在 2022/6/20 下午7:42, Greg KH 写道: > On Mon, Jun 20, 2022 at 06:54:44PM +0800, Xianting Tian wrote: >> 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 >>>> --- >>>> 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 >> 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 >>     Signed-off-by: Zi Yan >>     Signed-off-by: Linus Torvalds > This commit looks nothing like what you posted here. > > Why the vast difference with no explaination as to why these are so > different from the other backports you provided here? Also why is the > subject lines changed? Yes, the changes of 5.15 are not same with others branches, because we need additional fix for 5.15, You can check it in the thread: https://lore.kernel.org/linux-mm/435B45C3-E6A5-43B2-A5A2-318C748691FC@nvidia.com/ Right. But pfn_valid_within() was removed since 5.15. So your fix is required for kernels between 5.15 and 5.17 (inclusive). > Something went really wrong here, I'm going to drop all of these from > the stable queues and wait for a full series of all new backports, with > the correct upstream commit id added, and the original signed-off-by > lines preserved. > > thanks, > > greg k-h