| Message ID | 20220616161928.3565294-1-xianting.tian@linux.alibaba.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [4.9] mm: page_alloc: validate buddy page before using | expand |
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
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
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(+)