[android-common:android15-6.6-2026-04 2/2] include/linux/compiler.h:57:31: warning: 'tick_cpu' is used uninitialized

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

Hi Thomas,

FYI, the error/warning still remains.

tree:   https://android.googlesource.com/kernel/common android15-6.6-2026-04
head:   96be303f915dceac57b49fb3825e6f1cb1f9ae35
commit: a94ba5ab288780f141d741107751b4866bc24be3 [2/2] BACKPORT: timekeeping: Use READ/WRITE_ONCE() for tick_do_timer_cpu
config: arm64-randconfig-1002-20260928 (https://download.01.org/0day-ci/archive/20260928/202609282355.vr6vUo32-lkp@intel.com/config)
compiler: aarch64-linux-gcc (GCC) 15.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260928/202609282355.vr6vUo32-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/202609282355.vr6vUo32-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from include/linux/dev_printk.h:14,
                    from include/linux/device.h:15,
                    from include/linux/node.h:18,
                    from include/linux/cpu.h:17,
                    from kernel/time/tick-sched.c:11:
   kernel/time/tick-sched.c: In function 'tick_sched_do_timer':
>> include/linux/compiler.h:57:31: warning: 'tick_cpu' is used uninitialized [-Wuninitialized]
      57 | #define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
         |                               ^~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/compiler.h:55:28: note: in expansion of macro '__trace_if_var'
      55 | #define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
         |                            ^~~~~~~~~~~~~~
   kernel/time/tick-sched.c:212:9: note: in expansion of macro 'if'
     212 |         if (tick_cpu == cpu) {
         |         ^~
   kernel/time/tick-sched.c:188:13: note: 'tick_cpu' was declared here
     188 |         int tick_cpu, cpu = smp_processor_id();
         |             ^~~~~~~~


vim +/tick_cpu +57 include/linux/compiler.h

a15fd609ad53a63 Linus Torvalds 2019-03-20  56  
a15fd609ad53a63 Linus Torvalds 2019-03-20 @57  #define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
a15fd609ad53a63 Linus Torvalds 2019-03-20  58  

:::::: The code at line 57 was first introduced by commit
:::::: a15fd609ad53a631a927c6680e8fb606f42a712b tracing: Simplify "if" macro code

:::::: TO: Linus Torvalds <torvalds@linux-foundation.org>
:::::: CC: Steven Rostedt (VMware) <rostedt@goodmis.org>

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https://github.com/intel/lkp-tests/wiki