Re: [PATCH] srcutree: Skip torture to-big transition for atomic SRCU

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

Hi Kunwu,

kernel test robot noticed the following build errors:

[auto build test ERROR on rcu/rcu/dev]
[also build test ERROR on linus/master v7.3-rc2 next-20260909]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Kunwu-Chan/srcutree-Skip-torture-to-big-transition-for-atomic-SRCU/20260910-121427
base:   https://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux.git rcu/dev
patch link:    https://lore.kernel.org/r/20260910041427.3579817-1-kunwu.chan%40gmail.com
patch subject: [PATCH] srcutree: Skip torture to-big transition for atomic SRCU
config: s390-allnoconfig (https://download.01.org/0day-ci/archive/20260910/202609102247.8X7GUWSj-lkp@intel.com/config)
compiler: clang version 24.0.0git (https://github.com/llvm/llvm-project d3db069999553568848400c84cbf815c03f5470f)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260910/202609102247.8X7GUWSj-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/202609102247.8X7GUWSj-lkp@intel.com/

All errors (new ones prefixed by >>):

>> kernel/rcu/srcutree.c:2080:61: error: use of undeclared identifier 'SRCU_READ_FLAVOR_ATOMIC'
    2080 |         if (SRCU_SIZING_IS_TORTURE() && ssp->srcu_reader_flavor != SRCU_READ_FLAVOR_ATOMIC)
         |                                                                    ^~~~~~~~~~~~~~~~~~~~~~~
   1 error generated.


vim +/SRCU_READ_FLAVOR_ATOMIC +2080 kernel/rcu/srcutree.c

  2031	
  2032	void srcu_torture_stats_print(struct srcu_struct *ssp, char *tt, char *tf)
  2033	{
  2034		int cpu;
  2035		int idx;
  2036		unsigned long s0 = 0, s1 = 0;
  2037		int ss_state = READ_ONCE(ssp->srcu_sup->srcu_size_state);
  2038		int ss_state_idx = ss_state;
  2039	
  2040		idx = ssp->srcu_ctrp - &ssp->sda->srcu_ctrs[0];
  2041		if (ss_state < 0 || ss_state >= ARRAY_SIZE(srcu_size_state_name))
  2042			ss_state_idx = ARRAY_SIZE(srcu_size_state_name) - 1;
  2043		pr_alert("%s%s Tree SRCU g%ld state %d (%s)",
  2044			 tt, tf, rcu_seq_current(&ssp->srcu_sup->srcu_gp_seq), ss_state,
  2045			 srcu_size_state_name[ss_state_idx]);
  2046		if (!ssp->sda) {
  2047			// Called after cleanup_srcu_struct(), perhaps.
  2048			pr_cont(" No per-CPU srcu_data structures (->sda == NULL).\n");
  2049		} else {
  2050			pr_cont(" per-CPU(idx=%d):", idx);
  2051			for_each_possible_cpu(cpu) {
  2052				unsigned long l0, l1;
  2053				unsigned long u0, u1;
  2054				long c0, c1;
  2055				struct srcu_data *sdp;
  2056	
  2057				sdp = per_cpu_ptr(ssp->sda, cpu);
  2058				u0 = data_race(atomic_long_read(&sdp->srcu_ctrs[!idx].srcu_unlocks));
  2059				u1 = data_race(atomic_long_read(&sdp->srcu_ctrs[idx].srcu_unlocks));
  2060	
  2061				/*
  2062				 * Make sure that a lock is always counted if the corresponding
  2063				 * unlock is counted.
  2064				 */
  2065				smp_rmb();
  2066	
  2067				l0 = data_race(atomic_long_read(&sdp->srcu_ctrs[!idx].srcu_locks));
  2068				l1 = data_race(atomic_long_read(&sdp->srcu_ctrs[idx].srcu_locks));
  2069	
  2070				c0 = l0 - u0;
  2071				c1 = l1 - u1;
  2072				pr_cont(" %d(%ld,%ld %c)",
  2073					cpu, c0, c1,
  2074					"C."[rcu_segcblist_empty(&sdp->srcu_cblist)]);
  2075				s0 += c0;
  2076				s1 += c1;
  2077			}
  2078			pr_cont(" T(%ld,%ld)\n", s0, s1);
  2079		}
> 2080		if (SRCU_SIZING_IS_TORTURE() && ssp->srcu_reader_flavor != SRCU_READ_FLAVOR_ATOMIC)
  2081			srcu_transition_to_big(ssp);
  2082	}
  2083	EXPORT_SYMBOL_GPL(srcu_torture_stats_print);
  2084	

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