From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>
The KHO framework uses a notifier chain as the mechanism for clients to
participate in the finalization process. While this works for a single,
central state machine, it is too restrictive for kernel-internal
components like pstore/reserve_mem or IMA. These components need a
simpler, direct way to register their state for preservation (e.g.,
during their initcall) without being part of a complex,
shutdown-time notifier sequence. The notifier model forces all
participants into a single finalization flow and makes direct
preservation from an arbitrary context difficult.
This patch refactors the client participation model by removing the
notifier chain and introducing a direct API for managing FDT subtrees.
The core kho_finalize() and kho_abort() state machine remains, but
clients now register their data with KHO beforehand.
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Co-developed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
---
include/linux/kexec_handover.h | 28 +-----
kernel/kexec_handover.c | 166 +++++++++++++++++--------------
kernel/kexec_handover_debugfs.c | 17 ++--
kernel/kexec_handover_internal.h | 5 +-
lib/test_kho.c | 35 +------
mm/memblock.c | 62 +++---------
6 files changed, 125 insertions(+), 188 deletions(-)
diff --git a/include/linux/kexec_handover.h b/include/linux/kexec_handover.h
index 25042c1d8d54..0d860d793b66 100644
--- a/include/linux/kexec_handover.h
+++ b/include/linux/kexec_handover.h
@@ -10,14 +10,7 @@ struct kho_scratch {
phys_addr_t size;
};
-/* KHO Notifier index */
-enum kho_event {
- KEXEC_KHO_FINALIZE = 0,
- KEXEC_KHO_ABORT = 1,
-};
-
struct folio;
-struct notifier_block;
struct page;
#define DECLARE_KHOSER_PTR(name, type) \
@@ -37,8 +30,6 @@ struct page;
(typeof((s).ptr))((s).phys ? phys_to_virt((s).phys) : NULL); \
})
-struct kho_serialization;
-
struct kho_vmalloc_chunk;
struct kho_vmalloc {
DECLARE_KHOSER_PTR(first, struct kho_vmalloc_chunk *);
@@ -57,12 +48,10 @@ int kho_preserve_vmalloc(void *ptr, struct kho_vmalloc *preservation);
struct folio *kho_restore_folio(phys_addr_t phys);
struct page *kho_restore_pages(phys_addr_t phys, unsigned int nr_pages);
void *kho_restore_vmalloc(const struct kho_vmalloc *preservation);
-int kho_add_subtree(struct kho_serialization *ser, const char *name, void *fdt);
+int kho_add_subtree(const char *name, void *fdt);
+void kho_remove_subtree(void *fdt);
int kho_retrieve_subtree(const char *name, phys_addr_t *phys);
-int register_kho_notifier(struct notifier_block *nb);
-int unregister_kho_notifier(struct notifier_block *nb);
-
void kho_memory_init(void);
void kho_populate(phys_addr_t fdt_phys, u64 fdt_len, phys_addr_t scratch_phys,
@@ -110,23 +99,16 @@ static inline void *kho_restore_vmalloc(const struct kho_vmalloc *preservation)
return NULL;
}
-static inline int kho_add_subtree(struct kho_serialization *ser,
- const char *name, void *fdt)
+static inline int kho_add_subtree(const char *name, void *fdt)
{
return -EOPNOTSUPP;
}
-static inline int kho_retrieve_subtree(const char *name, phys_addr_t *phys)
+static inline void kho_remove_subtree(void *fdt)
{
- return -EOPNOTSUPP;
}
-static inline int register_kho_notifier(struct notifier_block *nb)
-{
- return -EOPNOTSUPP;
-}
-
-static inline int unregister_kho_notifier(struct notifier_block *nb)
+static inline int kho_retrieve_subtree(const char *name, phys_addr_t *phys)
{
return -EOPNOTSUPP;
}
diff --git a/kernel/kexec_handover.c b/kernel/kexec_handover.c
index da071277d85e..82137eba1474 100644
--- a/kernel/kexec_handover.c
+++ b/kernel/kexec_handover.c
@@ -16,7 +16,6 @@
#include <linux/libfdt.h>
#include <linux/list.h>
#include <linux/memblock.h>
-#include <linux/notifier.h>
#include <linux/page-isolation.h>
#include <linux/vmalloc.h>
@@ -103,29 +102,34 @@ struct kho_mem_track {
struct khoser_mem_chunk;
-struct kho_serialization {
- struct page *fdt;
- struct kho_mem_track track;
- /* First chunk of serialized preserved memory map */
- struct khoser_mem_chunk *preserved_mem_map;
+struct kho_sub_fdt {
+ struct list_head l;
+ const char *name;
+ void *fdt;
};
struct kho_out {
- struct blocking_notifier_head chain_head;
- struct mutex lock; /* protects KHO FDT finalization */
- struct kho_serialization ser;
+ void *fdt;
bool finalized;
+ struct mutex lock; /* protects KHO FDT finalization */
+
+ struct list_head sub_fdts;
+ struct mutex fdts_lock;
+
+ struct kho_mem_track track;
+ /* First chunk of serialized preserved memory map */
+ struct khoser_mem_chunk *preserved_mem_map;
+
struct kho_debugfs dbg;
};
static struct kho_out kho_out = {
- .chain_head = BLOCKING_NOTIFIER_INIT(kho_out.chain_head),
.lock = __MUTEX_INITIALIZER(kho_out.lock),
- .ser = {
- .track = {
- .orders = XARRAY_INIT(kho_out.ser.track.orders, 0),
- },
+ .track = {
+ .orders = XARRAY_INIT(kho_out.track.orders, 0),
},
+ .sub_fdts = LIST_HEAD_INIT(kho_out.sub_fdts),
+ .fdts_lock = __MUTEX_INITIALIZER(kho_out.fdts_lock),
.finalized = false,
};
@@ -369,7 +373,7 @@ static void kho_mem_ser_free(struct khoser_mem_chunk *first_chunk)
}
}
-static int kho_mem_serialize(struct kho_serialization *ser)
+static int kho_mem_serialize(struct kho_out *kho_out)
{
struct khoser_mem_chunk *first_chunk = NULL;
struct khoser_mem_chunk *chunk = NULL;
@@ -377,7 +381,7 @@ static int kho_mem_serialize(struct kho_serialization *ser)
unsigned long order;
int err = -ENOMEM;
- xa_for_each(&ser->track.orders, order, physxa) {
+ xa_for_each(&kho_out->track.orders, order, physxa) {
struct kho_mem_phys_bits *bits;
unsigned long phys;
@@ -409,7 +413,7 @@ static int kho_mem_serialize(struct kho_serialization *ser)
}
}
- ser->preserved_mem_map = first_chunk;
+ kho_out->preserved_mem_map = first_chunk;
return 0;
@@ -670,7 +674,6 @@ static void __init kho_reserve_scratch(void)
/**
* kho_add_subtree - record the physical address of a sub FDT in KHO root tree.
