Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 426 insertions, 0 deletions

diff --git a/drivers/usb/host/ehci-timer.c b/drivers/usb/host/ehci-timer.c
new file mode 100644
index 000000000..a79c8ac0a
--- /dev/null
+++ b/drivers/usb/host/ehci-timer.c
@@ -0,0 +1,426 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2012 by Alan Stern
+ */
+
+/* This file is part of ehci-hcd.c */
+
+/*-------------------------------------------------------------------------*/
+
+/* Set a bit in the USBCMD register */
+static void ehci_set_command_bit(struct ehci_hcd *ehci, u32 bit)
+{
+	ehci->command |= bit;
+	ehci_writel(ehci, ehci->command, &ehci->regs->command);
+
+	/* unblock posted write */
+	ehci_readl(ehci, &ehci->regs->command);
+}
+
+/* Clear a bit in the USBCMD register */
+static void ehci_clear_command_bit(struct ehci_hcd *ehci, u32 bit)
+{
+	ehci->command &= ~bit;
+	ehci_writel(ehci, ehci->command, &ehci->regs->command);
+
+	/* unblock posted write */
+	ehci_readl(ehci, &ehci->regs->command);
+}
+
+/*-------------------------------------------------------------------------*/
+
+/*
+ * EHCI timer support...  Now using hrtimers.
+ *
+ * Lots of different events are triggered from ehci->hrtimer.  Whenever
+ * the timer routine runs, it checks each possible event; events that are
+ * currently enabled and whose expiration time has passed get handled.
+ * The set of enabled events is stored as a collection of bitflags in
+ * ehci->enabled_hrtimer_events, and they are numbered in order of
+ * increasing delay values (ranging between 1 ms and 100 ms).
+ *
+ * Rather than implementing a sorted list or tree of all pending events,
+ * we keep track only of the lowest-numbered pending event, in
+ * ehci->next_hrtimer_event.  Whenever ehci->hrtimer gets restarted, its
+ * expiration time is set to the timeout value for this event.
+ *
+ * As a result, events might not get handled right away; the actual delay
+ * could be anywhere up to twice the requested delay.  This doesn't
+ * matter, because none of the events are especially time-critical.  The
+ * ones that matter most all have a delay of 1 ms, so they will be
+ * handled after 2 ms at most, which is okay.  In addition to this, we
+ * allow for an expiration range of 1 ms.
+ */
+
+/*
+ * Delay lengths for the hrtimer event types.
+ * Keep this list sorted by delay length, in the same order as
+ * the event types indexed by enum ehci_hrtimer_event in ehci.h.
+ */
+static unsigned event_delays_ns[] = {
+	1 * NSEC_PER_MSEC,	/* EHCI_HRTIMER_POLL_ASS */
+	1 * NSEC_PER_MSEC,	/* EHCI_HRTIMER_POLL_PSS */
+	1 * NSEC_PER_MSEC,	/* EHCI_HRTIMER_POLL_DEAD */
+	1125 * NSEC_PER_USEC,	/* EHCI_HRTIMER_UNLINK_INTR */
+	2 * NSEC_PER_MSEC,	/* EHCI_HRTIMER_FREE_ITDS */
+	2 * NSEC_PER_MSEC,	/* EHCI_HRTIMER_ACTIVE_UNLINK */
+	5 * NSEC_PER_MSEC,	/* EHCI_HRTIMER_START_UNLINK_INTR */
+	6 * NSEC_PER_MSEC,	/* EHCI_HRTIMER_ASYNC_UNLINKS */
+	10 * NSEC_PER_MSEC,	/* EHCI_HRTIMER_IAA_WATCHDOG */
+	10 * NSEC_PER_MSEC,	/* EHCI_HRTIMER_DISABLE_PERIODIC */
+	15 * NSEC_PER_MSEC,	/* EHCI_HRTIMER_DISABLE_ASYNC */
+	100 * NSEC_PER_MSEC,	/* EHCI_HRTIMER_IO_WATCHDOG */
+};
+
+/* Enable a pending hrtimer event */
+static void ehci_enable_event(struct ehci_hcd *ehci, unsigned event,
+		bool resched)
+{
+	ktime_t		*timeout = &ehci->hr_timeouts[event];
+
+	if (resched)
+		*timeout = ktime_add(ktime_get(), event_delays_ns[event]);
+	ehci->enabled_hrtimer_events |= (1 << event);
+
+	/* Track only the lowest-numbered pending event */
+	if (event < ehci->next_hrtimer_event) {
+		ehci->next_hrtimer_event = event;
+		hrtimer_start_range_ns(&ehci->hrtimer, *timeout,
+				NSEC_PER_MSEC, HRTIMER_MODE_ABS);
+	}
+}
+
+
