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, 581 insertions, 0 deletions

diff --git a/fs/lockd/mon.c b/fs/lockd/mon.c
new file mode 100644
index 000000000..a8f5ac6f0
--- /dev/null
+++ b/fs/lockd/mon.c
@@ -0,0 +1,581 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/fs/lockd/mon.c
+ *
+ * The kernel statd client.
+ *
+ * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
+ */
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/ktime.h>
+#include <linux/slab.h>
+
+#include <linux/sunrpc/clnt.h>
+#include <linux/sunrpc/addr.h>
+#include <linux/sunrpc/xprtsock.h>
+#include <linux/sunrpc/svc.h>
+
+#include <linux/unaligned.h>
+
+#include "lockd.h"
+#include "netns.h"
+
+#define NLMDBG_FACILITY		NLMDBG_MONITOR
+#define NSM_PROGRAM		100024
+#define NSM_VERSION		1
+
+enum {
+	NSMPROC_NULL,
+	NSMPROC_STAT,
+	NSMPROC_MON,
+	NSMPROC_UNMON,
+	NSMPROC_UNMON_ALL,
+	NSMPROC_SIMU_CRASH,
+	NSMPROC_NOTIFY,
+};
+
+struct nsm_args {
+	struct nsm_private	*priv;
+	u32			prog;		/* RPC callback info */
+	u32			vers;
+	u32			proc;
+
+	char			*mon_name;
+	const char		*nodename;
+};
+
+struct nsm_res {
+	u32			status;
+	u32			state;
+};
+
+static const struct rpc_program	nsm_program;
+static				DEFINE_SPINLOCK(nsm_lock);
+
+/*
+ * Local NSM state
+ */
+u32	__read_mostly		nsm_local_state;
+bool	__read_mostly		nsm_use_hostnames;
+
+static inline struct sockaddr *nsm_addr(const struct nsm_handle *nsm)
+{
+	return (struct sockaddr *)&nsm->sm_addr;
+}
+
+static struct rpc_clnt *nsm_create(struct net *net, const char *nodename)
+{
+	struct sockaddr_in sin = {
+		.sin_family		= AF_INET,
+		.sin_addr.s_addr	= htonl(INADDR_LOOPBACK),
+	};
+	struct rpc_create_args args = {
+		.net			= net,
+		.protocol		= XPRT_TRANSPORT_TCP,
+		.address		= (struct sockaddr *)&sin,
+		.addrsize		= sizeof(sin),
+		.servername		= "rpc.statd",
+		.nodename		= nodename,
+		.program		= &nsm_program,
+		.version		= NSM_VERSION,
+		.authflavor		= RPC_AUTH_NULL,
+		.flags			= RPC_CLNT_CREATE_NOPING,
+		.cred			= current_cred(),
+	};
+
+	return rpc_create(&args);
+}
+
+static int nsm_mon_unmon(struct nsm_handle *nsm, u32 proc, struct nsm_res *res,
+			 const struct nlm_host *host)
+{
+	int		status;
+	struct rpc_clnt *clnt;
+	struct nsm_args args = {
+		.priv		= &nsm->sm_priv,
+		.prog		= NLM_PROGRAM,
+		.vers		= 3,
+		.proc		= NLMPROC_NSM_NOTIFY,
+		.mon_name	= nsm->sm_mon_name,
+		.nodename	= host->nodename,
+	};
+	struct rpc_message msg = {
+		.rpc_argp	= &args,
+		.rpc_resp	= res,
+	};
+
+	memset(res, 0, sizeof(*res));
+
+	clnt = nsm_create(host->net, host->nodename);
+	if (IS_ERR(clnt)) {
+		dprintk("lockd: failed to create NSM upcall transport, "
+			"status=%ld, net=%x\n", PTR_ERR(clnt),
+			host->net->ns.inum);
+		return PTR_ERR(clnt);
+	}
+
+	msg.rpc_proc = &clnt->cl_procinfo[proc];
+	status = rpc_call_sync(clnt, &msg, RPC_TASK_SOFTCONN);
+	if (status == -ECONNREFUSED) {
+		dprintk("lockd:	NSM upcall RPC failed, status=%d, forcing rebind\n",
+				status);
+		rpc_force_rebind(clnt);
+		status = rpc_call_sync(clnt, &msg, RPC_TASK_SOFTCONN);
+	}
+	if (status < 0)
+		dprintk("lockd: NSM upcall RPC failed, status=%d\n",
+				status);
+	else
+		status = 0;
+
+	rpc_shutdown_client(clnt);
+	return status;
+}
+
+/**
+ * nsm_monitor - Notify a peer in case we reboot
+ * @host: pointer to nlm_host of peer to notify
+ *
+ * If this peer is not already monitored, this function sends an
+ * upcall to the local rpc.statd to record the name/address of
+ * the peer to notify in case we reboot.
