* [PATCH] mm/migrate: initialize pud_entry in migrate_vma()
@ 2019-07-19 23:32 Ralph Campbell
2019-07-20 2:03 ` John Hubbard
2019-08-26 15:11 ` Vlastimil Babka
0 siblings, 2 replies; 4+ messages in thread
From: Ralph Campbell @ 2019-07-19 23:32 UTC (permalink / raw)
To: linux-mm
Cc: linux-kernel, Ralph Campbell, stable, Jérôme Glisse,
Andrew Morton
When CONFIG_MIGRATE_VMA_HELPER is enabled, migrate_vma() calls
migrate_vma_collect() which initializes a struct mm_walk but
didn't initialize mm_walk.pud_entry. (Found by code inspection)
Use a C structure initialization to make sure it is set to NULL.
Fixes: 8763cb45ab967 ("mm/migrate: new memory migration helper for use with
device memory")
Cc: stable@vger.kernel.org
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
---
mm/migrate.c | 17 +++++++----------
1 file changed, 7 insertions(+), 10 deletions(-)
diff --git a/mm/migrate.c b/mm/migrate.c
index 515718392b24..a42858d8e00b 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2340,16 +2340,13 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
static void migrate_vma_collect(struct migrate_vma *migrate)
{
struct mmu_notifier_range range;
- struct mm_walk mm_walk;
-
- mm_walk.pmd_entry = migrate_vma_collect_pmd;
- mm_walk.pte_entry = NULL;
- mm_walk.pte_hole = migrate_vma_collect_hole;
- mm_walk.hugetlb_entry = NULL;
- mm_walk.test_walk = NULL;
- mm_walk.vma = migrate->vma;
- mm_walk.mm = migrate->vma->vm_mm;
- mm_walk.private = migrate;
+ struct mm_walk mm_walk = {
+ .pmd_entry = migrate_vma_collect_pmd,
+ .pte_hole = migrate_vma_collect_hole,
+ .vma = migrate->vma,
+ .mm = migrate->vma->vm_mm,
+ .private = migrate,
+ };
mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, NULL, mm_walk.mm,
migrate->start,
--
2.20.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] mm/migrate: initialize pud_entry in migrate_vma()
2019-07-19 23:32 [PATCH] mm/migrate: initialize pud_entry in migrate_vma() Ralph Campbell
@ 2019-07-20 2:03 ` John Hubbard
2019-08-26 15:11 ` Vlastimil Babka
1 sibling, 0 replies; 4+ messages in thread
From: John Hubbard @ 2019-07-20 2:03 UTC (permalink / raw)
To: Ralph Campbell, linux-mm
Cc: linux-kernel, stable, Jérôme Glisse, Andrew Morton
On 7/19/19 4:32 PM, Ralph Campbell wrote:
> When CONFIG_MIGRATE_VMA_HELPER is enabled, migrate_vma() calls
> migrate_vma_collect() which initializes a struct mm_walk but
> didn't initialize mm_walk.pud_entry. (Found by code inspection)
> Use a C structure initialization to make sure it is set to NULL.
>
> Fixes: 8763cb45ab967 ("mm/migrate: new memory migration helper for use with
> device memory")
> Cc: stable@vger.kernel.org
> Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
> Cc: "Jérôme Glisse" <jglisse@redhat.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> ---
> mm/migrate.c | 17 +++++++----------
> 1 file changed, 7 insertions(+), 10 deletions(-)
>
> diff --git a/mm/migrate.c b/mm/migrate.c
> index 515718392b24..a42858d8e00b 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -2340,16 +2340,13 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
> static void migrate_vma_collect(struct migrate_vma *migrate)
> {
> struct mmu_notifier_range range;
> - struct mm_walk mm_walk;
> -
> - mm_walk.pmd_entry = migrate_vma_collect_pmd;
> - mm_walk.pte_entry = NULL;
> - mm_walk.pte_hole = migrate_vma_collect_hole;
> - mm_walk.hugetlb_entry = NULL;
> - mm_walk.test_walk = NULL;
> - mm_walk.vma = migrate->vma;
> - mm_walk.mm = migrate->vma->vm_mm;
> - mm_walk.private = migrate;
> + struct mm_walk mm_walk = {
> + .pmd_entry = migrate_vma_collect_pmd,
> + .pte_hole = migrate_vma_collect_hole,
> + .vma = migrate->vma,
> + .mm = migrate->vma->vm_mm,
> + .private = migrate,
> + };
Neatly done.
>
> mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, NULL, mm_walk.mm,
> migrate->start,
>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
thanks,
--
John Hubbard
NVIDIA
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] mm/migrate: initialize pud_entry in migrate_vma()
2019-07-19 23:32 [PATCH] mm/migrate: initialize pud_entry in migrate_vma() Ralph Campbell
2019-07-20 2:03 ` John Hubbard
@ 2019-08-26 15:11 ` Vlastimil Babka
2019-08-26 17:30 ` Ralph Campbell
1 sibling, 1 reply; 4+ messages in thread
From: Vlastimil Babka @ 2019-08-26 15:11 UTC (permalink / raw)
To: Ralph Campbell, linux-mm
Cc: linux-kernel, stable, Jérôme Glisse, Andrew Morton
On 7/20/19 1:32 AM, Ralph Campbell wrote:
> When CONFIG_MIGRATE_VMA_HELPER is enabled, migrate_vma() calls
> migrate_vma_collect() which initializes a struct mm_walk but
> didn't initialize mm_walk.pud_entry. (Found by code inspection)
> Use a C structure initialization to make sure it is set to NULL.
