Commit db08c53fdd542bb7f83b ("scripts/gdb: fix parameter handling in
$lx_per_cpu") changed the parameter handling of lx_per_cpu to use GdbValue
instead of parsing the variable name.  Update the documentation to reflect
the new lx_per_cpu usage.  Update the hrtimer_bases example to use rb_tree
instead of the timerqueue_head.next pointer removed in commit
511885d7061eda3eb1fa ("lib/timerqueue: Rely on rbtree semantics for next
timer").

Link: https://lkml.kernel.org/r/20250503123234.2407184-3-illia@yshyn.com
Signed-off-by: Illia Ostapyshyn <illia@yshyn.com>
Cc: Alex Shi <alexs@kernel.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Dongliang Mu <dzm91@hust.edu.cn>
Cc: Florian Rommel <mail@florommel.de>
Cc: Hu Haowen <2023002089@link.tyut.edu.cn>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kieran Bingham <kbingham@kernel.org>
Cc: Yanteng Si <si.yanteng@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

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
  ...

We currently have $lx_per_cpu() which works fine for stuff that kernel
code would access via per_cpu().  But this doesn't work for stuff that
kernel code accesses via per_cpu_ptr():

(gdb) p $lx_per_cpu(node_data[1].node_zones[2]->per_cpu_pageset)
Cannot access memory at address 0xffff11105fbd6c28

This is because we take the address of the pointer and use that as the
offset, instead of using the stored value.

Add a GDB version that mirrors the kernel API, which uses the pointer
value.

To be consistent with per_cpu_ptr(), we need to return the pointer value
instead of dereferencing it for the user.  Therefore, move the existing
dereference out of the per_cpu() Python helper and do that only in the
$lx_per_cpu() implementation.

Link: https://lkml.kernel.org/r/20250220-lx-per-cpu-ptr-v2-1-945dee8d8d38@google.com
Signed-off-by: Brendan Jackman <jackmanb@google.com>
Reviewed-by: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Florian Rommel <mail@florommel.de>
Cc: Kieran Bingham <kbingham@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

No functional change.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250303165246.2175811-10-brgerst@gmail.com

At least recent gdb releases (seen with 14.2) return SP_EL0 as signed long
which lets the right-shift always return 0.

Link: https://lkml.kernel.org/r/dcd2fabc-9131-4b48-8419-6444e2d67454@siemens.com
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Kieran Bingham <kbingham@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Directly read the current CPU number from the kgdb_active variable.

Before, the active CPU was obtained through the current task, which
required searching the task list for the pid of GDB's selected thread. 
Obtaining the pid was buggy: GDB may use selected_thread().ptid[1] (LWPID)
instead of .ptid[2] (TID) to store the threads pid; see
https://sourceware.org/gdb/current/onlinedocs/gdb.html/Threads-In-Python.html
As a result, the detection could return the wrong CPU number, leading to
incorrect results for $lx_per_cpu and $lx_current.

As a side effect, the patch significantly speeds up $lx_per_cpu and
$lx_current in KGDB by avoiding the task-list iteration.

Link: https://lkml.kernel.org/r/20240425153501.749966-5-mail@florommel.de
Signed-off-by: Florian Rommel <mail@florommel.de>
Cc: Andrew Jones <ajones@ventanamicro.com>
Cc: Deepak Gupta <debug@rivosinc.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Kieran Bingham <kbingham@kernel.org>
Cc: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
Cc: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Before, the script tried to get the address by constructing a pointer to
the parameter (by name).  However, since GDB now passes the parameter as a
GdbValue, we cannot get its name.  Instead, we retrieve the address
through GdbValue's address attribute.

Before:
>>> p $lx_per_cpu(cpu_info)
Traceback (most recent call last):
  File "./scripts/gdb/linux/cpus.py", line 152, in invoke
    var_ptr = gdb.parse_and_eval("&" + var_name.string())
                                       ^^^^^^^^^^^^^^^^^
gdb.error: Trying to read string with inappropriate type `struct cpuinfo_x86'.

Link: https://lkml.kernel.org/r/20240425153501.749966-3-mail@florommel.de
Signed-off-by: Florian Rommel <mail@florommel.de>
Cc: Andrew Jones <ajones@ventanamicro.com>
Cc: Deepak Gupta <debug@rivosinc.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Kieran Bingham <kbingham@kernel.org>
Cc: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
Cc: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

csr_sscratch CSR holds current task_struct address when hart is in user
space.  Trap handler on entry spills csr_sscratch into "tp" (x2) register
and zeroes out csr_sscratch CSR.  Trap handler on exit reloads "tp" with
expected user mode value and place current task_struct address again in
csr_sscratch CSR.

This patch assumes "tp" is pointing to task_struct. If value in
csr_sscratch is numerically greater than "tp" then it assumes csr_sscratch
is correct address of current task_struct. This logic holds when
   - hart is in user space, "tp" will be less than csr_sscratch.
   - hart is in kernel space but not in trap handler, "tp" will be more
     than csr_sscratch (csr_sscratch being equal to 0).
   - hart is executing trap handler
       - "tp" is still pointing to user mode but csr_sscratch contains
          ptr to task_struct. Thus numerically higher.
       - "tp" is  pointing to task_struct but csr_sscratch now contains
          either 0 or numerically smaller value (transiently holds
          user mode tp)

Link: https://lkml.kernel.org/r/20231026233837.612405-1-debug@rivosinc.com
Signed-off-by: Deepak Gupta <debug@rivosinc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Tested-by: Hsieh-Tseng Shen <woodrow.shen@sifive.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Glenn Washburn <development@efficientek.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Jeff Xie <xiehuan09@gmail.com>
Cc: Kieran Bingham <kbingham@kernel.org>
Cc: Palmer Dabbelt <palmer@rivosinc.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

A running x86 UML kernel reports with architecture "i386:x86-64" as it is
a sub-architecture.  However, a difference with bare-metal x86 kernels is
in how it manages tasks and the current task struct.  To identify that the
inferior is a UML kernel and not bare-metal, check for the existence of
the UML specific symbol "cpu_tasks" which contains the current task
struct.

Link: https://lkml.kernel.org/r/b839d611e2906ccef2725c34d8e353fab35fe75e.1677469905.git.development@efficientek.com
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Anton Ivanov <anton.ivanov@kot-begemot.co.uk>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Kieran Bingham <kbingham@kernel.org>
Cc: Richard Weinberger <richard@nod.at>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Patch series "scripts/gdb: Support getting current task struct in UML",
v3.

A running x86 UML kernel reports with architecture "i386:x86-64" as it is
a sub-architecture.  However, a difference with bare-metal x86 kernels is
in how it manages tasks and the current task struct.  To identify that the
inferior is a UML kernel and not bare-metal, check for the existence of
the UML specific symbol "cpu_tasks" which contains the current task
struct.


This patch (of 3):

There is an extra space in a couple blocks in get_current_task.  Though
python does not care, let's make the spacing consistent.  Also, format
better an if expression, removing unneeded parenthesis.

Link: https://lkml.kernel.org/r/cover.1677469905.git.development@efficientek.com
Link: https://lkml.kernel.org/r/2e117b82240de6893f27cb6507242ce455ed7b5b.1677469905.git.development@efficientek.com
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Anton Ivanov <anton.ivanov@kot-begemot.co.uk>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Kieran Bingham <kbingham@kernel.org>
Cc: Richard Weinberger <richard@nod.at>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>