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b=WoJ0nypqalaeViN45nqZS61DwLJvLaxS6Va7RYXhmCPffYKzA4qdEjCMvwy+oegw3 aKfV7IBM1CmTPICv1FsvAfImMRMKEOCG5X7MpI/dePfmYI/JByz/LZYC0ZjrjP55Ao 1SLnMSBL0Ke+sW43iPtgeIe6b9D4ydUSHzhKWjeaNBWdI0tlqCKYh3EUSBhdXc6j4g Syov6+OE4ubSQiSv1TfW/S9MSNsX9kLpZ7rHBdyf0+q1aYZRzbIOAAPe6UFwRdniIj QulhEZGmEzx4jlQmft7zPoZK+lQp6gZSh8Julc8gkPGTBfQXKSy2OVFVJHkJx/uMUy Jy70fsy4UJnYQ== Date: Fri, 23 Jan 2026 10:55:34 +0200 From: Mike Rapoport To: ranxiaokai627@163.com Cc: pratyush@kernel.org, surenb@google.com, akpm@linux-foundation.org, pasha.tatashin@soleen.com, kent.overstreet@linux.dev, graf@amazon.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, ran.xiaokai@zte.com.cn, stable@vger.kernel.org Subject: Re: [PATCH RESEND v3] kho: init alloc tags when restoring pages from reserved memory Message-ID: References: <20260122132740.176468-1-ranxiaokai627@163.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260122132740.176468-1-ranxiaokai627@163.com> X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 02ABD100003 X-Stat-Signature: 5416jsef3e8d7zxichz7nid5fsrd1c58 X-Rspam-User: X-HE-Tag: 1769158542-518986 X-HE-Meta: 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 2Am5Guu2 1z3qARfu6irm98ayEo30nO8rfbteUrhpYa4Q8H5zNu/o/qO8JSR3nx3sIK1bz6LgwAC82yy+r1i/Smcel4PZMi/PAHODeIzVs1KX7ZU2EXHGoIufExp1QAGauwAeB3ldQNEq2CfI2ZuHWgVpFiztkzKCxdW4hgSVPAd1EpM0ZeO5jS358tzRQ84JfvzjwOc3vtrEfQjl5pguUyHEWuk8lPPZu4ggpgoRsH4j3C5U7VxVOeOPFFy7HJr2PbA+GHGrz1QYsTIfbuRgc+ZJOeF35XqhDXnub+xYz4YS6bg7DYWISz5a8ULKuDqnIpQOuPNLQqox6feSoAbZae5nHEpGJ17WIuuoOJiQ7vGZ4vB++9vy+f5I= 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 Thu, Jan 22, 2026 at 01:27:40PM +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 below warning message: > > alloc_tag was not set > WARNING: include/linux/alloc_tag.h:164 at ___free_pages+0xb8/0x260, CPU#1: swapper/0/1 > RIP: 0010:___free_pages+0xb8/0x260 > kho_restore_vmalloc+0x187/0x2e0 > kho_test_init+0x3c4/0xa30 > do_one_initcall+0x62/0x2b0 > kernel_init_freeable+0x25b/0x480 > kernel_init+0x1a/0x1c0 > ret_from_fork+0x2d1/0x360 > > Add missing clear_page_tag_ref() annotation in kho_restore_page() to > fix this. > > Fixes: fc33e4b44b27 ("kexec: enable KHO support for memory preservation") > Cc: > Signed-off-by: Ran Xiaokai Reviewed-by: Mike Rapoport (Microsoft) > --- > > v2 -> v3: > - also call clear_page_tag_ref() for non-compound order-0 tail pages > > kernel/liveupdate/kexec_handover.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/kernel/liveupdate/kexec_handover.c b/kernel/liveupdate/kexec_handover.c > index d4482b6e3cae..96767b106cac 100644 > --- a/kernel/liveupdate/kexec_handover.c > +++ b/kernel/liveupdate/kexec_handover.c > @@ -255,6 +255,14 @@ static struct page *kho_restore_page(phys_addr_t phys, bool is_folio) > if (is_folio && info.order) > prep_compound_page(page, info.order); > > + /* Always mark headpage's codetag as empty to avoid accounting mismatch */ > + clear_page_tag_ref(page); > + if (!is_folio) { > + /* Also do that for the non-compound tail pages */ > + for (unsigned int i = 1; i < nr_pages; i++) > + clear_page_tag_ref(page + i); > + } > + > adjust_managed_page_count(page, nr_pages); > return page; > } > -- > 2.25.1 > > -- Sincerely yours, Mike.