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imf04.hostedemail.com; dkim=pass header.d=linuxfoundation.org header.s=korg header.b=kO8bPvqD; dmarc=pass (policy=none) header.from=linuxfoundation.org; spf=pass (imf04.hostedemail.com: domain of gregkh@linuxfoundation.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=linuxfoundation.org header.s=korg header.b=kO8bPvqD; dmarc=pass (policy=none) header.from=linuxfoundation.org; spf=pass (imf04.hostedemail.com: domain of gregkh@linuxfoundation.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 7E8114009C X-Stat-Signature: 5zt4fp1jakezms57ht3web8rej5pyq33 X-HE-Tag: 1655726811-617742 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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 > > > > > --- > > > > > 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). 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. thanks, greg k-h