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, 798 insertions, 0 deletions

diff --git a/init/initramfs.c b/init/initramfs.c
new file mode 100644
index 000000000..3cee8b50a
--- /dev/null
+++ b/init/initramfs.c
@@ -0,0 +1,798 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/async.h>
+#include <linux/delay.h>
+#include <linux/dirent.h>
+#include <linux/export.h>
+#include <linux/fcntl.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/fs_struct.h>
+#include <linux/hex.h>
+#include <linux/init.h>
+#include <linux/init_syscalls.h>
+#include <linux/kstrtox.h>
+#include <linux/memblock.h>
+#include <linux/mm.h>
+#include <linux/namei.h>
+#include <linux/overflow.h>
+#include <linux/security.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/syscalls.h>
+#include <linux/types.h>
+#include <linux/umh.h>
+#include <linux/utime.h>
+
+#include <asm/byteorder.h>
+
+#include "do_mounts.h"
+#include "initramfs_internal.h"
+
+static __initdata bool csum_present;
+static __initdata u32 io_csum;
+
+static ssize_t __init xwrite(struct file *file, const unsigned char *p,
+		size_t count, loff_t *pos)
+{
+	ssize_t out = 0;
+
+	/* sys_write only can write MAX_RW_COUNT aka 2G-4K bytes at most */
+	while (count) {
+		ssize_t rv = kernel_write(file, p, count, pos);
+
+		if (rv < 0) {
+			if (rv == -EINTR || rv == -EAGAIN)
+				continue;
+			return out ? out : rv;
+		} else if (rv == 0)
+			break;
+
+		if (csum_present) {
+			ssize_t i;
+
+			for (i = 0; i < rv; i++)
+				io_csum += p[i];
+		}
+
+		p += rv;
+		out += rv;
+		count -= rv;
+	}
+
+	return out;
+}
+
+static __initdata char *message;
+static void __init error(char *x)
+{
+	if (!message)
+		message = x;
+}
+
+#define panic_show_mem(fmt, ...) \
+	({ show_mem(); panic(fmt, ##__VA_ARGS__); })
+
+/* link hash */
+
+#define N_ALIGN(len) ((((len) + 1) & ~3) + 2)
+
+static __initdata struct hash {
+	int ino, minor, major;
+	umode_t mode;
+	struct hash *next;
+	char name[N_ALIGN(PATH_MAX)];
+} *head[32];
+static __initdata bool hardlink_seen;
+
+static inline int hash(int major, int minor, int ino)
+{
+	unsigned long tmp = ino + minor + (major << 3);
+	tmp += tmp >> 5;
+	return tmp & 31;
+}
+
+static char __init *find_link(int major, int minor, int ino,
+			      umode_t mode, char *name)
+{
+	struct hash **p, *q;
+	for (p = head + hash(major, minor, ino); *p; p = &(*p)->next) {
+		if ((*p)->ino != ino)
+			continue;
+		if ((*p)->minor != minor)
+			continue;
+		if ((*p)->major != major)
+			continue;
+		if (((*p)->mode ^ mode) & S_IFMT)
+			continue;
+		return (*p)->name;
+	}
+	q = kmalloc_obj(struct hash);
+	if (!q)
+		panic_show_mem("can't allocate link hash entry");
+	q->major = major;
+	q->minor = minor;
+	q->ino = ino;
+	q->mode = mode;
+	strscpy(q->name, name);
+	q->next = NULL;
+	*p = q;
+	hardlink_seen = true;
+	return NULL;
+}
+
+static void __init free_hash(void)
+{
+	struct hash **p, *q;
+	for (p = head; hardlink_seen && p < head + 32; p++) {
+		while (*p) {
+			q = *p;
+			*p = q->next;
+			kfree(q);
+		}
+	}
+	hardlink_seen = false;
+}
+
+#ifdef CONFIG_INITRAMFS_PRESERVE_MTIME
+static void __init do_utime(char *filename, time64_t mtime)
+{
+	struct timespec64 t[2] = { { .tv_sec = mtime }, { .tv_sec = mtime } };
+	init_utimes(filename, t);
+}
+
+static void __init do_utime_path(const struct path *path, time64_t mtime)
