Messages in this thread | | | Subject | Re: [PATCH 5.15] mm: validate buddy page before using | From | Xianting Tian <> | Date | Mon, 20 Jun 2022 20:41:43 +0800 |
| |
在 2022/6/20 下午8:24, Greg KH 写道: > On Mon, Jun 20, 2022 at 08:18:40PM +0800, Xianting Tian wrote: >> 在 2022/6/20 下午8:06, Greg KH 写道: >>> On Mon, Jun 20, 2022 at 07:57:05PM +0800, Xianting Tian wrote: >>>> 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 <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> >>>>> 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/ <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). >>> What is "your fix" here? >>> >>> This change differs a lot from what is in Linus's tree now, so this all >>> needs to be resend and fixed up as I mention above if we are going to be >>> able to take this. As-is, it's all not correct so are dropped. >> I think, for branches except 5.15, you can just backport Zi Yan's commit >> 787af64d05cd in Linus tree. I won't send more patches further, > So just for 5.18? I am confused. Sorry, 5.18 needs the same fix with 5.15. I will send the patch for it. > >> For 5.15, because it need additional fix except commit 787af64d05cd, I will >> send a new patch as your comments. >> >> Is it ok for you? > No, please send fixed up patches for all branches you want them applied > to as I do not understand what to do here at all, sorry. Understood. I will send for all branches. > > greg k-h
| |