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, 253 insertions, 0 deletions

diff --git a/scripts/gdb/linux/bpf.py b/scripts/gdb/linux/bpf.py
new file mode 100644
index 000000000000..1870534ef6f9
--- /dev/null
+++ b/scripts/gdb/linux/bpf.py
@@ -0,0 +1,253 @@
+# SPDX-License-Identifier: GPL-2.0
+
+import json
+import subprocess
+import tempfile
+
+import gdb
+
+from linux import constants, lists, radixtree, utils
+
+
+if constants.LX_CONFIG_BPF and constants.LX_CONFIG_BPF_JIT:
+    bpf_ksym_type = utils.CachedType("struct bpf_ksym")
+if constants.LX_CONFIG_BPF_SYSCALL:
+    bpf_prog_type = utils.CachedType("struct bpf_prog")
+
+
+def get_ksym_name(ksym):
+    name = ksym["name"].bytes
+    end = name.find(b"\x00")
+    if end != -1:
+        name = name[:end]
+    return name.decode()
+
+
+def list_ksyms():
+    if not (constants.LX_CONFIG_BPF and constants.LX_CONFIG_BPF_JIT):
+        return []
+    bpf_kallsyms = gdb.parse_and_eval("&bpf_kallsyms")
+    bpf_ksym_ptr_type = bpf_ksym_type.get_type().pointer()
+    return list(lists.list_for_each_entry(bpf_kallsyms,
+                                          bpf_ksym_ptr_type,
+                                          "lnode"))
+
+
+class KsymAddBreakpoint(gdb.Breakpoint):
+    def __init__(self, monitor):
+        super(KsymAddBreakpoint, self).__init__("bpf_ksym_add", internal=True)
+        self.silent = True
+        self.monitor = monitor
+
+    def stop(self):
+        self.monitor.add(gdb.parse_and_eval("ksym"))
+        return False
+
+
+class KsymRemoveBreakpoint(gdb.Breakpoint):
+    def __init__(self, monitor):
+        super(KsymRemoveBreakpoint, self).__init__("bpf_ksym_del",
+                                                   internal=True)
+        self.silent = True
+        self.monitor = monitor
+
+    def stop(self):
+        self.monitor.remove(gdb.parse_and_eval("ksym"))
+        return False
+
+
+class KsymMonitor:
+    def __init__(self, add, remove):
+        self.add = add
+        self.remove = remove
+
+        self.add_bp = KsymAddBreakpoint(self)
+        self.remove_bp = KsymRemoveBreakpoint(self)
+
+        self.notify_initial()
+
+    def notify_initial(self):
+        for ksym in list_ksyms():
+            self.add(ksym)
+
+    def delete(self):
+        self.add_bp.delete()
+        self.remove_bp.delete()
+
+
+def list_progs():
+    if not constants.LX_CONFIG_BPF_SYSCALL:
+        return []
+    idr_rt = gdb.parse_and_eval("&prog_idr.idr_rt")
+    bpf_prog_ptr_type = bpf_prog_type.get_type().pointer()
+    progs = []
+    for _, slot in radixtree.for_each_slot(idr_rt):
+        prog = slot.dereference().cast(bpf_prog_ptr_type)
+        progs.append(prog)
+        # Subprogs are not registered in prog_idr, fetch them manually.
+        # func[0] is the current prog.
+        aux = prog["aux"]
+        func = aux["func"]
+        real_func_cnt = int(aux["real_func_cnt"])
+        for i in range(1, real_func_cnt):
+            progs.append(func[i])
+    return progs
+
+
+class ProgAddBreakpoint(gdb.Breakpoint):
+    def __init__(self, monitor):
+        super(ProgAddBreakpoint, self).__init__("bpf_prog_kallsyms_add",
+                                                internal=True)
+        self.silent = True
+        self.monitor = monitor
+
+    def stop(self):
+        self.monitor.add(gdb.parse_and_eval("fp"))
+        return False
+
+
+class ProgRemoveBreakpoint(gdb.Breakpoint):
+    def __init__(self, monitor):
+        super(ProgRemoveBreakpoint, self).__init__("bpf_prog_free_id",
+                                                   internal=True)
+        self.silent = True
+        self.monitor = monitor
+
+    def stop(self):
+        self.monitor.remove(gdb.parse_and_eval("prog"))
+        return False
+
+
+class ProgMonitor:
+    def __init__(self, add, remove):
+        self.add = add
+        self.remove = remove
+
+        self.add_bp = ProgAddBreakpoint(self)
+        self.remove_bp = ProgRemoveBreakpoint(self)
+
+        self.notify_initial()
+
+    def notify_initial(self):
+        for prog in list_progs():
+            self.add(prog)
+
+    def delete(self):
+        self.add_bp.delete()
+        self.remove_bp.delete()
+
+
+def btf_str_by_offset(btf, offset):
+    while offset < btf["start_str_off"]:
+        btf = btf["base_btf"]
+
+    offset -= btf["start_str_off"]
+    if offset < btf["hdr"]["str_len"]:
+        return (btf["strings"] + offset).string()
+
+    return None
+
+
+def bpf_line_info_line_num(line_col):
+    return line_col >> 10
+
+
+def bpf_line_info_line_col(line_col):
+    return line_col & 0x3ff
+
+
+class LInfoIter:
+    def __init__(self, prog):
+        # See bpf_prog_get_file_line() for details.