+{
+	struct timespec64 t[2] = { { .tv_sec = mtime }, { .tv_sec = mtime } };
+	vfs_utimes(path, t);
+}
+
+static __initdata LIST_HEAD(dir_list);
+struct dir_entry {
+	struct list_head list;
+	time64_t mtime;
+	char name[];
+};
+
+static void __init dir_add(const char *name, size_t nlen, time64_t mtime)
+{
+	struct dir_entry *de;
+
+	de = kmalloc_flex(*de, name, nlen);
+	if (!de)
+		panic_show_mem("can't allocate dir_entry buffer");
+	INIT_LIST_HEAD(&de->list);
+	strscpy(de->name, name, nlen);
+	de->mtime = mtime;
+	list_add(&de->list, &dir_list);
+}
+
+static void __init dir_utime(void)
+{
+	struct dir_entry *de, *tmp;
+	list_for_each_entry_safe(de, tmp, &dir_list, list) {
+		list_del(&de->list);
+		do_utime(de->name, de->mtime);
+		kfree(de);
+	}
+}
+#else
+static void __init do_utime(char *filename, time64_t mtime) {}
+static void __init do_utime_path(const struct path *path, time64_t mtime) {}
+static void __init dir_add(const char *name, size_t nlen, time64_t mtime) {}
+static void __init dir_utime(void) {}
+#endif
+
+static __initdata time64_t mtime;
+
+/* cpio header parsing */
+
+static __initdata unsigned long ino, major, minor, nlink;
+static __initdata umode_t mode;
+static __initdata unsigned long body_len, name_len;
+static __initdata uid_t uid;
+static __initdata gid_t gid;
+static __initdata unsigned rdev;
+static __initdata u32 hdr_csum;
+
+static int __init parse_header(char *s)
+{
+	__be32 header[13];
+	int ret;
+
+	ret = hex2bin((u8 *)header, s + 6, sizeof(header));
+	if (ret) {
+		error("damaged header");
+		return ret;
+	}
+
+	ino = be32_to_cpu(header[0]);
+	mode = be32_to_cpu(header[1]);
+	uid = be32_to_cpu(header[2]);
+	gid = be32_to_cpu(header[3]);
+	nlink = be32_to_cpu(header[4]);
+	mtime = be32_to_cpu(header[5]); /* breaks in y2106 */
+	body_len = be32_to_cpu(header[6]);
+	major = be32_to_cpu(header[7]);
+	minor = be32_to_cpu(header[8]);
+	rdev = new_encode_dev(MKDEV(be32_to_cpu(header[9]), be32_to_cpu(header[10])));
+	name_len = be32_to_cpu(header[11]);
+	hdr_csum = be32_to_cpu(header[12]);
+	return 0;
+}
+
+/* Finite-state machine */
+
+static __initdata enum state {
+	Start,
+	Collect,
+	GotHeader,
+	SkipIt,
+	GotName,
+	CopyFile,
+	GotSymlink,
+	Reset
+} state, next_state;
+
+static __initdata char *victim;
+static unsigned long byte_count __initdata;
+static __initdata loff_t this_header, next_header;
+
+static inline void __init eat(unsigned n)
+{
+	victim += n;
+	this_header += n;
+	byte_count -= n;
+}
+
+static __initdata char *collected;
+static long remains __initdata;
+static __initdata char *collect;
+
+static void __init read_into(char *buf, unsigned size, enum state next)
+{
+	if (byte_count >= size) {
+		collected = victim;
+		eat(size);
+		state = next;
+	} else {
+		collect = collected = buf;
+		remains = size;
+		next_state = next;
+		state = Collect;
+	}
+}
+
+static __initdata char *header_buf, *symlink_buf, *name_buf;
+
+static int __init do_start(void)
+{
+	read_into(header_buf, CPIO_HDRLEN, GotHeader);
+	return 0;
+}
+
+static int __init do_collect(void)
+{
+	unsigned long n = remains;
+	if (byte_count < n)
+		n = byte_count;
+	memcpy(collect, victim, n);
+	eat(n);
+	collect += n;
+	if ((remains -= n) != 0)
+		return 1;
+	state = next_state;
+	return 0;
+}
+
+static int __init do_header(void)
