Re: [linux-next:master 7183/13846] kernel/hazptr.c:178: Warning: missing closing `"'

On Sat, Aug 08, 2026 at 08:58:42AM +0800, kernel test robot wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> head:   6b8c8af514d739d0335f5579b585e02babe8a727
> commit: 9d30872a4c09c2e8a97084ef1fe6913f6bf9e34d [7183/13846] hazptr: Implement Hazard Pointers
> config: s390-randconfig-001-20260808 (https://download.01.org/0day-ci/archive/20260808/[email protected]/config)
> compiler: s390-linux-gcc (GCC) 8.5.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260808/[email protected]/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 <[email protected]>
> | Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
> 
> All warnings (new ones prefixed by >>):
> 
>    kernel/hazptr.c: Assembler messages:
> >> kernel/hazptr.c:178: Warning: missing closing `"'
> >> kernel/hazptr.c:178: Warning: missing closing `"'
> >> kernel/hazptr.c:178: Warning: missing closing `"'
> >> kernel/hazptr.c:178: Warning: missing closing `"'
> >> kernel/hazptr.c:178: Warning: missing closing `"'
> >> kernel/hazptr.c:178: Warning: missing closing `"'
> >> kernel/hazptr.c:178: Warning: missing closing `"'
> >> kernel/hazptr.c:178: Warning: missing closing `"'
> >> kernel/hazptr.c:178: Warning: missing closing `"'
> >> kernel/hazptr.c:178: Warning: missing closing `"'
> >> kernel/hazptr.c:178: Warning: missing closing `"'
> >> kernel/hazptr.c:178: Warning: missing closing `"'
> >> kernel/hazptr.c:178: Warning: missing closing `"'
> >> kernel/hazptr.c:178: Warning: missing closing `"'
> >> kernel/hazptr.c:178: Warning: missing closing `"'
> >> kernel/hazptr.c:178: Warning: missing closing `"'
> >> kernel/hazptr.c:178: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
> >> kernel/hazptr.c:178: Warning: missing closing `"'
> >> kernel/hazptr.c:178: Warning: missing closing `"'
> >> kernel/hazptr.c:178: Warning: missing closing `"'
>    kernel/hazptr.c:178: Warning: missing closing `"'
>    kernel/hazptr.c:178: Warning: missing closing `"'
>    kernel/hazptr.c:178: Warning: missing closing `"'
>    kernel/hazptr.c:178: Warning: missing closing `"'
>    kernel/hazptr.c:178: Warning: missing closing `"'
>    kernel/hazptr.c:178: Warning: missing closing `"'
>    kernel/hazptr.c:178: Warning: missing closing `"'
>    kernel/hazptr.c:178: Warning: missing closing `"'
>    kernel/hazptr.c:178: Warning: missing closing `"'
>    kernel/hazptr.c:178: Warning: missing closing `"'
>    kernel/hazptr.c:178: Warning: missing closing `"'
>    kernel/hazptr.c:178: Warning: missing closing `"'
>    kernel/hazptr.c:178: Warning: missing closing `"'
>    kernel/hazptr.c:178: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
>    kernel/hazptr.c:183: Warning: missing closing `"'
> 
> 
> vim +178 kernel/hazptr.c
> 
>    154	
>    155	/*
>    156	 * hazptr_synchronize: Wait until @addr is released from all slots.
>    157	 *
>    158	 * Wait to observe that each slot contains a value that differs from
>    159	 * @addr before returning.
>    160	 * Should be called from preemptible context.
>    161	 */
>    162	void hazptr_synchronize(void *addr)
>    163	{
>    164		int cpu;
>    165	
>    166		/*
>    167		 * Busy-wait should only be done from preemptible context.
>    168		 */
>    169		lockdep_assert_preemption_enabled();
>    170	
>    171		/*
>    172		 * Store A precedes hazptr_scan(): it unpublishes addr (sets it to
>    173		 * NULL or to a different value), and thus hides it from hazard
>    174		 * pointer readers.
>    175		 */
>    176		if (!addr)
>    177			return;
>  > 178		/* Memory ordering: Store A before Load B. */

Is this perhaps a typo in s390 smp_mb() or similar?  I freely confess
that I am having trouble seeing how the above comment causes trouble.

						Thanx, Paul

>    179		smp_mb();
>    180		/* Scan all CPUs slots. */
>    181		for_each_possible_cpu(cpu) {
>    182			struct hazptr_overflow_list_flip *overflow_list_flip = per_cpu_ptr(&percpu_overflow_list_flip, cpu);
>    183			unsigned int scan_idx;
>    184	
>    185			/* Scan CPU slots. */
>    186			hazptr_synchronize_cpu_slots(cpu, addr);
>    187	
>    188			/*
>    189			 * Scan backup slots in percpu overflow lists.
>    190			 * Forward progress is guaranteed by scanning one list
>    191			 * while new elements are added into the other list.
>    192			 */
>    193			guard(mutex)(&overflow_list_flip->lock);
>    194			scan_idx = overflow_list_flip->add_idx ^ 1;
>    195			hazptr_synchronize_overflow_list(&overflow_list_flip->array[scan_idx], addr);
>    196			/* Flip current list. */
>    197			WRITE_ONCE(overflow_list_flip->add_idx, scan_idx);
>    198			hazptr_synchronize_overflow_list(&overflow_list_flip->array[scan_idx ^ 1], addr);
>    199		}
>    200	}
>    201	EXPORT_SYMBOL_GPL(hazptr_synchronize);
>    202	
> 
> --
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki