Merge branch 'freezer'

* freezer:
  af_unix: use freezable blocking calls in read
  sigtimedwait: use freezable blocking call
  nanosleep: use freezable blocking call
  futex: use freezable blocking call
  select: use freezable blocking call
  epoll: use freezable blocking call
  binder: use freezable blocking calls
  freezer: add new freezable helpers using freezer_do_not_count()
  freezer: convert freezable helpers to static inline where possible
  freezer: convert freezable helpers to freezer_do_not_count()
  freezer: skip waking up tasks with PF_FREEZER_SKIP set
  freezer: shorten freezer sleep time using exponential backoff
  lockdep: check that no locks held at freeze time
  lockdep: remove task argument from debug_check_no_locks_held
  freezer: add unsafe versions of freezable helpers for CIFS
  freezer: add unsafe versions of freezable helpers for NFS

drivers/staging/android/binder.c

@@ -20,6 +20,7 @@
 #include <asm/cacheflush.h>
 #include <linux/fdtable.h>
 #include <linux/file.h>
+#include <linux/freezer.h>
 #include <linux/fs.h>
 #include <linux/list.h>
 #include <linux/miscdevice.h>
@@ -2140,13 +2141,13 @@ retry:
 			if (!binder_has_proc_work(proc, thread))
 				ret = -EAGAIN;
 		} else
-			ret = wait_event_interruptible_exclusive(proc->wait, binder_has_proc_work(proc, thread));
+			ret = wait_event_freezable_exclusive(proc->wait, binder_has_proc_work(proc, thread));
 	} else {
 		if (non_block) {
 			if (!binder_has_thread_work(thread))
 				ret = -EAGAIN;
 		} else
-			ret = wait_event_interruptible(thread->wait, binder_has_thread_work(thread));
+			ret = wait_event_freezable(thread->wait, binder_has_thread_work(thread));
 	}
 
 	binder_lock(__func__);

fs/cifs/transport.c

@@ -447,7 +447,7 @@ wait_for_response(struct TCP_Server_Info *server, struct mid_q_entry *midQ)
 {
 	int error;
 
-	error = wait_event_freezekillable(server->response_q,
+	error = wait_event_freezekillable_unsafe(server->response_q,
 				    midQ->mid_state != MID_REQUEST_SUBMITTED);
 	if (error < 0)
 		return -ERESTARTSYS;

fs/eventpoll.c

@@ -34,6 +34,7 @@
 #include <linux/mutex.h>
 #include <linux/anon_inodes.h>
 #include <linux/device.h>
+#include <linux/freezer.h>
 #include <asm/uaccess.h>
 #include <asm/io.h>
 #include <asm/mman.h>
@@ -1602,7 +1603,8 @@ fetch_events:
 			}
 
 			spin_unlock_irqrestore(&ep->lock, flags);
-			if (!schedule_hrtimeout_range(to, slack, HRTIMER_MODE_ABS))
+			if (!freezable_schedule_hrtimeout_range(to, slack,
+								HRTIMER_MODE_ABS))
 				timed_out = 1;
 
 			spin_lock_irqsave(&ep->lock, flags);

fs/nfs/inode.c

@@ -79,7 +79,7 @@ int nfs_wait_bit_killable(void *word)
 {
 	if (fatal_signal_pending(current))
 		return -ERESTARTSYS;
-	freezable_schedule();
+	freezable_schedule_unsafe();
 	return 0;
 }
 EXPORT_SYMBOL_GPL(nfs_wait_bit_killable);

fs/nfs/nfs3proc.c

@@ -33,7 +33,7 @@ nfs3_rpc_wrapper(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
 		res = rpc_call_sync(clnt, msg, flags);
 		if (res != -EJUKEBOX)
 			break;
-		freezable_schedule_timeout_killable(NFS_JUKEBOX_RETRY_TIME);
+		freezable_schedule_timeout_killable_unsafe(NFS_JUKEBOX_RETRY_TIME);
 		res = -ERESTARTSYS;
 	} while (!fatal_signal_pending(current));
 	return res;