+/* Poll the STS_ASS status bit; see when it agrees with CMD_ASE */
+static void ehci_poll_ASS(struct ehci_hcd *ehci)
+{
+	unsigned	actual, want;
+
+	/* Don't enable anything if the controller isn't running (e.g., died) */
+	if (ehci->rh_state != EHCI_RH_RUNNING)
+		return;
+
+	want = (ehci->command & CMD_ASE) ? STS_ASS : 0;
+	actual = ehci_readl(ehci, &ehci->regs->status) & STS_ASS;
+
+	if (want != actual) {
+
+		/* Poll again later, but give up after about 2-4 ms */
+		if (ehci->ASS_poll_count++ < 2) {
+			ehci_enable_event(ehci, EHCI_HRTIMER_POLL_ASS, true);
+			return;
+		}
+		ehci_dbg(ehci, "Waited too long for the async schedule status (%x/%x), giving up\n",
+				want, actual);
+	}
+	ehci->ASS_poll_count = 0;
+
+	/* The status is up-to-date; restart or stop the schedule as needed */
+	if (want == 0) {	/* Stopped */
+		if (ehci->async_count > 0)
+			ehci_set_command_bit(ehci, CMD_ASE);
+
+	} else {		/* Running */
+		if (ehci->async_count == 0) {
+
+			/* Turn off the schedule after a while */
+			ehci_enable_event(ehci, EHCI_HRTIMER_DISABLE_ASYNC,
+					true);
+		}
+	}
+}
+
+/* Turn off the async schedule after a brief delay */
+static void ehci_disable_ASE(struct ehci_hcd *ehci)
+{
+	ehci_clear_command_bit(ehci, CMD_ASE);
+}
+
+
+/* Poll the STS_PSS status bit; see when it agrees with CMD_PSE */
+static void ehci_poll_PSS(struct ehci_hcd *ehci)
+{
+	unsigned	actual, want;
+
+	/* Don't do anything if the controller isn't running (e.g., died) */
+	if (ehci->rh_state != EHCI_RH_RUNNING)
+		return;
+
+	want = (ehci->command & CMD_PSE) ? STS_PSS : 0;
+	actual = ehci_readl(ehci, &ehci->regs->status) & STS_PSS;
+
+	if (want != actual) {
+
+		/* Poll again later, but give up after about 2-4 ms */
+		if (ehci->PSS_poll_count++ < 2) {
+			ehci_enable_event(ehci, EHCI_HRTIMER_POLL_PSS, true);
+			return;
+		}
+		ehci_dbg(ehci, "Waited too long for the periodic schedule status (%x/%x), giving up\n",
+				want, actual);
+	}
+	ehci->PSS_poll_count = 0;
+
+	/* The status is up-to-date; restart or stop the schedule as needed */
+	if (want == 0) {	/* Stopped */
+		if (ehci->periodic_count > 0)
+			ehci_set_command_bit(ehci, CMD_PSE);
+
+	} else {		/* Running */
+		if (ehci->periodic_count == 0) {
+
+			/* Turn off the schedule after a while */
+			ehci_enable_event(ehci, EHCI_HRTIMER_DISABLE_PERIODIC,
+					true);
+		}
+	}
+}
+
+/* Turn off the periodic schedule after a brief delay */
+static void ehci_disable_PSE(struct ehci_hcd *ehci)
+{
+	ehci_clear_command_bit(ehci, CMD_PSE);
+}
+
+
+/* Poll the STS_HALT status bit; see when a dead controller stops */
+static void ehci_handle_controller_death(struct ehci_hcd *ehci)
+{
+	if (!(ehci_readl(ehci, &ehci->regs->status) & STS_HALT)) {
+
+		/* Give up after a few milliseconds */
+		if (ehci->died_poll_count++ < 5) {
+			/* Try again later */
+			ehci_enable_event(ehci, EHCI_HRTIMER_POLL_DEAD, true);
+			return;
+		}
+		ehci_warn(ehci, "Waited too long for the controller to stop, giving up\n");
+	}
+
+	/* Clean up the mess */
+	ehci->rh_state = EHCI_RH_HALTED;
+	ehci_writel(ehci, 0, &ehci->regs->configured_flag);
+	ehci_writel(ehci, 0, &ehci->regs->intr_enable);
+	ehci_work(ehci);
+	end_unlink_async(ehci);
+
+	/* Not in process context, so don't try to reset the controller */
+}
+
+/* start to unlink interrupt QHs  */
+static void ehci_handle_start_intr_unlinks(struct ehci_hcd *ehci)
+{
+	bool		stopped = (ehci->rh_state < EHCI_RH_RUNNING);
+
+	/*
+	 * Process all the QHs on the intr_unlink list that were added
+	 * before the current unlink cycle began.  The list is in
+	 * temporal order, so stop when we reach the first entry in the
+	 * current cycle.  But if the root hub isn't running then
+	 * process all the QHs on the list.