+{
+	if (!memcmp(collected, "070701", 6)) {
+		csum_present = false;
+	} else if (!memcmp(collected, "070702", 6)) {
+		csum_present = true;
+	} else {
+		if (memcmp(collected, "070707", 6) == 0)
+			error("incorrect cpio method used: use -H newc option");
+		else
+			error("no cpio magic");
+		return 1;
+	}
+	if (parse_header(collected))
+		return 1;
+	next_header = this_header + N_ALIGN(name_len) + body_len;
+	next_header = (next_header + 3) & ~3;
+	state = SkipIt;
+	if (name_len <= 0 || name_len > PATH_MAX)
+		return 0;
+	if (S_ISLNK(mode)) {
+		if (body_len > PATH_MAX)
+			return 0;
+		collect = collected = symlink_buf;
+		remains = N_ALIGN(name_len) + body_len;
+		next_state = GotSymlink;
+		state = Collect;
+		return 0;
+	}
+	if (S_ISREG(mode) || !body_len)
+		read_into(name_buf, N_ALIGN(name_len), GotName);
+	return 0;
+}
+
+static int __init do_skip(void)
+{
+	if (this_header + byte_count < next_header) {
+		eat(byte_count);
+		return 1;
+	} else {
+		eat(next_header - this_header);
+		state = next_state;
+		return 0;
+	}
+}
+
+static int __init do_reset(void)
+{
+	while (byte_count && *victim == '\0')
+		eat(1);
+	if (byte_count && (this_header & 3))
+		error("broken padding");
+	return 1;
+}
+
+static void __init clean_path(char *path, umode_t fmode)
+{
+	struct kstat st;
+
+	if (!init_stat(path, &st, AT_SYMLINK_NOFOLLOW) &&
+	    (st.mode ^ fmode) & S_IFMT) {
+		if (S_ISDIR(st.mode))
+			init_rmdir(path);
+		else
+			init_unlink(path);
+	}
+}
+
+static int __init maybe_link(void)
+{
+	if (nlink >= 2) {
+		char *old = find_link(major, minor, ino, mode, collected);
+		if (old) {
+			clean_path(collected, 0);
+			return (init_link(old, collected) < 0) ? -1 : 1;
+		}
+	}
+	return 0;
+}
+
+static __initdata struct file *wfile;
+static __initdata loff_t wfile_pos;
+
+static int __init do_name(void)
+{
+	state = SkipIt;
+	next_state = Reset;
+
+	/* name_len > 0 && name_len <= PATH_MAX checked in do_header */
+	if (collected[name_len - 1] != '\0') {
+		pr_err("initramfs name without nulterm: %.*s\n",
+		       (int)name_len, collected);
+		error("malformed archive");
+		return 1;
+	}
+
+	if (strcmp(collected, "TRAILER!!!") == 0) {
+		free_hash();
+		return 0;
+	}
+	clean_path(collected, mode);
+	if (S_ISREG(mode)) {
+		int ml = maybe_link();
+		if (ml >= 0) {
+			int openflags = O_WRONLY|O_CREAT|O_LARGEFILE;
+			if (ml != 1)
+				openflags |= O_TRUNC;
+			wfile = filp_open(collected, openflags, mode);
+			if (IS_ERR(wfile))
+				return 0;
+			wfile_pos = 0;
+			io_csum = 0;
+
+			vfs_fchown(wfile, uid, gid);
+			vfs_fchmod(wfile, mode);
+			if (body_len)
+				vfs_truncate(&wfile->f_path, body_len);
+			state = CopyFile;
+		}
+	} else if (S_ISDIR(mode)) {
+		init_mkdir(collected, mode);
+		init_chown(collected, uid, gid, 0);
+		init_chmod(collected, mode);
+		dir_add(collected, name_len, mtime);
+	} else if (S_ISBLK(mode) || S_ISCHR(mode) ||
+		   S_ISFIFO(mode) || S_ISSOCK(mode)) {
+		if (maybe_link() == 0) {
+			init_mknod(collected, mode, rdev);
+			init_chown(collected, uid, gid, 0);
+			init_chmod(collected, mode);
+			do_utime(collected, mtime);
+		}
+	}
+	return 0;
+}
+
+static int __init do_copy(void)
+{
+	if (byte_count >= body_len) {
+		if (xwrite(wfile, victim, body_len, &wfile_pos) != body_len)
+			error("write error");
+