- * @ser: serialization control object passed by KHO notifiers.
* @name: name of the sub tree.
* @fdt: the sub tree blob.
*
@@ -684,34 +687,41 @@ static void __init kho_reserve_scratch(void)
*
* Return: 0 on success, error code on failure
*/
-int kho_add_subtree(struct kho_serialization *ser, const char *name, void *fdt)
+int kho_add_subtree(const char *name, void *fdt)
{
- int err = 0;
- u64 phys = (u64)virt_to_phys(fdt);
- void *root = page_to_virt(ser->fdt);
+ struct kho_sub_fdt *sub_fdt;
- err |= fdt_begin_node(root, name);
- err |= fdt_property(root, PROP_SUB_FDT, &phys, sizeof(phys));
- err |= fdt_end_node(root);
+ sub_fdt = kmalloc(sizeof(*sub_fdt), GFP_KERNEL);
+ if (!sub_fdt)
+ return -ENOMEM;
- if (err)
- return err;
+ INIT_LIST_HEAD(&sub_fdt->l);
+ sub_fdt->name = name;
+ sub_fdt->fdt = fdt;
- return kho_debugfs_fdt_add(&kho_out.dbg, name, fdt, false);
-}
-EXPORT_SYMBOL_GPL(kho_add_subtree);
+ guard(mutex)(&kho_out.fdts_lock);
+ list_add_tail(&sub_fdt->l, &kho_out.sub_fdts);
+ WARN_ON_ONCE(kho_debugfs_fdt_add(&kho_out.dbg, name, fdt, false));
-int register_kho_notifier(struct notifier_block *nb)
-{
- return blocking_notifier_chain_register(&kho_out.chain_head, nb);
+ return 0;
}
-EXPORT_SYMBOL_GPL(register_kho_notifier);
+EXPORT_SYMBOL_GPL(kho_add_subtree);
-int unregister_kho_notifier(struct notifier_block *nb)
+void kho_remove_subtree(void *fdt)
{
- return blocking_notifier_chain_unregister(&kho_out.chain_head, nb);
+ struct kho_sub_fdt *sub_fdt;
+
+ guard(mutex)(&kho_out.fdts_lock);
+ list_for_each_entry(sub_fdt, &kho_out.sub_fdts, l) {
+ if (sub_fdt->fdt == fdt) {
+ list_del(&sub_fdt->l);
+ kfree(sub_fdt);
+ kho_debugfs_fdt_remove(&kho_out.dbg, fdt);
+ break;
+ }
+ }
}
-EXPORT_SYMBOL_GPL(unregister_kho_notifier);
+EXPORT_SYMBOL_GPL(kho_remove_subtree);
/**
* kho_preserve_folio - preserve a folio across kexec.
@@ -726,7 +736,7 @@ int kho_preserve_folio(struct folio *folio)
{
const unsigned long pfn = folio_pfn(folio);
const unsigned int order = folio_order(folio);
- struct kho_mem_track *track = &kho_out.ser.track;
+ struct kho_mem_track *track = &kho_out.track;
if (WARN_ON(kho_scratch_overlap(pfn << PAGE_SHIFT, PAGE_SIZE << order)))
return -EINVAL;
@@ -747,7 +757,7 @@ EXPORT_SYMBOL_GPL(kho_preserve_folio);
*/
int kho_preserve_pages(struct page *page, unsigned int nr_pages)
{
- struct kho_mem_track *track = &kho_out.ser.track;
+ struct kho_mem_track *track = &kho_out.track;
const unsigned long start_pfn = page_to_pfn(page);
const unsigned long end_pfn = start_pfn + nr_pages;
unsigned long pfn = start_pfn;
@@ -848,7 +858,7 @@ static struct kho_vmalloc_chunk *new_vmalloc_chunk(struct kho_vmalloc_chunk *cur
static void kho_vmalloc_unpreserve_chunk(struct kho_vmalloc_chunk *chunk)
{
- struct kho_mem_track *track = &kho_out.ser.track;
+ struct kho_mem_track *track = &kho_out.track;
unsigned long pfn = PHYS_PFN(virt_to_phys(chunk));
__kho_unpreserve(track, pfn, pfn + 1);
@@ -1030,11 +1040,11 @@ EXPORT_SYMBOL_GPL(kho_restore_vmalloc);
static int __kho_abort(void)
{
- int err;
+ int err = 0;
unsigned long order;
struct kho_mem_phys *physxa;
- xa_for_each(&kho_out.ser.track.orders, order, physxa) {
+ xa_for_each(&kho_out.track.orders, order, physxa) {
struct kho_mem_phys_bits *bits;
unsigned long phys;
@@ -1044,17 +1054,13 @@ static int __kho_abort(void)
xa_destroy(&physxa->phys_bits);
kfree(physxa);
}
- xa_destroy(&kho_out.ser.track.orders);
+ xa_destroy(&kho_out.track.orders);
- if (kho_out.ser.preserved_mem_map) {
- kho_mem_ser_free(kho_out.ser.preserved_mem_map);
- kho_out.ser.preserved_mem_map = NULL;
+ if (kho_out.preserved_mem_map) {
+ kho_mem_ser_free(kho_out.preserved_mem_map);
+ kho_out.preserved_mem_map = NULL;
}
- err = blocking_notifier_call_chain(&kho_out.chain_head, KEXEC_KHO_ABORT,
- NULL);
- err = notifier_to_errno(err);
-
if (err)
pr_err("Failed to abort KHO finalization: %d\n", err);
@@ -1077,7 +1083,8 @@ int kho_abort(void)
return ret;
kho_out.finalized = false;
- kho_debugfs_cleanup(&kho_out.dbg);
+
+ kho_debugfs_fdt_remove(&kho_out.dbg, kho_out.fdt);
return 0;
}
@@ -1086,41 +1093,46 @@ static int __kho_finalize(void)
{
int err = 0;
u64 *preserved_mem_map;
- void *fdt = page_to_virt(kho_out.ser.fdt);
+ void *root = kho_out.fdt;
+ struct kho_sub_fdt *fdt;
- err |= fdt_create(fdt, PAGE_SIZE);
- err |= fdt_finish_reservemap(fdt);
- err |= fdt_begin_node(fdt, "");
- err |= fdt_property_string(fdt, "compatible", KHO_FDT_COMPATIBLE);
+ err |= fdt_create(root, PAGE_SIZE);
+ err |= fdt_finish_reservemap(root);
+ err |= fdt_begin_node(root, "");
+ err |= fdt_property_string(root, "compatible", KHO_FDT_COMPATIBLE);
/**
* Reserve the preserved-memory-map property in the root FDT, so
* that all property definitions will precede subnodes created by
* KHO callers.
