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, 513 insertions, 0 deletions

diff --git a/fs/autofs/waitq.c b/fs/autofs/waitq.c
new file mode 100644
index 000000000..d46241342
--- /dev/null
+++ b/fs/autofs/waitq.c
@@ -0,0 +1,513 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
+ * Copyright 2001-2006 Ian Kent <raven@themaw.net>
+ */
+
+#include <linux/sched/signal.h>
+#include "autofs_i.h"
+
+/* We make this a static variable rather than a part of the superblock; it
+ * is better if we don't reassign numbers easily even across filesystems
+ */
+static autofs_wqt_t autofs_next_wait_queue = 1;
+
+void autofs_catatonic_mode(struct autofs_sb_info *sbi)
+{
+	struct autofs_wait_queue *wq, *nwq;
+
+	mutex_lock(&sbi->wq_mutex);
+	if (sbi->flags & AUTOFS_SBI_CATATONIC) {
+		mutex_unlock(&sbi->wq_mutex);
+		return;
+	}
+
+	pr_debug("entering catatonic mode\n");
+
+	sbi->flags |= AUTOFS_SBI_CATATONIC;
+	wq = sbi->queues;
+	sbi->queues = NULL;	/* Erase all wait queues */
+	while (wq) {
+		nwq = wq->next;
+		wq->status = -ENOENT; /* Magic is gone - report failure */
+		kfree(wq->name.name - wq->offset);
+		wq->name.name = NULL;
+		wake_up(&wq->queue);
+		if (!--wq->wait_ctr)
+			kfree(wq);
+		wq = nwq;
+	}
+	fput(sbi->pipe);	/* Close the pipe */
+	sbi->pipe = NULL;
+	sbi->pipefd = -1;
+	mutex_unlock(&sbi->wq_mutex);
+}
+
+static int autofs_write(struct autofs_sb_info *sbi,
+			struct file *file, const void *addr, int bytes)
+{
+	unsigned long sigpipe, flags;
+	const char *data = (const char *)addr;
+	ssize_t wr = 0;
+
+	sigpipe = sigismember(&current->pending.signal, SIGPIPE);
+
+	mutex_lock(&sbi->pipe_mutex);
+	while (bytes) {
+		wr = __kernel_write(file, data, bytes, NULL);
+		if (wr <= 0)
+			break;
+		data += wr;
+		bytes -= wr;
+	}
+	mutex_unlock(&sbi->pipe_mutex);
+
+	/* Keep the currently executing process from receiving a
+	 * SIGPIPE unless it was already supposed to get one
+	 */
+	if (wr == -EPIPE && !sigpipe) {
+		spin_lock_irqsave(&current->sighand->siglock, flags);
+		sigdelset(&current->pending.signal, SIGPIPE);
+		recalc_sigpending();
+		spin_unlock_irqrestore(&current->sighand->siglock, flags);
+	}
+
+	/* if 'wr' returned 0 (impossible) we assume -EIO (safe) */
+	return bytes == 0 ? 0 : wr < 0 ? wr : -EIO;
+}
+
+static void autofs_notify_daemon(struct autofs_sb_info *sbi,
+				 struct autofs_wait_queue *wq,
+				 int type)
+{
+	union {
+		struct autofs_packet_hdr hdr;
+		union autofs_packet_union v4_pkt;
+		union autofs_v5_packet_union v5_pkt;
+	} pkt;
+	struct file *pipe = NULL;
+	size_t pktsz;
+	int ret;
+
+	pr_debug("wait id = 0x%08lx, name = %.*s, type=%d\n",
+		 (unsigned long) wq->wait_queue_token,
+		 wq->name.len, wq->name.name, type);
+
+	memset(&pkt, 0, sizeof(pkt)); /* For security reasons */
+
+	pkt.hdr.proto_version = sbi->version;
+	pkt.hdr.type = type;
+
+	switch (type) {
+	/* Kernel protocol v4 missing and expire packets */
+	case autofs_ptype_missing:
+	{
+		struct autofs_packet_missing *mp = &pkt.v4_pkt.missing;
+
+		pktsz = sizeof(*mp);
+
+		mp->wait_queue_token = wq->wait_queue_token;
+		mp->len = wq->name.len;
+		memcpy(mp->name, wq->name.name, wq->name.len);
+		mp->name[wq->name.len] = '\0';
+		break;
+	}
+	case autofs_ptype_expire_multi:
+	{
+		struct autofs_packet_expire_multi *ep =
+					&pkt.v4_pkt.expire_multi;
+
+		pktsz = sizeof(*ep);
+
+		ep->wait_queue_token = wq->wait_queue_token;
+		ep->len = wq->name.len;
+		memcpy(ep->name, wq->name.name, wq->name.len);