+ *
+ * Returns zero if the peer is monitored by the local rpc.statd;
+ * otherwise a negative errno value is returned.
+ */
+int nsm_monitor(const struct nlm_host *host)
+{
+	struct nsm_handle *nsm = host->h_nsmhandle;
+	struct nsm_res	res;
+	int		status;
+
+	dprintk("lockd: nsm_monitor(%s)\n", nsm->sm_name);
+
+	if (nsm->sm_monitored)
+		return 0;
+
+	/*
+	 * Choose whether to record the caller_name or IP address of
+	 * this peer in the local rpc.statd's database.
+	 */
+	nsm->sm_mon_name = nsm_use_hostnames ? nsm->sm_name : nsm->sm_addrbuf;
+
+	status = nsm_mon_unmon(nsm, NSMPROC_MON, &res, host);
+	if (unlikely(res.status != 0))
+		status = -EIO;
+	if (unlikely(status < 0)) {
+		pr_notice_ratelimited("lockd: cannot monitor %s\n", nsm->sm_name);
+		return status;
+	}
+
+	nsm->sm_monitored = 1;
+	if (unlikely(nsm_local_state != res.state)) {
+		nsm_local_state = res.state;
+		dprintk("lockd: NSM state changed to %d\n", nsm_local_state);
+	}
+	return 0;
+}
+
+/**
+ * nsm_unmonitor - Unregister peer notification
+ * @host: pointer to nlm_host of peer to stop monitoring
+ *
+ * If this peer is monitored, this function sends an upcall to
+ * tell the local rpc.statd not to send this peer a notification
+ * when we reboot.
+ */
+void nsm_unmonitor(const struct nlm_host *host)
+{
+	struct nsm_handle *nsm = host->h_nsmhandle;
+	struct nsm_res	res;
+	int status;
+
+	if (refcount_read(&nsm->sm_count) == 1
+	 && nsm->sm_monitored && !nsm->sm_sticky) {
+		dprintk("lockd: nsm_unmonitor(%s)\n", nsm->sm_name);
+
+		status = nsm_mon_unmon(nsm, NSMPROC_UNMON, &res, host);
+		if (res.status != 0)
+			status = -EIO;
+		if (status < 0)
+			printk(KERN_NOTICE "lockd: cannot unmonitor %s\n",
+					nsm->sm_name);
+		else
+			nsm->sm_monitored = 0;
+	}
+}
+
+static struct nsm_handle *nsm_lookup_hostname(const struct list_head *nsm_handles,
+					const char *hostname, const size_t len)
+{
+	struct nsm_handle *nsm;
+
+	list_for_each_entry(nsm, nsm_handles, sm_link)
+		if (strlen(nsm->sm_name) == len &&
+		    memcmp(nsm->sm_name, hostname, len) == 0)
+			return nsm;
+	return NULL;
+}
+
+static struct nsm_handle *nsm_lookup_addr(const struct list_head *nsm_handles,
+					const struct sockaddr *sap)
+{
+	struct nsm_handle *nsm;
+
+	list_for_each_entry(nsm, nsm_handles, sm_link)
+		if (rpc_cmp_addr(nsm_addr(nsm), sap))
+			return nsm;
+	return NULL;
+}
+
+static struct nsm_handle *nsm_lookup_priv(const struct list_head *nsm_handles,
+					const struct nsm_private *priv)
+{
+	struct nsm_handle *nsm;
+
+	list_for_each_entry(nsm, nsm_handles, sm_link)
+		if (memcmp(nsm->sm_priv.data, priv->data,
+					sizeof(priv->data)) == 0)
+			return nsm;
+	return NULL;
+}
+
+/*
+ * Construct a unique cookie to match this nsm_handle to this monitored
+ * host.  It is passed to the local rpc.statd via NSMPROC_MON, and
+ * returned via NLMPROC_SM_NOTIFY, in the "priv" field of these
+ * requests.
