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 9192535B12B for ; Fri, 14 Nov 2025 21:35:16 +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=1763156116; cv=none; b=luLinqtxmCz9kjvrxCqQrd50RAJQulNaFPH42U80GVhSsRl8O/Uz/4+zoKZen5BEgkq+vPq3bnpbFcLjOsPmETWps5VAEof8AO+5/Z2pjK+QrPdr63YYUFCvjk41feWGfLmpoGPHxRMt1ajXew1iOEBMm+SVvaqe1Y4b86kSHfw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763156116; c=relaxed/simple; bh=SqJB08PfmipHfIRde7r+8L/1t2pWJQwt0NrUGYBWTgU=; h=Date:To:From:Subject:Message-Id; b=losxeEd/JPUaNuk3+RgBPy5sIHxUhbgZKSumJzrSVCmv0hZiRy4g5T62w5BI4OtZgD4+skeMrGImiJK3n8/rLUo4A4oCvO3CncthccV1w8gMnbvU9Z74hhZ52BTxv07GCphGRCNooh700jU7VaN9VddUHpjH2QhpO/lwcKaezdc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=aIGWuKj9; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="aIGWuKj9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1C50DC4CEF1; Fri, 14 Nov 2025 21:35:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1763156116; bh=SqJB08PfmipHfIRde7r+8L/1t2pWJQwt0NrUGYBWTgU=; h=Date:To:From:Subject:From; b=aIGWuKj9kAQMvtY7REABXq8FYYc5IC4+OfGpHogOd2kW7STkp3hP2ScczR+VV4GOp uw55DuyRa67AfwEDJLVowpclMuWAaTSqJENeg0oUcJYT6MMEbaSR6BjrOfbEpCAboe mvOIsKAcd3qKuQLZuEIMy7UN8PlBIWis2V/QzQf0= Date: Fri, 14 Nov 2025 13:35:14 -0800 To: mm-commits@vger.kernel.org,rppt@kernel.org,pratyush@kernel.org,kees@kernel.org,graf@amazon.com,ebiggers@google.com,dave@vasilevsky.ca,coxu@redhat.com,bhe@redhat.com,arnd@arndb.de,pasha.tatashin@soleen.com,akpm@linux-foundation.org From: Andrew Morton Subject: + kho-preserve-fdt-folio-only-once-during-initialization.patch added to mm-nonmm-unstable branch Message-Id: <20251114213516.1C50DC4CEF1@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: kho: preserve FDT folio only once during initialization has been added to the -mm mm-nonmm-unstable branch. Its filename is kho-preserve-fdt-folio-only-once-during-initialization.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/kho-preserve-fdt-folio-only-once-during-initialization.patch This patch will later appear in the mm-nonmm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Pasha Tatashin Subject: kho: preserve FDT folio only once during initialization Date: Fri, 14 Nov 2025 13:59:53 -0500 Currently, the FDT folio is preserved inside __kho_finalize(). If the user performs multiple finalize/abort cycles, kho_preserve_folio() is called repeatedly for the same FDT folio. Since the FDT folio is allocated once during kho_init(), it should be marked for preservation at the same time. Move the preservation call to kho_init() to align the preservation state with the object's lifecycle and simplify the finalize path. Also, pre-zero the FDT tree so we do not expose random bits to the user and to the next kernel by using the new kho_alloc_preserve() api. Link: https://lkml.kernel.org/r/20251114190002.3311679-5-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin Reviewed-by: Mike Rapoport (Microsoft) Reviewed-by: Pratyush Yadav Cc: Alexander Graf Cc: Arnd Bergmann Cc: Baoquan He Cc: Coiby Xu Cc: Dave Vasilevsky Cc: Eric Biggers Cc: Kees Cook Signed-off-by: Andrew Morton --- kernel/liveupdate/kexec_handover.c | 18 ++++++------------ 1 file changed, 6 insertions(+), 12 