+	 */
+	while (!list_empty(&ehci->intr_unlink_wait)) {
+		struct ehci_qh	*qh;
+
+		qh = list_first_entry(&ehci->intr_unlink_wait,
+				struct ehci_qh, unlink_node);
+		if (!stopped && (qh->unlink_cycle ==
+				ehci->intr_unlink_wait_cycle))
+			break;
+		list_del_init(&qh->unlink_node);
+		qh->unlink_reason |= QH_UNLINK_QUEUE_EMPTY;
+		start_unlink_intr(ehci, qh);
+	}
+
+	/* Handle remaining entries later */
+	if (!list_empty(&ehci->intr_unlink_wait)) {
+		ehci_enable_event(ehci, EHCI_HRTIMER_START_UNLINK_INTR, true);
+		++ehci->intr_unlink_wait_cycle;
+	}
+}
+
+/* Handle unlinked interrupt QHs once they are gone from the hardware */
+static void ehci_handle_intr_unlinks(struct ehci_hcd *ehci)
+{
+	bool		stopped = (ehci->rh_state < EHCI_RH_RUNNING);
+
+	/*
+	 * Process all the QHs on the intr_unlink list that were added
+	 * before the current unlink cycle began.  The list is in
+	 * temporal order, so stop when we reach the first entry in the
+	 * current cycle.  But if the root hub isn't running then
+	 * process all the QHs on the list.
+	 */
+	ehci->intr_unlinking = true;
+	while (!list_empty(&ehci->intr_unlink)) {
+		struct ehci_qh	*qh;
+
+		qh = list_first_entry(&ehci->intr_unlink, struct ehci_qh,
+				unlink_node);
+		if (!stopped && qh->unlink_cycle == ehci->intr_unlink_cycle)
+			break;
+		list_del_init(&qh->unlink_node);
+		end_unlink_intr(ehci, qh);
+	}
+
+	/* Handle remaining entries later */
+	if (!list_empty(&ehci->intr_unlink)) {
+		ehci_enable_event(ehci, EHCI_HRTIMER_UNLINK_INTR, true);
+		++ehci->intr_unlink_cycle;
+	}
+	ehci->intr_unlinking = false;
+}
+
+
+/* Start another free-iTDs/siTDs cycle */
+static void start_free_itds(struct ehci_hcd *ehci)
+{
+	if (!(ehci->enabled_hrtimer_events & BIT(EHCI_HRTIMER_FREE_ITDS))) {
+		ehci->last_itd_to_free = list_entry(
+				ehci->cached_itd_list.prev,
+				struct ehci_itd, itd_list);
+		ehci->last_sitd_to_free = list_entry(
+				ehci->cached_sitd_list.prev,
+				struct ehci_sitd, sitd_list);
+		ehci_enable_event(ehci, EHCI_HRTIMER_FREE_ITDS, true);
+	}
+}
+
+/* Wait for controller to stop using old iTDs and siTDs */
+static void end_free_itds(struct ehci_hcd *ehci)
+{
+	struct ehci_itd		*itd, *n;
+	struct ehci_sitd	*sitd, *sn;
+
+	if (ehci->rh_state < EHCI_RH_RUNNING) {
+		ehci->last_itd_to_free = NULL;
+		ehci->last_sitd_to_free = NULL;
+	}
+
+	list_for_each_entry_safe(itd, n, &ehci->cached_itd_list, itd_list) {
+		list_del(&itd->itd_list);
+		dma_pool_free(ehci->itd_pool, itd, itd->itd_dma);
+		if (itd == ehci->last_itd_to_free)
+			break;
+	}
+	list_for_each_entry_safe(sitd, sn, &ehci->cached_sitd_list, sitd_list) {
+		list_del(&sitd->sitd_list);
+		dma_pool_free(ehci->sitd_pool, sitd, sitd->sitd_dma);
+		if (sitd == ehci->last_sitd_to_free)
+			break;
+	}
+
+	if (!list_empty(&ehci->cached_itd_list) ||
+			!list_empty(&ehci->cached_sitd_list))
+		start_free_itds(ehci);
+}
+
+
+/* Handle lost (or very late) IAA interrupts */
+static void ehci_iaa_watchdog(struct ehci_hcd *ehci)
+{
+	u32 cmd, status;
+
+	/*
+	 * Lost IAA irqs wedge things badly; seen first with a vt8235.
+	 * So we need this watchdog, but must protect it against both
+	 * (a) SMP races against real IAA firing and retriggering, and
+	 * (b) clean HC shutdown, when IAA watchdog was pending.
