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, 251 insertions, 0 deletions

diff --git a/drivers/video/fbdev/hecubafb.c b/drivers/video/fbdev/hecubafb.c
new file mode 100644
index 000000000..dd2af980f
--- /dev/null
+++ b/drivers/video/fbdev/hecubafb.c
@@ -0,0 +1,251 @@
+/*
+ * linux/drivers/video/hecubafb.c -- FB driver for Hecuba/Apollo controller
+ *
+ * Copyright (C) 2006, Jaya Kumar
+ * This work was sponsored by CIS(M) Sdn Bhd
+ *
+ * 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.
+ *
+ * Layout is based on skeletonfb.c by James Simmons and Geert Uytterhoeven.
+ * This work was possible because of apollo display code from E-Ink's website
+ * http://support.eink.com/community
+ * All information used to write this code is from public material made
+ * available by E-Ink on its support site. Some commands such as 0xA4
+ * were found by looping through cmd=0x00 thru 0xFF and supplying random
+ * values. There are other commands that the display is capable of,
+ * beyond the 5 used here but they are more complex.
+ *
+ * This driver is written to be used with the Hecuba display architecture.
+ * The actual display chip is called Apollo and the interface electronics
+ * it needs is called Hecuba.
+ *
+ * It is intended to be architecture independent. A board specific driver
+ * must be used to perform all the physical IO interactions. An example
+ * is provided as n411.c
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/fb.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/list.h>
+#include <linux/uaccess.h>
+
+#include <video/hecubafb.h>
+
+/* Display specific information */
+#define DPY_W 600
+#define DPY_H 800
+
+static const struct fb_fix_screeninfo hecubafb_fix = {
+	.id =		"hecubafb",
+	.type =		FB_TYPE_PACKED_PIXELS,
+	.visual =	FB_VISUAL_MONO01,
+	.xpanstep =	0,
+	.ypanstep =	0,
+	.ywrapstep =	0,
+	.line_length =	DPY_W,
+	.accel =	FB_ACCEL_NONE,
+};
+
+static const struct fb_var_screeninfo hecubafb_var = {
+	.xres		= DPY_W,
+	.yres		= DPY_H,
+	.xres_virtual	= DPY_W,
+	.yres_virtual	= DPY_H,
+	.bits_per_pixel	= 1,
+	.nonstd		= 1,
+};
+
+/* main hecubafb functions */
+
+static void apollo_send_data(struct hecubafb_par *par, unsigned char data)
+{
+	/* set data */
+	par->board->set_data(par, data);
+
+	/* set DS low */
+	par->board->set_ctl(par, HCB_DS_BIT, 0);
+
+	/* wait for ack */
+	par->board->wait_for_ack(par, 0);
+
+	/* set DS hi */
+	par->board->set_ctl(par, HCB_DS_BIT, 1);
+
+	/* wait for ack to clear */
+	par->board->wait_for_ack(par, 1);
+}
+
+static void apollo_send_command(struct hecubafb_par *par, unsigned char data)
+{
+	/* command so set CD to high */
+	par->board->set_ctl(par, HCB_CD_BIT, 1);
+
+	/* actually strobe with command */
+	apollo_send_data(par, data);
+
+	/* clear CD back to low */
+	par->board->set_ctl(par, HCB_CD_BIT, 0);
+}
+
+static void hecubafb_dpy_update(struct hecubafb_par *par)
+{
+	int i;
+	unsigned char *buf = par->info->screen_buffer;
+
+	apollo_send_command(par, APOLLO_START_NEW_IMG);
+
+	for (i=0; i < (DPY_W*DPY_H/8); i++) {
+		apollo_send_data(par, *(buf++));
+	}
+
+	apollo_send_command(par, APOLLO_STOP_IMG_DATA);
+	apollo_send_command(par, APOLLO_DISPLAY_IMG);
+}
+
+/* this is called back from the deferred io workqueue */