+		ep->name[wq->name.len] = '\0';
+		break;
+	}
+	/*
+	 * Kernel protocol v5 packet for handling indirect and direct
+	 * mount missing and expire requests
+	 */
+	case autofs_ptype_missing_indirect:
+	case autofs_ptype_expire_indirect:
+	case autofs_ptype_missing_direct:
+	case autofs_ptype_expire_direct:
+	{
+		struct autofs_v5_packet *packet = &pkt.v5_pkt.v5_packet;
+		struct user_namespace *user_ns = sbi->pipe->f_cred->user_ns;
+
+		pktsz = sizeof(*packet);
+
+		packet->wait_queue_token = wq->wait_queue_token;
+		packet->len = wq->name.len;
+		memcpy(packet->name, wq->name.name, wq->name.len);
+		packet->name[wq->name.len] = '\0';
+		packet->dev = wq->dev;
+		packet->ino = wq->ino;
+		packet->uid = from_kuid_munged(user_ns, wq->uid);
+		packet->gid = from_kgid_munged(user_ns, wq->gid);
+		packet->pid = wq->pid;
+		packet->tgid = wq->tgid;
+		break;
+	}
+	default:
+		pr_warn("bad type %d!\n", type);
+		mutex_unlock(&sbi->wq_mutex);
+		return;
+	}
+
+	pipe = get_file(sbi->pipe);
+
+	mutex_unlock(&sbi->wq_mutex);
+
+	switch (ret = autofs_write(sbi, pipe, &pkt, pktsz)) {
+	case 0:
+		break;
+	case -ENOMEM:
+	case -ERESTARTSYS:
+		/* Just fail this one */
+		autofs_wait_release(sbi, wq->wait_queue_token, ret);
+		break;
+	default:
+		autofs_catatonic_mode(sbi);
+		break;
+	}
+	fput(pipe);
+}
+
+static struct autofs_wait_queue *
+autofs_find_wait(struct autofs_sb_info *sbi, const struct qstr *qstr)
+{
+	struct autofs_wait_queue *wq;
+
+	for (wq = sbi->queues; wq; wq = wq->next) {
+		if (wq->name.hash == qstr->hash &&
+		    wq->name.len == qstr->len &&
+		    wq->name.name &&
+		    !memcmp(wq->name.name, qstr->name, qstr->len))
+			break;
+	}
+	return wq;
+}
+
+/*
+ * Check if we have a valid request.
+ * Returns
+ * 1 if the request should continue.
+ *   In this case we can return an autofs_wait_queue entry if one is
+ *   found or NULL to idicate a new wait needs to be created.
+ * 0 or a negative errno if the request shouldn't continue.
+ */
+static int validate_request(struct autofs_wait_queue **wait,
+			    struct autofs_sb_info *sbi,
+			    const struct qstr *qstr,
+			    const struct path *path, enum autofs_notify notify)
+{
+	struct dentry *dentry = path->dentry;
+	struct autofs_wait_queue *wq;
+	struct autofs_info *ino;
+
+	if (sbi->flags & AUTOFS_SBI_CATATONIC)
+		return -ENOENT;
+
+	/* Wait in progress, continue; */
+	wq = autofs_find_wait(sbi, qstr);
+	if (wq) {
+		*wait = wq;
+		return 1;
+	}
+
+	*wait = NULL;
+
+	/* If we don't yet have any info this is a new request */
+	ino = autofs_dentry_ino(dentry);
+	if (!ino)
+		return 1;
+
+	/*
+	 * If we've been asked to wait on an existing expire (NFY_NONE)
+	 * but there is no wait in the queue ...
+	 */
+	if (notify == NFY_NONE) {
+		/*
+		 * Either we've betean the pending expire to post it's
+		 * wait or it finished while we waited on the mutex.
+		 * So we need to wait till either, the wait appears
+		 * or the expire finishes.
+		 */
+
+		while (ino->flags & AUTOFS_INF_EXPIRING) {
+			mutex_unlock(&sbi->wq_mutex);
+			schedule_timeout_interruptible(HZ/10);
+			if (mutex_lock_interruptible(&sbi->wq_mutex))
+				return -EINTR;
+
+			if (sbi->flags & AUTOFS_SBI_CATATONIC)
+				return -ENOENT;
+
+			wq = autofs_find_wait(sbi, qstr);
+			if (wq) {
+				*wait = wq;
+				return 1;
+			}
+		}
+
+		/*
+		 * Not ideal but the status has already gone. Of the two
+		 * cases where we wait on NFY_NONE neither depend on the
+		 * return status of the wait.