+	 */
+	if (!ehci->iaa_in_progress || ehci->rh_state != EHCI_RH_RUNNING)
+		return;
+
+	/* If we get here, IAA is *REALLY* late.  It's barely
+	 * conceivable that the system is so busy that CMD_IAAD
+	 * is still legitimately set, so let's be sure it's
+	 * clear before we read STS_IAA.  (The HC should clear
+	 * CMD_IAAD when it sets STS_IAA.)
+	 */
+	cmd = ehci_readl(ehci, &ehci->regs->command);
+
+	/*
+	 * If IAA is set here it either legitimately triggered
+	 * after the watchdog timer expired (_way_ late, so we'll
+	 * still count it as lost) ... or a silicon erratum:
+	 * - VIA seems to set IAA without triggering the IRQ;
+	 * - IAAD potentially cleared without setting IAA.
+	 */
+	status = ehci_readl(ehci, &ehci->regs->status);
+	if ((status & STS_IAA) || !(cmd & CMD_IAAD)) {
+		INCR(ehci->stats.lost_iaa);
+		ehci_writel(ehci, STS_IAA, &ehci->regs->status);
+	}
+
+	ehci_dbg(ehci, "IAA watchdog: status %x cmd %x\n", status, cmd);
+	end_iaa_cycle(ehci);
+}
+
+
+/* Enable the I/O watchdog, if appropriate */
+static void turn_on_io_watchdog(struct ehci_hcd *ehci)
+{
+	/* Not needed if the controller isn't running or it's already enabled */
+	if (ehci->rh_state != EHCI_RH_RUNNING ||
+			(ehci->enabled_hrtimer_events &
+				BIT(EHCI_HRTIMER_IO_WATCHDOG)))
+		return;
+
+	/*
+	 * Isochronous transfers always need the watchdog.
+	 * For other sorts we use it only if the flag is set.
+	 */
+	if (ehci->isoc_count > 0 || (ehci->need_io_watchdog &&
+			ehci->async_count + ehci->intr_count > 0))
+		ehci_enable_event(ehci, EHCI_HRTIMER_IO_WATCHDOG, true);
+}
+
+
+/*
+ * Handler functions for the hrtimer event types.
+ * Keep this array in the same order as the event types indexed by
+ * enum ehci_hrtimer_event in ehci.h.
+ */
+static void (*event_handlers[])(struct ehci_hcd *) = {
+	ehci_poll_ASS,			/* EHCI_HRTIMER_POLL_ASS */
+	ehci_poll_PSS,			/* EHCI_HRTIMER_POLL_PSS */
+	ehci_handle_controller_death,	/* EHCI_HRTIMER_POLL_DEAD */
+	ehci_handle_intr_unlinks,	/* EHCI_HRTIMER_UNLINK_INTR */
+	end_free_itds,			/* EHCI_HRTIMER_FREE_ITDS */
+	end_unlink_async,		/* EHCI_HRTIMER_ACTIVE_UNLINK */
+	ehci_handle_start_intr_unlinks,	/* EHCI_HRTIMER_START_UNLINK_INTR */
+	unlink_empty_async,		/* EHCI_HRTIMER_ASYNC_UNLINKS */
+	ehci_iaa_watchdog,		/* EHCI_HRTIMER_IAA_WATCHDOG */
+	ehci_disable_PSE,		/* EHCI_HRTIMER_DISABLE_PERIODIC */
+	ehci_disable_ASE,		/* EHCI_HRTIMER_DISABLE_ASYNC */
+	ehci_work,			/* EHCI_HRTIMER_IO_WATCHDOG */
+};
+
+static enum hrtimer_restart ehci_hrtimer_func(struct hrtimer *t)
+{
+	struct ehci_hcd	*ehci = container_of(t, struct ehci_hcd, hrtimer);
+	ktime_t		now;
+	unsigned long	events;
+	unsigned long	flags;
+	unsigned	e;
+
+	spin_lock_irqsave(&ehci->lock, flags);
+
+	events = ehci->enabled_hrtimer_events;
+	ehci->enabled_hrtimer_events = 0;
+	ehci->next_hrtimer_event = EHCI_HRTIMER_NO_EVENT;
+
+	/*
+	 * Check each pending event.  If its time has expired, handle
+	 * the event; otherwise re-enable it.
+	 */
+	now = ktime_get();
+	for_each_set_bit(e, &events, EHCI_HRTIMER_NUM_EVENTS) {
+		if (ktime_compare(now, ehci->hr_timeouts[e]) >= 0)
+			event_handlers[e](ehci);
+		else
+			ehci_enable_event(ehci, e, false);
+	}
+
+	spin_unlock_irqrestore(&ehci->lock, flags);
+	return HRTIMER_NORESTART;
+}