在 2022/6/20 下午6:17, Greg KH 写道:
On Fri, Jun 17, 2022 at 12:17:45AM +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 unset_migratetype_isolate(), we also need the fix, so move page_is_buddy() from mm/page_alloc.c to mm/internal.h
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/internal.h | 34 ++++++++++++++++++++++++++++++++++ mm/page_alloc.c | 37 +++---------------------------------- mm/page_isolation.c | 3 ++- 3 files changed, 39 insertions(+), 35 deletions(-)
What is the commit id of this in Linus's tree?
It is also 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