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, 274 insertions, 0 deletions

diff --git a/drivers/parport/probe.c b/drivers/parport/probe.c
new file mode 100644
index 000000000..5d1b9aacb
--- /dev/null
+++ b/drivers/parport/probe.c
@@ -0,0 +1,274 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Parallel port device probing code
+ *
+ * Authors:    Carsten Gross, carsten@sol.wohnheim.uni-ulm.de
+ *             Philip Blundell <philb@gnu.org>
+ */
+
+#include <linux/module.h>
+#include <linux/parport.h>
+#include <linux/string.h>
+#include <linux/string_helpers.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+
+static const struct {
+	const char *token;
+	const char *descr;
+} classes[] = {
+	{ "",            "Legacy device" },
+	{ "PRINTER",     "Printer" },
+	{ "MODEM",       "Modem" },
+	{ "NET",         "Network device" },
+	{ "HDC",       	 "Hard disk" },
+	{ "PCMCIA",      "PCMCIA" },
+	{ "MEDIA",       "Multimedia device" },
+	{ "FDC",         "Floppy disk" },
+	{ "PORTS",       "Ports" },
+	{ "SCANNER",     "Scanner" },
+	{ "DIGICAM",     "Digital camera" },
+	{ "",            "Unknown device" },
+	{ "",            "Unspecified" },
+	{ "SCSIADAPTER", "SCSI adapter" },
+	{ NULL,          NULL }
+};
+
+static void pretty_print(struct parport *port, int device)
+{
+	struct parport_device_info *info = &port->probe_info[device + 1];
+
+	pr_info("%s", port->name);
+
+	if (device >= 0)
+		pr_cont(" (addr %d)", device);
+
+	pr_cont(": %s", classes[info->class].descr);
+	if (info->class)
+		pr_cont(", %s %s", info->mfr, info->model);
+
+	pr_cont("\n");
+}
+
+static void parse_data(struct parport *port, int device, char *str)
+{
+	char *txt = kmalloc(strlen(str)+1, GFP_KERNEL);
+	char *p = txt, *q;
+	int guessed_class = PARPORT_CLASS_UNSPEC;
+	struct parport_device_info *info = &port->probe_info[device + 1];
+
+	if (!txt) {
+		pr_warn("%s probe: memory squeeze\n", port->name);
+		return;
+	}
+	strcpy(txt, str);
+	while (p) {
+		char *sep;
+		q = strchr(p, ';');
+		if (q) *q = 0;
+		sep = strchr(p, ':');
+		if (sep) {
+			char *u;
+			*(sep++) = 0;
+			/* Get rid of trailing blanks */
+			u = sep + strlen (sep) - 1;
+			while (u >= p && *u == ' ')
+				*u-- = '\0';
+			string_upper(p, p);
+			if (!strcmp(p, "MFG") || !strcmp(p, "MANUFACTURER")) {
+				kfree(info->mfr);
+				info->mfr = kstrdup(sep, GFP_KERNEL);
+			} else if (!strcmp(p, "MDL") || !strcmp(p, "MODEL")) {
+				kfree(info->model);
+				info->model = kstrdup(sep, GFP_KERNEL);
+			} else if (!strcmp(p, "CLS") || !strcmp(p, "CLASS")) {
+				int i;
+
+				kfree(info->class_name);
+				info->class_name = kstrdup(sep, GFP_KERNEL);
+				string_upper(sep, sep);
+				for (i = 0; classes[i].token; i++) {
+					if (!strcmp(classes[i].token, sep)) {
+						info->class = i;
+						goto rock_on;
+					}
+				}
+				pr_warn("%s probe: warning, class '%s' not understood\n",
+					port->name, sep);
+				info->class = PARPORT_CLASS_OTHER;
+			} else if (!strcmp(p, "CMD") ||
+				   !strcmp(p, "COMMAND SET")) {
+				kfree(info->cmdset);
+				info->cmdset = kstrdup(sep, GFP_KERNEL);
+				/* if it speaks printer language, it's
+				   probably a printer */
+				if (strstr(sep, "PJL") || strstr(sep, "PCL"))
+					guessed_class = PARPORT_CLASS_PRINTER;
+			} else if (!strcmp(p, "DES") || !strcmp(p, "DESCRIPTION")) {
+				kfree(info->description);
+				info->description = kstrdup(sep, GFP_KERNEL);
+			}
+		}
+	rock_on:
+		if (q)
+			p = q + 1;
+		else
+			p = NULL;
+	}
+
+	/* If the device didn't tell us its class, maybe we have managed to
+	   guess one from the things it did say. */
+	if (info->class == PARPORT_CLASS_UNSPEC)
+		info->class = guessed_class;
+
+	pretty_print (port, device);
+
+	kfree(txt);
+}
+
+/* Read up to count-1 bytes of device id. Terminate buffer with
+ * '\0'. Buffer begins with two Device ID length bytes as given by
+ * device. */
+static ssize_t parport_read_device_id (struct parport *port, char *buffer,
+				       size_t count)
+{
+	unsigned char length[2];
+	unsigned lelen, belen;
