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b=XBx97/xKW55BHFhSVToAhSY74nwEwwCtS78dADYRniDyX4CCS+3en/HYGMkyrXmoV /AuPJB3Y2UD40BzYuaBuU1jtdVgm9eTzkA5RElTPjcTOCpNVq5sSYYp6Dk99gditdt 3M6U8KdpHXpkSSryv8WSVPFLVJFtZPDmWbsJm+2MyeoVvwSUP5+yJHQyvE+DvBLKCR hIUoLfNEZvCsRTUjPlIeBfo3bK/hQ0ujKZrqXZe+/+BLDgjSa23ix6CXF1Jw0Wl2gc 5alBnwzzdT2yyhiSc2/ET4a+K+T/6OUo2CHG7R++XQrj1+wOBneVJ8fdWC/d1VSHRz 62nNZ6eZ6EuzQ== Date: Sun, 11 Jan 2026 11:11:42 +0200 From: Mike Rapoport To: Andrew Morton Cc: ranxiaokai627@163.com, graf@amazon.com, pasha.tatashin@soleen.com, pratyush@kernel.org, surenb@google.com, kexec@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, ran.xiaokai@zte.com.cn Subject: Re: [PATCH] kho: init alloc tags when restoring pages from reserved memory Message-ID: References: <20260109104251.157767-1-ranxiaokai627@163.com> <20260110162843.ecd8e731bdc281f4cd8e4764@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260110162843.ecd8e731bdc281f4cd8e4764@linux-foundation.org> X-Rspamd-Queue-Id: F3AC91A000A X-Stat-Signature: tk7h346sydmcyuwkqfnoeekrphzas8h4 X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1768122710-968057 X-HE-Meta: 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 9q1V8b0H vumq7xsLOuFqZAEP/QhWMcHtjl0VbgHYX9DOKC0S9LDNQoDZh50XfPox1iJmqqo7rLepnDvBteMU20BuhhVGbLrsaBjd9cKLDV/MmV+H+oCX9m7uuTdS05PhPnYY6U446awk3cFoIFtk6fR9mVCq9lFmcK9ttWnJifY9W7XaVycqLEDdI2sJxO+1aAOdEWZB1Xb7/R82RVtED4/FnTg5PCTRvEqDjLihhyBevR5Hay8mrp/vEFGs7FUNEdo2WQfAVWBUcAHOnfoJQZwsEdLogTerpZ9WkesMR/QITGTIafFASWYo7+V7aVuNqd8Rok+lKWAW4XvYhLkBnECjP7eUF0DvAVw== 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: List-Subscribe: List-Unsubscribe: On Sat, Jan 10, 2026 at 04:28:43PM -0800, Andrew Morton wrote: > On Fri, 9 Jan 2026 10:42:51 +0000 ranxiaokai627@163.com wrote: > > > From: Ran Xiaokai > > > > Memblock pages (including reserved memory) should have their allocation > > tags initialized to CODETAG_EMPTY via clear_page_tag_ref() before being > > released to the page allocator. When kho restores pages through > > kho_restore_page(), missing this call causes mismatched > > allocation/deallocation tracking and warning message: > > alloc_tag was not set. > > > > Add missing clear_page_tag_ref() annotation in kho_restore_page() to > > fix this. > > Great, thanks. > > It would be helpful to quote that warning message in the patch > changelog, please. > > > --- a/kernel/liveupdate/kexec_handover.c > > +++ b/kernel/liveupdate/kexec_handover.c > > @@ -268,6 +268,7 @@ static struct page *kho_restore_page(phys_addr_t phys, bool is_folio) > > else > > kho_init_pages(page, nr_pages); > > > > + clear_page_tag_ref(page); > > adjust_managed_page_count(page, nr_pages); > > return page; > > } > > Warning splats are pretty bad and it's desirable to fix this in > previous kernel versions. > > To do that it's best for us to identify which kernel version(s) should > be patched, via a Fixes: tag in the changelog. > > From a quick look, it appears that Pratyush's 12b9a2c05d1b ("kho: > initialize tail pages for higher order folios properly") is a suitable > anchor, what do people think? I think it should be even earlier: fc33e4b44b27 ("kexec: enable KHO support for memory preservation") > Meanwhile I'll queue this up for some testing while awaiting maintainer > feedback. -- Sincerely yours, Mike.