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, 132 insertions, 7 deletions

diff --git a/scripts/gdb/linux/radixtree.py b/scripts/gdb/linux/radixtree.py
index 074543ac763d..bc2954e45c32 100644
--- a/scripts/gdb/linux/radixtree.py
+++ b/scripts/gdb/linux/radixtree.py
@@ -30,13 +30,16 @@ def entry_to_node(node):
 def node_maxindex(node):
     return (constants.LX_RADIX_TREE_MAP_SIZE << node['shift']) - 1
 
-def lookup(root, index):
+def resolve_root(root):
+    if root.type == radix_tree_root_type.get_type():
+        return root
     if root.type == radix_tree_root_type.get_type().pointer():
-        node = root.dereference()
-    elif root.type != radix_tree_root_type.get_type():
-        raise gdb.GdbError("must be {} not {}"
-                           .format(radix_tree_root_type.get_type(), root.type))
+        return root.dereference()
+    raise gdb.GdbError("must be {} not {}"
+                       .format(radix_tree_root_type.get_type(), root.type))
 
+def lookup(root, index):
+    root = resolve_root(root)
     node = root['xa_head']
     if node == 0:
         return None
@@ -71,14 +74,120 @@ def lookup(root, index):
 
     return node
 
-class LxRadixTree(gdb.Function):
+def descend(parent, index):
+    offset = (index >> int(parent["shift"])) & constants.LX_RADIX_TREE_MAP_MASK
+    return offset, parent["slots"][offset]
+
+def load_root(root):
+    node = root["xa_head"]
+    nodep = node
+
+    if is_internal_node(node):
+        node = entry_to_node(node)
+        maxindex = node_maxindex(node)
+        return int(node["shift"]) + constants.LX_RADIX_TREE_MAP_SHIFT, \
+               nodep, maxindex
+
+    return 0, nodep, 0
+
+class RadixTreeIter:
+    def __init__(self, start):
+        self.index = 0
+        self.next_index = start
+        self.node = None
+
+def xa_mk_internal(v):
+    return (v << 2) | 2
+
+LX_XA_RETRY_ENTRY = xa_mk_internal(256)
+LX_RADIX_TREE_RETRY = LX_XA_RETRY_ENTRY
+
+def next_chunk(root, iter):
+    mask = (1 << (utils.get_ulong_type().sizeof * 8)) - 1
+
+    index = iter.next_index
+    if index == 0 and iter.index != 0:
+        return None
+
+    restart = True
+    while restart:
+        restart = False
+
+        _, child, maxindex = load_root(root)
+        if index > maxindex:
+            return None
+        if not child:
+            return None
+
+        if not is_internal_node(child):
+            iter.index = index
+            iter.next_index = (maxindex + 1) & mask
+            iter.node = None
+            return root["xa_head"].address
+
+        while True:
+            node = entry_to_node(child)
+            offset, child = descend(node, index)
+
+            if not child:
+                while True:
+                    offset += 1
+                    if offset >= constants.LX_RADIX_TREE_MAP_SIZE:
+                        break
+                    slot = node["slots"][offset]
+                    if slot:
+                        break
+                index &= ~node_maxindex(node)
+                index = (index + (offset << int(node["shift"]))) & mask
+                if index == 0:
+                    return None
+                if offset == constants.LX_RADIX_TREE_MAP_SIZE:
+                    restart = True
+                    break
+                child = node["slots"][offset]
+
+            if not child:
+                restart = True
+                break
+            if child == LX_XA_RETRY_ENTRY:
+                break
+            if not node["shift"] or not is_internal_node(child):
+                break
+
+    iter.index = (index & ~node_maxindex(node)) | offset
+    iter.next_index = ((index | node_maxindex(node)) + 1) & mask
+    iter.node = node
+
+    return node["slots"][offset].address
+
+def next_slot(slot, iter):
+    mask = (1 << (utils.get_ulong_type().sizeof * 8)) - 1
+    for _ in range(iter.next_index - iter.index - 1):
+        slot += 1
+        iter.index = (iter.index + 1) & mask
+        if slot.dereference():
+            return slot
+    return None
+
+def for_each_slot(root, start=0):
+    iter = RadixTreeIter(start)
+    slot = None
+    while True:
+        if not slot:
+            slot = next_chunk(root, iter)
+            if not slot:
+                break
+        yield iter.index, slot
+        slot = next_slot(slot, iter)
+
+class LxRadixTreeLookup(gdb.Function):
     """ Lookup and return a node from a RadixTree.
 
 $lx_radix_tree_lookup(root_node [, index]): Return the node at the given index.
 If index is omitted, the root node is dereference and returned."""
 
     def __init__(self):
-        super(LxRadixTree, self).__init__("lx_radix_tree_lookup")
+        super(LxRadixTreeLookup, self).__init__("lx_radix_tree_lookup")
 
     def invoke(self, root, index=0):
         result = lookup(root, index)
@@ -87,4 +196,20 @@ If index is omitted, the root node is dereference and returned."""
 
         return result
 
+class LxRadixTree(gdb.Command):
+    """Show all values stored in a RadixTree."""
+
+    def __init__(self):
+        super(LxRadixTree, self).__init__("lx-radix-tree", gdb.COMMAND_DATA,
+                                          gdb.COMPLETE_NONE)
+
+    def invoke(self, argument, from_tty):
+        args = gdb.string_to_argv(argument)
+        if len(args) != 1:
+            raise gdb.GdbError("Usage: lx-radix-tree ROOT")
+        root = gdb.parse_and_eval(args[0])
+        for index, slot in for_each_slot(root):
+            gdb.write("[{}] = {}\n".format(index, slot.dereference()))
+
 LxRadixTree()
+LxRadixTreeLookup()