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, 726 insertions, 0 deletions

diff --git a/arch/um/os-Linux/file.c b/arch/um/os-Linux/file.c
new file mode 100644
index 000000000..21f0e50fb
--- /dev/null
+++ b/arch/um/os-Linux/file.c
@@ -0,0 +1,726 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <linux/falloc.h>
+#include <sys/ioctl.h>
+#include <sys/mount.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/sysmacros.h>
+#include <sys/un.h>
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <sys/eventfd.h>
+#include <poll.h>
+#include <os.h>
+
+static void copy_stat(struct uml_stat *dst, const struct stat64 *src)
+{
+	*dst = ((struct uml_stat) {
+		.ust_dev     = src->st_dev,     /* device */
+		.ust_ino     = src->st_ino,     /* inode */
+		.ust_mode    = src->st_mode,    /* protection */
+		.ust_nlink   = src->st_nlink,   /* number of hard links */
+		.ust_uid     = src->st_uid,     /* user ID of owner */
+		.ust_gid     = src->st_gid,     /* group ID of owner */
+		.ust_size    = src->st_size,    /* total size, in bytes */
+		.ust_blksize = src->st_blksize, /* blocksize for filesys I/O */
+		.ust_blocks  = src->st_blocks,  /* number of blocks allocated */
+		.ust_atime   = src->st_atime,   /* time of last access */
+		.ust_mtime   = src->st_mtime,   /* time of last modification */
+		.ust_ctime   = src->st_ctime,   /* time of last change */
+	});
+}
+
+int os_stat_fd(const int fd, struct uml_stat *ubuf)
+{
+	struct stat64 sbuf;
+	int err;
+
+	CATCH_EINTR(err = fstat64(fd, &sbuf));
+	if (err < 0)
+		return -errno;
+
+	if (ubuf != NULL)
+		copy_stat(ubuf, &sbuf);
+	return err;
+}
+
+int os_stat_file(const char *file_name, struct uml_stat *ubuf)
+{
+	struct stat64 sbuf;
+	int err;
+
+	CATCH_EINTR(err = stat64(file_name, &sbuf));
+	if (err < 0)
+		return -errno;
+
+	if (ubuf != NULL)
+		copy_stat(ubuf, &sbuf);
+	return err;
+}
+
+int os_access(const char *file, int mode)
+{
+	int amode, err;
+
+	amode = (mode & OS_ACC_R_OK ? R_OK : 0) |
+		(mode & OS_ACC_W_OK ? W_OK : 0) |
+		(mode & OS_ACC_X_OK ? X_OK : 0) |
+		(mode & OS_ACC_F_OK ? F_OK : 0);
+
+	err = access(file, amode);
+	if (err < 0)
+		return -errno;
+
+	return 0;
+}
+
+/* FIXME? required only by hostaudio (because it passes ioctls verbatim) */
+int os_ioctl_generic(int fd, unsigned int cmd, unsigned long arg)
+{
+	int err;
+
+	err = ioctl(fd, cmd, arg);
+	if (err < 0)
+		return -errno;
+
+	return err;
+}
+
+/* FIXME: ensure namebuf in os_get_if_name is big enough */
+int os_get_ifname(int fd, char* namebuf)
+{
+	if (ioctl(fd, SIOCGIFNAME, namebuf) < 0)
+		return -errno;
+
+	return 0;
+}
+
+int os_mode_fd(int fd, int mode)
+{
+	int err;
+
+	CATCH_EINTR(err = fchmod(fd, mode));
+	if (err < 0)
+		return -errno;
+
+	return 0;
+}
+
+int os_file_type(char *file)
+{
+	struct uml_stat buf;
+	int err;
+