fs/nfs/nfs4proc.c

@@ -268,7 +268,7 @@ static int nfs4_delay(struct rpc_clnt *clnt, long *timeout)
 		*timeout = NFS4_POLL_RETRY_MIN;
 	if (*timeout > NFS4_POLL_RETRY_MAX)
 		*timeout = NFS4_POLL_RETRY_MAX;
-	freezable_schedule_timeout_killable(*timeout);
+	freezable_schedule_timeout_killable_unsafe(*timeout);
 	if (fatal_signal_pending(current))
 		res = -ERESTARTSYS;
 	*timeout <<= 1;
@@ -4528,7 +4528,7 @@ int nfs4_proc_delegreturn(struct inode *inode, struct rpc_cred *cred, const nfs4
 static unsigned long
 nfs4_set_lock_task_retry(unsigned long timeout)
 {
-	freezable_schedule_timeout_killable(timeout);
+	freezable_schedule_timeout_killable_unsafe(timeout);
 	timeout <<= 1;
 	if (timeout > NFS4_LOCK_MAXTIMEOUT)
 		return NFS4_LOCK_MAXTIMEOUT;

fs/select.c

@@ -27,6 +27,7 @@
 #include <linux/rcupdate.h>
 #include <linux/hrtimer.h>
 #include <linux/sched/rt.h>
+#include <linux/freezer.h>
 
 #include <asm/uaccess.h>
 
@@ -236,7 +237,8 @@ int poll_schedule_timeout(struct poll_wqueues *pwq, int state,
 
 	set_current_state(state);
 	if (!pwq->triggered)
-		rc = schedule_hrtimeout_range(expires, slack, HRTIMER_MODE_ABS);
+		rc = freezable_schedule_hrtimeout_range(expires, slack,
+							HRTIMER_MODE_ABS);
 	__set_current_state(TASK_RUNNING);
 
 	/*

include/linux/debug_locks.h

@@ -51,7 +51,7 @@ struct task_struct;
 extern void debug_show_all_locks(void);
 extern void debug_show_held_locks(struct task_struct *task);
 extern void debug_check_no_locks_freed(const void *from, unsigned long len);
-extern void debug_check_no_locks_held(struct task_struct *task);
+extern void debug_check_no_locks_held(void);
 #else
 static inline void debug_show_all_locks(void)
 {
@@ -67,7 +67,7 @@ debug_check_no_locks_freed(const void *from, unsigned long len)
 }
 
 static inline void
-debug_check_no_locks_held(struct task_struct *task)
+debug_check_no_locks_held(void)
 {
 }
 #endif

include/linux/freezer.h

@@ -3,6 +3,7 @@
 #ifndef FREEZER_H_INCLUDED
 #define FREEZER_H_INCLUDED
 
+#include <linux/debug_locks.h>
 #include <linux/sched.h>
 #include <linux/wait.h>
 #include <linux/atomic.h>
@@ -46,7 +47,11 @@ extern int freeze_kernel_threads(void);
 extern void thaw_processes(void);
 extern void thaw_kernel_threads(void);
 
-static inline bool try_to_freeze(void)
+/*
+ * DO NOT ADD ANY NEW CALLERS OF THIS FUNCTION
+ * If try_to_freeze causes a lockdep warning it means the caller may deadlock
+ */
+static inline bool try_to_freeze_unsafe(void)
 {
 	might_sleep();
 	if (likely(!freezing(current)))
@@ -54,6 +59,13 @@ static inline bool try_to_freeze(void)
 	return __refrigerator(false);
 }
 
+static inline bool try_to_freeze(void)
+{
+	if (!(current->flags & PF_NOFREEZE))
+		debug_check_no_locks_held();
+	return try_to_freeze_unsafe();
+}
+
 extern bool freeze_task(struct task_struct *p);
 extern bool set_freezable(void);
 
@@ -115,6 +127,14 @@ static inline void freezer_count(void)
 	try_to_freeze();
 }
 
+/* DO NOT ADD ANY NEW CALLERS OF THIS FUNCTION */
+static inline void freezer_count_unsafe(void)
+{
+	current->flags &= ~PF_FREEZER_SKIP;
+	smp_mb();
+	try_to_freeze_unsafe();
+}
+
 /**
  * freezer_should_skip - whether to skip a task when determining frozen
  *			 state is reached
@@ -139,28 +159,86 @@ static inline bool freezer_should_skip(struct task_struct *p)
 }
 
 /*
- * These macros are intended to be used whenever you want allow a sleeping
+ * These functions are intended to be used whenever you want allow a sleeping
  * task to be frozen. Note that neither return any clear indication of
  * whether a freeze event happened while in this function.
  */
 
