Merge tag 'mm-nonmm-stable-2025-12-06-11-14' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull non-MM updates from Andrew Morton:

 - "panic: sys_info: Refactor and fix a potential issue" (Andy Shevchenko)
   fixes a build issue and does some cleanup in ib/sys_info.c

 - "Implement mul_u64_u64_div_u64_roundup()" (David Laight)
   enhances the 64-bit math code on behalf of a PWM driver and beefs up
   the test module for these library functions

 - "scripts/gdb/symbols: make BPF debug info available to GDB" (Ilya Leoshkevich)
   makes BPF symbol names, sizes, and line numbers available to the GDB
   debugger

 - "Enable hung_task and lockup cases to dump system info on demand" (Feng Tang)
   adds a sysctl which can be used to cause additional info dumping when
   the hung-task and lockup detectors fire

 - "lib/base64: add generic encoder/decoder, migrate users" (Kuan-Wei Chiu)
   adds a general base64 encoder/decoder to lib/ and migrates several
   users away from their private implementations

 - "rbree: inline rb_first() and rb_last()" (Eric Dumazet)
   makes TCP a little faster

 - "liveupdate: Rework KHO for in-kernel users" (Pasha Tatashin)
   reworks the KEXEC Handover interfaces in preparation for Live Update
   Orchestrator (LUO), and possibly for other future clients

 - "kho: simplify state machine and enable dynamic updates" (Pasha Tatashin)
   increases the flexibility of KEXEC Handover. Also preparation for LUO

 - "Live Update Orchestrator" (Pasha Tatashin)
   is a major new feature targeted at cloud environments. Quoting the
   cover letter:

      This series introduces the Live Update Orchestrator, a kernel
      subsystem designed to facilitate live kernel updates using a
      kexec-based reboot. This capability is critical for cloud
      environments, allowing hypervisors to be updated with minimal
      downtime for running virtual machines. LUO achieves this by
      preserving the state of selected resources, such as memory,
      devices and their dependencies, across the kernel transition.

      As a key feature, this series includes support for preserving
      memfd file descriptors, which allows critical in-memory data, such
      as guest RAM or any other large memory region, to be maintained in
      RAM across the kexec reboot.

   Mike Rappaport merits a mention here, for his extensive review and
   testing work.

 - "kexec: reorganize kexec and kdump sysfs" (Sourabh Jain)
   moves the kexec and kdump sysfs entries from /sys/kernel/ to
   /sys/kernel/kexec/ and adds back-compatibility symlinks which can
   hopefully be removed one day

 - "kho: fixes for vmalloc restoration" (Mike Rapoport)
   fixes a BUG which was being hit during KHO restoration of vmalloc()
   regions

* tag 'mm-nonmm-stable-2025-12-06-11-14' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (139 commits)
  calibrate: update header inclusion
  Reinstate "resource: avoid unnecessary lookups in find_next_iomem_res()"
  vmcoreinfo: track and log recoverable hardware errors
  kho: fix restoring of contiguous ranges of order-0 pages
  kho: kho_restore_vmalloc: fix initialization of pages array
  MAINTAINERS: TPM DEVICE DRIVER: update the W-tag
  init: replace simple_strtoul with kstrtoul to improve lpj_setup
  KHO: fix boot failure due to kmemleak access to non-PRESENT pages
  Documentation/ABI: new kexec and kdump sysfs interface
  Documentation/ABI: mark old kexec sysfs deprecated
  kexec: move sysfs entries to /sys/kernel/kexec
  test_kho: always print restore status
  kho: free chunks using free_page() instead of kfree()
  selftests/liveupdate: add kexec test for multiple and empty sessions
  selftests/liveupdate: add simple kexec-based selftest for LUO
  selftests/liveupdate: add userspace API selftests
  docs: add documentation for memfd preservation via LUO
  mm: memfd_luo: allow preserving memfd
  liveupdate: luo_file: add private argument to store runtime state
  mm: shmem: export some functions to internal.h
  ...