*/
- err |= fdt_property_placeholder(fdt, PROP_PRESERVED_MEMORY_MAP,
+ err |= fdt_property_placeholder(root, PROP_PRESERVED_MEMORY_MAP,
sizeof(*preserved_mem_map),
(void **)&preserved_mem_map);
if (err)
goto abort;
- err = kho_preserve_folio(page_folio(kho_out.ser.fdt));
+ err = kho_preserve_folio(virt_to_folio(kho_out.fdt));
if (err)
goto abort;
- err = blocking_notifier_call_chain(&kho_out.chain_head,
- KEXEC_KHO_FINALIZE, &kho_out.ser);
- err = notifier_to_errno(err);
+ err = kho_mem_serialize(&kho_out);
if (err)
goto abort;
- err = kho_mem_serialize(&kho_out.ser);
- if (err)
- goto abort;
+ *preserved_mem_map = (u64)virt_to_phys(kho_out.preserved_mem_map);
+
+ mutex_lock(&kho_out.fdts_lock);
+ list_for_each_entry(fdt, &kho_out.sub_fdts, l) {
+ phys_addr_t phys = virt_to_phys(fdt->fdt);
- *preserved_mem_map = (u64)virt_to_phys(kho_out.ser.preserved_mem_map);
+ err |= fdt_begin_node(root, fdt->name);
+ err |= fdt_property(root, PROP_SUB_FDT, &phys, sizeof(phys));
+ err |= fdt_end_node(root);
+ }
+ mutex_unlock(&kho_out.fdts_lock);
- err |= fdt_end_node(fdt);
- err |= fdt_finish(fdt);
+ err |= fdt_end_node(root);
+ err |= fdt_finish(root);
abort:
if (err) {
@@ -1148,8 +1160,10 @@ int kho_finalize(void)
kho_out.finalized = true;
- return kho_debugfs_fdt_add(&kho_out.dbg, "fdt",
- page_to_virt(kho_out.ser.fdt), true);
+ WARN_ON_ONCE(kho_debugfs_fdt_add(&kho_out.dbg, "fdt",
+ kho_out.fdt, true));
+
+ return 0;
}
bool kho_finalized(void)
@@ -1232,15 +1246,17 @@ static __init int kho_init(void)
{
int err = 0;
const void *fdt = kho_get_fdt();
+ struct page *fdt_page;
if (!kho_enable)
return 0;
- kho_out.ser.fdt = alloc_page(GFP_KERNEL);
- if (!kho_out.ser.fdt) {
+ fdt_page = alloc_page(GFP_KERNEL);
+ if (!fdt_page) {
err = -ENOMEM;
goto err_free_scratch;
}
+ kho_out.fdt = page_to_virt(fdt_page);
err = kho_debugfs_init();
if (err)
@@ -1268,8 +1284,8 @@ static __init int kho_init(void)
return 0;
err_free_fdt:
- put_page(kho_out.ser.fdt);
- kho_out.ser.fdt = NULL;
+ put_page(fdt_page);
+ kho_out.fdt = NULL;
err_free_scratch:
for (int i = 0; i < kho_scratch_cnt; i++) {
void *start = __va(kho_scratch[i].addr);
@@ -1280,7 +1296,7 @@ static __init int kho_init(void)
kho_enable = false;
return err;
}
-late_initcall(kho_init);
+fs_initcall(kho_init);
static void __init kho_release_scratch(void)
{
@@ -1416,7 +1432,7 @@ int kho_fill_kimage(struct kimage *image)
if (!kho_out.finalized)
return 0;
- image->kho.fdt = page_to_phys(kho_out.ser.fdt);
+ image->kho.fdt = virt_to_phys(kho_out.fdt);
scratch_size = sizeof(*kho_scratch) * kho_scratch_cnt;
scratch = (struct kexec_buf){
diff --git a/kernel/kexec_handover_debugfs.c b/kernel/kexec_handover_debugfs.c
index a91b279f1b23..46e9e6c0791f 100644
--- a/kernel/kexec_handover_debugfs.c
+++ b/kernel/kexec_handover_debugfs.c
@@ -61,14 +61,17 @@ int kho_debugfs_fdt_add(struct kho_debugfs *dbg, const char *name,
return __kho_debugfs_fdt_add(&dbg->fdt_list, dir, name, fdt);
}
-void kho_debugfs_cleanup(struct kho_debugfs *dbg)
+void kho_debugfs_fdt_remove(struct kho_debugfs *dbg, void *fdt)
{
- struct fdt_debugfs *ff, *tmp;
-
- list_for_each_entry_safe(ff, tmp, &dbg->fdt_list, list) {
- debugfs_remove(ff->file);
- list_del(&ff->list);
- kfree(ff);
+ struct fdt_debugfs *ff;
+
+ list_for_each_entry(ff, &dbg->fdt_list, list) {
+ if (ff->wrapper.data == fdt) {
+ debugfs_remove(ff->file);
+ list_del(&ff->list);
+ kfree(ff);
+ break;
+ }
}
}
diff --git a/kernel/kexec_handover_internal.h b/kernel/kexec_handover_internal.h
index 217b8b25a542..52ed73659fe6 100644
--- a/kernel/kexec_handover_internal.h
+++ b/kernel/kexec_handover_internal.h
@@ -32,7 +32,7 @@ void kho_in_debugfs_init(struct kho_debugfs *dbg, const void *fdt);
int kho_out_debugfs_init(struct kho_debugfs *dbg);
int kho_debugfs_fdt_add(struct kho_debugfs *dbg, const char *name,
const void *fdt, bool root);
-void kho_debugfs_cleanup(struct kho_debugfs *dbg);
+void kho_debugfs_fdt_remove(struct kho_debugfs *dbg, void *fdt);
#else
static inline int kho_debugfs_init(void) { return 0; }
static inline void kho_in_debugfs_init(struct kho_debugfs *dbg,
@@ -40,7 +40,8 @@ static inline void kho_in_debugfs_init(struct kho_debugfs *dbg,
static inline int kho_out_debugfs_init(struct kho_debugfs *dbg) { return 0; }
static inline int kho_debugfs_fdt_add(struct kho_debugfs *dbg, const char *name,
const void *fdt, bool root) { return 0; }
-static inline void kho_debugfs_cleanup(struct kho_debugfs *dbg) {}
+static inline void kho_debugfs_fdt_remove(struct kho_debugfs *dbg,
+ void *fdt) { }
#endif /* CONFIG_KEXEC_HANDOVER_DEBUGFS */
#ifdef CONFIG_KEXEC_HANDOVER_DEBUG
diff --git a/lib/test_kho.c b/lib/test_kho.c
index 60cd899ea745..9f7cfa6ac855 100644
--- a/lib/test_kho.c
+++ b/lib/test_kho.c
@@ -39,33 +39,6 @@ struct kho_test_state {
static struct kho_test_state kho_test_state;
-static int kho_test_notifier(struct notifier_block *self, unsigned long cmd,
