By commit 510d25c92ec4 ("mm/hwpoison: disable pcp for
page_handle_poison()"), __page_handle_poison() was
introduced, and if we mark:
RET_A = dissolve_free_huge_page();
RET_B = take_page_off_buddy();
then __page_handle_poison was supposed to return TRUE When
RET_A == 0 && RET_B == TRUE
But since it failed to take care the case when RET_A is
-EBUSY or -ENOMEM, and just return the ret as a bool which
actually become TRUE, it break the original logical.
The following result is a huge page in freelist but was
referenced as poisoned, and lead into the final panic:
kernel BUG at mm/internal.h:95!
invalid opcode: 0000 [#1] SMP PTI
skip...
RIP: 0010:set_page_refcounted mm/internal.h:95 [inline]
RIP: 0010:remove_hugetlb_page+0x23c/0x240 mm/hugetlb.c:1371
skip...
Call Trace:
remove_pool_huge_page+0xe4/0x110 mm/hugetlb.c:1892
return_unused_surplus_pages+0x8d/0x150 mm/hugetlb.c:2272
hugetlb_acct_memory.part.91+0x524/0x690 mm/hugetlb.c:4017
This patch replace 'bool' with 'int' to handle RET_A correctly.
Reported-by: Abaci <[email protected]>
Signed-off-by: Michael Wang <[email protected]>
---
mm/memory-failure.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 470400c..0fff717 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -68,7 +68,7 @@
static bool __page_handle_poison(struct page *page)
{
- bool ret;
+ int ret;
zone_pcp_disable(page_zone(page));
ret = dissolve_free_huge_page(page);
@@ -76,7 +76,7 @@ static bool __page_handle_poison(struct page *page)
ret = take_page_off_buddy(page);
zone_pcp_enable(page_zone(page));
- return ret;
+ return ret > 0;
}
static bool page_handle_poison(struct page *page, bool hugepage_or_freepage, bool release)
--
1.8.3.1
On Mon, Aug 30, 2021 at 06:07:56PM +0800, 王贇 wrote:
> By commit 510d25c92ec4 ("mm/hwpoison: disable pcp for
> page_handle_poison()"), __page_handle_poison() was
> introduced, and if we mark:
>
> RET_A = dissolve_free_huge_page();
> RET_B = take_page_off_buddy();
>
> then __page_handle_poison was supposed to return TRUE When
> RET_A == 0 && RET_B == TRUE
>
> But since it failed to take care the case when RET_A is
> -EBUSY or -ENOMEM, and just return the ret as a bool which
> actually become TRUE, it break the original logical.
s/logical/logic/ ?
>
> The following result is a huge page in freelist but was
> referenced as poisoned, and lead into the final panic:
>
> kernel BUG at mm/internal.h:95!
> invalid opcode: 0000 [#1] SMP PTI
> skip...
> RIP: 0010:set_page_refcounted mm/internal.h:95 [inline]
> RIP: 0010:remove_hugetlb_page+0x23c/0x240 mm/hugetlb.c:1371
> skip...
> Call Trace:
> remove_pool_huge_page+0xe4/0x110 mm/hugetlb.c:1892
> return_unused_surplus_pages+0x8d/0x150 mm/hugetlb.c:2272
> hugetlb_acct_memory.part.91+0x524/0x690 mm/hugetlb.c:4017
>
> This patch replace 'bool' with 'int' to handle RET_A correctly.
>
> Reported-by: Abaci <[email protected]>
> Signed-off-by: Michael Wang <[email protected]>
Thank you very much, this fix is totally right.
Acked-by: Naoya Horiguchi <[email protected]>
Could you add the following tags, too?
