Merge tag 'sched_ext-for-7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tj...

Pull sched_ext updates from Tejun Heo:
 "Most of this continues the in-development sub-scheduler support, which
  lets a root BPF scheduler delegate to nested sub-schedulers. The
  dispatch-path building blocks landed in 7.1. A follow-up patchset in
  development will complete enqueue-path support for hierarchical
  scheduling. This cycle adds most of that infrastructure:

   - Topological CPU IDs (cids): a dense, topology-ordered CPU numbering
     where the CPUs of a core, LLC, or NUMA node form contiguous ranges,
     so a topology unit becomes a (start, length) slice. Raw CPU numbers
     are sparse and don't track topological closeness, which makes them
     clumsy for sharding work across sub-schedulers and awkward in BPF.

   - cmask: bitmaps windowed over a slice of cid space, so a
     sub-scheduler can track, for example, the idle cids of its shard
     without a full NR_CPUS cpumask.

   - A struct_ops variant that cid-form sub-schedulers register with,
     along with the cid-form kfuncs they call.

   - BPF arena integration, which sub-scheduler support is built on. The
     bpf-next additions let the kernel read and write the BPF
     scheduler's arena directly, turning it into a real kernel/BPF
     shared-memory channel. Shared state like the per-CPU cmask now
     lives there.

   - scx_qmap is reworked to exercise the new arena and cid interfaces.

  Additionally:

   - Exit-dump improvements: dump the faulting CPU first, expose the
     exit CPU to BPF and userspace, and normalize the dump header.

   - Misc kfuncs and cleanups: a task-ID lookup kfunc, __printf checking
     on the error and dump formatters, header reorganization, and
     assorted fixes"

* tag 'sched_ext-for-7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext: (59 commits)
  sched_ext: Add scx_arena_to_kaddr() / scx_kaddr_to_arena()
  sched_ext: Make scx_bpf_kick_cid() return s32
  sched_ext: Add scx_cmask_test() and scx_cmask_for_each_cid()
  tools/sched_ext: Order single-cid cmask helpers as (cid, mask)
  sched_ext: Order single-cid cmask helpers as (cid, mask)
  selftests/sched_ext: Fix dsq_move_to_local check
  sched_ext: Guard BPF arena helper calls to fix 32-bit build
  sched_ext: idle: Fix errno loss in scx_idle_init()
  sched_ext: Convert ops.set_cmask() to arena-resident cmask
  sched_ext: Sub-allocator over kernel-claimed BPF arena pages
  sched_ext: Require an arena for cid-form schedulers
  sched_ext: Add cmask mask ops
  sched_ext: Track bits[] storage size in struct scx_cmask
  sched_ext: Rename scx_cmask.nr_bits to nr_cids
  tools/sched_ext: scx_qmap: Fix qa arena placement
  sched_ext: Mark !CONFIG_EXT_SUB_SCHED dummy stubs static inline
  sched_ext: Replace tryget_task_struct() with get_task_struct()
  sched_ext: Add scx_task_iter_relock() and use it in scx_root_enable_workfn()
  sched_ext: Fix ops_cid layout assert
  sched_ext: Use offsetofend on both sides of the ops_cid layout assert
  ...

diff --cc kernel/sched/ext.c
index f5a3233ead1a4b5ff8f9240b490924b0692a0d6c,6567f626b3f06835b388e6af2790a790db2ef768..0db6fa2daea39cbe1acc4c04b1c4a4379fd1a2f8
--- 1/kernel/sched/ext.c
--- 2/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@@ -5908,10 -6108,8 +6123,9 @@@ static inline void scx_sub_disable(stru
  
  static void scx_root_disable(struct scx_sched *sch)
  {
-       struct scx_exit_info *ei = sch->exit_info;
        struct scx_task_iter sti;
        struct task_struct *p;
 +      bool was_switched_all;
        int cpu;
  
        /* guarantee forward progress and wait for descendants to be disabled */

diff --cc kernel/sched/ext_idle.c
Simple merge