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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2014-01-31 17:37:28 -0800
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2014-02-23 09:03:21 -0800
commit7fafaac5b9ce22cc57777865390520476ad2262d (patch)
treec857b24b21d277b45803878af0715c817fb4716a /kernel/rcu
parent14562d1cf12b434da2c69b5603a4149ac43f3b48 (diff)
rcutorture: Fix rcutorture shutdown races
Not all of the rcutorture kthreads waited for kthread_should_stop() before returning from their top-level functions, and none of them used torture_shutdown_absorb() properly. These problems can result in segfaults and hangs at shutdown time, and some recent changes perturbed timing sufficiently to make them much more probable. This commit therefore creates a torture_kthread_stopping() function that does the proper kthread shutdown dance in one centralized location. Accommodate this grouping by making VERBOSE_TOROUT_STRING() capable of taking a non-const string as its argument, which allows the new torture_kthread_stopping() to pass its "title" argument directly to the updated version of VERBOSE_TOROUT_STRING(). Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcu')
-rw-r--r--kernel/rcu/rcutorture.c39
1 files changed, 11 insertions, 28 deletions
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 6e9ba51b23b9..bcaafd6cf633 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -602,12 +602,13 @@ checkwait: stutter_wait("rcu_torture_boost");
} while (!torture_must_stop());
/* Clean up and exit. */
- VERBOSE_TOROUT_STRING("rcu_torture_boost task stopping");
- torture_shutdown_absorb("rcu_torture_boost");
- while (!kthread_should_stop() || rbi.inflight)
+ while (!kthread_should_stop() || rbi.inflight) {
+ torture_shutdown_absorb("rcu_torture_boost");
schedule_timeout_uninterruptible(1);
+ }
smp_mb(); /* order accesses to ->inflight before stack-frame death. */
destroy_rcu_head_on_stack(&rbi.rcu);
+ torture_kthread_stopping("rcu_torture_boost");
return 0;
}
@@ -638,10 +639,7 @@ rcu_torture_fqs(void *arg)
}
stutter_wait("rcu_torture_fqs");
} while (!torture_must_stop());
- VERBOSE_TOROUT_STRING("rcu_torture_fqs task stopping");
- torture_shutdown_absorb("rcu_torture_fqs");
- while (!kthread_should_stop())
- schedule_timeout_uninterruptible(1);
+ torture_kthread_stopping("rcu_torture_fqs");
return 0;
}
@@ -710,10 +708,7 @@ rcu_torture_writer(void *arg)
rcutorture_record_progress(++rcu_torture_current_version);
stutter_wait("rcu_torture_writer");
} while (!torture_must_stop());
- VERBOSE_TOROUT_STRING("rcu_torture_writer task stopping");
- torture_shutdown_absorb("rcu_torture_writer");
- while (!kthread_should_stop())
- schedule_timeout_uninterruptible(1);
+ torture_kthread_stopping("rcu_torture_writer");
return 0;
}
@@ -748,10 +743,7 @@ rcu_torture_fakewriter(void *arg)
stutter_wait("rcu_torture_fakewriter");
} while (!torture_must_stop());
- VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task stopping");
- torture_shutdown_absorb("rcu_torture_fakewriter");
- while (!kthread_should_stop())
- schedule_timeout_uninterruptible(1);
+ torture_kthread_stopping("rcu_torture_fakewriter");
return 0;
}
@@ -892,12 +884,9 @@ rcu_torture_reader(void *arg)
schedule();
stutter_wait("rcu_torture_reader");
} while (!torture_must_stop());
- VERBOSE_TOROUT_STRING("rcu_torture_reader task stopping");
- torture_shutdown_absorb("rcu_torture_reader");
if (irqreader && cur_ops->irq_capable)
del_timer_sync(&t);
- while (!kthread_should_stop())
- schedule_timeout_uninterruptible(1);
+ torture_kthread_stopping("rcu_torture_reader");
return 0;
}
@@ -1010,7 +999,7 @@ rcu_torture_stats(void *arg)
rcu_torture_stats_print();
torture_shutdown_absorb("rcu_torture_stats");
} while (!torture_must_stop());
- VERBOSE_TOROUT_STRING("rcu_torture_stats task stopping");
+ torture_kthread_stopping("rcu_torture_stats");
return 0;
}
@@ -1171,12 +1160,9 @@ static int rcu_torture_barrier_cbs(void *arg)
if (atomic_dec_and_test(&barrier_cbs_count))
wake_up(&barrier_wq);
} while (!torture_must_stop());
- VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task stopping");
- torture_shutdown_absorb("rcu_torture_barrier_cbs");
- while (!kthread_should_stop())
- schedule_timeout_interruptible(1);
cur_ops->cb_barrier();
destroy_rcu_head_on_stack(&rcu);
+ torture_kthread_stopping("rcu_torture_barrier_cbs");
return 0;
}
@@ -1207,10 +1193,7 @@ static int rcu_torture_barrier(void *arg)
n_barrier_successes++;
schedule_timeout_interruptible(HZ / 10);
} while (!torture_must_stop());
- VERBOSE_TOROUT_STRING("rcu_torture_barrier task stopping");
- torture_shutdown_absorb("rcu_torture_barrier");
- while (!kthread_should_stop())
- schedule_timeout_interruptible(1);
+ torture_kthread_stopping("rcu_torture_barrier");
return 0;
}