[thomas-weissschuh:b4/auxclock-nanosleep 1/28] kernel/fork.c:549:undefined reference to `rt_mutex_debug_task_free'

[kernel test robot <lkp@intel.com>]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/thomas.weissschuh/linux.git b4/auxclock-nanosleep
head:   90614b63ef6a2f10b6e486e486ca8d5bfd2b7a81
commit: 3d3535e426c8e15bef8f2b193de5a970bbc84a20 [1/28] debugging
config: powerpc-adder875_defconfig (https://download.01.org/0day-ci/archive/20260121/202601211003.aAKWT2re-lkp@intel.com/config)
compiler: powerpc-linux-gcc (GCC) 15.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260121/202601211003.aAKWT2re-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202601211003.aAKWT2re-lkp@intel.com/

All errors (new ones prefixed by >>):

   powerpc-linux-ld: kernel/fork.o: in function `free_task':
>> kernel/fork.c:549:(.text+0x1f28): undefined reference to `rt_mutex_debug_task_free'

Kconfig warnings: (for reference only)
   WARNING: unmet direct dependencies detected for DEBUG_RT_MUTEXES
   Depends on [n]: DEBUG_KERNEL [=y] && RT_MUTEXES [=n]
   Selected by [y]:
   - DEBUG_TIMERS [=y]


vim +549 kernel/fork.c

68f24b08ee892d Andy Lutomirski     2016-09-15  527  
68f24b08ee892d Andy Lutomirski     2016-09-15  528  void free_task(struct task_struct *tsk)
68f24b08ee892d Andy Lutomirski     2016-09-15  529  {
a1140cb215fa13 Kuniyuki Iwashima   2022-08-23  530  #ifdef CONFIG_SECCOMP
a1140cb215fa13 Kuniyuki Iwashima   2022-08-23  531  	WARN_ON_ONCE(tsk->seccomp.filter);
a1140cb215fa13 Kuniyuki Iwashima   2022-08-23  532  #endif
b90ca8badbd114 Will Deacon         2021-07-30  533  	release_user_cpus_ptr(tsk);
d08b9f0ca6605e Sami Tolvanen       2020-04-27  534  	scs_release(tsk);
d08b9f0ca6605e Sami Tolvanen       2020-04-27  535  
68f24b08ee892d Andy Lutomirski     2016-09-15  536  #ifndef CONFIG_THREAD_INFO_IN_TASK
68f24b08ee892d Andy Lutomirski     2016-09-15  537  	/*
68f24b08ee892d Andy Lutomirski     2016-09-15  538  	 * The task is finally done with both the stack and thread_info,
68f24b08ee892d Andy Lutomirski     2016-09-15  539  	 * so free both.
68f24b08ee892d Andy Lutomirski     2016-09-15  540  	 */
68f24b08ee892d Andy Lutomirski     2016-09-15  541  	release_task_stack(tsk);
68f24b08ee892d Andy Lutomirski     2016-09-15  542  #else
68f24b08ee892d Andy Lutomirski     2016-09-15  543  	/*
68f24b08ee892d Andy Lutomirski     2016-09-15  544  	 * If the task had a separate stack allocation, it should be gone
68f24b08ee892d Andy Lutomirski     2016-09-15  545  	 * by now.
68f24b08ee892d Andy Lutomirski     2016-09-15  546  	 */
f0b89d3958d73c Elena Reshetova     2019-01-18  547  	WARN_ON_ONCE(refcount_read(&tsk->stack_refcount) != 0);
68f24b08ee892d Andy Lutomirski     2016-09-15  548  #endif
23f78d4a03c53c Ingo Molnar         2006-06-27 @549  	rt_mutex_debug_task_free(tsk);
fb52607afcd062 Frederic Weisbecker 2008-11-25  550  	ftrace_graph_exit_task(tsk);
f19b9f74b7ea3b Akinobu Mita        2012-07-30  551  	arch_release_task_struct(tsk);
1da5c46fa965ff Oleg Nesterov       2016-11-29  552  	if (tsk->flags & PF_KTHREAD)
1da5c46fa965ff Oleg Nesterov       2016-11-29  553  		free_kthread_struct(tsk);
b0fd1852bcc21a KP Singh            2023-06-02  554  	bpf_task_storage_free(tsk);
^1da177e4c3f41 Linus Torvalds      2005-04-16  555  	free_task_struct(tsk);
^1da177e4c3f41 Linus Torvalds      2005-04-16  556  }
^1da177e4c3f41 Linus Torvalds      2005-04-16  557  EXPORT_SYMBOL(free_task);
^1da177e4c3f41 Linus Torvalds      2005-04-16  558  

:::::: The code at line 549 was first introduced by commit
:::::: 23f78d4a03c53cbd75d87a795378ea540aa08c86 [PATCH] pi-futex: rt mutex core

:::::: TO: Ingo Molnar <mingo@elte.hu>
:::::: CC: Linus Torvalds <torvalds@g5.osdl.org>

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