+		 */
+		return 0;
+	}
+
+	/*
+	 * If we've been asked to trigger a mount and the request
+	 * completed while we waited on the mutex ...
+	 */
+	if (notify == NFY_MOUNT) {
+		struct dentry *new = NULL;
+		struct path this;
+		int valid = 1;
+
+		/*
+		 * If the dentry was successfully mounted while we slept
+		 * on the wait queue mutex we can return success. If it
+		 * isn't mounted (doesn't have submounts for the case of
+		 * a multi-mount with no mount at it's base) we can
+		 * continue on and create a new request.
+		 */
+		if (!IS_ROOT(dentry)) {
+			if (d_unhashed(dentry) &&
+			    d_really_is_positive(dentry)) {
+				struct dentry *parent = dentry->d_parent;
+
+				new = d_lookup(parent, &dentry->d_name);
+				if (new)
+					dentry = new;
+			}
+		}
+		this.mnt = path->mnt;
+		this.dentry = dentry;
+		if (path_has_submounts(&this))
+			valid = 0;
+
+		if (new)
+			dput(new);
+		return valid;
+	}
+
+	return 1;
+}
+
+int autofs_wait(struct autofs_sb_info *sbi,
+		 const struct path *path, enum autofs_notify notify)
+{
+	struct dentry *dentry = path->dentry;
+	struct autofs_wait_queue *wq;
+	struct qstr qstr;
+	char *name;
+	int status, ret, type;
+	unsigned int offset = 0;
+	pid_t pid;
+	pid_t tgid;
+
+	/* In catatonic mode, we don't wait for nobody */
+	if (sbi->flags & AUTOFS_SBI_CATATONIC)
+		return -ENOENT;
+
+	/*
+	 * Try translating pids to the namespace of the daemon.
+	 *
+	 * Zero means failure: we are in an unrelated pid namespace.
+	 */
+	pid = task_pid_nr_ns(current, ns_of_pid(sbi->oz_pgrp));
+	tgid = task_tgid_nr_ns(current, ns_of_pid(sbi->oz_pgrp));
+	if (pid == 0 || tgid == 0)
+		return -ENOENT;
+
+	if (d_really_is_negative(dentry)) {
+		/*
+		 * A wait for a negative dentry is invalid for certain
+		 * cases. A direct or offset mount "always" has its mount
+		 * point directory created and so the request dentry must
+		 * be positive or the map key doesn't exist. The situation
+		 * is very similar for indirect mounts except only dentrys
+		 * in the root of the autofs file system may be negative.
+		 */
+		if (autofs_type_trigger(sbi->type))
+			return -ENOENT;
+		else if (!IS_ROOT(dentry->d_parent))
+			return -ENOENT;
+	}
+
+	name = kmalloc(NAME_MAX + 1, GFP_KERNEL);
+	if (!name)
+		return -ENOMEM;
+
+	/* If this is a direct mount request create a dummy name */
+	if (IS_ROOT(dentry) && autofs_type_trigger(sbi->type)) {
+		qstr.name = name;
+		qstr.len = sprintf(name, "%p", dentry);
+	} else {
+		char *p = dentry_path_raw(dentry, name, NAME_MAX);
+		if (IS_ERR(p)) {
+			kfree(name);
+			return -ENOENT;
+		}
+		qstr.name = ++p; // skip the leading slash
+		qstr.len = strlen(p);
+		offset = p - name;
+	}
+	qstr.hash = full_name_hash(dentry, qstr.name, qstr.len);
+
+	if (mutex_lock_interruptible(&sbi->wq_mutex)) {
+		kfree(name);
+		return -EINTR;
+	}
+
+	ret = validate_request(&wq, sbi, &qstr, path, notify);
+	if (ret <= 0) {
+		if (ret != -EINTR)
+			mutex_unlock(&sbi->wq_mutex);
+		kfree(name);
+		return ret;
+	}
+
+	if (!wq) {
+		/* Create a new wait queue */
+		wq = kmalloc_obj(struct autofs_wait_queue);
+		if (!wq) {
+			kfree(name);
+			mutex_unlock(&sbi->wq_mutex);
+			return -ENOMEM;
+		}
+
+		wq->wait_queue_token = autofs_next_wait_queue;
+		if (++autofs_next_wait_queue == 0)
+			autofs_next_wait_queue = 1;
+		wq->next = sbi->queues;
+		sbi->queues = wq;
+		init_waitqueue_head(&wq->queue);
+		memcpy(&wq->name, &qstr, sizeof(struct qstr));
+		wq->offset = offset;
+		wq->dev = autofs_get_dev(sbi);
+		wq->ino = autofs_get_ino(sbi);
+		wq->uid = current_uid();
+		wq->gid = current_gid();
+		wq->pid = pid;
+		wq->tgid = tgid;
+		wq->status = -EINTR; /* Status return if interrupted */
+		wq->wait_ctr = 2;
+
+		if (sbi->version < 5) {
+			if (notify == NFY_MOUNT)
+				type = autofs_ptype_missing;
+			else
+				type = autofs_ptype_expire_multi;
+		} else {
+			if (notify == NFY_MOUNT)
+				type = autofs_type_trigger(sbi->type) ?