 /* Like schedule(), but should not block the freezer. */
-#define freezable_schedule()						\
-({									\
-	freezer_do_not_count();						\
-	schedule();							\
-	freezer_count();						\
-})
+static inline void freezable_schedule(void)
+{
+	freezer_do_not_count();
+	schedule();
+	freezer_count();
+}
+
+/* DO NOT ADD ANY NEW CALLERS OF THIS FUNCTION */
+static inline void freezable_schedule_unsafe(void)
+{
+	freezer_do_not_count();
+	schedule();
+	freezer_count_unsafe();
+}
+
+/*
+ * Like freezable_schedule_timeout(), but should not block the freezer.  Do not
+ * call this with locks held.
+ */
+static inline long freezable_schedule_timeout(long timeout)
+{
+	long __retval;
+	freezer_do_not_count();
+	__retval = schedule_timeout(timeout);
+	freezer_count();
+	return __retval;
+}
+
+/*
+ * Like schedule_timeout_interruptible(), but should not block the freezer.  Do not
+ * call this with locks held.
+ */
+static inline long freezable_schedule_timeout_interruptible(long timeout)
+{
+	long __retval;
+	freezer_do_not_count();
+	__retval = schedule_timeout_interruptible(timeout);
+	freezer_count();
+	return __retval;
+}
 
 /* Like schedule_timeout_killable(), but should not block the freezer. */
-#define freezable_schedule_timeout_killable(timeout)			\
-({									\
-	long __retval;							\
-	freezer_do_not_count();						\
-	__retval = schedule_timeout_killable(timeout);			\
-	freezer_count();						\
-	__retval;							\
-})
+static inline long freezable_schedule_timeout_killable(long timeout)
+{
+	long __retval;
+	freezer_do_not_count();
+	__retval = schedule_timeout_killable(timeout);
+	freezer_count();
+	return __retval;
+}
+
+/* DO NOT ADD ANY NEW CALLERS OF THIS FUNCTION */
+static inline long freezable_schedule_timeout_killable_unsafe(long timeout)
+{
+	long __retval;
+	freezer_do_not_count();
+	__retval = schedule_timeout_killable(timeout);
+	freezer_count_unsafe();
+	return __retval;
+}
+
+/*
+ * Like schedule_hrtimeout_range(), but should not block the freezer.  Do not
+ * call this with locks held.
+ */
+static inline int freezable_schedule_hrtimeout_range(ktime_t *expires,
+		unsigned long delta, const enum hrtimer_mode mode)
+{
+	int __retval;
+	freezer_do_not_count();
+	__retval = schedule_hrtimeout_range(expires, delta, mode);
+	freezer_count();
+	return __retval;
+}
 
 /*
  * Freezer-friendly wrappers around wait_event_interruptible(),
@@ -177,33 +255,45 @@ static inline bool freezer_should_skip(struct task_struct *p)
 	__retval;							\
 })
 
+/* DO NOT ADD ANY NEW CALLERS OF THIS FUNCTION */
+#define wait_event_freezekillable_unsafe(wq, condition)			\
+({									\
+	int __retval;							\
+	freezer_do_not_count();						\
+	__retval = wait_event_killable(wq, (condition));		\
+	freezer_count_unsafe();						\
+	__retval;							\
+})
+
 #define wait_event_freezable(wq, condition)				\
 ({									\
 	int __retval;							\
-	for (;;) {							\
-		__retval = wait_event_interruptible(wq, 		\
-				(condition) || freezing(current));	\
-		if (__retval || (condition))				\
-			break;						\
-		try_to_freeze();					\
-	}								\
+	freezer_do_not_count();						\
+	__retval = wait_event_interruptible(wq, (condition));		\
+	freezer_count();						\
 	__retval;							\
 })
 
 #define wait_event_freezable_timeout(wq, condition, timeout)		\
 ({									\
 	long __retval = timeout;					\
-	for (;;) {							\
-		__retval = wait_event_interruptible_timeout(wq,		\
-				(condition) || freezing(current),	\
+	freezer_do_not_count();						\
+	__retval = wait_event_interruptible_timeout(wq,	(condition),	\
 				__retval);				\
-		if (__retval <= 0 || (condition))			\
-			break;						\
-		try_to_freeze();					\
-	}								\
+	freezer_count();						\
 	__retval;							\
 })
 
+#define wait_event_freezable_exclusive(wq, condition)			\
+({									\
+	int __retval;							\
+	freezer_do_not_count();						\
+	__retval = wait_event_interruptible_exclusive(wq, condition);	\
+	freezer_count();						\
+	__retval;							\
+})
+
+
 #else /* !CONFIG_FREEZER */
 static inline bool frozen(struct task_struct *p) { return false; }
 static inline bool freezing(struct task_struct *p) { return false; }
@@ -225,18 +315,37 @@ static inline void set_freezable(void) {}
 
 #define freezable_schedule()  schedule()
 