+	err = os_stat_file(file, &buf);
+	if (err < 0)
+		return err;
+
+	if (S_ISDIR(buf.ust_mode))
+		return OS_TYPE_DIR;
+	else if (S_ISLNK(buf.ust_mode))
+		return OS_TYPE_SYMLINK;
+	else if (S_ISCHR(buf.ust_mode))
+		return OS_TYPE_CHARDEV;
+	else if (S_ISBLK(buf.ust_mode))
+		return OS_TYPE_BLOCKDEV;
+	else if (S_ISFIFO(buf.ust_mode))
+		return OS_TYPE_FIFO;
+	else if (S_ISSOCK(buf.ust_mode))
+		return OS_TYPE_SOCK;
+	else return OS_TYPE_FILE;
+}
+
+int os_file_mode(const char *file, struct openflags *mode_out)
+{
+	int err;
+
+	*mode_out = OPENFLAGS();
+
+	err = access(file, W_OK);
+	if (err && (errno != EACCES))
+		return -errno;
+	else if (!err)
+		*mode_out = of_write(*mode_out);
+
+	err = access(file, R_OK);
+	if (err && (errno != EACCES))
+		return -errno;
+	else if (!err)
+		*mode_out = of_read(*mode_out);
+
+	return err;
+}
+
+int os_open_file(const char *file, struct openflags flags, int mode)
+{
+	int fd, err, f = 0;
+
+	if (flags.r && flags.w)
+		f = O_RDWR;
+	else if (flags.r)
+		f = O_RDONLY;
+	else if (flags.w)
+		f = O_WRONLY;
+	else f = 0;
+
+	if (flags.s)
+		f |= O_SYNC;
+	if (flags.c)
+		f |= O_CREAT;
+	if (flags.t)
+		f |= O_TRUNC;
+	if (flags.e)
+		f |= O_EXCL;
+	if (flags.a)
+		f |= O_APPEND;
+
+	fd = open64(file, f, mode);
+	if (fd < 0)
+		return -errno;
+
+	if (flags.cl && fcntl(fd, F_SETFD, 1)) {
+		err = -errno;
+		close(fd);
+		return err;
+	}
+
+	return fd;
+}
+
+int os_connect_socket(const char *name)
+{
+	struct sockaddr_un sock;
+	int fd, err;
+
+	sock.sun_family = AF_UNIX;
+	snprintf(sock.sun_path, sizeof(sock.sun_path), "%s", name);
+
+	fd = socket(AF_UNIX, SOCK_STREAM, 0);
+	if (fd < 0) {
+		err = -errno;
+		goto out;
+	}
+
+	err = connect(fd, (struct sockaddr *) &sock, sizeof(sock));
+	if (err) {
+		err = -errno;
+		goto out_close;
+	}
+
+	return fd;
+
+out_close:
+	close(fd);
+out:
+	return err;
+}
+
+int os_dup_file(int fd)
+{
+	int new_fd = dup(fd);
+
+	if (new_fd < 0)
+		return -errno;
+
+	return new_fd;
+}
+
+void os_close_file(int fd)
+{
+	close(fd);
+}
+
+int os_seek_file(int fd, unsigned long long offset)
+{
+	unsigned long long actual;
+
+	actual = lseek64(fd, offset, SEEK_SET);
+	if (actual != offset)
+		return -errno;
+	return 0;
+}
+
+int os_read_file(int fd, void *buf, int len)
+{
+	int n = read(fd, buf, len);
+
+	if (n < 0)
+		return -errno;
+	return n;
+}
+
+int os_pread_file(int fd, void *buf, int len, unsigned long long offset)
+{
+	int n = pread(fd, buf, len, offset);
+
+	if (n < 0)
+		return -errno;
+	return n;
+}
+
+int os_write_file(int fd, const void *buf, int len)
+{
+	int n = write(fd, (void *) buf, len);
+
+	if (n < 0)
+		return -errno;
+	return n;
+}
+
+int os_sync_file(int fd)
+{
+	int n = fdatasync(fd);
+
+	if (n < 0)
+		return -errno;
+	return n;
+}
+
+int os_pwrite_file(int fd, const void *buf, int len, unsigned long long offset)