+		do_utime_path(&wfile->f_path, mtime);
+		fput(wfile);
+		if (csum_present && io_csum != hdr_csum)
+			error("bad data checksum");
+		eat(body_len);
+		state = SkipIt;
+		return 0;
+	} else {
+		if (xwrite(wfile, victim, byte_count, &wfile_pos) != byte_count)
+			error("write error");
+		body_len -= byte_count;
+		eat(byte_count);
+		return 1;
+	}
+}
+
+static int __init do_symlink(void)
+{
+	if (collected[name_len - 1] != '\0') {
+		pr_err("initramfs symlink without nulterm: %.*s\n",
+		       (int)name_len, collected);
+		error("malformed archive");
+		return 1;
+	}
+	collected[N_ALIGN(name_len) + body_len] = '\0';
+	clean_path(collected, 0);
+	init_symlink(collected + N_ALIGN(name_len), collected);
+	init_chown(collected, uid, gid, AT_SYMLINK_NOFOLLOW);
+	do_utime(collected, mtime);
+	state = SkipIt;
+	next_state = Reset;
+	return 0;
+}
+
+static __initdata int (*actions[])(void) = {
+	[Start]		= do_start,
+	[Collect]	= do_collect,
+	[GotHeader]	= do_header,
+	[SkipIt]	= do_skip,
+	[GotName]	= do_name,
+	[CopyFile]	= do_copy,
+	[GotSymlink]	= do_symlink,
+	[Reset]		= do_reset,
+};
+
+static long __init write_buffer(char *buf, unsigned long len)
+{
+	byte_count = len;
+	victim = buf;
+
+	while (!actions[state]())
+		;
+	return len - byte_count;
+}
+
+static long __init flush_buffer(void *bufv, unsigned long len)
+{
+	char *buf = bufv;
+	long written;
+	long origLen = len;
+	if (message)
+		return -1;
+	while ((written = write_buffer(buf, len)) < len && !message) {
+		char c = buf[written];
+		if (c == '0') {
+			buf += written;
+			len -= written;
+			state = Start;
+		} else if (c == 0) {
+			buf += written;
+			len -= written;
+			state = Reset;
+		} else
+			error("junk within compressed archive");
+	}
+	return origLen;
+}
+
+static unsigned long my_inptr __initdata; /* index of next byte to be processed in inbuf */
+
+#include <linux/decompress/generic.h>
+
+/**
+ * unpack_to_rootfs - decompress and extract an initramfs archive
+ * @buf: input initramfs archive to extract
+ * @len: length of initramfs data to process
+ *
+ * Returns: NULL for success or an error message string
+ *
+ * This symbol shouldn't be used externally. It's available for unit tests.
+ */
+char * __init unpack_to_rootfs(char *buf, unsigned long len)
+{
+	long written;
+	decompress_fn decompress;
+	const char *compress_name;
+	struct {
+		char header[CPIO_HDRLEN];
+		char symlink[PATH_MAX + N_ALIGN(PATH_MAX) + 1];
+		char name[N_ALIGN(PATH_MAX)];
+	} *bufs = kmalloc_obj(*bufs);
+
+	if (!bufs)
+		panic_show_mem("can't allocate buffers");
+
+	header_buf = bufs->header;
+	symlink_buf = bufs->symlink;
+	name_buf = bufs->name;
+
+	state = Start;
+	this_header = 0;
+	message = NULL;
+	while (!message && len) {
+		loff_t saved_offset = this_header;
+		if (*buf == '0' && !(this_header & 3)) {
+			state = Start;
+			written = write_buffer(buf, len);
+			buf += written;
+			len -= written;
+			continue;
+		}
+		if (!*buf) {
+			buf++;
+			len--;
+			this_header++;
+			continue;
+		}
+		this_header = 0;
+		decompress = decompress_method(buf, len, &compress_name);
+		pr_debug("Detected %s compressed data\n", compress_name);
+		if (decompress) {
+			int res = decompress(buf, len, NULL, flush_buffer, NULL,
+				   &my_inptr, error);
+			if (res)
+				error("decompressor failed");
