Commit 787af64d05cd ("mm: page_alloc: validate buddy before check its migratetype.") fixes a bug in 1dd214b8f21c and there is a similar bug in d9dddbf55667 that can be fixed in a similar way too.
In addition, for RISC-V arch the first 2MB RAM could be reserved for opensbi, so it would have pfn_base=512 and mem_map began with 512th PFN when CONFIG_FLATMEM=y. But __find_buddy_pfn algorithm thinks the start pfn 0, it could get 0 pfn or less than the pfn_base value. We need page_is_buddy() to verify the buddy to prevent accessing an invalid buddy.
Fixes: d9dddbf55667 ("mm/page_alloc: prevent merging between isolated and other pageblocks") Cc: stable@vger.kernel.org Reported-by: zjb194813@alibaba-inc.com Reported-by: tianhu.hh@alibaba-inc.com Signed-off-by: Xianting Tian xianting.tian@linux.alibaba.com --- mm/page_alloc.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index a6e682569e5b..1c423faa4b62 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -864,6 +864,9 @@ static inline void __free_one_page(struct page *page,
buddy_idx = __find_buddy_index(page_idx, order); buddy = page + (buddy_idx - page_idx); + + if (!page_is_buddy(page, buddy, order)) + goto done_merging; buddy_mt = get_pageblock_migratetype(buddy);
if (migratetype != buddy_mt
On Fri, Jun 17, 2022 at 12:19:28AM +0800, Xianting Tian wrote:
Commit 787af64d05cd ("mm: page_alloc: validate buddy before check its migratetype.") fixes a bug in 1dd214b8f21c and there is a similar bug in d9dddbf55667 that can be fixed in a similar way too.
In addition, for RISC-V arch the first 2MB RAM could be reserved for opensbi, so it would have pfn_base=512 and mem_map began with 512th PFN when CONFIG_FLATMEM=y. But __find_buddy_pfn algorithm thinks the start pfn 0, it could get 0 pfn or less than the pfn_base value. We need page_is_buddy() to verify the buddy to prevent accessing an invalid buddy.
Fixes: d9dddbf55667 ("mm/page_alloc: prevent merging between isolated and other pageblocks") Cc: stable@vger.kernel.org Reported-by: zjb194813@alibaba-inc.com Reported-by: tianhu.hh@alibaba-inc.com Signed-off-by: Xianting Tian xianting.tian@linux.alibaba.com
mm/page_alloc.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index a6e682569e5b..1c423faa4b62 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -864,6 +864,9 @@ static inline void __free_one_page(struct page *page, buddy_idx = __find_buddy_index(page_idx, order); buddy = page + (buddy_idx - page_idx);
if (!page_is_buddy(page, buddy, order))goto done_merging; buddy_mt = get_pageblock_migratetype(buddy);if (migratetype != buddy_mt -- 2.17.1
What is the git commit id of this change in Linus's tree?
thanks,
greg k-h
在 2022/6/17 下午4:20, Greg KH 写道:
On Fri, Jun 17, 2022 at 12:19:28AM +0800, Xianting Tian wrote:
Commit 787af64d05cd ("mm: page_alloc: validate buddy before check its migratetype.") fixes a bug in 1dd214b8f21c and there is a similar bug in d9dddbf55667 that can be fixed in a similar way too.
In addition, for RISC-V arch the first 2MB RAM could be reserved for opensbi, so it would have pfn_base=512 and mem_map began with 512th PFN when CONFIG_FLATMEM=y. But __find_buddy_pfn algorithm thinks the start pfn 0, it could get 0 pfn or less than the pfn_base value. We need page_is_buddy() to verify the buddy to prevent accessing an invalid buddy.