+{
+	int n = pwrite(fd, (void *) buf, len, offset);
+
+	if (n < 0)
+		return -errno;
+	return n;
+}
+
+
+int os_file_size(const char *file, unsigned long long *size_out)
+{
+	struct uml_stat buf;
+	int err;
+
+	err = os_stat_file(file, &buf);
+	if (err < 0) {
+		printk(UM_KERN_ERR "Couldn't stat \"%s\" : err = %d\n", file,
+		       -err);
+		return err;
+	}
+
+	if (S_ISBLK(buf.ust_mode)) {
+		int fd;
+		long blocks;
+
+		fd = open(file, O_RDONLY, 0);
+		if (fd < 0) {
+			err = -errno;
+			printk(UM_KERN_ERR "Couldn't open \"%s\", "
+			       "errno = %d\n", file, errno);
+			return err;
+		}
+		if (ioctl(fd, BLKGETSIZE, &blocks) < 0) {
+			err = -errno;
+			printk(UM_KERN_ERR "Couldn't get the block size of "
+			       "\"%s\", errno = %d\n", file, errno);
+			close(fd);
+			return err;
+		}
+		*size_out = ((long long) blocks) * 512;
+		close(fd);
+	}
+	else *size_out = buf.ust_size;
+
+	return 0;
+}
+
+int os_file_modtime(const char *file, long long *modtime)
+{
+	struct uml_stat buf;
+	int err;
+
+	err = os_stat_file(file, &buf);
+	if (err < 0) {
+		printk(UM_KERN_ERR "Couldn't stat \"%s\" : err = %d\n", file,
+		       -err);
+		return err;
+	}
+
+	*modtime = buf.ust_mtime;
+	return 0;
+}
+
+int os_set_exec_close(int fd)
+{
+	int err;
+
+	CATCH_EINTR(err = fcntl(fd, F_SETFD, FD_CLOEXEC));
+
+	if (err < 0)
+		return -errno;
+	return err;
+}
+
+int os_pipe(int *fds, int stream, int close_on_exec)
+{
+	int err, type = stream ? SOCK_STREAM : SOCK_DGRAM;
+
+	err = socketpair(AF_UNIX, type, 0, fds);
+	if (err < 0)
+		return -errno;
+
+	if (!close_on_exec)
+		return 0;
+
+	err = os_set_exec_close(fds[0]);
+	if (err < 0)
+		goto error;
+
+	err = os_set_exec_close(fds[1]);
+	if (err < 0)
+		goto error;
+
+	return 0;
+
+ error:
+	printk(UM_KERN_ERR "os_pipe : Setting FD_CLOEXEC failed, err = %d\n",
+	       -err);
+	close(fds[1]);
+	close(fds[0]);
+	return err;
+}
+
+int os_set_fd_async(int fd)
+{
+	int err, flags;
+
+	flags = fcntl(fd, F_GETFL);
+	if (flags < 0)
+		return -errno;
+
+	flags |= O_ASYNC | O_NONBLOCK;
+	if (fcntl(fd, F_SETFL, flags) < 0) {
+		err = -errno;
+		printk(UM_KERN_ERR "os_set_fd_async : failed to set O_ASYNC "
+		       "and O_NONBLOCK on fd # %d, errno = %d\n", fd, errno);
+		return err;
+	}
+
+	if ((fcntl(fd, F_SETSIG, SIGIO) < 0) ||
+	    (fcntl(fd, F_SETOWN, os_getpid()) < 0)) {
+		err = -errno;
+		printk(UM_KERN_ERR "os_set_fd_async : Failed to fcntl F_SETOWN "
+		       "(or F_SETSIG) fd %d, errno = %d\n", fd, errno);
+		return err;
+	}
+
+	return 0;
+}
+
+int os_clear_fd_async(int fd)
+{
+	int flags;
+
+	flags = fcntl(fd, F_GETFL);
+	if (flags < 0)
+		return -errno;
+
+	flags &= ~(O_ASYNC | O_NONBLOCK);
+	if (fcntl(fd, F_SETFL, flags) < 0)
+		return -errno;
+	return 0;
+}
+
+int os_set_fd_block(int fd, int blocking)
+{
+	int flags;
+