1 files changed, 80 insertions, 60 deletions

diff --git a/lib/test_kho.c b/lib/test_kho.c
index fff018e5548d..47de56280795 100644
--- a/lib/test_kho.c
+++ b/lib/test_kho.c
@@ -33,44 +33,28 @@ struct kho_test_state {
 	unsigned int nr_folios;
 	struct folio **folios;
 	phys_addr_t *folios_info;
+	struct kho_vmalloc folios_info_phys;
+	int nr_folios_preserved;
 	struct folio *fdt;
 	__wsum csum;
 };
 
 static struct kho_test_state kho_test_state;
 
-static int kho_test_notifier(struct notifier_block *self, unsigned long cmd,
-			     void *v)
+static void kho_test_unpreserve_data(struct kho_test_state *state)
 {
-	struct kho_test_state *state = &kho_test_state;
-	struct kho_serialization *ser = v;
-	int err = 0;
-
-	switch (cmd) {
-	case KEXEC_KHO_ABORT:
-		return NOTIFY_DONE;
-	case KEXEC_KHO_FINALIZE:
-		/* Handled below */
-		break;
-	default:
-		return NOTIFY_BAD;
-	}
-
-	err |= kho_preserve_folio(state->fdt);
-	err |= kho_add_subtree(ser, KHO_TEST_FDT, folio_address(state->fdt));
+	for (int i = 0; i < state->nr_folios_preserved; i++)
+		kho_unpreserve_folio(state->folios[i]);
 
-	return err ? NOTIFY_BAD : NOTIFY_DONE;
+	kho_unpreserve_vmalloc(&state->folios_info_phys);
+	vfree(state->folios_info);
 }
 
-static struct notifier_block kho_test_nb = {
-	.notifier_call = kho_test_notifier,
-};
-
-static int kho_test_save_data(struct kho_test_state *state, void *fdt)
+static int kho_test_preserve_data(struct kho_test_state *state)
 {
-	phys_addr_t *folios_info __free(kvfree) = NULL;
 	struct kho_vmalloc folios_info_phys;
-	int err = 0;
+	phys_addr_t *folios_info;
+	int err;
 
 	folios_info = vmalloc_array(state->nr_folios, sizeof(*folios_info));
 	if (!folios_info)
@@ -78,62 +62,98 @@ static int kho_test_save_data(struct kho_test_state *state, void *fdt)
 
 	err = kho_preserve_vmalloc(folios_info, &folios_info_phys);
 	if (err)
-		return err;
+		goto err_free_info;
+
+	state->folios_info_phys = folios_info_phys;
+	state->folios_info = folios_info;
 
 	for (int i = 0; i < state->nr_folios; i++) {
 		struct folio *folio = state->folios[i];
 		unsigned int order = folio_order(folio);
 
 		folios_info[i] = virt_to_phys(folio_address(folio)) | order;
-
 		err = kho_preserve_folio(folio);
 		if (err)
-			break;
+			goto err_unpreserve;
+		state->nr_folios_preserved++;
 	}
 
+	return 0;
+
+err_unpreserve:
+	/*
+	 * kho_test_unpreserve_data frees folio_info, bail out immediately to
+	 * avoid double free
+	 */
+	kho_test_unpreserve_data(state);
+	return err;
+
+err_free_info:
+	vfree(folios_info);
+	return err;
+}
+
+static int kho_test_prepare_fdt(struct kho_test_state *state, ssize_t fdt_size)
+{
+	const char compatible[] = KHO_TEST_COMPAT;
+	unsigned int magic = KHO_TEST_MAGIC;
+	void *fdt = folio_address(state->fdt);
+	int err;
+
+	err = fdt_create(fdt, fdt_size);
+	err |= fdt_finish_reservemap(fdt);
+	err |= fdt_begin_node(fdt, "");
+	err |= fdt_property(fdt, "compatible", compatible, sizeof(compatible));
+	err |= fdt_property(fdt, "magic", &magic, sizeof(magic));
+
 	err |= fdt_begin_node(fdt, "data");
 	err |= fdt_property(fdt, "nr_folios", &state->nr_folios,
 			    sizeof(state->nr_folios));
-	err |= fdt_property(fdt, "folios_info", &folios_info_phys,
-			    sizeof(folios_info_phys));
+	err |= fdt_property(fdt, "folios_info", &state->folios_info_phys,
+			    sizeof(state->folios_info_phys));
 	err |= fdt_property(fdt, "csum", &state->csum, sizeof(state->csum));
 	err |= fdt_end_node(fdt);
 
