From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6116130ACE5; Thu, 22 Jan 2026 13:35:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769088945; cv=none; b=JQlCX6er30lwBgftTzBE+LhqcmBS7IX70BUa2SW+knv6KYp8Fy0m0+GoDvn5ZuZ2YKpDSBfppzs1qncY0F6uzx9TXJd71+tp1IEOY8s+e+HLu7nS2RuHRKheI0dYMfOrWvixXDT3bLnsi1BBLC28WYpwbB3zrQHdVVspIg5cMlo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769088945; c=relaxed/simple; bh=wED3dXV0kHkiBnPWNUBgYlSUdtgP2fArJ/kzjZEMltI=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=e/EXWOJujFOpxmnJGY3feMK56hHGpAFvQ+YrtxSFHlTExd9S/buznqbJVgsZJniz4nxAk7F1dMkLSYMsvfe1UhqTWZ72BzF+dwHUhV/ILftNGKUVV7KHmUzsCpMRPsnsEp0Jdm+nTed3qdQpxI/0xH4pzE5+H/kCUmH0b28VgBw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mrM43KnI; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="mrM43KnI" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E4CE5C116C6; Thu, 22 Jan 2026 13:35:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1769088945; bh=wED3dXV0kHkiBnPWNUBgYlSUdtgP2fArJ/kzjZEMltI=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=mrM43KnIhyHDnc8ivUCX5HTrM9Pl42GBN8gXbejQ3Jl7OGoZ6s6TYv7Q9f+Ds41mV +atyWBT9K1XOmZr0pF5xVDisRvZ3G+sA0qlf+8xqzuMhEvZp4UEln1+29gf3zF8UIM hDr0aYGQEDqiPxMYnxspQa3y7BzZqMUsjuoGrP0jIAK+PgK0D2VLGCIn2k5S95TWLs uieNDly2PL9lHs2HFOjsXJgRHIrcw5486a5jYlh+T2wfAUhDov1hXXSAUo6cTbh/uZ yD8mWEN/VEDP5hyMTo/uckvNJclqUK7clMtEpzkS9kYenRw3CDQY2ZRB1Qh1ai61Ql pXhD2DGjTqOBQ== From: Pratyush Yadav To: ranxiaokai627@163.com Cc: pratyush@kernel.org, surenb@google.com, akpm@linux-foundation.org, pasha.tatashin@soleen.com, kent.overstreet@linux.dev, rppt@kernel.org, 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 In-Reply-To: <20260122132740.176468-1-ranxiaokai627@163.com> (ranxiaokai's message of "Thu, 22 Jan 2026 13:27:40 +0000") References: <20260122132740.176468-1-ranxiaokai627@163.com> Date: Thu, 22 Jan 2026 14:35:41 +0100 Message-ID: <2vxzcy31bwia.fsf@kernel.org> User-Agent: Gnus/5.13 (Gnus v5.13) Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain On Thu, Jan 22 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") > Cc: > Signed-off-by: Ran Xiaokai > --- > > 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); > + } > + I think it would be a little bit better if we just did this in the loop above instead of looping again. But I think it is fine for now. I can fix it up in the next release. Reviewed-by: Pratyush Yadav > adjust_managed_page_count(page, nr_pages); > return page; > } -- Regards, Pratyush Yadav