- void *v)
-{
- 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));
-
- return err ? NOTIFY_BAD : NOTIFY_DONE;
-}
-
-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)
{
phys_addr_t *folios_info __free(kvfree) = NULL;
@@ -120,6 +93,7 @@ static int kho_test_prepare_fdt(struct kho_test_state *state)
fdt = folio_address(state->fdt);
+ err |= kho_preserve_folio(state->fdt);
err |= fdt_create(fdt, fdt_size);
err |= fdt_finish_reservemap(fdt);
@@ -131,6 +105,7 @@ static int kho_test_prepare_fdt(struct kho_test_state *state)
err |= fdt_finish(fdt);
+ err = kho_add_subtree(KHO_TEST_FDT, folio_address(state->fdt));
if (err)
folio_put(state->fdt);
@@ -203,10 +178,6 @@ static int kho_test_save(void)
if (err)
goto err_free_folios;
- err = register_kho_notifier(&kho_test_nb);
- if (err)
- goto err_free_fdt;
-
return 0;
err_free_fdt:
@@ -326,7 +297,7 @@ 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);
diff --git a/mm/memblock.c b/mm/memblock.c
index e23e16618e9b..e3bef9b35d63 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -2444,53 +2444,18 @@ int reserve_mem_release_by_name(const char *name)
#define MEMBLOCK_KHO_FDT "memblock"
#define MEMBLOCK_KHO_NODE_COMPATIBLE "memblock-v1"
#define RESERVE_MEM_KHO_NODE_COMPATIBLE "reserve-mem-v1"
-static struct page *kho_fdt;
-
-static int reserve_mem_kho_finalize(struct kho_serialization *ser)
-{
- int err = 0, i;
-
- for (i = 0; i < reserved_mem_count; i++) {
- struct reserve_mem_table *map = &reserved_mem_table[i];
- struct page *page = phys_to_page(map->start);
- unsigned int nr_pages = map->size >> PAGE_SHIFT;
-
- err |= kho_preserve_pages(page, nr_pages);
- }
-
- err |= kho_preserve_folio(page_folio(kho_fdt));
- err |= kho_add_subtree(ser, MEMBLOCK_KHO_FDT, page_to_virt(kho_fdt));
-
- return notifier_from_errno(err);
-}
-
-static int reserve_mem_kho_notifier(struct notifier_block *self,
- unsigned long cmd, void *v)
-{
- switch (cmd) {
- case KEXEC_KHO_FINALIZE:
- return reserve_mem_kho_finalize((struct kho_serialization *)v);
- case KEXEC_KHO_ABORT:
- return NOTIFY_DONE;
- default:
- return NOTIFY_BAD;
- }
-}
-
-static struct notifier_block reserve_mem_kho_nb = {
- .notifier_call = reserve_mem_kho_notifier,
-};
static int __init prepare_kho_fdt(void)
{
int err = 0, i;
+ struct page *fdt_page;
void *fdt;
- kho_fdt = alloc_page(GFP_KERNEL);
- if (!kho_fdt)
+ fdt_page = alloc_page(GFP_KERNEL);
+ if (!fdt_page)
return -ENOMEM;
- fdt = page_to_virt(kho_fdt);
+ fdt = page_to_virt(fdt_page);
err |= fdt_create(fdt, PAGE_SIZE);
err |= fdt_finish_reservemap(fdt);
@@ -2499,7 +2464,10 @@ static int __init prepare_kho_fdt(void)
err |= fdt_property_string(fdt, "compatible", MEMBLOCK_KHO_NODE_COMPATIBLE);
for (i = 0; i < reserved_mem_count; i++) {
struct reserve_mem_table *map = &reserved_mem_table[i];
+ struct page *page = phys_to_page(map->start);
+ unsigned int nr_pages = map->size >> PAGE_SHIFT;
+ err |= kho_preserve_pages(page, nr_pages);
err |= fdt_begin_node(fdt, map->name);
err |= fdt_property_string(fdt, "compatible", RESERVE_MEM_KHO_NODE_COMPATIBLE);
err |= fdt_property(fdt, "start", &map->start, sizeof(map->start));
@@ -2507,13 +2475,16 @@ static int __init prepare_kho_fdt(void)
err |= fdt_end_node(fdt);
}
err |= fdt_end_node(fdt);
-
err |= fdt_finish(fdt);
+ err |= kho_preserve_folio(page_folio(fdt_page));
+
+ if (!err)
+ err = kho_add_subtree(MEMBLOCK_KHO_FDT, fdt);
+
if (err) {
pr_err("failed to prepare memblock FDT for KHO: %d\n", err);
- put_page(kho_fdt);
- kho_fdt = NULL;
+ put_page(fdt_page);
}
return err;
@@ -2529,13 +2500,6 @@ static int __init reserve_mem_init(void)
err = prepare_kho_fdt();
if (err)
return err;
-
- err = register_kho_notifier(&reserve_mem_kho_nb);
- if (err) {
- put_page(kho_fdt);
- kho_fdt = NULL;
- }
-
return err;
}
late_initcall(reserve_mem_init);
--
2.51.1.930.gacf6e81ea2-goog
Hello,
kernel test robot noticed "WARNING:at_kernel/kexec_handover.c:#kho_add_subtree" on:
commit: e44a700c561d1e892a8d0829d557e221604a7b93 ("[PATCH v9 2/9] kho: drop notifiers")
url: https://github.com/intel-lab-lkp/linux/commits/Pasha-Tatashin/kho-make-debugfs-interface-optional/20251101-222610
patch link: https://lore.kernel.org/all/20251101142325.1326536-3-pasha.tatashin@soleen.com/
patch subject: [PATCH v9 2/9] kho: drop notifiers
in testcase: boot
config: x86_64-randconfig-001-20251015
compiler: gcc-14
test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G
(please refer to attached dmesg/kmsg for entire log/backtrace)
+--------------------------------------------------------+------------+------------+
| | 93e4b3b2e9 | e44a700c56 |
+--------------------------------------------------------+------------+------------+
| WARNING:at_kernel/kexec_handover.c:#kho_add_subtree | 0 | 8 |
| RIP:kho_add_subtree | 0 | 8 |
+--------------------------------------------------------+------------+------------+
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <oliver.sang@intel.com>