+		} else if (compress_name) {
+			pr_err("compression method %s not configured\n",
+			       compress_name);
+			error("decompressor failed");
+		} else
+			error("invalid magic at start of compressed archive");
+		if (state != Reset)
+			error("junk at the end of compressed archive");
+		this_header = saved_offset + my_inptr;
+		buf += my_inptr;
+		len -= my_inptr;
+	}
+	dir_utime();
+	/* free any hardlink state collected without optional TRAILER!!! */
+	free_hash();
+	kfree(bufs);
+	return message;
+}
+
+static int __initdata do_retain_initrd;
+
+static int __init retain_initrd_param(char *str)
+{
+	if (*str)
+		return 0;
+	do_retain_initrd = 1;
+	return 1;
+}
+__setup("retain_initrd", retain_initrd_param);
+
+#ifdef CONFIG_ARCH_HAS_KEEPINITRD
+static int __init keepinitrd_setup(char *__unused)
+{
+	do_retain_initrd = 1;
+	return 1;
+}
+__setup("keepinitrd", keepinitrd_setup);
+#endif
+
+static bool __initdata initramfs_async = true;
+static int __init initramfs_async_setup(char *str)
+{
+	return kstrtobool(str, &initramfs_async) == 0;
+}
+__setup("initramfs_async=", initramfs_async_setup);
+
+extern char __initramfs_start[];
+extern unsigned long __initramfs_size;
+#include <linux/initrd.h>
+#include <linux/kexec.h>
+
+static BIN_ATTR(initrd, 0440, sysfs_bin_attr_simple_read, NULL, 0);
+
+void __init reserve_initrd_mem(void)
+{
+	phys_addr_t start;
+	unsigned long size;
+
+	/* Ignore the virtual address computed during device tree parsing */
+	initrd_start = initrd_end = 0;
+
+	if (!phys_initrd_size)
+		return;
+	/*
+	 * Round the memory region to page boundaries as per free_initrd_mem()
+	 * This allows us to detect whether the pages overlapping the initrd
+	 * are in use, but more importantly, reserves the entire set of pages
+	 * as we don't want these pages allocated for other purposes.
+	 */
+	start = round_down(phys_initrd_start, PAGE_SIZE);
+	size = phys_initrd_size + (phys_initrd_start - start);
+	size = round_up(size, PAGE_SIZE);
+
+	if (!memblock_is_region_memory(start, size)) {
+		pr_err("INITRD: 0x%08llx+0x%08lx is not a memory region",
+		       (u64)start, size);
+		goto disable;
+	}
+
+	if (memblock_is_region_reserved(start, size)) {
+		pr_err("INITRD: 0x%08llx+0x%08lx overlaps in-use memory region\n",
+		       (u64)start, size);
+		goto disable;
+	}
+
+	memblock_reserve(start, size);
+	/* Now convert initrd to virtual addresses */
+	initrd_start = (unsigned long)__va(phys_initrd_start);
+	initrd_end = initrd_start + phys_initrd_size;
+	initrd_below_start_ok = 1;
+
+	return;
+disable:
+	pr_cont(" - disabling initrd\n");
+	initrd_start = 0;
+	initrd_end = 0;
+}
+
+void __weak __init free_initrd_mem(unsigned long start, unsigned long end)
+{
+	free_reserved_area((void *)start, (void *)end, POISON_FREE_INITMEM,
+			"initrd");
+}
+
+#ifdef CONFIG_CRASH_RESERVE
+static bool __init kexec_free_initrd(void)
+{
+	unsigned long crashk_start = (unsigned long)__va(crashk_res.start);
+	unsigned long crashk_end   = (unsigned long)__va(crashk_res.end);
+
+	/*
+	 * If the initrd region is overlapped with crashkernel reserved region,
+	 * free only memory that is not part of crashkernel region.
+	 */
+	if (initrd_start >= crashk_end || initrd_end <= crashk_start)
+		return false;
+
+	/*
+	 * Initialize initrd memory region since the kexec boot does not do.