-	if (!err)
-		state->folios_info = no_free_ptr(folios_info);
+	err |= fdt_end_node(fdt);
+	err |= fdt_finish(fdt);
 
 	return err;
 }
 
-static int kho_test_prepare_fdt(struct kho_test_state *state)
+static int kho_test_preserve(struct kho_test_state *state)
 {
-	const char compatible[] = KHO_TEST_COMPAT;
-	unsigned int magic = KHO_TEST_MAGIC;
 	ssize_t fdt_size;
-	int err = 0;
-	void *fdt;
+	int err;
 
 	fdt_size = state->nr_folios * sizeof(phys_addr_t) + PAGE_SIZE;
 	state->fdt = folio_alloc(GFP_KERNEL, get_order(fdt_size));
 	if (!state->fdt)
 		return -ENOMEM;
 
-	fdt = folio_address(state->fdt);
-
-	err |= fdt_create(fdt, fdt_size);
-	err |= fdt_finish_reservemap(fdt);
+	err = kho_preserve_folio(state->fdt);
+	if (err)
+		goto err_free_fdt;
 
-	err |= fdt_begin_node(fdt, "");
-	err |= fdt_property(fdt, "compatible", compatible, sizeof(compatible));
-	err |= fdt_property(fdt, "magic", &magic, sizeof(magic));
-	err |= kho_test_save_data(state, fdt);
-	err |= fdt_end_node(fdt);
+	err = kho_test_preserve_data(state);
+	if (err)
+		goto err_unpreserve_fdt;
 
-	err |= fdt_finish(fdt);
+	err = kho_test_prepare_fdt(state, fdt_size);
+	if (err)
+		goto err_unpreserve_data;
 
+	err = kho_add_subtree(KHO_TEST_FDT, folio_address(state->fdt));
 	if (err)
-		folio_put(state->fdt);
+		goto err_unpreserve_data;
+
+	return 0;
 
+err_unpreserve_data:
+	kho_test_unpreserve_data(state);
+err_unpreserve_fdt:
+	kho_unpreserve_folio(state->fdt);
+err_free_fdt:
+	folio_put(state->fdt);
 	return err;
 }
 
@@ -199,18 +219,12 @@ static int kho_test_save(void)
 	if (err)
 		goto err_free_folios;
 
-	err = kho_test_prepare_fdt(state);
+	err = kho_test_preserve(state);
 	if (err)
 		goto err_free_folios;
 
-	err = register_kho_notifier(&kho_test_nb);
-	if (err)
-		goto err_free_fdt;
-
 	return 0;
 
-err_free_fdt:
-	folio_put(state->fdt);
 err_free_folios:
 	kvfree(folios);
 	return err;
@@ -292,7 +306,6 @@ static int kho_test_restore(phys_addr_t fdt_phys)
 	if (err)
 		return err;
 
-	pr_info("KHO restore succeeded\n");
 	return 0;
 }
 
@@ -305,8 +318,15 @@ static int __init kho_test_init(void)
 		return 0;
 
 	err = kho_retrieve_subtree(KHO_TEST_FDT, &fdt_phys);
-	if (!err)
-		return kho_test_restore(fdt_phys);
+	if (!err) {
+		err = kho_test_restore(fdt_phys);
+		if (err)
+			pr_err("KHO restore failed\n");
+		else
+			pr_info("KHO restore succeeded\n");
+
+		return err;
+	}
 
 	if (err != -ENOENT) {
 		pr_warn("failed to retrieve %s FDT: %d\n", KHO_TEST_FDT, err);
@@ -329,7 +349,7 @@ static void kho_test_cleanup(void)
 
 static void __exit kho_test_exit(void)
 {
-	unregister_kho_notifier(&kho_test_nb);
+	kho_remove_subtree(folio_address(kho_test_state.fdt));
 	kho_test_cleanup();
 }
 module_exit(kho_test_exit);