| Closes: https://lore.kernel.org/oe-lkp/202511061629.e242724-lkp@intel.com
[ 13.620111][ T1] ------------[ cut here ]------------
[ 13.620739][ T1] WARNING: CPU: 1 PID: 1 at kernel/kexec_handover.c:704 kho_add_subtree (kernel/kexec_handover.c:704)
[ 13.621665][ T1] Modules linked in:
[ 13.622090][ T1] CPU: 1 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.18.0-rc3-00211-ge44a700c561d #1 VOLUNTARY
[ 13.623073][ T1] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 13.624054][ T1] RIP: 0010:kho_add_subtree (kernel/kexec_handover.c:704)
[ 13.624596][ T1] Code: c7 38 b4 ac 85 31 ed e8 01 1c 00 00 48 c7 c7 70 5a ca 86 85 c0 89 c3 40 0f 95 c5 31 c9 31 d2 89 ee e8 37 b5 0a 00 85 db 74 02 <0f> 0b b9 01 00 00 00 31 d2 89 ee 48 c7 c7 40 5a ca 86 e8 1c b5 0a
All code
========
0: c7 38 b4 ac 85 xbegin 0xffffffff85acb43d,(bad)
5: 31 ed xor %ebp,%ebp
7: e8 01 1c 00 00 call 0x1c0d
c: 48 c7 c7 70 5a ca 86 mov $0xffffffff86ca5a70,%rdi
13: 85 c0 test %eax,%eax
15: 89 c3 mov %eax,%ebx
17: 40 0f 95 c5 setne %bpl
1b: 31 c9 xor %ecx,%ecx
1d: 31 d2 xor %edx,%edx
1f: 89 ee mov %ebp,%esi
21: e8 37 b5 0a 00 call 0xab55d
26: 85 db test %ebx,%ebx
28: 74 02 je 0x2c
2a:* 0f 0b ud2 <-- trapping instruction
2c: b9 01 00 00 00 mov $0x1,%ecx
31: 31 d2 xor %edx,%edx
33: 89 ee mov %ebp,%esi
35: 48 c7 c7 40 5a ca 86 mov $0xffffffff86ca5a40,%rdi
3c: e8 .byte 0xe8
3d: 1c b5 sbb $0xb5,%al
3f: 0a .byte 0xa
Code starting with the faulting instruction
===========================================
0: 0f 0b ud2
2: b9 01 00 00 00 mov $0x1,%ecx
7: 31 d2 xor %edx,%edx
9: 89 ee mov %ebp,%esi
b: 48 c7 c7 40 5a ca 86 mov $0xffffffff86ca5a40,%rdi
12: e8 .byte 0xe8
13: 1c b5 sbb $0xb5,%al
15: 0a .byte 0xa
[ 13.626370][ T1] RSP: 0018:ffffc9000001fca0 EFLAGS: 00010286
[ 13.626951][ T1] RAX: dffffc0000000000 RBX: 00000000ffffffff RCX: 0000000000000000
[ 13.627737][ T1] RDX: 1ffffffff0d94b52 RSI: 0000000000000001 RDI: ffffffff86ca5a90
[ 13.628523][ T1] RBP: 0000000000000001 R08: 0000000000000008 R09: fffffbfff0dfac4c
[ 13.629330][ T1] R10: 0000000000000000 R11: ffffffff86fd6267 R12: ffff888133ee2000
[ 13.630101][ T1] R13: ffffffff85acb340 R14: ffff888117a5f988 R15: dffffc0000000000
[ 13.630869][ T1] FS: 0000000000000000(0000) GS:ffff888426ea0000(0000) knlGS:0000000000000000
[ 13.631727][ T1] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 13.632370][ T1] CR2: 00007f586df260ac CR3: 00000000054ea000 CR4: 00000000000406f0
[ 13.633154][ T1] Call Trace:
[ 13.633506][ T1] <TASK>
[ 13.633833][ T1] kho_test_prepare_fdt+0x145/0x180
[ 13.634446][ T1] ? kho_test_save_data+0x210/0x210
[ 13.635097][ T1] ? csum_partial (lib/checksum.c:123)
[ 13.635546][ T1] kho_test_init (lib/test_kho.c:177 lib/test_kho.c:284)
[ 13.636018][ T1] ? vmalloc_test_init (lib/test_kho.c:271)
[ 13.636508][ T1] ? add_device_randomness (drivers/char/random.c:944)
[ 13.637485][ T1] ? mix_pool_bytes (drivers/char/random.c:944)
[ 13.637955][ T1] ? trace_initcall_start (include/trace/events/initcall.h:27 (discriminator 3))
[ 13.638498][ T1] ? vmalloc_test_init (lib/test_kho.c:271)
[ 13.638989][ T1] do_one_initcall (init/main.c:1284)
[ 13.639477][ T1] ? trace_initcall_start (init/main.c:1274)
[ 13.639998][ T1] ? parse_one (kernel/params.c:143)
[ 13.640455][ T1] ? kasan_save_track (mm/kasan/common.c:69 (discriminator 1) mm/kasan/common.c:78 (discriminator 1))
[ 13.640948][ T1] ? __kmalloc_noprof (mm/slub.c:5659)
[ 13.641465][ T1] do_initcalls (init/main.c:1344 (discriminator 3) init/main.c:1361 (discriminator 3))
[ 13.641924][ T1] kernel_init_freeable (init/main.c:1595)
[ 13.642441][ T1] ? rest_init (init/main.c:1475)
[ 13.642891][ T1] kernel_init (init/main.c:1485)
[ 13.643345][ T1] ? rest_init (init/main.c:1475)
[ 13.643788][ T1] ret_from_fork (arch/x86/kernel/process.c:164)
[ 13.644256][ T1] ? rest_init (init/main.c:1475)
[ 13.644703][ T1] ret_from_fork_asm (arch/x86/entry/entry_64.S:255)
[ 13.645213][ T1] </TASK>
[ 13.645540][ T1] irq event stamp: 132025
[ 13.645971][ T1] hardirqs last enabled at (132035): __up_console_sem (arch/x86/include/asm/irqflags.h:26 arch/x86/include/asm/irqflags.h:109 arch/x86/include/asm/irqflags.h:151 kernel/printk/printk.c:345)
[ 13.646887][ T1] hardirqs last disabled at (132046): __up_console_sem (kernel/printk/printk.c:343 (discriminator 3))
[ 13.648253][ T1] softirqs last enabled at (131286): handle_softirqs (kernel/softirq.c:469 (discriminator 1) kernel/softirq.c:650 (discriminator 1))
[ 13.649690][ T1] softirqs last disabled at (131281): __irq_exit_rcu (kernel/softirq.c:496 kernel/softirq.c:723)
[ 13.651128][ T1] ---[ end trace 0000000000000000 ]---
The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20251106/202511061629.e242724-lkp@intel.com
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
The bug is in lib/test_kho.c, when KHO is not enabled, it should not
run KHO commands, there is a function to test that: kho_is_enabled().
