1 files changed, 68 insertions, 45 deletions

diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c
index 1cff28db56b6..7c4142a79f0a 100644
--- a/kernel/rcutorture.c
+++ b/kernel/rcutorture.c
@@ -136,29 +136,47 @@ static int stutter_pause_test = 0;
 #endif
 int rcutorture_runnable = RCUTORTURE_RUNNABLE_INIT;
 
-#define FULLSTOP_SHUTDOWN 1     /* Bail due to system shutdown/panic. */
-#define FULLSTOP_CLEANUP  2     /* Orderly shutdown. */
-static int fullstop;            /* stop generating callbacks at test end. */
-DEFINE_MUTEX(fullstop_mutex);   /* protect fullstop transitions and */
-                                /*  spawning of kthreads. */
+/* Mediate rmmod and system shutdown.  Concurrent rmmod & shutdown illegal! */
+
+#define FULLSTOP_DONTSTOP 0     /* Normal operation. */
+#define FULLSTOP_SHUTDOWN 1     /* System shutdown with rcutorture running. */
+#define FULLSTOP_RMMOD    2     /* Normal rmmod of rcutorture. */
+static int fullstop = FULLSTOP_RMMOD;
+DEFINE_MUTEX(fullstop_mutex);   /* Protect fullstop transitions and spawning */
+                                /*  of kthreads. */
 
 /*
- * Detect and respond to a signal-based shutdown.
+ * Detect and respond to a system shutdown.
  */
 static int
 rcutorture_shutdown_notify(struct notifier_block *unused1,
                            unsigned long unused2, void *unused3)
 {
-        if (fullstop)
-                return NOTIFY_DONE;
         mutex_lock(&fullstop_mutex);
-        if (!fullstop)
+        if (fullstop == FULLSTOP_DONTSTOP)
                 fullstop = FULLSTOP_SHUTDOWN;
+        else
+                printk(KERN_WARNING /* but going down anyway, so... */
+                       "Concurrent 'rmmod rcutorture' and shutdown illegal!\n");
         mutex_unlock(&fullstop_mutex);
         return NOTIFY_DONE;
 }
 
 /*
+ * Absorb kthreads into a kernel function that won't return, so that
+ * they won't ever access module text or data again.
+ */
+static void rcutorture_shutdown_absorb(char *title)
+{
+        if (ACCESS_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
+                printk(KERN_NOTICE
+                       "rcutorture thread %s parking due to system shutdown\n",
+                       title);
+                schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT);
+        }
+}
+
+/*
  * Allocate an element from the rcu_tortures pool.
  */
 static struct rcu_torture *
@@ -219,13 +237,14 @@ rcu_random(struct rcu_random_state *rrsp)
 }
 
 static void
-rcu_stutter_wait(void)
+rcu_stutter_wait(char *title)
 {
-        while ((stutter_pause_test || !rcutorture_runnable) && !fullstop) {
+        while (stutter_pause_test || !rcutorture_runnable) {
                 if (rcutorture_runnable)
                         schedule_timeout_interruptible(1);
                 else
                         schedule_timeout_interruptible(round_jiffies_relative(HZ));
+                rcutorture_shutdown_absorb(title);
         }
 }
 
@@ -287,7 +306,7 @@ rcu_torture_cb(struct rcu_head *p)
         int i;
         struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
 
-        if (fullstop) {
+        if (fullstop != FULLSTOP_DONTSTOP) {
                 /* Test is ending, just drop callbacks on the floor. */
                 /* The next initialization will pick up the pieces. */
                 return;
@@ -619,10 +638,11 @@ rcu_torture_writer(void *arg)
                 }
                 rcu_torture_current_version++;
                 oldbatch = cur_ops->completed();
-                rcu_stutter_wait();
-        } while (!kthread_should_stop() && !fullstop);
+                rcu_stutter_wait("rcu_torture_writer");
+        } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
         VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping");
-        while (!kthread_should_stop() && fullstop != FULLSTOP_SHUTDOWN)
+        rcutorture_shutdown_absorb("rcu_torture_writer");
+        while (!kthread_should_stop())
                 schedule_timeout_uninterruptible(1);
         return 0;
 }
@@ -643,11 +663,12 @@ rcu_torture_fakewriter(void *arg)
                 schedule_timeout_uninterruptible(1 + rcu_random(&rand)%10);
                 udelay(rcu_random(&rand) & 0x3ff);
                 cur_ops->sync();
-                rcu_stutter_wait();
-        } while (!kthread_should_stop() && !fullstop);
+                rcu_stutter_wait("rcu_torture_fakewriter");
+        } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
 
         VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task stopping");
-        while (!kthread_should_stop() && fullstop != FULLSTOP_SHUTDOWN)
+        rcutorture_shutdown_absorb("rcu_torture_fakewriter");
+        while (!kthread_should_stop())
                 schedule_timeout_uninterruptible(1);
         return 0;
 }
@@ -752,12 +773,13 @@ rcu_torture_reader(void *arg)
                 preempt_enable();
                 cur_ops->readunlock(idx);
                 schedule();
-                rcu_stutter_wait();
-        } while (!kthread_should_stop() && !fullstop);
+                rcu_stutter_wait("rcu_torture_reader");
+        } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
         VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping");
+        rcutorture_shutdown_absorb("rcu_torture_reader");
         if (irqreader && cur_ops->irqcapable)
                 del_timer_sync(&t);
-        while (!kthread_should_stop() && fullstop != FULLSTOP_SHUTDOWN)
+        while (!kthread_should_stop())
                 schedule_timeout_uninterruptible(1);
         return 0;
 }
@@ -854,7 +876,8 @@ rcu_torture_stats(void *arg)
         do {
                 schedule_timeout_interruptible(stat_interval * HZ);
                 rcu_torture_stats_print();
-        } while (!kthread_should_stop() && !fullstop);
+                rcutorture_shutdown_absorb("rcu_torture_stats");
+        } while (!kthread_should_stop());
         VERBOSE_PRINTK_STRING("rcu_torture_stats task stopping");
         return 0;
 }
@@ -866,52 +889,49 @@ static int rcu_idle_cpu;	/* Force all torture tasks off this CPU */
  */
 static void rcu_torture_shuffle_tasks(void)
 {
-        cpumask_var_t tmp_mask;
+        cpumask_t tmp_mask;
         int i;
 
-        if (!alloc_cpumask_var(&tmp_mask, GFP_KERNEL))
-                BUG();
-
-        cpumask_setall(tmp_mask);
+        cpus_setall(tmp_mask);
         get_online_cpus();
 
         /* No point in shuffling if there is only one online CPU (ex: UP) */
-        if (num_online_cpus() == 1)
-                goto out;
+        if (num_online_cpus() == 1) {
+                put_online_cpus();
+                return;
+        }
 
         if (rcu_idle_cpu != -1)
-                cpumask_clear_cpu(rcu_idle_cpu, tmp_mask);
+                cpu_clear(rcu_idle_cpu, tmp_mask);
 
-        set_cpus_allowed_ptr(current, tmp_mask);
+        set_cpus_allowed_ptr(current, &tmp_mask);
 
         if (reader_tasks) {
                 for (i = 0; i < nrealreaders; i++)
                         if (reader_tasks[i])
                                 set_cpus_allowed_ptr(reader_tasks[i],
-                                                     tmp_mask);
+                                                     &tmp_mask);
         }
 
         if (fakewriter_tasks) {
                 for (i = 0; i < nfakewriters; i++)
                         if (fakewriter_tasks[i])
                                 set_cpus_allowed_ptr(fakewriter_tasks[i],
-                                                     tmp_mask);
+                                                     &tmp_mask);
         }
 
         if (writer_task)
-                set_cpus_allowed_ptr(writer_task, tmp_mask);
+                set_cpus_allowed_ptr(writer_task, &tmp_mask);
 
         if (stats_task)
-                set_cpus_allowed_ptr(stats_task, tmp_mask);
+                set_cpus_allowed_ptr(stats_task, &tmp_mask);
 
         if (rcu_idle_cpu == -1)
                 rcu_idle_cpu = num_online_cpus() - 1;
         else
                 rcu_idle_cpu--;
 
-out:
         put_online_cpus();
-        free_cpumask_var(tmp_mask);
 }
 
 /* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
@@ -925,7 +945,8 @@ rcu_torture_shuffle(void *arg)
         do {
                 schedule_timeout_interruptible(shuffle_interval * HZ);
                 rcu_torture_shuffle_tasks();
-        } while (!kthread_should_stop() && !fullstop);
+                rcutorture_shutdown_absorb("rcu_torture_shuffle");
+        } while (!kthread_should_stop());
         VERBOSE_PRINTK_STRING("rcu_torture_shuffle task stopping");
         return 0;
 }
@@ -940,10 +961,11 @@ rcu_torture_stutter(void *arg)
         do {
                 schedule_timeout_interruptible(stutter * HZ);
                 stutter_pause_test = 1;
-                if (!kthread_should_stop() && !fullstop)
+                if (!kthread_should_stop())
                         schedule_timeout_interruptible(stutter * HZ);
                 stutter_pause_test = 0;
-        } while (!kthread_should_stop() && !fullstop);
+                rcutorture_shutdown_absorb("rcu_torture_stutter");
+        } while (!kthread_should_stop());
         VERBOSE_PRINTK_STRING("rcu_torture_stutter task stopping");
         return 0;
 }
@@ -970,15 +992,16 @@ rcu_torture_cleanup(void)
         int i;
 
         mutex_lock(&fullstop_mutex);
-        if (!fullstop) {
-                /* If being signaled, let it happen, then exit. */
+        if (fullstop == FULLSTOP_SHUTDOWN) {
+                printk(KERN_WARNING /* but going down anyway, so... */
+                       "Concurrent 'rmmod rcutorture' and shutdown illegal!\n");
                 mutex_unlock(&fullstop_mutex);
-                schedule_timeout_interruptible(10 * HZ);
+                schedule_timeout_uninterruptible(10);
                 if (cur_ops->cb_barrier != NULL)
                         cur_ops->cb_barrier();
                 return;
         }
-        fullstop = FULLSTOP_CLEANUP;
+        fullstop = FULLSTOP_RMMOD;
         mutex_unlock(&fullstop_mutex);
         unregister_reboot_notifier(&rcutorture_nb);
         if (stutter_task) {
@@ -1078,7 +1101,7 @@ rcu_torture_init(void)
         else
                 nrealreaders = 2 * num_online_cpus();
         rcu_torture_print_module_parms("Start of test");
-        fullstop = 0;
+        fullstop = FULLSTOP_DONTSTOP;
 
         /* Set up the freelist. */