
+ continue;
+ if (old->mode != MPOL_BIND && old->mode != MPOL_PREFERRED_MANY) {
err = -EOPNOTSUPP;
break;
}
+ new = mpol_dup(old);
+ if (IS_ERR(new)) {
+ err = PTR_ERR(new);
+ break;
+ }
new->home_node = home_node;
+ vmstart = max(start, vma->vm_start);
+ vmend = min(end, vma->vm_end);
err = mbind_range(mm, vmstart, vmend, new);
mpol_put(new);
if (err)
--
2.30.2
--
Michal Hocko
SUSE Labs
On 2022-12-15 09:49, Michal Hocko wrote:
> On Thu 15-12-22 09:33:54, Mathieu Desnoyers wrote:
>> On 2022-12-15 02:51, Michal Hocko wrote:
> [...]
>>> Btw. looking at the code again it seems rather pointless to duplicate
>>> the policy just to throw it away anyway. A slightly bigger diff but this
>>> looks more reasonable to me. What do you think? I can also send it as a
>>> clean up on top of your fix.
>>
>> I think it would be best if this comes as a cleanup on top of my fix. The
>> diff is larger than the minimal change needed to fix the leak in stable
>> branches.
>>
>> Your approach looks fine, except for the vma_policy(vma) -> old change
>> already spotted by Aneesh.
>
> This shouldn't have any real effect on the functionality. Anyway, here
> is a follow up cleanup:
> ---
> From f3fdb6f65fa3977aab13378b8e299b168719577c Mon Sep 17 00:00:00 2001
> From: Michal Hocko <[email protected]>
> Date: Thu, 15 Dec 2022 15:41:27 +0100
> Subject: [PATCH] mm/mempolicy: do not duplicate policy if it is not applicable
> for set_mempolicy_home_node
>
> set_mempolicy_home_node tries to duplicate a memory policy before
> checking it whether it is applicable for the operation. There is
> no real reason for doing that and it might actually be a pointless
> memory allocation and deallocation exercise for MPOL_INTERLEAVE.
>
> Not a big problem but we can do better. Simply check the policy before
> acting on it.
>
> Signed-off-by: Michal Hocko <[email protected]>
Reviewed-by: Mathieu Desnoyers <[email protected]>
> ---
> mm/mempolicy.c | 28 ++++++++++++----------------
> 1 file changed, 12 insertions(+), 16 deletions(-)
>
> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> index 02c8a712282f..becf41e10076 100644
> --- a/mm/mempolicy.c
> +++ b/mm/mempolicy.c
> @@ -1489,7 +1489,7 @@ SYSCALL_DEFINE4(set_mempolicy_home_node, unsigned long, start, unsigned long, le
> {
> struct mm_struct *mm = current->mm;
> struct vm_area_struct *vma;
> - struct mempolicy *new;
> + struct mempolicy *new, *old;
> unsigned long vmstart;
> unsigned long vmend;
> unsigned long end;
> @@ -1521,31 +1521,27 @@ SYSCALL_DEFINE4(set_mempolicy_home_node, unsigned long, start, unsigned long, le
> return 0;
> mmap_write_lock(mm);
> for_each_vma_range(vmi, vma, end) {
> - vmstart = max(start, vma->vm_start);
> - vmend = min(end, vma->vm_end);
> - new = mpol_dup(vma_policy(vma));
> - if (IS_ERR(new)) {
> - err = PTR_ERR(new);
> - break;
> - }
> - /*
> - * Only update home node if there is an existing vma policy
> - */
> - if (!new)
> - continue;
> -
> /*
> * If any vma in the range got policy other than MPOL_BIND
> * or MPOL_PREFERRED_MANY we return error. We don't reset
> * the home node for vmas we already updated before.
> */
> - if (new->mode != MPOL_BIND && new->mode != MPOL_PREFERRED_MANY) {
> - mpol_put(new);
> + old = vma_policy(vma);
> + if (!old)
> + continue;
> + if (old->mode != MPOL_BIND && old->mode != MPOL_PREFERRED_MANY) {
> err = -EOPNOTSUPP;
> break;
> }
> + new = mpol_dup(old);
> + if (IS_ERR(new)) {
> + err = PTR_ERR(new);
> + break;
> + }
>
> new->home_node = home_node;
> + vmstart = max(start, vma->vm_start);
> + vmend = min(end, vma->vm_end);
> err = mbind_range(mm, vmstart, vmend, new);
> mpol_put(new);
> if (err)
--
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com