So, KHO is disabled and kho_add_subtree() which calles add debugfs
entry, and the list is not initialized, because KHO is disabled. The
fix is:
diff --git a/lib/test_kho.c b/lib/test_kho.c
index 025ea251a186..85b60d87a50a 100644
--- a/lib/test_kho.c
+++ b/lib/test_kho.c
@@ -315,6 +315,9 @@ static int __init kho_test_init(void)
phys_addr_t fdt_phys;
int err;
+ if (!kho_is_enabled())
+ return 0;
+
err = kho_retrieve_subtree(KHO_TEST_FDT, &fdt_phys);
if (!err)
return kho_test_restore(fdt_phys);
On Thu, Nov 6, 2025 at 3:41 AM kernel test robot <oliver.sang@intel.com> wrote:
>
>
>
> Hello,
>
> kernel test robot noticed "WARNING:at_kernel/kexec_handover.c:#kho_add_subtree" on:
>
> commit: e44a700c561d1e892a8d0829d557e221604a7b93 ("[PATCH v9 2/9] kho: drop notifiers")
> url: https://github.com/intel-lab-lkp/linux/commits/Pasha-Tatashin/kho-make-debugfs-interface-optional/20251101-222610
> patch link: https://lore.kernel.org/all/20251101142325.1326536-3-pasha.tatashin@soleen.com/
> patch subject: [PATCH v9 2/9] kho: drop notifiers
>
> in testcase: boot
>
> config: x86_64-randconfig-001-20251015
> compiler: gcc-14
> test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G
>
> (please refer to attached dmesg/kmsg for entire log/backtrace)
>
>
> +--------------------------------------------------------+------------+------------+
> | | 93e4b3b2e9 | e44a700c56 |
> +--------------------------------------------------------+------------+------------+
> | WARNING:at_kernel/kexec_handover.c:#kho_add_subtree | 0 | 8 |
> | RIP:kho_add_subtree | 0 | 8 |
> +--------------------------------------------------------+------------+------------+
>
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <oliver.sang@intel.com>
> | Closes: https://lore.kernel.org/oe-lkp/202511061629.e242724-lkp@intel.com
>
>
> [ 13.620111][ T1] ------------[ cut here ]------------
> [ 13.620739][ T1] WARNING: CPU: 1 PID: 1 at kernel/kexec_handover.c:704 kho_add_subtree (kernel/kexec_handover.c:704)
> [ 13.621665][ T1] Modules linked in:
> [ 13.622090][ T1] CPU: 1 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.18.0-rc3-00211-ge44a700c561d #1 VOLUNTARY
> [ 13.623073][ T1] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
> [ 13.624054][ T1] RIP: 0010:kho_add_subtree (kernel/kexec_handover.c:704)
> [ 13.624596][ T1] Code: c7 38 b4 ac 85 31 ed e8 01 1c 00 00 48 c7 c7 70 5a ca 86 85 c0 89 c3 40 0f 95 c5 31 c9 31 d2 89 ee e8 37 b5 0a 00 85 db 74 02 <0f> 0b b9 01 00 00 00 31 d2 89 ee 48 c7 c7 40 5a ca 86 e8 1c b5 0a
> All code
> ========
> 0: c7 38 b4 ac 85 xbegin 0xffffffff85acb43d,(bad)
> 5: 31 ed xor %ebp,%ebp
> 7: e8 01 1c 00 00 call 0x1c0d
> c: 48 c7 c7 70 5a ca 86 mov $0xffffffff86ca5a70,%rdi
> 13: 85 c0 test %eax,%eax
> 15: 89 c3 mov %eax,%ebx
> 17: 40 0f 95 c5 setne %bpl
> 1b: 31 c9 xor %ecx,%ecx
> 1d: 31 d2 xor %edx,%edx
> 1f: 89 ee mov %ebp,%esi
> 21: e8 37 b5 0a 00 call 0xab55d
> 26: 85 db test %ebx,%ebx
> 28: 74 02 je 0x2c
> 2a:* 0f 0b ud2 <-- trapping instruction
> 2c: b9 01 00 00 00 mov $0x1,%ecx
> 31: 31 d2 xor %edx,%edx
> 33: 89 ee mov %ebp,%esi
> 35: 48 c7 c7 40 5a ca 86 mov $0xffffffff86ca5a40,%rdi
> 3c: e8 .byte 0xe8
> 3d: 1c b5 sbb $0xb5,%al
> 3f: 0a .byte 0xa
>
> Code starting with the faulting instruction
> ===========================================
> 0: 0f 0b ud2
> 2: b9 01 00 00 00 mov $0x1,%ecx
> 7: 31 d2 xor %edx,%edx
> 9: 89 ee mov %ebp,%esi
> b: 48 c7 c7 40 5a ca 86 mov $0xffffffff86ca5a40,%rdi
> 12: e8 .byte 0xe8
> 13: 1c b5 sbb $0xb5,%al
> 15: 0a .byte 0xa
> [ 13.626370][ T1] RSP: 0018:ffffc9000001fca0 EFLAGS: 00010286
> [ 13.626951][ T1] RAX: dffffc0000000000 RBX: 00000000ffffffff RCX: 0000000000000000
> [ 13.627737][ T1] RDX: 1ffffffff0d94b52 RSI: 0000000000000001 RDI: ffffffff86ca5a90
> [ 13.628523][ T1] RBP: 0000000000000001 R08: 0000000000000008 R09: fffffbfff0dfac4c
> [ 13.629330][ T1] R10: 0000000000000000 R11: ffffffff86fd6267 R12: ffff888133ee2000
> [ 13.630101][ T1] R13: ffffffff85acb340 R14: ffff888117a5f988 R15: dffffc0000000000
> [ 13.630869][ T1] FS: 0000000000000000(0000) GS:ffff888426ea0000(0000) knlGS:0000000000000000
> [ 13.631727][ T1] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 13.632370][ T1] CR2: 00007f586df260ac CR3: 00000000054ea000 CR4: 00000000000406f0
> [ 13.633154][ T1] Call Trace:
> [ 13.633506][ T1] <TASK>
> [ 13.633833][ T1] kho_test_prepare_fdt+0x145/0x180
> [ 13.634446][ T1] ? kho_test_save_data+0x210/0x210
> [ 13.635097][ T1] ? csum_partial (lib/checksum.c:123)
> [ 13.635546][ T1] kho_test_init (lib/test_kho.c:177 lib/test_kho.c:284)
> [ 13.636018][ T1] ? vmalloc_test_init (lib/test_kho.c:271)
> [ 13.636508][ T1] ? add_device_randomness (drivers/char/random.c:944)
> [ 13.637485][ T1] ? mix_pool_bytes (drivers/char/random.c:944)
