Merge tag 'mm-nonmm-stable-2025-03-30-18-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull non-MM updates from Andrew Morton:

 - The series "powerpc/crash: use generic crashkernel reservation" from
   Sourabh Jain changes powerpc's kexec code to use more of the generic
   layers.

 - The series "get_maintainer: report subsystem status separately" from
   Vlastimil Babka makes some long-requested improvements to the
   get_maintainer output.

 - The series "ucount: Simplify refcounting with rcuref_t" from
   Sebastian Siewior cleans up and optimizing the refcounting in the
   ucount code.

 - The series "reboot: support runtime configuration of emergency
   hw_protection action" from Ahmad Fatoum improves the ability for a
   driver to perform an emergency system shutdown or reboot.

 - The series "Converge on using secs_to_jiffies() part two" from Easwar
   Hariharan performs further migrations from msecs_to_jiffies() to
   secs_to_jiffies().

 - The series "lib/interval_tree: add some test cases and cleanup" from
   Wei Yang permits more userspace testing of kernel library code, adds
   some more tests and performs some cleanups.

 - The series "hung_task: Dump the blocking task stacktrace" from Masami
   Hiramatsu arranges for the hung_task detector to dump the stack of
   the blocking task and not just that of the blocked task.

 - The series "resource: Split and use DEFINE_RES*() macros" from Andy
   Shevchenko provides some cleanups to the resource definition macros.

 - Plus the usual shower of singleton patches - please see the
   individual changelogs for details.

* tag 'mm-nonmm-stable-2025-03-30-18-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (77 commits)
  mailmap: consolidate email addresses of Alexander Sverdlin
  fs/procfs: fix the comment above proc_pid_wchan()
  relay: use kasprintf() instead of fixed buffer formatting
  resource: replace open coded variant of DEFINE_RES()
  resource: replace open coded variants of DEFINE_RES_*_NAMED()
  resource: replace open coded variant of DEFINE_RES_NAMED_DESC()
  resource: split DEFINE_RES_NAMED_DESC() out of DEFINE_RES_NAMED()
  samples: add hung_task detector mutex blocking sample
  hung_task: show the blocker task if the task is hung on mutex
  kexec_core: accept unaccepted kexec segments' destination addresses
  watchdog/perf: optimize bytes copied and remove manual NUL-termination
  lib/interval_tree: fix the comment of interval_tree_span_iter_next_gap()
  lib/interval_tree: skip the check before go to the right subtree
  lib/interval_tree: add test case for span iteration
  lib/interval_tree: add test case for interval_tree_iter_xxx() helpers
  lib/rbtree: add random seed
  lib/rbtree: split tests
  lib/rbtree: enable userland test suite for rbtree related data structure
  checkpatch: describe --min-conf-desc-length
  scripts/gdb/symbols: determine KASLR offset on s390
  ...

1 files changed, 9 insertions, 3 deletions

diff --git a/lib/interval_tree.c b/lib/interval_tree.c
index 3412737ff365..324766e9bf63 100644
--- a/lib/interval_tree.c
+++ b/lib/interval_tree.c
@@ -20,9 +20,15 @@ EXPORT_SYMBOL_GPL(interval_tree_iter_next);
 /*
  * Roll nodes[1] into nodes[0] by advancing nodes[1] to the end of a contiguous
  * span of nodes. This makes nodes[0]->last the end of that contiguous used span
- * indexes that started at the original nodes[1]->start. nodes[1] is now the
- * first node starting the next used span. A hole span is between nodes[0]->last
- * and nodes[1]->start. nodes[1] must be !NULL.
+ * of indexes that started at the original nodes[1]->start.
+ *
+ * If there is an interior hole, nodes[1] is now the first node starting the
+ * next used span. A hole span is between nodes[0]->last and nodes[1]->start.
+ *
+ * If there is a tailing hole, nodes[1] is now NULL. A hole span is between
+ * nodes[0]->last and last_index.
+ *
+ * If the contiguous used range span to last_index, nodes[1] is set to NULL.
  */
 static void
 interval_tree_span_iter_next_gap(struct interval_tree_span_iter *state)