+ *
+ * The NSM protocol requires that these cookies be unique while the
+ * system is running.  We prefer a stronger requirement of making them
+ * unique across reboots.  If user space bugs cause a stale cookie to
+ * be sent to the kernel, it could cause the wrong host to lose its
+ * lock state if cookies were not unique across reboots.
+ *
+ * The cookies are exposed only to local user space via loopback.  They
+ * do not appear on the physical network.  If we want greater security
+ * for some reason, nsm_init_private() could perform a one-way hash to
+ * obscure the contents of the cookie.
+ */
+static void nsm_init_private(struct nsm_handle *nsm)
+{
+	u64 *p = (u64 *)&nsm->sm_priv.data;
+	s64 ns;
+
+	ns = ktime_get_ns();
+	put_unaligned(ns, p);
+	put_unaligned((unsigned long)nsm, p + 1);
+}
+
+static struct nsm_handle *nsm_create_handle(const struct sockaddr *sap,
+					    const size_t salen,
+					    const char *hostname,
+					    const size_t hostname_len)
+{
+	struct nsm_handle *new;
+
+	if (!hostname)
+		return NULL;
+
+	new = kzalloc(sizeof(*new) + hostname_len + 1, GFP_KERNEL);
+	if (unlikely(new == NULL))
+		return NULL;
+
+	refcount_set(&new->sm_count, 1);
+	new->sm_name = (char *)(new + 1);
+	memcpy(nsm_addr(new), sap, salen);
+	new->sm_addrlen = salen;
+	nsm_init_private(new);
+
+	if (rpc_ntop(nsm_addr(new), new->sm_addrbuf,
+					sizeof(new->sm_addrbuf)) == 0)
+		(void)snprintf(new->sm_addrbuf, sizeof(new->sm_addrbuf),
+				"unsupported address family");
+	memcpy(new->sm_name, hostname, hostname_len);
+	new->sm_name[hostname_len] = '\0';
+
+	return new;
+}
+
+/**
+ * nsm_get_handle - Find or create a cached nsm_handle
+ * @net: network namespace
+ * @sap: pointer to socket address of handle to find
+ * @salen: length of socket address
+ * @hostname: pointer to C string containing hostname to find
+ * @hostname_len: length of C string
+ *
+ * Behavior is modulated by the global nsm_use_hostnames variable.
+ *
+ * Returns a cached nsm_handle after bumping its ref count, or
+ * returns a fresh nsm_handle if a handle that matches @sap and/or
+ * @hostname cannot be found in the handle cache.  Returns NULL if
+ * an error occurs.
+ */
+struct nsm_handle *nsm_get_handle(const struct net *net,
+				  const struct sockaddr *sap,
+				  const size_t salen, const char *hostname,
+				  const size_t hostname_len)
+{
+	struct nsm_handle *cached, *new = NULL;
+	struct lockd_net *ln = net_generic(net, lockd_net_id);
+
+	if (hostname && memchr(hostname, '/', hostname_len) != NULL) {
+		if (printk_ratelimit()) {
+			printk(KERN_WARNING "Invalid hostname \"%.*s\" "
+					    "in NFS lock request\n",
+				(int)hostname_len, hostname);
+		}
+		return NULL;
+	}
+
+retry:
+	spin_lock(&nsm_lock);
+
+	if (nsm_use_hostnames && hostname != NULL)
+		cached = nsm_lookup_hostname(&ln->nsm_handles,
+					hostname, hostname_len);
+	else
+		cached = nsm_lookup_addr(&ln->nsm_handles, sap);
+
+	if (cached != NULL) {
+		refcount_inc(&cached->sm_count);
+		spin_unlock(&nsm_lock);
+		kfree(new);
+		dprintk("lockd: found nsm_handle for %s (%s), "
+				"cnt %d\n", cached->sm_name,
+				cached->sm_addrbuf,
+				refcount_read(&cached->sm_count));
+		return cached;
+	}
+
+	if (new != NULL) {
+		list_add(&new->sm_link, &ln->nsm_handles);
+		spin_unlock(&nsm_lock);
+		dprintk("lockd: created nsm_handle for %s (%s)\n",
+				new->sm_name, new->sm_addrbuf);
+		return new;
+	}
+
+	spin_unlock(&nsm_lock);
+
+	new = nsm_create_handle(sap, salen, hostname, hostname_len);
+	if (unlikely(new == NULL))
+		return NULL;
+	goto retry;
+}
+
+/**
+ * nsm_reboot_lookup - match NLMPROC_SM_NOTIFY arguments to an nsm_handle
+ * @net:  network namespace
+ * @info: pointer to NLMPROC_SM_NOTIFY arguments
+ *
+ * Returns a matching nsm_handle if found in the nsm cache. The returned
+ * nsm_handle's reference count is bumped. Otherwise returns NULL if some
+ * error occurred.