> [ 13.637955][ T1] ? trace_initcall_start (include/trace/events/initcall.h:27 (discriminator 3))
> [ 13.638498][ T1] ? vmalloc_test_init (lib/test_kho.c:271)
> [ 13.638989][ T1] do_one_initcall (init/main.c:1284)
> [ 13.639477][ T1] ? trace_initcall_start (init/main.c:1274)
> [ 13.639998][ T1] ? parse_one (kernel/params.c:143)
> [ 13.640455][ T1] ? kasan_save_track (mm/kasan/common.c:69 (discriminator 1) mm/kasan/common.c:78 (discriminator 1))
> [ 13.640948][ T1] ? __kmalloc_noprof (mm/slub.c:5659)
> [ 13.641465][ T1] do_initcalls (init/main.c:1344 (discriminator 3) init/main.c:1361 (discriminator 3))
> [ 13.641924][ T1] kernel_init_freeable (init/main.c:1595)
> [ 13.642441][ T1] ? rest_init (init/main.c:1475)
> [ 13.642891][ T1] kernel_init (init/main.c:1485)
> [ 13.643345][ T1] ? rest_init (init/main.c:1475)
> [ 13.643788][ T1] ret_from_fork (arch/x86/kernel/process.c:164)
> [ 13.644256][ T1] ? rest_init (init/main.c:1475)
> [ 13.644703][ T1] ret_from_fork_asm (arch/x86/entry/entry_64.S:255)
> [ 13.645213][ T1] </TASK>
> [ 13.645540][ T1] irq event stamp: 132025
> [ 13.645971][ T1] hardirqs last enabled at (132035): __up_console_sem (arch/x86/include/asm/irqflags.h:26 arch/x86/include/asm/irqflags.h:109 arch/x86/include/asm/irqflags.h:151 kernel/printk/printk.c:345)
> [ 13.646887][ T1] hardirqs last disabled at (132046): __up_console_sem (kernel/printk/printk.c:343 (discriminator 3))
> [ 13.648253][ T1] softirqs last enabled at (131286): handle_softirqs (kernel/softirq.c:469 (discriminator 1) kernel/softirq.c:650 (discriminator 1))
> [ 13.649690][ T1] softirqs last disabled at (131281): __irq_exit_rcu (kernel/softirq.c:496 kernel/softirq.c:723)
> [ 13.651128][ T1] ---[ end trace 0000000000000000 ]---
>
>
> The kernel config and materials to reproduce are available at:
> https://download.01.org/0day-ci/archive/20251106/202511061629.e242724-lkp@intel.com
>
>
>
> --
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki
>
On Thu, Nov 6, 2025 at 4:46 PM Pasha Tatashin <pasha.tatashin@soleen.com> wrote:
>
> The bug is in lib/test_kho.c, when KHO is not enabled, it should not
> run KHO commands, there is a function to test that: kho_is_enabled().
> So, KHO is disabled and kho_add_subtree() which calles add debugfs
> entry, and the list is not initialized, because KHO is disabled. The
> fix is:
Sent it as a patch:
https://lore.kernel.org/all/20251106220635.2608494-1-pasha.tatashin@soleen.com
>
> diff --git a/lib/test_kho.c b/lib/test_kho.c
> index 025ea251a186..85b60d87a50a 100644
> --- a/lib/test_kho.c
> +++ b/lib/test_kho.c
> @@ -315,6 +315,9 @@ static int __init kho_test_init(void)
> phys_addr_t fdt_phys;
> int err;
>
> + if (!kho_is_enabled())
> + return 0;
> +
> err = kho_retrieve_subtree(KHO_TEST_FDT, &fdt_phys);
> if (!err)
> return kho_test_restore(fdt_phys);
>
> On Thu, Nov 6, 2025 at 3:41 AM kernel test robot <oliver.sang@intel.com> wrote:
> >
> >
> >
> > Hello,
> >
> > kernel test robot noticed "WARNING:at_kernel/kexec_handover.c:#kho_add_subtree" on:
> >
> > commit: e44a700c561d1e892a8d0829d557e221604a7b93 ("[PATCH v9 2/9] kho: drop notifiers")
> > url: https://github.com/intel-lab-lkp/linux/commits/Pasha-Tatashin/kho-make-debugfs-interface-optional/20251101-222610
> > patch link: https://lore.kernel.org/all/20251101142325.1326536-3-pasha.tatashin@soleen.com/
> > patch subject: [PATCH v9 2/9] kho: drop notifiers
> >
> > in testcase: boot
> >
> > config: x86_64-randconfig-001-20251015
> > compiler: gcc-14
> > test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G
> >
> > (please refer to attached dmesg/kmsg for entire log/backtrace)
> >
> >
> > +--------------------------------------------------------+------------+------------+
> > | | 93e4b3b2e9 | e44a700c56 |
> > +--------------------------------------------------------+------------+------------+
> > | WARNING:at_kernel/kexec_handover.c:#kho_add_subtree | 0 | 8 |
> > | RIP:kho_add_subtree | 0 | 8 |
> > +--------------------------------------------------------+------------+------------+
> >
> >
> > If you fix the issue in a separate patch/commit (i.e. not just a new version of
> > the same patch/commit), kindly add following tags
> > | Reported-by: kernel test robot <oliver.sang@intel.com>
> > | Closes: https://lore.kernel.org/oe-lkp/202511061629.e242724-lkp@intel.com
> >
> >
> > [ 13.620111][ T1] ------------[ cut here ]------------
> > [ 13.620739][ T1] WARNING: CPU: 1 PID: 1 at kernel/kexec_handover.c:704 kho_add_subtree (kernel/kexec_handover.c:704)
> > [ 13.621665][ T1] Modules linked in:
> > [ 13.622090][ T1] CPU: 1 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.18.0-rc3-00211-ge44a700c561d #1 VOLUNTARY
> > [ 13.623073][ T1] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
