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a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1768409734; bh=QejQhjBMM5h7AWsceCq9AC06bxVTWkjs0XH1r2FG920=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=l9cMh3NYa7Vune+62JflcUh/D6FsoXVcIncMsmx9m1uHAvsMOsJ0VBRtSWsQFkdKm q0T25Zpz+3L4U/qdB52PuM4TlLl+mjHslNNC7rdsTvueMvj7IBx5xeELmQA887Kd5g r/q9ZVcRQ0R+CN78HxplGXk6u4WGm9V78oge/WgY1Hfj5jHls+HGsSNf2zbxjeofIU AObRipt1LcQligXXB7KD5EId1Uxf2f0HlyyrVCqRZ359G5WK9QXr8zkf8f2jsIAdp+ R1aioUFFtCTyNUDXeCUHpLv+sVv0QTbmluTuGvLNDU4qyXX2RDmwLe7uHgSjkMxJ4z rn3xvM2v3P6ag== From: Pratyush Yadav To: ranxiaokai627@163.com Cc: graf@amazon.com, rppt@kernel.org, pasha.tatashin@soleen.com, pratyush@kernel.org, akpm@linux-foundation.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 v2] kho: init alloc tags when restoring pages from reserved memory In-Reply-To: <20260113033403.161869-1-ranxiaokai627@163.com> (ranxiaokai's message of "Tue, 13 Jan 2026 03:34:03 +0000") References: <20260113033403.161869-1-ranxiaokai627@163.com> Date: Wed, 14 Jan 2026 16:55:31 +0000 Message-ID: <2vxztswoi16k.fsf@kernel.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Rspamd-Queue-Id: D8D7F4000A X-Rspamd-Server: rspam06 X-Stat-Signature: 9bkheephtfhnrqidcwfxawaib5xur5uq X-Rspam-User: X-HE-Tag: 1768409735-405101 X-HE-Meta: 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 U7pmYDdC ArbPzO+Ihrn5kZryd0ujJPTyxCAMH2e1ELXTqItEopD4jFlCpZRgEcwwZdBixgMhK9jxGfOFZJaJmweH09KTJRyqNGg8Zk42x8RVqIyqd35/pm96ZA5N3uqgGVwIQRYlfPw5Ii1raBcMDLTGBdT4uCxjOShyLH4l4gvVjWZT99BHmSfGkBx4pHFNkPs/pX8An92VuPTQvsQLqcVhmgeK2FsM77DArrpK3mbIeFV+0Rl28ZBJ2s9c6z6SRqkwy8lorTvS+dI/ysMxkSJSEOvbkQkkmGdbjZo8HIHGJVKYyDMWyvi4= 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: Hi Ran, On Tue, Jan 13 2026, 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") > Signed-off-by: Ran Xiaokai > Reviewed-by: Mike Rapoport (Microsoft) > Reviewed-by: Suren Baghdasaryan > --- > kernel/liveupdate/kexec_handover.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/kernel/liveupdate/kexec_handover.c b/kernel/liveupdate/kexec_handover.c > index cd6b3fb9dcae..2d47f2c50bd8 100644 > --- 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); You are only clearing the tag for the head page. The tail pages are still un-initialized. Is that intentional? What about non-compound pages (the ones you get from kho_restore_pages(), aka when is_folio is false)? Do we need to clear the tag on all pages in that case? > adjust_managed_page_count(page, nr_pages); > return page; > }