+					autofs_ptype_missing_direct :
+					 autofs_ptype_missing_indirect;
+			else
+				type = autofs_type_trigger(sbi->type) ?
+					autofs_ptype_expire_direct :
+					autofs_ptype_expire_indirect;
+		}
+
+		pr_debug("new wait id = 0x%08lx, name = %.*s, nfy=%d\n",
+			 (unsigned long) wq->wait_queue_token, wq->name.len,
+			 wq->name.name, notify);
+
+		/*
+		 * autofs_notify_daemon() may block; it will unlock ->wq_mutex
+		 */
+		autofs_notify_daemon(sbi, wq, type);
+	} else {
+		wq->wait_ctr++;
+		pr_debug("existing wait id = 0x%08lx, name = %.*s, nfy=%d\n",
+			 (unsigned long) wq->wait_queue_token, wq->name.len,
+			 wq->name.name, notify);
+		mutex_unlock(&sbi->wq_mutex);
+		kfree(name);
+	}
+
+	/*
+	 * wq->name.name is NULL iff the lock is already released
+	 * or the mount has been made catatonic.
+	 */
+	wait_event_killable(wq->queue, wq->name.name == NULL);
+	status = wq->status;
+
+	/*
+	 * For direct and offset mounts we need to track the requester's
+	 * uid and gid in the dentry info struct. This is so it can be
+	 * supplied, on request, by the misc device ioctl interface.
+	 * This is needed during daemon resatart when reconnecting
+	 * to existing, active, autofs mounts. The uid and gid (and
+	 * related string values) may be used for macro substitution
+	 * in autofs mount maps.
+	 */
+	if (!status) {
+		struct autofs_info *ino;
+		struct dentry *de = NULL;
+
+		/* direct mount or browsable map */
+		ino = autofs_dentry_ino(dentry);
+		if (!ino) {
+			/* If not lookup actual dentry used */
+			de = d_lookup(dentry->d_parent, &dentry->d_name);
+			if (de)
+				ino = autofs_dentry_ino(de);
+		}
+
+		/* Set mount requester */
+		if (ino) {
+			spin_lock(&sbi->fs_lock);
+			ino->uid = wq->uid;
+			ino->gid = wq->gid;
+			spin_unlock(&sbi->fs_lock);
+		}
+
+		if (de)
+			dput(de);
+	}
+
+	/* Are we the last process to need status? */
+	mutex_lock(&sbi->wq_mutex);
+	if (!--wq->wait_ctr)
+		kfree(wq);
+	mutex_unlock(&sbi->wq_mutex);
+
+	return status;
+}
+
+
+int autofs_wait_release(struct autofs_sb_info *sbi,
+			autofs_wqt_t wait_queue_token, int status)
+{
+	struct autofs_wait_queue *wq, **wql;
+
+	mutex_lock(&sbi->wq_mutex);
+	for (wql = &sbi->queues; (wq = *wql) != NULL; wql = &wq->next) {
+		if (wq->wait_queue_token == wait_queue_token)
+			break;
+	}
+
+	if (!wq) {
+		mutex_unlock(&sbi->wq_mutex);
+		return -EINVAL;
+	}
+
+	*wql = wq->next;	/* Unlink from chain */
+	kfree(wq->name.name - wq->offset);
+	wq->name.name = NULL;	/* Do not wait on this queue */
+	wq->status = status;
+	wake_up(&wq->queue);
+	if (!--wq->wait_ctr)
+		kfree(wq);
+	mutex_unlock(&sbi->wq_mutex);
+
+	return 0;
+}