>
> Fixes: 8763cb45ab967 ("mm/migrate: new memory migration helper for use with
> device memory")
> Cc: stable@vger.kernel.org
> Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
> Cc: "Jérôme Glisse" <jglisse@redhat.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
So this bug can manifest by some garbage address on stack being called, right? I
wonder, how comes it didn't actually happen yet?
> ---
> mm/migrate.c | 17 +++++++----------
> 1 file changed, 7 insertions(+), 10 deletions(-)
>
> diff --git a/mm/migrate.c b/mm/migrate.c
> index 515718392b24..a42858d8e00b 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -2340,16 +2340,13 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
> static void migrate_vma_collect(struct migrate_vma *migrate)
> {
> struct mmu_notifier_range range;
> - struct mm_walk mm_walk;
> -
> - mm_walk.pmd_entry = migrate_vma_collect_pmd;
> - mm_walk.pte_entry = NULL;
> - mm_walk.pte_hole = migrate_vma_collect_hole;
> - mm_walk.hugetlb_entry = NULL;
> - mm_walk.test_walk = NULL;
> - mm_walk.vma = migrate->vma;
> - mm_walk.mm = migrate->vma->vm_mm;
> - mm_walk.private = migrate;
> + struct mm_walk mm_walk = {
> + .pmd_entry = migrate_vma_collect_pmd,
> + .pte_hole = migrate_vma_collect_hole,
> + .vma = migrate->vma,
> + .mm = migrate->vma->vm_mm,
> + .private = migrate,
> + };
>
> mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, NULL, mm_walk.mm,
> migrate->start,
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] mm/migrate: initialize pud_entry in migrate_vma()
2019-08-26 15:11 ` Vlastimil Babka
@ 2019-08-26 17:30 ` Ralph Campbell
0 siblings, 0 replies; 4+ messages in thread
From: Ralph Campbell @ 2019-08-26 17:30 UTC (permalink / raw)
To: Vlastimil Babka, linux-mm
Cc: linux-kernel, stable, Jérôme Glisse, Andrew Morton
On 8/26/19 8:11 AM, Vlastimil Babka wrote:
> On 7/20/19 1:32 AM, Ralph Campbell wrote:
>> When CONFIG_MIGRATE_VMA_HELPER is enabled, migrate_vma() calls
>> migrate_vma_collect() which initializes a struct mm_walk but
>> didn't initialize mm_walk.pud_entry. (Found by code inspection)
>> Use a C structure initialization to make sure it is set to NULL.
>>
>> Fixes: 8763cb45ab967 ("mm/migrate: new memory migration helper for use with
>> device memory")
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
>> Cc: "Jérôme Glisse" <jglisse@redhat.com>
>> Cc: Andrew Morton <akpm@linux-foundation.org>
>
> So this bug can manifest by some garbage address on stack being called, right? I
> wonder, how comes it didn't actually happen yet?
Right.
Probably because HMM isn't widely being used in production yet.
>
>> ---
>> mm/migrate.c | 17 +++++++----------
>> 1 file changed, 7 insertions(+), 10 deletions(-)
>>
>> diff --git a/mm/migrate.c b/mm/migrate.c
>> index 515718392b24..a42858d8e00b 100644
>> --- a/mm/migrate.c
>> +++ b/mm/migrate.c
>> @@ -2340,16 +2340,13 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
>> static void migrate_vma_collect(struct migrate_vma *migrate)
>> {
>> struct mmu_notifier_range range;
>> - struct mm_walk mm_walk;
>> -
>> - mm_walk.pmd_entry = migrate_vma_collect_pmd;
>> - mm_walk.pte_entry = NULL;
>> - mm_walk.pte_hole = migrate_vma_collect_hole;
>> - mm_walk.hugetlb_entry = NULL;
>> - mm_walk.test_walk = NULL;
>> - mm_walk.vma = migrate->vma;
>> - mm_walk.mm = migrate->vma->vm_mm;
>> - mm_walk.private = migrate;
>> + struct mm_walk mm_walk = {
>> + .pmd_entry = migrate_vma_collect_pmd,
>> + .pte_hole = migrate_vma_collect_hole,
>> + .vma = migrate->vma,
>> + .mm = migrate->vma->vm_mm,
>> + .private = migrate,
>> + };
>>
>> mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, NULL, mm_walk.mm,
>> migrate->start,
>>
>
^ permalink raw reply [flat|nested] 4+ messages in thread
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2019-07-19 23:32 [PATCH] mm/migrate: initialize pud_entry in migrate_vma() Ralph Campbell
2019-07-20 2:03 ` John Hubbard
2019-08-26 15:11 ` Vlastimil Babka
2019-08-26 17:30 ` Ralph Campbell
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