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, 283 insertions, 0 deletions

diff --git a/drivers/md/md-autodetect.c b/drivers/md/md-autodetect.c
new file mode 100644
index 000000000..4b80165af
--- /dev/null
+++ b/drivers/md/md-autodetect.c
@@ -0,0 +1,283 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/kernel.h>
+#include <linux/blkdev.h>
+#include <linux/init.h>
+#include <linux/mount.h>
+#include <linux/major.h>
+#include <linux/delay.h>
+#include <linux/init_syscalls.h>
+#include <linux/raid/detect.h>
+#include <linux/raid/md_u.h>
+#include <linux/raid/md_p.h>
+#include "md.h"
+
+/*
+ * When md (and any require personalities) are compiled into the kernel
+ * (not a module), arrays can be assembles are boot time using with AUTODETECT
+ * where specially marked partitions are registered with md_autodetect_dev(),
+ * and with MD_BOOT where devices to be collected are given on the boot line
+ * with md=.....
+ * The code for that is here.
+ */
+
+#ifdef CONFIG_MD_AUTODETECT
+static int __initdata raid_noautodetect;
+#else
+static int __initdata raid_noautodetect=1;
+#endif
+static int __initdata raid_autopart;
+
+static struct md_setup_args {
+	int minor;
+	int partitioned;
+	int level;
+	int chunk;
+	char *device_names;
+} md_setup_args[256] __initdata;
+
+static int md_setup_ents __initdata;
+
+/*
+ * Parse the command-line parameters given our kernel, but do not
+ * actually try to invoke the MD device now; that is handled by
+ * md_setup_drive after the low-level disk drivers have initialised.
+ *
+ * 27/11/1999: Fixed to work correctly with the 2.3 kernel (which
+ *             assigns the task of parsing integer arguments to the
+ *             invoked program now).  Added ability to initialise all
+ *             the MD devices (by specifying multiple "md=" lines)
+ *             instead of just one.  -- KTK
+ * 18May2000: Added support for persistent-superblock arrays:
+ *             md=n,0,factor,fault,device-list   uses RAID0 for device n
+ *             md=n,-1,factor,fault,device-list  uses LINEAR for device n
+ *             md=n,device-list      reads a RAID superblock from the devices
+ *             elements in device-list are read by name_to_kdev_t so can be
+ *             a hex number or something like /dev/hda1 /dev/sdb
+ * 2001-06-03: Dave Cinege <dcinege@psychosis.com>
+ *		Shifted name_to_kdev_t() and related operations to md_set_drive()
+ *		for later execution. Rewrote section to make devfs compatible.
+ */
+static int __init md_setup(char *str)
+{
+	int minor, level, factor, fault, partitioned = 0;
+	char *pername = "";
+	char *str1;
+	int ent;
+
+	if (*str == 'd') {
+		partitioned = 1;
+		str++;
+	}
+	if (get_option(&str, &minor) != 2) {	/* MD Number */
+		printk(KERN_WARNING "md: Too few arguments supplied to md=.\n");
+		return 0;
+	}
+	str1 = str;
+	for (ent=0 ; ent< md_setup_ents ; ent++)
+		if (md_setup_args[ent].minor == minor &&
+		    md_setup_args[ent].partitioned == partitioned) {
+			printk(KERN_WARNING "md: md=%s%d, Specified more than once. "
+			       "Replacing previous definition.\n", partitioned?"d":"", minor);
+			break;
+		}
+	if (ent >= ARRAY_SIZE(md_setup_args)) {
+		printk(KERN_WARNING "md: md=%s%d - too many md initialisations\n", partitioned?"d":"", minor);
+		return 0;
+	}
+	if (ent >= md_setup_ents)
+		md_setup_ents++;
+	switch (get_option(&str, &level)) {	/* RAID level */
+	case 2: /* could be 0 or -1.. */
+		if (level == 0 || level == LEVEL_LINEAR) {
+			if (get_option(&str, &factor) != 2 ||	/* Chunk Size */
+					get_option(&str, &fault) != 2) {
+				printk(KERN_WARNING "md: Too few arguments supplied to md=.\n");
+				return 0;
+			}
+			md_setup_args[ent].level = level;
+			md_setup_args[ent].chunk = 1 << (factor+12);
+			if (level ==  LEVEL_LINEAR)
+				pername = "linear";
+			else
+				pername = "raid0";
+			break;
+		}
+		fallthrough;
+	case 1: /* the first device is numeric */
+		str = str1;
+		fallthrough;
+	case 0:
+		md_setup_args[ent].level = LEVEL_NONE;
+		pername="super-block";
+	}
+
