Hello Joel Fernandes (Google),
Commit 084e04fff160 ("rcuscale: Add laziness and kfree tests") from
Oct 16, 2022 (linux-next), leads to the following Smatch static
checker warning:
kernel/rcu/rcuscale.c:1215 rcu_scale_init()
warn: inconsistent returns 'global &fullstop_mutex'.
kernel/rcu/rcuscale.c
857 kfree_scale_init(void)
858 {
859 int firsterr = 0;
860 long i;
861 unsigned long jif_start;
862 unsigned long orig_jif;
863
864 pr_alert("%s" SCALE_FLAG
865 "--- kfree_rcu_test: kfree_mult=%d
kfree_by_call_rcu=%d kfree_nthreads=%d kfree_alloc_num=%d kfree_loops=%d
kfree_rcu_test_double=%d kfree_rcu_test_single=%d\n",
866 scale_type, kfree_mult, kfree_by_call_rcu,
kfree_nthreads, kfree_alloc_num, kfree_loops, kfree_rcu_test_double,
kfree_rcu_test_single);
867
868 // Also, do a quick self-test to ensure laziness is as much as
869 // expected.
870 if (kfree_by_call_rcu && !IS_ENABLED(CONFIG_RCU_LAZY)) {
871 pr_alert("CONFIG_RCU_LAZY is disabled, falling back to
kfree_rcu() for delayed RCU kfree'ing\n");
872 kfree_by_call_rcu = 0;
873 }
874
875 if (kfree_by_call_rcu) {
876 /* do a test to check the timeout. */
877 orig_jif = rcu_get_jiffies_lazy_flush();
878
879 rcu_set_jiffies_lazy_flush(2 * HZ);
880 rcu_barrier();
881
882 jif_start = jiffies;
883 jiffies_at_lazy_cb = 0;
884 call_rcu(&lazy_test1_rh, call_rcu_lazy_test1);
885
886 smp_cond_load_relaxed(&rcu_lazy_test1_cb_called, VAL ==
1);
887
888 rcu_set_jiffies_lazy_flush(orig_jif);
889
890 if (WARN_ON_ONCE(jiffies_at_lazy_cb - jif_start < 2 *
HZ)) {
891 pr_alert("ERROR: call_rcu() CBs are not being
lazy as expected!\n");
892 WARN_ON_ONCE(1);
893 return -1;
^^^^^^^^^^
894 }
895
896 if (WARN_ON_ONCE(jiffies_at_lazy_cb - jif_start > 3 *
HZ)) {
897 pr_alert("ERROR: call_rcu() CBs are being too
lazy!\n");
898 WARN_ON_ONCE(1);
899 return -1;
^^^^^^^^^^
The checker is complaining that we don't call torture_init_end(). Should these
do a goto unwind? Otherwise we're left holding the fullstop_mutex.
900 }
901 }
[ snip ]
938 unwind:
939 torture_init_end();
940 kfree_scale_cleanup();
941 return firsterr;
942 }
regards,
dan carpenter