deletions(-) --- a/kernel/liveupdate/kexec_handover.c~kho-preserve-fdt-folio-only-once-during-initialization +++ a/kernel/liveupdate/kexec_handover.c @@ -1251,10 +1251,6 @@ static int __kho_finalize(void) if (err) goto abort; - err = kho_preserve_folio(virt_to_folio(kho_out.fdt)); - if (err) - goto abort; - err = kho_mem_serialize(&kho_out); if (err) goto abort; @@ -1384,19 +1380,17 @@ EXPORT_SYMBOL_GPL(kho_retrieve_subtree); static __init int kho_init(void) { - int err = 0; const void *fdt = kho_get_fdt(); - struct page *fdt_page; + int err = 0; if (!kho_enable) return 0; - fdt_page = alloc_page(GFP_KERNEL); - if (!fdt_page) { - err = -ENOMEM; + kho_out.fdt = kho_alloc_preserve(PAGE_SIZE); + if (IS_ERR(kho_out.fdt)) { + err = PTR_ERR(kho_out.fdt); goto err_free_scratch; } - kho_out.fdt = page_to_virt(fdt_page); err = kho_debugfs_init(); if (err) @@ -1424,9 +1418,9 @@ static __init int kho_init(void) return 0; err_free_fdt: - put_page(fdt_page); - kho_out.fdt = NULL; + kho_unpreserve_free(kho_out.fdt); err_free_scratch: + kho_out.fdt = NULL; for (int i = 0; i < kho_scratch_cnt; i++) { void *start = __va(kho_scratch[i].addr); void *end = start + kho_scratch[i].size; _ Patches currently in -mm which might be from pasha.tatashin@soleen.com are lib-test_kho-check-if-kho-is-enabled.patch kho-make-debugfs-interface-optional.patch kho-add-interfaces-to-unpreserve-folios-page-ranges-and-vmalloc.patch memblock-unpreserve-memory-in-case-of-error.patch test_kho-unpreserve-memory-in-case-of-error.patch kho-dont-unpreserve-memory-during-abort.patch liveupdate-kho-move-to-kernel-liveupdate.patch liveupdate-kho-move-to-kernel-liveupdate-fix.patch maintainers-update-kho-maintainers.patch kho-fix-misleading-log-message-in-kho_populate.patch kho-convert-__kho_abort-to-return-void.patch kho-introduce-high-level-memory-allocation-api.patch kho-preserve-fdt-folio-only-once-during-initialization.patch kho-verify-deserialization-status-and-fix-fdt-alignment-access.patch kho-always-expose-output-fdt-in-debugfs.patch kho-simplify-serialization-and-remove-__kho_abort.patch kho-remove-global-preserved_mem_map-and-store-state-in-fdt.patch kho-remove-abort-functionality-and-support-state-refresh.patch kho-update-fdt-dynamically-for-subtree-addition-removal.patch kho-allow-kexec-load-before-kho-finalization.patch kho-allow-memory-preservation-state-updates-after-finalization.patch kho-add-kconfig-option-to-enable-kho-by-default.patch liveupdate-luo_core-luo_ioctl-live-update-orchestrator.patch liveupdate-luo_core-integrate-with-kho.patch reboot-call-liveupdate_reboot-before-kexec.patch liveupdate-luo_session-add-sessions-support.patch liveupdate-luo_ioctl-add-user-interface.patch liveupdate-luo_file-implement-file-systems-callbacks.patch liveupdate-luo_session-add-ioctls-for-file-preservation-and-state-management.patch liveupdate-luo_flb-introduce-file-lifecycle-bound-global-state.patch docs-add-luo-documentation.patch maintainers-add-liveupdate-entry.patch selftests-liveupdate-add-userspace-api-selftests.patch selftests-liveupdate-add-kexec-based-selftest-for-session-lifecycle.patch selftests-liveupdate-add-kexec-test-for-multiple-and-empty-sessions.patch tests-liveupdate-add-in-kernel-liveupdate-test.patch