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, 316 insertions, 0 deletions

diff --git a/fs/nfs/nfsroot.c b/fs/nfs/nfsroot.c
new file mode 100644
index 000000000..432612d22
--- /dev/null
+++ b/fs/nfs/nfsroot.c
@@ -0,0 +1,316 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  Copyright (C) 1995, 1996  Gero Kuhlmann <gero@gkminix.han.de>
+ *
+ *  Allow an NFS filesystem to be mounted as root. The way this works is:
+ *     (1) Use the IP autoconfig mechanism to set local IP addresses and routes.
+ *     (2) Construct the device string and the options string using DHCP
+ *         option 17 and/or kernel command line options.
+ *     (3) When mount_root() sets up the root file system, pass these strings
+ *         to the NFS client's regular mount interface via sys_mount().
+ *
+ *
+ *	Changes:
+ *
+ *	Alan Cox	:	Removed get_address name clash with FPU.
+ *	Alan Cox	:	Reformatted a bit.
+ *	Gero Kuhlmann	:	Code cleanup
+ *	Michael Rausch  :	Fixed recognition of an incoming RARP answer.
+ *	Martin Mares	: (2.0)	Auto-configuration via BOOTP supported.
+ *	Martin Mares	:	Manual selection of interface & BOOTP/RARP.
+ *	Martin Mares	:	Using network routes instead of host routes,
+ *				allowing the default configuration to be used
+ *				for normal operation of the host.
+ *	Martin Mares	:	Randomized timer with exponential backoff
+ *				installed to minimize network congestion.
+ *	Martin Mares	:	Code cleanup.
+ *	Martin Mares	: (2.1)	BOOTP and RARP made configuration options.
+ *	Martin Mares	:	Server hostname generation fixed.
+ *	Gerd Knorr	:	Fixed wired inode handling
+ *	Martin Mares	: (2.2)	"0.0.0.0" addresses from command line ignored.
+ *	Martin Mares	:	RARP replies not tested for server address.
+ *	Gero Kuhlmann	: (2.3) Some bug fixes and code cleanup again (please
+ *				send me your new patches _before_ bothering
+ *				Linus so that I don' always have to cleanup
+ *				_afterwards_ - thanks)
+ *	Gero Kuhlmann	:	Last changes of Martin Mares undone.
+ *	Gero Kuhlmann	: 	RARP replies are tested for specified server
+ *				again. However, it's now possible to have
+ *				different RARP and NFS servers.
+ *	Gero Kuhlmann	:	"0.0.0.0" addresses from command line are
+ *				now mapped to INADDR_NONE.
+ *	Gero Kuhlmann	:	Fixed a bug which prevented BOOTP path name
+ *				from being used (thanks to Leo Spiekman)
+ *	Andy Walker	:	Allow to specify the NFS server in nfs_root
+ *				without giving a path name
+ *	Swen Thümmler	:	Allow to specify the NFS options in nfs_root
+ *				without giving a path name. Fix BOOTP request
+ *				for domainname (domainname is NIS domain, not
+ *				DNS domain!). Skip dummy devices for BOOTP.
+ *	Jacek Zapala	:	Fixed a bug which prevented server-ip address
+ *				from nfsroot parameter from being used.
+ *	Olaf Kirch	:	Adapted to new NFS code.
+ *	Jakub Jelinek	:	Free used code segment.
+ *	Marko Kohtala	:	Fixed some bugs.
+ *	Martin Mares	:	Debug message cleanup
+ *	Martin Mares	:	Changed to use the new generic IP layer autoconfig
+ *				code. BOOTP and RARP moved there.
+ *	Martin Mares	:	Default path now contains host name instead of
+ *				host IP address (but host name defaults to IP
+ *				address anyway).
+ *	Martin Mares	:	Use root_server_addr appropriately during setup.
+ *	Martin Mares	:	Rewrote parameter parsing, now hopefully giving
+ *				correct overriding.
+ *	Trond Myklebust :	Add in preliminary support for NFSv3 and TCP.
+ *				Fix bug in root_nfs_addr(). nfs_data.namlen
+ *				is NOT for the length of the hostname.
+ *	Hua Qin		:	Support for mounting root file system via
+ *				NFS over TCP.
+ *	Fabian Frederick:	Option parser rebuilt (using parser lib)
+ *	Chuck Lever	:	Use super.c's text-based mount option parsing
+ *	Chuck Lever	:	Add "nfsrootdebug".