+	size_t idlens[4];
+	unsigned numidlens;
+	unsigned current_idlen;
+	ssize_t retval;
+	size_t len;
+
+	/* First two bytes are MSB,LSB of inclusive length. */
+	retval = parport_read (port, length, 2);
+
+	if (retval < 0)
+		return retval;
+	if (retval != 2)
+		return -EIO;
+
+	if (count < 2)
+		return 0;
+	memcpy(buffer, length, 2);
+	len = 2;
+
+	/* Some devices wrongly send LE length, and some send it two
+	 * bytes short. Construct a sorted array of lengths to try. */
+	belen = (length[0] << 8) + length[1];
+	lelen = (length[1] << 8) + length[0];
+	idlens[0] = min(belen, lelen);
+	idlens[1] = idlens[0]+2;
+	if (belen != lelen) {
+		int off = 2;
+		/* Don't try lengths of 0x100 and 0x200 as 1 and 2 */
+		if (idlens[0] <= 2)
+			off = 0;
+		idlens[off] = max(belen, lelen);
+		idlens[off+1] = idlens[off]+2;
+		numidlens = off+2;
+	}
+	else {
+		/* Some devices don't truly implement Device ID, but
+		 * just return constant nibble forever. This catches
+		 * also those cases. */
+		if (idlens[0] == 0 || idlens[0] > 0xFFF) {
+			printk(KERN_DEBUG "%s: reported broken Device ID length of %#zX bytes\n",
+			       port->name, idlens[0]);
+			return -EIO;
+		}
+		numidlens = 2;
+	}
+
+	/* Try to respect the given ID length despite all the bugs in
+	 * the ID length. Read according to shortest possible ID
+	 * first. */
+	for (current_idlen = 0; current_idlen < numidlens; ++current_idlen) {
+		size_t idlen = idlens[current_idlen];
+		if (idlen+1 >= count)
+			break;
+
+		retval = parport_read (port, buffer+len, idlen-len);
+
+		if (retval < 0)
+			return retval;
+		len += retval;
+
+		if (port->physport->ieee1284.phase != IEEE1284_PH_HBUSY_DAVAIL) {
+			if (belen != len) {
+				printk(KERN_DEBUG "%s: Device ID was %zd bytes while device told it would be %d bytes\n",
+				       port->name, len, belen);
+			}
+			goto done;
+		}
+
+		/* This might end reading the Device ID too
+		 * soon. Hopefully the needed fields were already in
+		 * the first 256 bytes or so that we must have read so
+		 * far. */
+		if (buffer[len-1] == ';') {
+			printk(KERN_DEBUG "%s: Device ID reading stopped before device told data not available. Current idlen %u of %u, len bytes %02X %02X\n",
+			       port->name, current_idlen, numidlens,
+			       length[0], length[1]);
+			goto done;
+		}
+	}
+	if (current_idlen < numidlens) {
+		/* Buffer not large enough, read to end of buffer. */
+		size_t idlen, len2;
+		if (len+1 < count) {
+			retval = parport_read (port, buffer+len, count-len-1);
+			if (retval < 0)
+				return retval;
+			len += retval;
+		}
+		/* Read the whole ID since some devices would not
+		 * otherwise give back the Device ID from beginning
+		 * next time when asked. */
+		idlen = idlens[current_idlen];
+		len2 = len;
+		while(len2 < idlen && retval > 0) {
+			char tmp[4];
+			retval = parport_read (port, tmp,
+					       min(sizeof tmp, idlen-len2));
+			if (retval < 0)
+				return retval;
+			len2 += retval;
+		}
+	}
+	/* In addition, there are broken devices out there that don't
+	   even finish off with a semi-colon. We do not need to care
+	   about those at this time. */
+ done:
+	buffer[len] = '\0';
+	return len;
+}
+
+/* Get Std 1284 Device ID. */
+ssize_t parport_device_id (int devnum, char *buffer, size_t count)
+{
+	ssize_t retval = -ENXIO;
+	struct pardevice *dev = parport_open(devnum, daisy_dev_name);
+	if (!dev)
+		return -ENXIO;
+
+	parport_claim_or_block (dev);
+
+	/* Negotiate to compatibility mode, and then to device ID
+	 * mode. (This so that we start form beginning of device ID if
+	 * already in device ID mode.) */
+	parport_negotiate (dev->port, IEEE1284_MODE_COMPAT);
+	retval = parport_negotiate (dev->port,
+				    IEEE1284_MODE_NIBBLE | IEEE1284_DEVICEID);
+
+	if (!retval) {
+		retval = parport_read_device_id (dev->port, buffer, count);
+		parport_negotiate (dev->port, IEEE1284_MODE_COMPAT);
+		if (retval > 2)
+			parse_data (dev->port, dev->daisy, buffer+2);
+	}
+
+	parport_release (dev);
+	parport_close (dev);
+	return retval;
+}