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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 02:39:48 +00:00
rcu: fix rcutorture behavior during reboot
Impact: fix very rare reboot hang Because rcutorture ignored all signals, it does not terminate in response to the signals sent at shutdown time. This can cause strange failures due to its continuing to make use of kernel function too late in the shutdown sequence. This patch therefore adds a shutdown notifier to rcutorture, causing it to shut down in response to a reboot or an orderly shutdown. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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parent
29cbda77a6
commit
343e9099c8
1 changed files with 56 additions and 10 deletions
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@ -39,6 +39,7 @@
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#include <linux/moduleparam.h>
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#include <linux/percpu.h>
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#include <linux/notifier.h>
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#include <linux/reboot.h>
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#include <linux/freezer.h>
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#include <linux/cpu.h>
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#include <linux/delay.h>
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@ -108,7 +109,6 @@ struct rcu_torture {
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int rtort_mbtest;
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};
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static int fullstop = 0; /* stop generating callbacks at test end. */
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static LIST_HEAD(rcu_torture_freelist);
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static struct rcu_torture *rcu_torture_current = NULL;
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static long rcu_torture_current_version = 0;
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@ -136,6 +136,30 @@ static int stutter_pause_test = 0;
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#endif
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int rcutorture_runnable = RCUTORTURE_RUNNABLE_INIT;
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#define FULLSTOP_SIGNALED 1 /* Bail due to signal. */
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#define FULLSTOP_CLEANUP 2 /* Orderly shutdown. */
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static int fullstop; /* stop generating callbacks at test end. */
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DEFINE_MUTEX(fullstop_mutex); /* protect fullstop transitions and */
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/* spawning of kthreads. */
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/*
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* Detect and respond to a signal-based shutdown.
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*/
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static int
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rcutorture_shutdown_notify(struct notifier_block *unused1,
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unsigned long unused2, void *unused3)
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{
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if (fullstop)
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return NOTIFY_DONE;
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if (signal_pending(current)) {
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mutex_lock(&fullstop_mutex);
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if (!ACCESS_ONCE(fullstop))
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fullstop = FULLSTOP_SIGNALED;
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mutex_unlock(&fullstop_mutex);
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}
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return NOTIFY_DONE;
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}
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/*
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* Allocate an element from the rcu_tortures pool.
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*/
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@ -199,11 +223,12 @@ rcu_random(struct rcu_random_state *rrsp)
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static void
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rcu_stutter_wait(void)
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{
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while (stutter_pause_test || !rcutorture_runnable)
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while ((stutter_pause_test || !rcutorture_runnable) && !fullstop) {
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if (rcutorture_runnable)
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schedule_timeout_interruptible(1);
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else
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schedule_timeout_interruptible(round_jiffies_relative(HZ));
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}
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}
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/*
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@ -599,7 +624,7 @@ rcu_torture_writer(void *arg)
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rcu_stutter_wait();
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} while (!kthread_should_stop() && !fullstop);
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VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping");
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while (!kthread_should_stop())
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while (!kthread_should_stop() && fullstop != FULLSTOP_SIGNALED)
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schedule_timeout_uninterruptible(1);
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return 0;
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}
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@ -624,7 +649,7 @@ rcu_torture_fakewriter(void *arg)
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} while (!kthread_should_stop() && !fullstop);
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VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task stopping");
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while (!kthread_should_stop())
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while (!kthread_should_stop() && fullstop != FULLSTOP_SIGNALED)
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schedule_timeout_uninterruptible(1);
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return 0;
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}
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@ -734,7 +759,7 @@ rcu_torture_reader(void *arg)
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VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping");
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if (irqreader && cur_ops->irqcapable)
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del_timer_sync(&t);
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while (!kthread_should_stop())
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while (!kthread_should_stop() && fullstop != FULLSTOP_SIGNALED)
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schedule_timeout_uninterruptible(1);
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return 0;
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}
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@ -831,7 +856,7 @@ rcu_torture_stats(void *arg)
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do {
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schedule_timeout_interruptible(stat_interval * HZ);
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rcu_torture_stats_print();
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} while (!kthread_should_stop());
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} while (!kthread_should_stop() && !fullstop);
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VERBOSE_PRINTK_STRING("rcu_torture_stats task stopping");
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return 0;
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}
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@ -899,7 +924,7 @@ rcu_torture_shuffle(void *arg)
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do {
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schedule_timeout_interruptible(shuffle_interval * HZ);
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rcu_torture_shuffle_tasks();
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} while (!kthread_should_stop());
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} while (!kthread_should_stop() && !fullstop);
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VERBOSE_PRINTK_STRING("rcu_torture_shuffle task stopping");
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return 0;
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}
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@ -914,10 +939,10 @@ rcu_torture_stutter(void *arg)
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do {
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schedule_timeout_interruptible(stutter * HZ);
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stutter_pause_test = 1;
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if (!kthread_should_stop())
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if (!kthread_should_stop() && !fullstop)
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schedule_timeout_interruptible(stutter * HZ);
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stutter_pause_test = 0;
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} while (!kthread_should_stop());
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} while (!kthread_should_stop() && !fullstop);
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VERBOSE_PRINTK_STRING("rcu_torture_stutter task stopping");
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return 0;
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}
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@ -934,12 +959,27 @@ rcu_torture_print_module_parms(char *tag)
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stutter, irqreader);
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}
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static struct notifier_block rcutorture_nb = {
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.notifier_call = rcutorture_shutdown_notify,
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};
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static void
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rcu_torture_cleanup(void)
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{
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int i;
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fullstop = 1;
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mutex_lock(&fullstop_mutex);
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if (!fullstop) {
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/* If being signaled, let it happen, then exit. */
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mutex_unlock(&fullstop_mutex);
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schedule_timeout_interruptible(10 * HZ);
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if (cur_ops->cb_barrier != NULL)
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cur_ops->cb_barrier();
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return;
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}
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fullstop = FULLSTOP_CLEANUP;
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mutex_unlock(&fullstop_mutex);
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unregister_reboot_notifier(&rcutorture_nb);
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if (stutter_task) {
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VERBOSE_PRINTK_STRING("Stopping rcu_torture_stutter task");
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kthread_stop(stutter_task);
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@ -1015,6 +1055,8 @@ rcu_torture_init(void)
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{ &rcu_ops, &rcu_sync_ops, &rcu_bh_ops, &rcu_bh_sync_ops,
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&srcu_ops, &sched_ops, &sched_ops_sync, };
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mutex_lock(&fullstop_mutex);
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/* Process args and tell the world that the torturer is on the job. */
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for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
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cur_ops = torture_ops[i];
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@ -1024,6 +1066,7 @@ rcu_torture_init(void)
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if (i == ARRAY_SIZE(torture_ops)) {
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printk(KERN_ALERT "rcutorture: invalid torture type: \"%s\"\n",
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torture_type);
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mutex_unlock(&fullstop_mutex);
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return (-EINVAL);
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}
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if (cur_ops->init)
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@ -1146,9 +1189,12 @@ rcu_torture_init(void)
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goto unwind;
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}
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}
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register_reboot_notifier(&rcutorture_nb);
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mutex_unlock(&fullstop_mutex);
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return 0;
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unwind:
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mutex_unlock(&fullstop_mutex);
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rcu_torture_cleanup();
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return firsterr;
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}
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