+ */
+
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/init.h>
+#include <linux/nfs.h>
+#include <linux/nfs_fs.h>
+#include <linux/utsname.h>
+#include <linux/root_dev.h>
+#include <net/ipconfig.h>
+
+#include "internal.h"
+
+#define NFSDBG_FACILITY NFSDBG_ROOT
+
+/* Default path we try to mount. "%s" gets replaced by our IP address */
+#define NFS_ROOT		"/tftpboot/%s"
+
+/* Default NFSROOT mount options. */
+#if defined(CONFIG_NFS_V2)
+#define NFS_DEF_OPTIONS		"vers=2,tcp,rsize=4096,wsize=4096"
+#elif defined(CONFIG_NFS_V3)
+#define NFS_DEF_OPTIONS		"vers=3,tcp,rsize=4096,wsize=4096"
+#else
+#define NFS_DEF_OPTIONS		"vers=4,tcp,rsize=4096,wsize=4096"
+#endif
+
+/* Parameters passed from the kernel command line */
+static char nfs_root_parms[NFS_MAXPATHLEN + 1] __initdata = "";
+
+/* Text-based mount options passed to super.c */
+static char nfs_root_options[256] __initdata = NFS_DEF_OPTIONS;
+
+/* Address of NFS server */
+static __be32 servaddr __initdata = htonl(INADDR_NONE);
+
+/* Name of directory to mount */
+static char nfs_export_path[NFS_MAXPATHLEN + 1] __initdata = "";
+
+/* server:export path string passed to super.c */
+static char nfs_root_device[NFS_MAXPATHLEN + 1] __initdata = "";
+
+#ifdef NFS_DEBUG
+/*
+ * When the "nfsrootdebug" kernel command line option is specified,
+ * enable debugging messages for NFSROOT.
+ */
+static int __init nfs_root_debug(char *__unused)
+{
+	nfs_debug |= NFSDBG_ROOT | NFSDBG_MOUNT;
+	return 1;
+}
+
+__setup("nfsrootdebug", nfs_root_debug);
+#endif
+
+/*
+ *  Parse NFS server and directory information passed on the kernel
+ *  command line.
+ *
+ *  nfsroot=[<server-ip>:]<root-dir>[,<nfs-options>]
+ *
+ *  If there is a "%s" token in the <root-dir> string, it is replaced
+ *  by the ASCII-representation of the client's IP address.
+ */
+static int __init nfs_root_setup(char *line)
+{
+	ROOT_DEV = Root_NFS;
+
+	if (line[0] == '/' || line[0] == ',' || (line[0] >= '0' && line[0] <= '9')) {
+		strscpy(nfs_root_parms, line, sizeof(nfs_root_parms));
+	} else {
+		size_t n = strlen(line) + sizeof(NFS_ROOT) - 1;
+		if (n >= sizeof(nfs_root_parms))
+			line[sizeof(nfs_root_parms) - sizeof(NFS_ROOT) - 2] = '\0';
+		sprintf(nfs_root_parms, NFS_ROOT, line);
+	}
+
+	/*
+	 * Extract the IP address of the NFS server containing our
+	 * root file system, if one was specified.
+	 *
+	 * Note: root_nfs_parse_addr() removes the server-ip from
+	 *	 nfs_root_parms, if it exists.
+	 */
+	root_server_addr = root_nfs_parse_addr(nfs_root_parms);
+
+	return 1;
+}
+
+__setup("nfsroot=", nfs_root_setup);
+
+static int __init root_nfs_copy(char *dest, const char *src,
+				     const size_t destlen)
+{
+	if (strscpy(dest, src, destlen) == -E2BIG)
+		return -1;
+	return 0;
+}
+
+static int __init root_nfs_cat(char *dest, const char *src,
+			       const size_t destlen)
+{
+	size_t len = strlen(dest);
+
+	if (len && dest[len - 1] != ',')
+		if (strlcat(dest, ",", destlen) >= destlen)
+			return -1;
+
+	if (strlcat(dest, src, destlen) >= destlen)
+		return -1;
+	return 0;
+}
+
+/*
+ * Parse out root export path and mount options from
+ * passed-in string @incoming.
+ *
+ * Copy the export path into @exppath.