Fixes: 510d25c92ec4 ("mm/hwpoison: disable pcp for page_handle_poison()")
Cc: <[email protected]> # 5.14
Thanks,
Naoya Horiguchi
On 2021/8/31 下午5:11, HORIGUCHI NAOYA(堀口 直也) wrote:
> On Mon, Aug 30, 2021 at 06:07:56PM +0800, 王贇 wrote:
>> By commit 510d25c92ec4 ("mm/hwpoison: disable pcp for
>> page_handle_poison()"), __page_handle_poison() was
>> introduced, and if we mark:
>>
>> RET_A = dissolve_free_huge_page();
>> RET_B = take_page_off_buddy();
>>
>> then __page_handle_poison was supposed to return TRUE When
>> RET_A == 0 && RET_B == TRUE
>>
>> But since it failed to take care the case when RET_A is
>> -EBUSY or -ENOMEM, and just return the ret as a bool which
>> actually become TRUE, it break the original logical.
>
> s/logical/logic/ ?
Will Fix it in v2.
>
>>
>> The following result is a huge page in freelist but was
>> referenced as poisoned, and lead into the final panic:
>>
>> kernel BUG at mm/internal.h:95!
>> invalid opcode: 0000 [#1] SMP PTI
>> skip...
>> RIP: 0010:set_page_refcounted mm/internal.h:95 [inline]
>> RIP: 0010:remove_hugetlb_page+0x23c/0x240 mm/hugetlb.c:1371
>> skip...
>> Call Trace:
>> remove_pool_huge_page+0xe4/0x110 mm/hugetlb.c:1892
>> return_unused_surplus_pages+0x8d/0x150 mm/hugetlb.c:2272
>> hugetlb_acct_memory.part.91+0x524/0x690 mm/hugetlb.c:4017
>>
>> This patch replace 'bool' with 'int' to handle RET_A correctly.
>>
>> Reported-by: Abaci <[email protected]>
>> Signed-off-by: Michael Wang <[email protected]>
>
> Thank you very much, this fix is totally right.
>
> Acked-by: Naoya Horiguchi <[email protected]>
>
> Could you add the following tags, too?
>
> Fixes: 510d25c92ec4 ("mm/hwpoison: disable pcp for page_handle_poison()")
> Cc: <[email protected]> # 5.14
Thanks for the review, will add in v2 and send out soon.
Regards,
Michael Wang
>
> Thanks,
> Naoya Horiguchi
>
By commit 510d25c92ec4 ("mm/hwpoison: disable pcp for
page_handle_poison()"), __page_handle_poison() was
introduced, and if we mark:
RET_A = dissolve_free_huge_page();
RET_B = take_page_off_buddy();
then __page_handle_poison was supposed to return TRUE When
RET_A == 0 && RET_B == TRUE
But since it failed to take care the case when RET_A is
-EBUSY or -ENOMEM, and just return the ret as a bool which
actually become TRUE, it break the original logic.
The following result is a huge page in freelist but was
referenced as poisoned, and lead into the final panic:
kernel BUG at mm/internal.h:95!
invalid opcode: 0000 [#1] SMP PTI
skip...
RIP: 0010:set_page_refcounted mm/internal.h:95 [inline]
RIP: 0010:remove_hugetlb_page+0x23c/0x240 mm/hugetlb.c:1371
skip...
Call Trace:
remove_pool_huge_page+0xe4/0x110 mm/hugetlb.c:1892
return_unused_surplus_pages+0x8d/0x150 mm/hugetlb.c:2272
hugetlb_acct_memory.part.91+0x524/0x690 mm/hugetlb.c:4017
This patch replace 'bool' with 'int' to handle RET_A correctly.
Fixes: 510d25c92ec4 ("mm/hwpoison: disable pcp for page_handle_poison()")
Cc: <[email protected]> # 5.14
Acked-by: Naoya Horiguchi <[email protected]>
Reported-by: Abaci <[email protected]>
Signed-off-by: Michael Wang <[email protected]>
---
mm/memory-failure.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 470400c..0fff717 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -68,7 +68,7 @@
static bool __page_handle_poison(struct page *page)
{
- bool ret;
+ int ret;
zone_pcp_disable(page_zone(page));
ret = dissolve_free_huge_page(page);
@@ -76,7 +76,7 @@ static bool __page_handle_poison(struct page *page)
ret = take_page_off_buddy(page);
zone_pcp_enable(page_zone(page));
- return ret;
+ return ret > 0;
}
static bool page_handle_poison(struct page *page, bool hugepage_or_freepage, bool release)
--
1.8.3.1