Fixes: d9dddbf55667 ("mm/page_alloc: prevent merging between isolated and other pageblocks") Cc: stable@vger.kernel.org Reported-by: zjb194813@alibaba-inc.com Reported-by: tianhu.hh@alibaba-inc.com Signed-off-by: Xianting Tian xianting.tian@linux.alibaba.com
mm/page_alloc.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index a6e682569e5b..1c423faa4b62 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -864,6 +864,9 @@ static inline void __free_one_page(struct page *page, buddy_idx = __find_buddy_index(page_idx, order); buddy = page + (buddy_idx - page_idx);
if (!page_is_buddy(page, buddy, order))goto done_merging; buddy_mt = get_pageblock_migratetype(buddy);if (migratetype != buddy_mt -- 2.17.1
What is the git commit id of this change in Linus's tree?
It is this one,
commit 787af64d05cd528aac9ad16752d11bb1c6061bb9 Author: Zi Yan ziy@nvidia.com Date: Wed Mar 30 15:45:43 2022 -0700
mm: page_alloc: validate buddy before check its migratetype.
Whenever a buddy page is found, page_is_buddy() should be called to check its validity. Add the missing check during pageblock merge check.
Fixes: 1dd214b8f21c ("mm: page_alloc: avoid merging non-fallbackable pageblocks with others") Link: https://lore.kernel.org/all/20220330154208.71aca532@gandalf.local.home/ Reported-and-tested-by: Steven Rostedt rostedt@goodmis.org Signed-off-by: Zi Yan ziy@nvidia.com Signed-off-by: Linus Torvalds torvalds@linux-foundation.org
thanks,
greg k-h
On Fri, Jun 17, 2022 at 04:25:35PM +0800, Xianting Tian wrote:
在 2022/6/17 下午4:20, Greg KH 写道:
On Fri, Jun 17, 2022 at 12:19:28AM +0800, Xianting Tian wrote:
Commit 787af64d05cd ("mm: page_alloc: validate buddy before check its migratetype.") fixes a bug in 1dd214b8f21c and there is a similar bug in d9dddbf55667 that can be fixed in a similar way too.
In addition, for RISC-V arch the first 2MB RAM could be reserved for opensbi, so it would have pfn_base=512 and mem_map began with 512th PFN when CONFIG_FLATMEM=y. But __find_buddy_pfn algorithm thinks the start pfn 0, it could get 0 pfn or less than the pfn_base value. We need page_is_buddy() to verify the buddy to prevent accessing an invalid buddy.
Fixes: d9dddbf55667 ("mm/page_alloc: prevent merging between isolated and other pageblocks") Cc: stable@vger.kernel.org Reported-by: zjb194813@alibaba-inc.com Reported-by: tianhu.hh@alibaba-inc.com Signed-off-by: Xianting Tian xianting.tian@linux.alibaba.com
mm/page_alloc.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index a6e682569e5b..1c423faa4b62 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -864,6 +864,9 @@ static inline void __free_one_page(struct page *page, buddy_idx = __find_buddy_index(page_idx, order); buddy = page + (buddy_idx - page_idx);
if (!page_is_buddy(page, buddy, order))goto done_merging; buddy_mt = get_pageblock_migratetype(buddy); if (migratetype != buddy_mt-- 2.17.1
What is the git commit id of this change in Linus's tree?
It is this one,
commit 787af64d05cd528aac9ad16752d11bb1c6061bb9 Author: Zi Yan ziy@nvidia.com Date: Wed Mar 30 15:45:43 2022 -0700
mm: page_alloc: validate buddy before check its migratetype.
Whenever a buddy page is found, page_is_buddy() should be called to check its validity. Add the missing check during pageblock merge check.
Fixes: 1dd214b8f21c ("mm: page_alloc: avoid merging non-fallbackable pageblocks with others") Link: https://lore.kernel.org/all/20220330154208.71aca532@gandalf.local.home/ Reported-and-tested-by: Steven Rostedt rostedt@goodmis.org Signed-off-by: Zi Yan ziy@nvidia.com Signed-off-by: Linus Torvalds torvalds@linux-foundation.org
All now queued up, thanks.
greg k-h
linux-stable-mirror@lists.linaro.org
-
Greg KH -
Xianting Tian