+        self.pos = 0
+        self.nr_linfo = 0
+
+        if prog is None:
+            return
+
+        self.bpf_func = int(prog["bpf_func"])
+        aux = prog["aux"]
+        self.btf = aux["btf"]
+        linfo_idx = aux["linfo_idx"]
+        self.nr_linfo = int(aux["nr_linfo"]) - linfo_idx
+        if self.nr_linfo == 0:
+            return
+
+        linfo_ptr = aux["linfo"]
+        tpe = linfo_ptr.type.target().array(self.nr_linfo).pointer()
+        self.linfo = (linfo_ptr + linfo_idx).cast(tpe).dereference()
+        jited_linfo_ptr = aux["jited_linfo"]
+        tpe = jited_linfo_ptr.type.target().array(self.nr_linfo).pointer()
+        self.jited_linfo = (jited_linfo_ptr + linfo_idx).cast(tpe).dereference()
+
+        self.filenos = {}
+
+    def get_code_off(self):
+        if self.pos >= self.nr_linfo:
+            return -1
+        return self.jited_linfo[self.pos] - self.bpf_func
+
+    def advance(self):
+        self.pos += 1
+
+    def get_fileno(self):
+        file_name_off = int(self.linfo[self.pos]["file_name_off"])
+        fileno = self.filenos.get(file_name_off)
+        if fileno is not None:
+            return fileno, None
+        file_name = btf_str_by_offset(self.btf, file_name_off)
+        fileno = len(self.filenos) + 1
+        self.filenos[file_name_off] = fileno
+        return fileno, file_name
+
+    def get_line_col(self):
+        line_col = int(self.linfo[self.pos]["line_col"])
+        return bpf_line_info_line_num(line_col), \
+               bpf_line_info_line_col(line_col)
+
+
+def generate_debug_obj(ksym, prog):
+    name = get_ksym_name(ksym)
+    # Avoid read_memory(); it throws bogus gdb.MemoryError in some contexts.
+    start = ksym["start"]
+    code = start.cast(gdb.lookup_type("unsigned char")
+                      .array(int(ksym["end"]) - int(start))
+                      .pointer()).dereference().bytes
+    linfo_iter = LInfoIter(prog)
+
+    result = tempfile.NamedTemporaryFile(suffix=".o", mode="wb")
+    try:
+        with tempfile.NamedTemporaryFile(suffix=".s", mode="w") as src:
+            # ".loc" does not apply to ".byte"s, only to ".insn"s, but since
+            # this needs to work for all architectures, the latter are not an
+            # option. Ask the assembler to apply ".loc"s to labels as well,
+            # and generate dummy labels after each ".loc".
+            src.write(".loc_mark_labels 1\n")
+
+            src.write(".globl {}\n".format(name))
+            src.write(".type {},@function\n".format(name))
+            src.write("{}:\n".format(name))
+            for code_off, code_byte in enumerate(code):
+                if linfo_iter.get_code_off() == code_off:
+                    fileno, file_name = linfo_iter.get_fileno()
+                    if file_name is not None:
+                        src.write(".file {} {}\n".format(
+                            fileno, json.dumps(file_name)))
+                    line, col = linfo_iter.get_line_col()
+                    src.write(".loc {} {} {}\n".format(fileno, line, col))
+                    src.write("0:\n")
+                    linfo_iter.advance()
+                src.write(".byte {}\n".format(code_byte))
+            src.write(".size {},{}\n".format(name, len(code)))
+            src.flush()
+
+            try:
+                subprocess.check_call(["as", "-c", src.name, "-o", result.name])
+            except FileNotFoundError:
+                # "as" is not installed.
+                result.close()
+                return None
+        return result
+    except:
+        result.close()
+        raise