+	 */
+	memset((void *)initrd_start, 0, initrd_end - initrd_start);
+	if (initrd_start < crashk_start)
+		free_initrd_mem(initrd_start, crashk_start);
+	if (initrd_end > crashk_end)
+		free_initrd_mem(crashk_end, initrd_end);
+	return true;
+}
+#else
+static inline bool kexec_free_initrd(void)
+{
+	return false;
+}
+#endif /* CONFIG_KEXEC_CORE */
+
+#ifdef CONFIG_BLK_DEV_RAM
+static void __init populate_initrd_image(char *err)
+{
+	ssize_t written;
+	struct file *file;
+	loff_t pos = 0;
+
+	printk(KERN_INFO "rootfs image is not initramfs (%s); looks like an initrd\n",
+			err);
+	file = filp_open("/initrd.image", O_WRONLY|O_CREAT|O_LARGEFILE, 0700);
+	if (IS_ERR(file))
+		return;
+
+	written = xwrite(file, (char *)initrd_start, initrd_end - initrd_start,
+			&pos);
+	if (written != initrd_end - initrd_start)
+		pr_err("/initrd.image: incomplete write (%zd != %ld)\n",
+		       written, initrd_end - initrd_start);
+	fput(file);
+}
+#endif /* CONFIG_BLK_DEV_RAM */
+
+static void __init unpack_initramfs(async_cookie_t cookie)
+{
+	/* Load the built in initramfs */
+	char *err = unpack_to_rootfs(__initramfs_start, __initramfs_size);
+	if (err)
+		panic_show_mem("%s", err); /* Failed to decompress INTERNAL initramfs */
+
+	if (!initrd_start || IS_ENABLED(CONFIG_INITRAMFS_FORCE))
+		return;
+
+	if (IS_ENABLED(CONFIG_BLK_DEV_RAM))
+		printk(KERN_INFO "Trying to unpack rootfs image as initramfs...\n");
+	else
+		printk(KERN_INFO "Unpacking initramfs...\n");
+
+	err = unpack_to_rootfs((char *)initrd_start, initrd_end - initrd_start);
+	if (err) {
+#ifdef CONFIG_BLK_DEV_RAM
+		populate_initrd_image(err);
+#else
+		printk(KERN_EMERG "Initramfs unpacking failed: %s\n", err);
+#endif
+	}
+}
+
+static void __init do_populate_rootfs(void *unused, async_cookie_t cookie)
+{
+	scoped_with_init_fs() {
+		unpack_initramfs(cookie);
+		security_initramfs_populated();
+	}
+
+	/*
+	 * If the initrd region is overlapped with crashkernel reserved region,
+	 * free only memory that is not part of crashkernel region.
+	 */
+	if (!do_retain_initrd && initrd_start && !kexec_free_initrd()) {
+		free_initrd_mem(initrd_start, initrd_end);
+	} else if (do_retain_initrd && initrd_start) {
+		bin_attr_initrd.size = initrd_end - initrd_start;
+		bin_attr_initrd.private = (void *)initrd_start;
+		if (sysfs_create_bin_file(firmware_kobj, &bin_attr_initrd))
+			pr_err("Failed to create initrd sysfs file");
+	}
+	initrd_start = 0;
+	initrd_end = 0;
+
+	init_flush_fput();
+}
+
+static ASYNC_DOMAIN_EXCLUSIVE(initramfs_domain);
+static async_cookie_t initramfs_cookie;
+
+void wait_for_initramfs(void)
+{
+	if (!initramfs_cookie) {
+		/*
+		 * Something before rootfs_initcall wants to access
+		 * the filesystem/initramfs. Probably a bug. Make a
+		 * note, avoid deadlocking the machine, and let the
+		 * caller's access fail as it used to.
+		 */
+		pr_warn_once("wait_for_initramfs() called before rootfs_initcalls\n");
+		return;
+	}
+	async_synchronize_cookie_domain(initramfs_cookie + 1, &initramfs_domain);
+}
+EXPORT_SYMBOL_GPL(wait_for_initramfs);
+
+static int __init populate_rootfs(void)
+{
+	initramfs_cookie = async_schedule_domain(do_populate_rootfs, NULL,
+						 &initramfs_domain);
+	usermodehelper_enable();
+	if (!initramfs_async)
+		wait_for_initramfs();
+	return 0;
+}
+rootfs_initcall(populate_rootfs);