+static void hecubafb_dpy_deferred_io(struct fb_info *info, struct list_head *pagereflist)
+{
+	hecubafb_dpy_update(info->par);
+}
+
+static void hecubafb_defio_damage_range(struct fb_info *info, off_t off, size_t len)
+{
+	struct hecubafb_par *par = info->par;
+
+	hecubafb_dpy_update(par);
+}
+
+static void hecubafb_defio_damage_area(struct fb_info *info, u32 x, u32 y,
+				       u32 width, u32 height)
+{
+	struct hecubafb_par *par = info->par;
+
+	hecubafb_dpy_update(par);
+}
+
+FB_GEN_DEFAULT_DEFERRED_SYSMEM_OPS(hecubafb,
+				   hecubafb_defio_damage_range,
+				   hecubafb_defio_damage_area)
+
+static const struct fb_ops hecubafb_ops = {
+	.owner	= THIS_MODULE,
+	FB_DEFAULT_DEFERRED_OPS(hecubafb),
+};
+
+static struct fb_deferred_io hecubafb_defio = {
+	.delay		= HZ,
+	.deferred_io	= hecubafb_dpy_deferred_io,
+};
+
+static int hecubafb_probe(struct platform_device *dev)
+{
+	struct fb_info *info;
+	struct hecuba_board *board;
+	int retval = -ENOMEM;
+	int videomemorysize;
+	unsigned char *videomemory;
+	struct hecubafb_par *par;
+
+	/* pick up board specific routines */
+	board = dev->dev.platform_data;
+	if (!board)
+		return -EINVAL;
+
+	/* try to count device specific driver, if can't, platform recalls */
+	if (!try_module_get(board->owner))
+		return -ENODEV;
+
+	videomemorysize = (DPY_W*DPY_H)/8;
+
+	videomemory = vzalloc(videomemorysize);
+	if (!videomemory)
+		goto err_videomem_alloc;
+
+	info = framebuffer_alloc(sizeof(struct hecubafb_par), &dev->dev);
+	if (!info)
+		goto err_fballoc;
+
+	info->screen_buffer = videomemory;
+	info->fbops = &hecubafb_ops;
+
+	info->var = hecubafb_var;
+	info->fix = hecubafb_fix;
+	info->fix.smem_len = videomemorysize;
+	par = info->par;
+	par->info = info;
+	par->board = board;
+	par->send_command = apollo_send_command;
+	par->send_data = apollo_send_data;
+
+	info->flags = FBINFO_VIRTFB;
+
+	info->fbdefio = &hecubafb_defio;
+	retval = fb_deferred_io_init(info);
+	if (retval)
+		goto err_fbdefio;
+
+	retval = register_framebuffer(info);
+	if (retval < 0)
+		goto err_fbreg;
+	platform_set_drvdata(dev, info);
+
+	fb_info(info, "Hecuba frame buffer device, using %dK of video memory\n",
+		videomemorysize >> 10);
+
+	/* this inits the dpy */
+	retval = par->board->init(par);
+	if (retval < 0)
+		goto err_fbreg;
+
+	return 0;
+err_fbreg:
+	fb_deferred_io_cleanup(info);
+err_fbdefio:
+	framebuffer_release(info);
+err_fballoc:
+	vfree(videomemory);
+err_videomem_alloc:
+	module_put(board->owner);
+	return retval;
+}
+
+static void hecubafb_remove(struct platform_device *dev)
+{
+	struct fb_info *info = platform_get_drvdata(dev);
+
+	if (info) {
+		struct hecubafb_par *par = info->par;
+		fb_deferred_io_cleanup(info);
+		unregister_framebuffer(info);
+		vfree(info->screen_buffer);
+		if (par->board->remove)
+			par->board->remove(par);
+		module_put(par->board->owner);
+		framebuffer_release(info);
+	}
+}
+
+static struct platform_driver hecubafb_driver = {
+	.probe	= hecubafb_probe,
+	.remove	= hecubafb_remove,
+	.driver	= {
+		.name	= "hecubafb",
+	},
+};
+module_platform_driver(hecubafb_driver);
+
+MODULE_DESCRIPTION("fbdev driver for Hecuba/Apollo controller");
+MODULE_AUTHOR("Jaya Kumar");
+MODULE_LICENSE("GPL");