+#define freezable_schedule_unsafe()  schedule()
+
+#define freezable_schedule_timeout(timeout)  schedule_timeout(timeout)
+
+#define freezable_schedule_timeout_interruptible(timeout)		\
+	schedule_timeout_interruptible(timeout)
+
 #define freezable_schedule_timeout_killable(timeout)			\
 	schedule_timeout_killable(timeout)
 
+#define freezable_schedule_timeout_killable_unsafe(timeout)		\
+	schedule_timeout_killable(timeout)
+
+#define freezable_schedule_hrtimeout_range(expires, delta, mode)	\
+	schedule_hrtimeout_range(expires, delta, mode)
+
 #define wait_event_freezable(wq, condition)				\
 		wait_event_interruptible(wq, condition)
 
 #define wait_event_freezable_timeout(wq, condition, timeout)		\
 		wait_event_interruptible_timeout(wq, condition, timeout)
 
+#define wait_event_freezable_exclusive(wq, condition)			\
+		wait_event_interruptible_exclusive(wq, condition)
+
 #define wait_event_freezekillable(wq, condition)		\
 		wait_event_killable(wq, condition)
 
+#define wait_event_freezekillable_unsafe(wq, condition)			\
+		wait_event_killable(wq, condition)
+
 #endif /* !CONFIG_FREEZER */
 
 #endif	/* FREEZER_H_INCLUDED */

kernel/exit.c

@@ -835,7 +835,7 @@ void do_exit(long code)
 	/*
 	 * Make sure we are holding no locks:
 	 */
-	debug_check_no_locks_held(tsk);
+	debug_check_no_locks_held();
 	/*
 	 * We can do this unlocked here. The futex code uses this flag
 	 * just to verify whether the pi state cleanup has been done

kernel/freezer.c

@@ -110,6 +110,18 @@ bool freeze_task(struct task_struct *p)
 {
 	unsigned long flags;
 
+	/*
+	 * This check can race with freezer_do_not_count, but worst case that
+	 * will result in an extra wakeup being sent to the task.  It does not
+	 * race with freezer_count(), the barriers in freezer_count() and
+	 * freezer_should_skip() ensure that either freezer_count() sees
+	 * freezing == true in try_to_freeze() and freezes, or
+	 * freezer_should_skip() sees !PF_FREEZE_SKIP and freezes the task
+	 * normally.
+	 */
+	if (freezer_should_skip(p))
+		return false;
+
 	spin_lock_irqsave(&freezer_lock, flags);
 	if (!freezing(p) || frozen(p)) {
 		spin_unlock_irqrestore(&freezer_lock, flags);

kernel/futex.c

@@ -61,6 +61,7 @@
 #include <linux/nsproxy.h>
 #include <linux/ptrace.h>
 #include <linux/sched/rt.h>
+#include <linux/freezer.h>
 
 #include <asm/futex.h>
 
@@ -1807,7 +1808,7 @@ static void futex_wait_queue_me(struct futex_hash_bucket *hb, struct futex_q *q,
 		 * is no timeout, or if it has yet to expire.
 		 */
 		if (!timeout || timeout->task)
-			schedule();
+			freezable_schedule();
 	}
 	__set_current_state(TASK_RUNNING);
 }

kernel/hrtimer.c

@@ -47,6 +47,7 @@
 #include <linux/sched/sysctl.h>
 #include <linux/sched/rt.h>
 #include <linux/timer.h>
+#include <linux/freezer.h>
 
 #include <asm/uaccess.h>
 
@@ -1545,7 +1546,7 @@ static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mod
 			t->task = NULL;
 
 		if (likely(t->task))
-			schedule();
+			freezable_schedule();
 
 		hrtimer_cancel(&t->timer);
 		mode = HRTIMER_MODE_ABS;

kernel/lockdep.c

@@ -4090,7 +4090,7 @@ void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len)
 }
 EXPORT_SYMBOL_GPL(debug_check_no_locks_freed);
 
-static void print_held_locks_bug(struct task_struct *curr)
+static void print_held_locks_bug(void)
 {
 	if (!debug_locks_off())
 		return;
@@ -4099,22 +4099,21 @@ static void print_held_locks_bug(struct task_struct *curr)
 
 	printk("\n");
 	printk("=====================================\n");
-	printk("[ BUG: lock held at task exit time! ]\n");
+	printk("[ BUG: %s/%d still has locks held! ]\n",
+	       current->comm, task_pid_nr(current));
 	print_kernel_ident();
 	printk("-------------------------------------\n");
-	printk("%s/%d is exiting with locks still held!\n",
-		curr->comm, task_pid_nr(curr));
-	lockdep_print_held_locks(curr);
-
+	lockdep_print_held_locks(current);
 	printk("\nstack backtrace:\n");
 	dump_stack();
 }
 