+	flags = fcntl(fd, F_GETFL);
+	if (flags < 0)
+		return -errno;
+
+	if (blocking)
+		flags &= ~O_NONBLOCK;
+	else
+		flags |= O_NONBLOCK;
+
+	if (fcntl(fd, F_SETFL, flags) < 0)
+		return -errno;
+
+	return 0;
+}
+
+int os_accept_connection(int fd)
+{
+	int new;
+
+	new = accept(fd, NULL, 0);
+	if (new < 0)
+		return -errno;
+	return new;
+}
+
+#ifndef SHUT_RD
+#define SHUT_RD 0
+#endif
+
+#ifndef SHUT_WR
+#define SHUT_WR 1
+#endif
+
+#ifndef SHUT_RDWR
+#define SHUT_RDWR 2
+#endif
+
+int os_shutdown_socket(int fd, int r, int w)
+{
+	int what, err;
+
+	if (r && w)
+		what = SHUT_RDWR;
+	else if (r)
+		what = SHUT_RD;
+	else if (w)
+		what = SHUT_WR;
+	else
+		return -EINVAL;
+
+	err = shutdown(fd, what);
+	if (err < 0)
+		return -errno;
+	return 0;
+}
+
+/**
+ * os_rcv_fd_msg - receive message with (optional) FDs
+ * @fd: the FD to receive from
+ * @fds: the array for FDs to write to
+ * @n_fds: number of FDs to receive (@fds array size)
+ * @data: the message buffer
+ * @data_len: the size of the message to receive
+ *
+ * Receive a message with FDs.
+ *
+ * Returns: the size of the received message, or an error code
+ */
+ssize_t os_rcv_fd_msg(int fd, int *fds, unsigned int n_fds,
+		      void *data, size_t data_len)
+{
+#define MAX_RCV_FDS	2
+	char buf[CMSG_SPACE(sizeof(*fds) * MAX_RCV_FDS)];
+	struct cmsghdr *cmsg;
+	struct iovec iov = {
+		.iov_base = data,
+		.iov_len = data_len,
+	};
+	struct msghdr msg = {
+		.msg_iov = &iov,
+		.msg_iovlen = 1,
+		.msg_control = buf,
+		.msg_controllen = CMSG_SPACE(sizeof(*fds) * n_fds),
+	};
+	int n;
+
+	if (n_fds > MAX_RCV_FDS)
+		return -EINVAL;
+
+	n = recvmsg(fd, &msg, 0);
+	if (n < 0)
+		return -errno;
+
+	cmsg = CMSG_FIRSTHDR(&msg);
+	if (!cmsg ||
+	    cmsg->cmsg_level != SOL_SOCKET ||
+	    cmsg->cmsg_type != SCM_RIGHTS)
+		return n;
+
+	memcpy(fds, CMSG_DATA(cmsg), cmsg->cmsg_len - CMSG_LEN(0));
+	return n;
+}
+
+int os_create_unix_socket(const char *file, int len, int close_on_exec)
+{
+	struct sockaddr_un addr;
+	int sock, err;
+
+	sock = socket(PF_UNIX, SOCK_DGRAM, 0);
+	if (sock < 0)
+		return -errno;
+
+	if (close_on_exec) {
+		err = os_set_exec_close(sock);
+		if (err < 0)
+			printk(UM_KERN_ERR "create_unix_socket : "
+			       "close_on_exec failed, err = %d", -err);
+	}
+
+	addr.sun_family = AF_UNIX;
+
+	snprintf(addr.sun_path, len, "%s", file);
+
+	err = bind(sock, (struct sockaddr *) &addr, sizeof(addr));
+	if (err < 0)
+		return -errno;
+
+	return sock;
+}
+
+void os_flush_stdout(void)
+{
+	fflush(stdout);
+}
+
+int os_lock_file(int fd, int excl)
+{
+	int type = excl ? F_WRLCK : F_RDLCK;
+	struct flock lock = ((struct flock) { .l_type	= type,
+					      .l_whence	= SEEK_SET,
+					      .l_start	= 0,
+					      .l_len	= 0 } );
+	int err, save;
+
+	err = fcntl(fd, F_SETLK, &lock);
+	if (!err)
+		goto out;
+
+	save = -errno;