> > [ 13.624054][ T1] RIP: 0010:kho_add_subtree (kernel/kexec_handover.c:704)
> > [ 13.624596][ T1] Code: c7 38 b4 ac 85 31 ed e8 01 1c 00 00 48 c7 c7 70 5a ca 86 85 c0 89 c3 40 0f 95 c5 31 c9 31 d2 89 ee e8 37 b5 0a 00 85 db 74 02 <0f> 0b b9 01 00 00 00 31 d2 89 ee 48 c7 c7 40 5a ca 86 e8 1c b5 0a
> > All code
> > ========
> > 0: c7 38 b4 ac 85 xbegin 0xffffffff85acb43d,(bad)
> > 5: 31 ed xor %ebp,%ebp
> > 7: e8 01 1c 00 00 call 0x1c0d
> > c: 48 c7 c7 70 5a ca 86 mov $0xffffffff86ca5a70,%rdi
> > 13: 85 c0 test %eax,%eax
> > 15: 89 c3 mov %eax,%ebx
> > 17: 40 0f 95 c5 setne %bpl
> > 1b: 31 c9 xor %ecx,%ecx
> > 1d: 31 d2 xor %edx,%edx
> > 1f: 89 ee mov %ebp,%esi
> > 21: e8 37 b5 0a 00 call 0xab55d
> > 26: 85 db test %ebx,%ebx
> > 28: 74 02 je 0x2c
> > 2a:* 0f 0b ud2 <-- trapping instruction
> > 2c: b9 01 00 00 00 mov $0x1,%ecx
> > 31: 31 d2 xor %edx,%edx
> > 33: 89 ee mov %ebp,%esi
> > 35: 48 c7 c7 40 5a ca 86 mov $0xffffffff86ca5a40,%rdi
> > 3c: e8 .byte 0xe8
> > 3d: 1c b5 sbb $0xb5,%al
> > 3f: 0a .byte 0xa
> >
> > Code starting with the faulting instruction
> > ===========================================
> > 0: 0f 0b ud2
> > 2: b9 01 00 00 00 mov $0x1,%ecx
> > 7: 31 d2 xor %edx,%edx
> > 9: 89 ee mov %ebp,%esi
> > b: 48 c7 c7 40 5a ca 86 mov $0xffffffff86ca5a40,%rdi
> > 12: e8 .byte 0xe8
> > 13: 1c b5 sbb $0xb5,%al
> > 15: 0a .byte 0xa
> > [ 13.626370][ T1] RSP: 0018:ffffc9000001fca0 EFLAGS: 00010286
> > [ 13.626951][ T1] RAX: dffffc0000000000 RBX: 00000000ffffffff RCX: 0000000000000000
> > [ 13.627737][ T1] RDX: 1ffffffff0d94b52 RSI: 0000000000000001 RDI: ffffffff86ca5a90
> > [ 13.628523][ T1] RBP: 0000000000000001 R08: 0000000000000008 R09: fffffbfff0dfac4c
> > [ 13.629330][ T1] R10: 0000000000000000 R11: ffffffff86fd6267 R12: ffff888133ee2000
> > [ 13.630101][ T1] R13: ffffffff85acb340 R14: ffff888117a5f988 R15: dffffc0000000000
> > [ 13.630869][ T1] FS: 0000000000000000(0000) GS:ffff888426ea0000(0000) knlGS:0000000000000000
> > [ 13.631727][ T1] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > [ 13.632370][ T1] CR2: 00007f586df260ac CR3: 00000000054ea000 CR4: 00000000000406f0
> > [ 13.633154][ T1] Call Trace:
> > [ 13.633506][ T1] <TASK>
> > [ 13.633833][ T1] kho_test_prepare_fdt+0x145/0x180
> > [ 13.634446][ T1] ? kho_test_save_data+0x210/0x210
> > [ 13.635097][ T1] ? csum_partial (lib/checksum.c:123)
> > [ 13.635546][ T1] kho_test_init (lib/test_kho.c:177 lib/test_kho.c:284)
> > [ 13.636018][ T1] ? vmalloc_test_init (lib/test_kho.c:271)
> > [ 13.636508][ T1] ? add_device_randomness (drivers/char/random.c:944)
> > [ 13.637485][ T1] ? mix_pool_bytes (drivers/char/random.c:944)
> > [ 13.637955][ T1] ? trace_initcall_start (include/trace/events/initcall.h:27 (discriminator 3))
> > [ 13.638498][ T1] ? vmalloc_test_init (lib/test_kho.c:271)
> > [ 13.638989][ T1] do_one_initcall (init/main.c:1284)
> > [ 13.639477][ T1] ? trace_initcall_start (init/main.c:1274)
> > [ 13.639998][ T1] ? parse_one (kernel/params.c:143)
> > [ 13.640455][ T1] ? kasan_save_track (mm/kasan/common.c:69 (discriminator 1) mm/kasan/common.c:78 (discriminator 1))
> > [ 13.640948][ T1] ? __kmalloc_noprof (mm/slub.c:5659)
> > [ 13.641465][ T1] do_initcalls (init/main.c:1344 (discriminator 3) init/main.c:1361 (discriminator 3))
> > [ 13.641924][ T1] kernel_init_freeable (init/main.c:1595)
> > [ 13.642441][ T1] ? rest_init (init/main.c:1475)
> > [ 13.642891][ T1] kernel_init (init/main.c:1485)
> > [ 13.643345][ T1] ? rest_init (init/main.c:1475)
> > [ 13.643788][ T1] ret_from_fork (arch/x86/kernel/process.c:164)
> > [ 13.644256][ T1] ? rest_init (init/main.c:1475)
> > [ 13.644703][ T1] ret_from_fork_asm (arch/x86/entry/entry_64.S:255)
> > [ 13.645213][ T1] </TASK>
> > [ 13.645540][ T1] irq event stamp: 132025
> > [ 13.645971][ T1] hardirqs last enabled at (132035): __up_console_sem (arch/x86/include/asm/irqflags.h:26 arch/x86/include/asm/irqflags.h:109 arch/x86/include/asm/irqflags.h:151 kernel/printk/printk.c:345)
> > [ 13.646887][ T1] hardirqs last disabled at (132046): __up_console_sem (kernel/printk/printk.c:343 (discriminator 3))
> > [ 13.648253][ T1] softirqs last enabled at (131286): handle_softirqs (kernel/softirq.c:469 (discriminator 1) kernel/softirq.c:650 (discriminator 1))
> > [ 13.649690][ T1] softirqs last disabled at (131281): __irq_exit_rcu (kernel/softirq.c:496 kernel/softirq.c:723)
> > [ 13.651128][ T1] ---[ end trace 0000000000000000 ]---
> >
> >
> > The kernel config and materials to reproduce are available at:
> > https://download.01.org/0day-ci/archive/20251106/202511061629.e242724-lkp@intel.com
> >
> >
> >
> > --
> > 0-DAY CI Kernel Test Service
> > https://github.com/intel/lkp-tests/wiki
> >
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