+ */
+struct nsm_handle *nsm_reboot_lookup(const struct net *net,
+				const struct lockd_reboot *info)
+{
+	struct nsm_handle *cached;
+	struct lockd_net *ln = net_generic(net, lockd_net_id);
+
+	spin_lock(&nsm_lock);
+
+	cached = nsm_lookup_priv(&ln->nsm_handles, &info->priv);
+	if (unlikely(cached == NULL)) {
+		spin_unlock(&nsm_lock);
+		dprintk("lockd: never saw rebooted peer '%.*s' before\n",
+				info->len, info->mon);
+		return cached;
+	}
+
+	refcount_inc(&cached->sm_count);
+	spin_unlock(&nsm_lock);
+
+	dprintk("lockd: host %s (%s) rebooted, cnt %d\n",
+			cached->sm_name, cached->sm_addrbuf,
+			refcount_read(&cached->sm_count));
+	return cached;
+}
+
+/**
+ * nsm_release - Release an NSM handle
+ * @nsm: pointer to handle to be released
+ *
+ */
+void nsm_release(struct nsm_handle *nsm)
+{
+	if (refcount_dec_and_lock(&nsm->sm_count, &nsm_lock)) {
+		list_del(&nsm->sm_link);
+		spin_unlock(&nsm_lock);
+		dprintk("lockd: destroyed nsm_handle for %s (%s)\n",
+				nsm->sm_name, nsm->sm_addrbuf);
+		kfree(nsm);
+	}
+}
+
+/*
+ * XDR functions for NSM.
+ *
+ * See https://www.opengroup.org/ for details on the Network
+ * Status Monitor wire protocol.
+ */
+
+static void encode_nsm_string(struct xdr_stream *xdr, const char *string)
+{
+	const u32 len = strlen(string);
+	__be32 *p;
+
+	p = xdr_reserve_space(xdr, 4 + len);
+	xdr_encode_opaque(p, string, len);
+}
+
+/*
+ * "mon_name" specifies the host to be monitored.
+ */
+static void encode_mon_name(struct xdr_stream *xdr, const struct nsm_args *argp)
+{
+	encode_nsm_string(xdr, argp->mon_name);
+}
+
+/*
+ * The "my_id" argument specifies the hostname and RPC procedure
+ * to be called when the status manager receives notification
+ * (via the NLMPROC_SM_NOTIFY call) that the state of host "mon_name"
+ * has changed.
+ */
+static void encode_my_id(struct xdr_stream *xdr, const struct nsm_args *argp)
+{
+	__be32 *p;
+
+	encode_nsm_string(xdr, argp->nodename);
+	p = xdr_reserve_space(xdr, 4 + 4 + 4);
+	*p++ = cpu_to_be32(argp->prog);
+	*p++ = cpu_to_be32(argp->vers);
+	*p = cpu_to_be32(argp->proc);
+}
+
+/*
+ * The "mon_id" argument specifies the non-private arguments
+ * of an NSMPROC_MON or NSMPROC_UNMON call.
+ */
+static void encode_mon_id(struct xdr_stream *xdr, const struct nsm_args *argp)
+{
+	encode_mon_name(xdr, argp);
+	encode_my_id(xdr, argp);
+}
+
+/*
+ * The "priv" argument may contain private information required
+ * by the NSMPROC_MON call. This information will be supplied in the
+ * NLMPROC_SM_NOTIFY call.