+	err = fcntl(fd, F_GETLK, &lock);
+	if (err) {
+		err = -errno;
+		goto out;
+	}
+
+	printk(UM_KERN_ERR "F_SETLK failed, file already locked by pid %d\n",
+	       lock.l_pid);
+	err = save;
+ out:
+	return err;
+}
+
+unsigned os_major(unsigned long long dev)
+{
+	return major(dev);
+}
+
+unsigned os_minor(unsigned long long dev)
+{
+	return minor(dev);
+}
+
+unsigned long long os_makedev(unsigned major, unsigned minor)
+{
+	return makedev(major, minor);
+}
+
+int os_falloc_punch(int fd, unsigned long long offset, int len)
+{
+	int n = fallocate(fd, FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE, offset, len);
+
+	if (n < 0)
+		return -errno;
+	return n;
+}
+
+int os_falloc_zeroes(int fd, unsigned long long offset, int len)
+{
+	int n = fallocate(fd, FALLOC_FL_ZERO_RANGE|FALLOC_FL_KEEP_SIZE, offset, len);
+
+	if (n < 0)
+		return -errno;
+	return n;
+}
+
+int os_eventfd(unsigned int initval, int flags)
+{
+	int fd = eventfd(initval, flags);
+
+	if (fd < 0)
+		return -errno;
+	return fd;
+}
+
+int os_sendmsg_fds(int fd, const void *buf, unsigned int len, const int *fds,
+		   unsigned int fds_num)
+{
+	struct iovec iov = {
+		.iov_base = (void *) buf,
+		.iov_len = len,
+	};
+	union {
+		char control[CMSG_SPACE(sizeof(*fds) * OS_SENDMSG_MAX_FDS)];
+		struct cmsghdr align;
+	} u;
+	unsigned int fds_size = sizeof(*fds) * fds_num;
+	struct msghdr msg = {
+		.msg_iov = &iov,
+		.msg_iovlen = 1,
+		.msg_control = u.control,
+		.msg_controllen = CMSG_SPACE(fds_size),
+	};
+	struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
+	int err;
+
+	if (fds_num > OS_SENDMSG_MAX_FDS)
+		return -EINVAL;
+	memset(u.control, 0, sizeof(u.control));
+	cmsg->cmsg_level = SOL_SOCKET;
+	cmsg->cmsg_type = SCM_RIGHTS;
+	cmsg->cmsg_len = CMSG_LEN(fds_size);
+	memcpy(CMSG_DATA(cmsg), fds, fds_size);
+	err = sendmsg(fd, &msg, 0);
+
+	if (err < 0)
+		return -errno;
+	return err;
+}
+
+int os_poll(unsigned int n, const int *fds)
+{
+	/* currently need 2 FDs at most so avoid dynamic allocation */
+	struct pollfd pollfds[2] = {};
+	unsigned int i;
+	int ret;
+
+	if (n > ARRAY_SIZE(pollfds))
+		return -EINVAL;
+
+	for (i = 0; i < n; i++) {
+		pollfds[i].fd = fds[i];
+		pollfds[i].events = POLLIN;
+	}
+
+	ret = poll(pollfds, n, -1);
+	if (ret < 0)
+		return -errno;
+
+	/* Return the index of the available FD */
+	for (i = 0; i < n; i++) {
+		if (pollfds[i].revents)
+			return i;
+	}
+
+	return -EIO;
+}
+
+void *os_mmap_rw_shared(int fd, size_t size)
+{
+	void *res = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+
+	if (res == MAP_FAILED)
+		return NULL;
+
+	return res;
+}
+
+void *os_mremap_rw_shared(void *old_addr, size_t old_size, size_t new_size)
+{
+	void *res;
+
+	res = mremap(old_addr, old_size, new_size, MREMAP_MAYMOVE, NULL);
+
+	if (res == MAP_FAILED)
+		return NULL;
+
+	return res;
+}