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, 220 insertions, 0 deletions

diff --git a/arch/m68k/atari/stdma.c b/arch/m68k/atari/stdma.c
new file mode 100644
index 000000000..155fefff1
--- /dev/null
+++ b/arch/m68k/atari/stdma.c
@@ -0,0 +1,220 @@
+/*
+ *  linux/arch/m68k/atari/stmda.c
+ *
+ *  Copyright (C) 1994 Roman Hodek
+ *
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file COPYING in the main directory of this archive
+ * for more details.
+ */
+
+
+/* This file contains some function for controlling the access to the  */
+/* ST-DMA chip that may be shared between devices. Currently we have:  */
+/*   TT:     Floppy and ACSI bus                                       */
+/*   Falcon: Floppy and SCSI                                           */
+/*                                                                     */
+/* The controlling functions set up a wait queue for access to the     */
+/* ST-DMA chip. Callers to stdma_lock() that cannot granted access are */
+/* put onto a queue and waked up later if the owner calls              */
+/* stdma_release(). Additionally, the caller gives his interrupt       */
+/* service routine to stdma_lock().                                    */
+/*                                                                     */
+/* On the Falcon, the IDE bus uses just the ACSI/Floppy interrupt, but */
+/* not the ST-DMA chip itself. So falhd.c needs not to lock the        */
+/* chip. The interrupt is routed to falhd.c if IDE is configured, the  */
+/* model is a Falcon and the interrupt was caused by the HD controller */
+/* (can be determined by looking at its status register).              */
+
+
+#include <linux/types.h>
+#include <linux/kdev_t.h>
+#include <linux/sched.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/wait.h>
+#include <linux/module.h>
+
+#include <asm/atari_stdma.h>
+#include <asm/atariints.h>
+#include <asm/atarihw.h>
+#include <asm/io.h>
+#include <asm/irq.h>
+
+static int stdma_locked;			/* the semaphore */
+						/* int func to be called */
+static irq_handler_t stdma_isr;
+static void *stdma_isr_data;			/* data passed to isr */
+static DECLARE_WAIT_QUEUE_HEAD(stdma_wait);	/* wait queue for ST-DMA */
+
+
+
+
+/***************************** Prototypes *****************************/
+
+static irqreturn_t stdma_int (int irq, void *dummy);
+
+/************************* End of Prototypes **************************/
+
+
+/**
+ * stdma_try_lock - attempt to acquire ST DMA interrupt "lock"
+ * @handler: interrupt handler to use after acquisition
+ * @data: cookie passed to the interrupt handler function
+ *
+ * Returns !0 if lock was acquired; otherwise 0.
+ */
+
+int stdma_try_lock(irq_handler_t handler, void *data)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	if (stdma_locked) {
+		local_irq_restore(flags);
+		return 0;
+	}
+
+	stdma_locked   = 1;
+	stdma_isr      = handler;
+	stdma_isr_data = data;
+	local_irq_restore(flags);
+	return 1;
+}
+EXPORT_SYMBOL(stdma_try_lock);
+
+
+/*
+ * Function: void stdma_lock( isrfunc isr, void *data )
+ *
+ * Purpose: Tries to get a lock on the ST-DMA chip that is used by more
+ *   then one device driver. Waits on stdma_wait until lock is free.
+ *   stdma_lock() may not be called from an interrupt! You have to
+ *   get the lock in your main routine and release it when your
+ *   request is finished.
+ *
+ * Inputs: A interrupt function that is called until the lock is
+ *   released.
+ *
+ * Returns: nothing
+ *
+ */
+
+void stdma_lock(irq_handler_t handler, void *data)
+{
+	/* Since the DMA is used for file system purposes, we
+	 have to sleep uninterruptible (there may be locked
+	 buffers) */
+	wait_event(stdma_wait, stdma_try_lock(handler, data));
+}
+EXPORT_SYMBOL(stdma_lock);
+
+
+/*
+ * Function: void stdma_release( void )
+ *
+ * Purpose: Releases the lock on the ST-DMA chip.
+ *
+ * Inputs: none
+ *
+ * Returns: nothing
+ *
+ */
+
+void stdma_release(void)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+
+	stdma_locked   = 0;
+	stdma_isr      = NULL;
+	stdma_isr_data = NULL;
+	wake_up(&stdma_wait);
+
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL(stdma_release);
+
+
+/**
+ * stdma_is_locked_by - allow lock holder to check whether it needs to release.
+ * @handler: interrupt handler previously used to acquire lock.
+ *
+ * Returns !0 if locked for the given handler; 0 otherwise.
+ */
+
+int stdma_is_locked_by(irq_handler_t handler)
+{
+	unsigned long flags;
+	int result;
+
+	local_irq_save(flags);
+	result = stdma_locked && (stdma_isr == handler);
+	local_irq_restore(flags);
+
+	return result;
+}
+EXPORT_SYMBOL(stdma_is_locked_by);
+
+
+/*
+ * Function: int stdma_islocked( void )
+ *
+ * Purpose: Check if the ST-DMA is currently locked.
+ * Note: Returned status is only valid if ints are disabled while calling and
+ *       as long as they remain disabled.
+ *       If called with ints enabled, status can change only from locked to
+ *       unlocked, because ints may not lock the ST-DMA.
+ *
+ * Inputs: none
+ *
+ * Returns: != 0 if locked, 0 otherwise
+ *
+ */
+
+int stdma_islocked(void)
+{
+	return stdma_locked;
+}
+EXPORT_SYMBOL(stdma_islocked);
+
+
+/*
+ * Function: void stdma_init( void )
+ *
+ * Purpose: Initialize the ST-DMA chip access controlling.
+ *   It sets up the interrupt and its service routine. The int is registered
+ *   as slow int, client devices have to live with that (no problem
+ *   currently).
+ *
+ * Inputs: none
+ *
+ * Return: nothing
+ *
+ */
+
+void __init stdma_init(void)
+{
+	stdma_isr = NULL;
+	if (request_irq(IRQ_MFP_FDC, stdma_int, IRQF_SHARED,
+			"ST-DMA floppy,ACSI,IDE,Falcon-SCSI", stdma_int))
+		pr_err("Couldn't register ST-DMA interrupt\n");
+}
+
+
+/*
+ * Function: void stdma_int()
+ *
+ * Purpose: The interrupt routine for the ST-DMA. It calls the isr
+ *   registered by stdma_lock().
+ *
+ */
+
+static irqreturn_t stdma_int(int irq, void *dummy)
+{
+  if (stdma_isr)
+      (*stdma_isr)(irq, stdma_isr_data);
+  return IRQ_HANDLED;
+}