+ */
+static void encode_priv(struct xdr_stream *xdr, const struct nsm_args *argp)
+{
+	__be32 *p;
+
+	p = xdr_reserve_space(xdr, SM_PRIV_SIZE);
+	xdr_encode_opaque_fixed(p, argp->priv->data, SM_PRIV_SIZE);
+}
+
+static void nsm_xdr_enc_mon(struct rpc_rqst *req, struct xdr_stream *xdr,
+			    const void *argp)
+{
+	encode_mon_id(xdr, argp);
+	encode_priv(xdr, argp);
+}
+
+static void nsm_xdr_enc_unmon(struct rpc_rqst *req, struct xdr_stream *xdr,
+			      const void *argp)
+{
+	encode_mon_id(xdr, argp);
+}
+
+static int nsm_xdr_dec_stat_res(struct rpc_rqst *rqstp,
+				struct xdr_stream *xdr,
+				void *data)
+{
+	struct nsm_res *resp = data;
+	__be32 *p;
+
+	p = xdr_inline_decode(xdr, 4 + 4);
+	if (unlikely(p == NULL))
+		return -EIO;
+	resp->status = be32_to_cpup(p++);
+	resp->state = be32_to_cpup(p);
+
+	dprintk("lockd: %s status %d state %d\n",
+		__func__, resp->status, resp->state);
+	return 0;
+}
+
+static int nsm_xdr_dec_stat(struct rpc_rqst *rqstp,
+			    struct xdr_stream *xdr,
+			    void *data)
+{
+	struct nsm_res *resp = data;
+	__be32 *p;
+
+	p = xdr_inline_decode(xdr, 4);
+	if (unlikely(p == NULL))
+		return -EIO;
+	resp->state = be32_to_cpup(p);
+
+	dprintk("lockd: %s state %d\n", __func__, resp->state);
+	return 0;
+}
+
+#define SM_my_name_sz	(1+XDR_QUADLEN(SM_MAXSTRLEN))
+#define SM_my_id_sz	(SM_my_name_sz+3)
+#define SM_mon_name_sz	(1+XDR_QUADLEN(SM_MAXSTRLEN))
+#define SM_mon_id_sz	(SM_mon_name_sz+SM_my_id_sz)
+#define SM_priv_sz	(XDR_QUADLEN(SM_PRIV_SIZE))
+#define SM_mon_sz	(SM_mon_id_sz+SM_priv_sz)
+#define SM_monres_sz	2
+#define SM_unmonres_sz	1
+
+static const struct rpc_procinfo nsm_procedures[] = {
+[NSMPROC_MON] = {
+		.p_proc		= NSMPROC_MON,
+		.p_encode	= nsm_xdr_enc_mon,
+		.p_decode	= nsm_xdr_dec_stat_res,
+		.p_arglen	= SM_mon_sz,
+		.p_replen	= SM_monres_sz,
+		.p_statidx	= NSMPROC_MON,
+		.p_name		= "MONITOR",
+	},
+[NSMPROC_UNMON] = {
+		.p_proc		= NSMPROC_UNMON,
+		.p_encode	= nsm_xdr_enc_unmon,
+		.p_decode	= nsm_xdr_dec_stat,
+		.p_arglen	= SM_mon_id_sz,
+		.p_replen	= SM_unmonres_sz,
+		.p_statidx	= NSMPROC_UNMON,
+		.p_name		= "UNMONITOR",
+	},
+};
+
+static unsigned int nsm_version1_counts[ARRAY_SIZE(nsm_procedures)];
+static const struct rpc_version nsm_version1 = {
+	.number		= 1,
+	.nrprocs	= ARRAY_SIZE(nsm_procedures),
+	.procs		= nsm_procedures,
+	.counts		= nsm_version1_counts,
+};
+
+static const struct rpc_version *nsm_version[] = {
+	[1] = &nsm_version1,
+};
+
+static struct rpc_stat		nsm_stats;
+
+static const struct rpc_program nsm_program = {
+	.name		= "statd",
+	.number		= NSM_PROGRAM,
+	.nrvers		= ARRAY_SIZE(nsm_version),
+	.version	= nsm_version,
+	.stats		= &nsm_stats
+};