+ */
+static int __init root_nfs_parse_options(char *incoming, char *exppath,
+					 const size_t exppathlen)
+{
+	char *p;
+
+	/*
+	 * Set the NFS remote path
+	 */
+	p = strsep(&incoming, ",");
+	if (*p != '\0' && strcmp(p, "default") != 0)
+		if (root_nfs_copy(exppath, p, exppathlen))
+			return -1;
+
+	/*
+	 * @incoming now points to the rest of the string; if it
+	 * contains something, append it to our root options buffer
+	 */
+	if (incoming != NULL && *incoming != '\0')
+		if (root_nfs_cat(nfs_root_options, incoming,
+						sizeof(nfs_root_options)))
+			return -1;
+	return 0;
+}
+
+/*
+ *  Decode the export directory path name and NFS options from
+ *  the kernel command line.  This has to be done late in order to
+ *  use a dynamically acquired client IP address for the remote
+ *  root directory path.
+ *
+ *  Returns zero if successful; otherwise -1 is returned.
+ */
+static int __init root_nfs_data(char *cmdline)
+{
+	char mand_options[sizeof("nolock,addr=") + INET_ADDRSTRLEN + 1];
+	int len, retval = -1;
+	char *tmp = NULL;
+	const size_t tmplen = sizeof(nfs_export_path);
+
+	tmp = kzalloc(tmplen, GFP_KERNEL);
+	if (tmp == NULL)
+		goto out_nomem;
+	strcpy(tmp, NFS_ROOT);
+
+	if (root_server_path[0] != '\0') {
+		dprintk("Root-NFS: DHCPv4 option 17: %s\n",
+			root_server_path);
+		if (root_nfs_parse_options(root_server_path, tmp, tmplen))
+			goto out_optionstoolong;
+	}
+
+	if (cmdline[0] != '\0') {
+		dprintk("Root-NFS: nfsroot=%s\n", cmdline);
+		if (root_nfs_parse_options(cmdline, tmp, tmplen))
+			goto out_optionstoolong;
+	}
+
+	/*
+	 * Append mandatory options for nfsroot so they override
+	 * what has come before
+	 */
+	snprintf(mand_options, sizeof(mand_options), "nolock,addr=%pI4",
+			&servaddr);
+	if (root_nfs_cat(nfs_root_options, mand_options,
+						sizeof(nfs_root_options)))
+		goto out_optionstoolong;
+
+	/*
+	 * Set up nfs_root_device.  For NFS mounts, this looks like
+	 *
+	 *	server:/path
+	 *
+	 * At this point, utsname()->nodename contains our local
+	 * IP address or hostname, set by ipconfig.  If "%s" exists
+	 * in tmp, substitute the nodename, then shovel the whole
+	 * mess into nfs_root_device.
+	 */
+	len = snprintf(nfs_export_path, sizeof(nfs_export_path),
+				tmp, utsname()->nodename);
+	if (len >= (int)sizeof(nfs_export_path))
+		goto out_devnametoolong;
+	len = snprintf(nfs_root_device, sizeof(nfs_root_device),
+				"%pI4:%s", &servaddr, nfs_export_path);
+	if (len >= (int)sizeof(nfs_root_device))
+		goto out_devnametoolong;
+
+	retval = 0;
+
+out:
+	kfree(tmp);
+	return retval;
+out_nomem:
+	printk(KERN_ERR "Root-NFS: could not allocate memory\n");
+	goto out;
+out_optionstoolong:
+	printk(KERN_ERR "Root-NFS: mount options string too long\n");
+	goto out;
+out_devnametoolong:
+	printk(KERN_ERR "Root-NFS: root device name too long.\n");
+	goto out;
+}
+
+/**
+ * nfs_root_data - Return prepared 'data' for NFSROOT mount
+ * @root_device: OUT: address of string containing NFSROOT device
+ * @root_data: OUT: address of string containing NFSROOT mount options
+ *
+ * Returns zero and sets @root_device and @root_data if successful,
+ * otherwise -1 is returned.
+ */
+int __init nfs_root_data(char **root_device, char **root_data)
+{
+	servaddr = root_server_addr;
+	if (servaddr == htonl(INADDR_NONE)) {
+		printk(KERN_ERR "Root-NFS: no NFS server address\n");
+		return -1;
+	}
+
+	if (root_nfs_data(nfs_root_parms) < 0)
+		return -1;
+
+	*root_device = nfs_root_device;
+	*root_data = nfs_root_options;
+	return 0;
+}