-void debug_check_no_locks_held(struct task_struct *task)
+void debug_check_no_locks_held(void)
 {
-	if (unlikely(task->lockdep_depth > 0))
-		print_held_locks_bug(task);
+	if (unlikely(current->lockdep_depth > 0))
+		print_held_locks_bug();
 }
+EXPORT_SYMBOL_GPL(debug_check_no_locks_held);
 
 void debug_show_all_locks(void)
 {

kernel/power/process.c

@@ -30,9 +30,10 @@ static int try_to_freeze_tasks(bool user_only)
 	unsigned int todo;
 	bool wq_busy = false;
 	struct timeval start, end;
-	u64 elapsed_csecs64;
-	unsigned int elapsed_csecs;
+	u64 elapsed_msecs64;
+	unsigned int elapsed_msecs;
 	bool wakeup = false;
+	int sleep_usecs = USEC_PER_MSEC;
 
 	do_gettimeofday(&start);
 
@@ -68,22 +69,25 @@ static int try_to_freeze_tasks(bool user_only)
 
 		/*
 		 * We need to retry, but first give the freezing tasks some
-		 * time to enter the refrigerator.
+		 * time to enter the refrigerator.  Start with an initial
+		 * 1 ms sleep followed by exponential backoff until 8 ms.
 		 */
-		msleep(10);
+		usleep_range(sleep_usecs / 2, sleep_usecs);
+		if (sleep_usecs < 8 * USEC_PER_MSEC)
+			sleep_usecs *= 2;
 	}
 
 	do_gettimeofday(&end);
-	elapsed_csecs64 = timeval_to_ns(&end) - timeval_to_ns(&start);
-	do_div(elapsed_csecs64, NSEC_PER_SEC / 100);
-	elapsed_csecs = elapsed_csecs64;
+	elapsed_msecs64 = timeval_to_ns(&end) - timeval_to_ns(&start);
+	do_div(elapsed_msecs64, NSEC_PER_MSEC);
+	elapsed_msecs = elapsed_msecs64;
 
 	if (todo) {
 		printk("\n");
-		printk(KERN_ERR "Freezing of tasks %s after %d.%02d seconds "
+		printk(KERN_ERR "Freezing of tasks %s after %d.%03d seconds "
 		       "(%d tasks refusing to freeze, wq_busy=%d):\n",
 		       wakeup ? "aborted" : "failed",
-		       elapsed_csecs / 100, elapsed_csecs % 100,
+		       elapsed_msecs / 1000, elapsed_msecs % 1000,
 		       todo - wq_busy, wq_busy);
 
 		if (!wakeup) {
@@ -96,8 +100,8 @@ static int try_to_freeze_tasks(bool user_only)
 			read_unlock(&tasklist_lock);
 		}
 	} else {
-		printk("(elapsed %d.%02d seconds) ", elapsed_csecs / 100,
-			elapsed_csecs % 100);
+		printk("(elapsed %d.%03d seconds) ", elapsed_msecs / 1000,
+			elapsed_msecs % 1000);
 	}
 
 	return todo ? -EBUSY : 0;

kernel/signal.c

@@ -2848,7 +2848,7 @@ int do_sigtimedwait(const sigset_t *which, siginfo_t *info,
 		recalc_sigpending();
 		spin_unlock_irq(&tsk->sighand->siglock);
 
-		timeout = schedule_timeout_interruptible(timeout);
+		timeout = freezable_schedule_timeout_interruptible(timeout);
 
 		spin_lock_irq(&tsk->sighand->siglock);
 		__set_task_blocked(tsk, &tsk->real_blocked);

net/sunrpc/sched.c

@@ -254,7 +254,7 @@ static int rpc_wait_bit_killable(void *word)
 {
 	if (fatal_signal_pending(current))
 		return -ERESTARTSYS;
-	freezable_schedule();
+	freezable_schedule_unsafe();
 	return 0;
 }
 

net/unix/af_unix.c

@@ -114,6 +114,7 @@
 #include <linux/mount.h>
 #include <net/checksum.h>
 #include <linux/security.h>
+#include <linux/freezer.h>
 
 struct hlist_head unix_socket_table[2 * UNIX_HASH_SIZE];
 EXPORT_SYMBOL_GPL(unix_socket_table);
@@ -1879,7 +1880,7 @@ static long unix_stream_data_wait(struct sock *sk, long timeo,
 
 		set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
 		unix_state_unlock(sk);
-		timeo = schedule_timeout(timeo);
+		timeo = freezable_schedule_timeout(timeo);
 		unix_state_lock(sk);
 		clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
 	}