+	printk(KERN_INFO "md: Will configure md%d (%s) from %s, below.\n",
+		minor, pername, str);
+	md_setup_args[ent].device_names = str;
+	md_setup_args[ent].partitioned = partitioned;
+	md_setup_args[ent].minor = minor;
+
+	return 1;
+}
+
+static void __init md_setup_drive(struct md_setup_args *args)
+{
+	char *devname = args->device_names;
+	dev_t devices[MD_SB_DISKS + 1], mdev;
+	struct mdu_array_info_s ainfo = { };
+	struct mddev *mddev;
+	int err = 0, i;
+	char name[16];
+
+	if (args->partitioned) {
+		mdev = MKDEV(mdp_major, args->minor << MdpMinorShift);
+		sprintf(name, "md_d%d", args->minor);
+	} else {
+		mdev = MKDEV(MD_MAJOR, args->minor);
+		sprintf(name, "md%d", args->minor);
+	}
+
+	for (i = 0; i < MD_SB_DISKS && devname != NULL; i++) {
+		struct kstat stat;
+		char *p;
+		char comp_name[64];
+		dev_t dev;
+
+		p = strchr(devname, ',');
+		if (p)
+			*p++ = 0;
+
+		if (early_lookup_bdev(devname, &dev))
+			dev = 0;
+		if (strncmp(devname, "/dev/", 5) == 0)
+			devname += 5;
+		snprintf(comp_name, 63, "/dev/%s", devname);
+		if (init_stat(comp_name, &stat, 0) == 0 && S_ISBLK(stat.mode))
+			dev = new_decode_dev(stat.rdev);
+		if (!dev) {
+			pr_warn("md: Unknown device name: %s\n", devname);
+			break;
+		}
+
+		devices[i] = dev;
+		devname = p;
+	}
+	devices[i] = 0;
+
+	if (!i)
+		return;
+
+	pr_info("md: Loading %s: %s\n", name, args->device_names);
+
+	mddev = md_alloc(mdev, name);
+	if (IS_ERR(mddev)) {
+		pr_err("md: md_alloc failed - cannot start array %s\n", name);
+		return;
+	}
+
+	err = mddev_suspend_and_lock(mddev);
+	if (err) {
+		pr_err("md: failed to lock array %s\n", name);
+		goto out_mddev_put;
+	}
+
+	if (!list_empty(&mddev->disks) || mddev->raid_disks) {
+		pr_warn("md: Ignoring %s, already autodetected. (Use raid=noautodetect)\n",
+		       name);
+		goto out_unlock;
+	}
+
+	if (args->level != LEVEL_NONE) {
+		/* non-persistent */
+		ainfo.level = args->level;
+		ainfo.md_minor = args->minor;
+		ainfo.not_persistent = 1;
+		ainfo.state = (1 << MD_SB_CLEAN);
+		ainfo.chunk_size = args->chunk;
+		while (devices[ainfo.raid_disks])
+			ainfo.raid_disks++;
+	}
+
+	err = md_set_array_info(mddev, &ainfo);
+
+	for (i = 0; i <= MD_SB_DISKS && devices[i]; i++) {
+		struct mdu_disk_info_s dinfo = {
+			.major	= MAJOR(devices[i]),
+			.minor	= MINOR(devices[i]),
+		};
+
+		if (args->level != LEVEL_NONE) {
+			dinfo.number = i;
+			dinfo.raid_disk = i;
+			dinfo.state =
+				(1 << MD_DISK_ACTIVE) | (1 << MD_DISK_SYNC);
+		}
+
+		md_add_new_disk(mddev, &dinfo);
+	}
+
+	if (!err)
+		err = do_md_run(mddev);
+	if (err)
+		pr_warn("md: starting %s failed\n", name);
+out_unlock:
+	mddev_unlock_and_resume(mddev);
+out_mddev_put:
+	mddev_put(mddev);
+}
+
+static int __init raid_setup(char *str)
+{
+	int len, pos;
+
+	len = strlen(str) + 1;
+	pos = 0;
+
+	while (pos < len) {
+		char *comma = strchr(str+pos, ',');
+		int wlen;
+		if (comma)
+			wlen = (comma-str)-pos;
+		else	wlen = (len-1)-pos;
+
+		if (!strncmp(str, "noautodetect", wlen))
+			raid_noautodetect = 1;
+		if (!strncmp(str, "autodetect", wlen))
+			raid_noautodetect = 0;
+		if (strncmp(str, "partitionable", wlen)==0)
+			raid_autopart = 1;
+		if (strncmp(str, "part", wlen)==0)
+			raid_autopart = 1;
+		pos += wlen+1;
+	}
+	return 1;
+}
+
+__setup("raid=", raid_setup);
+__setup("md=", md_setup);
+
+static void __init autodetect_raid(void)
+{
+	/*
+	 * Since we don't want to detect and use half a raid array, we need to
+	 * wait for the known devices to complete their probing
+	 */
+	printk(KERN_INFO "md: Waiting for all devices to be available before autodetect\n");
+	printk(KERN_INFO "md: If you don't use raid, use raid=noautodetect\n");
+
+	wait_for_device_probe();
+	md_autostart_arrays(raid_autopart);
+}
+
+void __init md_run_setup(void)
+{
+	int ent;
+
+	if (raid_noautodetect)
+		printk(KERN_INFO "md: Skipping autodetection of RAID arrays. (raid=autodetect will force)\n");
+	else
+		autodetect_raid();
+
+	for (ent = 0; ent < md_setup_ents; ent++)
+		md_setup_drive(&md_setup_args[ent]);
+}