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, 190 insertions, 0 deletions

diff --git a/arch/um/drivers/Kconfig b/arch/um/drivers/Kconfig
new file mode 100644
index 000000000..6a0354ca0
--- /dev/null
+++ b/arch/um/drivers/Kconfig
@@ -0,0 +1,190 @@
+# SPDX-License-Identifier: GPL-2.0
+
+menu "UML Character Devices"
+
+config STDERR_CONSOLE
+	bool "stderr console"
+	default y
+	help
+	  console driver which dumps all printk messages to stderr.
+
+config SSL
+	bool "Virtual serial line"
+	help
+	  The User-Mode Linux environment allows you to create virtual serial
+	  lines on the UML that are usually made to show up on the host as
+	  ttys or ptys.
+
+	  See <http://user-mode-linux.sourceforge.net/old/input.html> for more
+	  information and command line examples of how to use this facility.
+
+	  Unless you have a specific reason for disabling this, say Y.
+
+config NULL_CHAN
+	bool "null channel support"
+	help
+	  This option enables support for attaching UML consoles and serial
+	  lines to a device similar to /dev/null.  Data written to it disappears
+	  and there is never any data to be read.
+
+config PORT_CHAN
+	bool "port channel support"
+	help
+	  This option enables support for attaching UML consoles and serial
+	  lines to host portals.  They may be accessed with 'telnet <host>
+	  <port number>'.  Any number of consoles and serial lines may be
+	  attached to a single portal, although what UML device you get when
+	  you telnet to that portal will be unpredictable.
+	  It is safe to say 'Y' here.
+
+config PTY_CHAN
+	bool "pty channel support"
+	help
+	  This option enables support for attaching UML consoles and serial
+	  lines to host pseudo-terminals.  Access to both traditional
+	  pseudo-terminals (/dev/pty*) and pts pseudo-terminals are controlled
+	  with this option.  The assignment of UML devices to host devices
+	  will be announced in the kernel message log.
+	  It is safe to say 'Y' here.
+
+config TTY_CHAN
+	bool "tty channel support"
+	help
+	  This option enables support for attaching UML consoles and serial
+	  lines to host terminals.  Access to both virtual consoles
+	  (/dev/tty*) and the slave side of pseudo-terminals (/dev/ttyp* and
+	  /dev/pts/*) are controlled by this option.
+	  It is safe to say 'Y' here.
+
+config XTERM_CHAN
+	bool "xterm channel support"
+	help
+	  This option enables support for attaching UML consoles and serial
+	  lines to xterms.  Each UML device so assigned will be brought up in
+	  its own xterm.
+	  It is safe to say 'Y' here.
+
+config XTERM_CHAN_DEFAULT_EMULATOR
+	string "xterm channel default terminal emulator"
+	depends on XTERM_CHAN
+	default "xterm"
+	help
+	  This option allows changing the default terminal emulator.
+
+config NOCONFIG_CHAN
+	bool
+	default !(XTERM_CHAN && TTY_CHAN && PTY_CHAN && PORT_CHAN && NULL_CHAN)
+
+config CON_ZERO_CHAN
+	string "Default main console channel initialization"
+	default "fd:0,fd:1"
+	help
+	  This is the string describing the channel to which the main console
+	  will be attached by default.  This value can be overridden from the
+	  command line.  The default value is "fd:0,fd:1", which attaches the
+	  main console to stdin and stdout.
+	  It is safe to leave this unchanged.
+
+config CON_CHAN
+	string "Default console channel initialization"
+	default "xterm"
+	help
+	  This is the string describing the channel to which all consoles
+	  except the main console will be attached by default.  This value can
+	  be overridden from the command line.  The default value is "xterm",
+	  which brings them up in xterms.
+	  It is safe to leave this unchanged, although you may wish to change
+	  this if you expect the UML that you build to be run in environments
+	  which don't have X or xterm available.
+
+config SSL_CHAN
+	string "Default serial line channel initialization"
+	default "pty"
+	help
+	  This is the string describing the channel to which the serial lines
+	  will be attached by default.  This value can be overridden from the
+	  command line.  The default value is "pty", which attaches them to
+	  traditional pseudo-terminals.
+	  It is safe to leave this unchanged, although you may wish to change
+	  this if you expect the UML that you build to be run in environments
+	  which don't have a set of /dev/pty* devices.
+
+config UML_SOUND
+	tristate "Sound support"
+	depends on SOUND
+	select SOUND_OSS_CORE
+	help
+	  This option enables UML sound support.  If enabled, it will pull in
+	  the UML hostaudio relay, which acts as a intermediary
+	  between the host's dsp and mixer devices and the UML sound system.
+	  It is safe to say 'Y' here.
+
+endmenu
+
+menu "UML Network Devices"
+	depends on NET
+
+config UML_NET_VECTOR
+	bool "Vector I/O high performance network devices"
+	select MAY_HAVE_RUNTIME_DEPS
+	help
+	  This User-Mode Linux network driver uses multi-message send
+	  and receive functions. The host running the UML guest must have
+	  a linux kernel version above 3.0 and a libc version > 2.13.
+	  This driver provides tap, raw, gre and l2tpv3 network transports.
+
+	  For more information, including explanations of the networking
+	  and sample configurations, see
+	  <file:Documentation/virt/uml/user_mode_linux_howto_v2.rst>.
+
+endmenu
+
+config VIRTIO_UML
+	bool "UML driver for virtio devices"
+	select VIRTIO
+	help
+	  This driver provides support for virtio based paravirtual device
+	  drivers over vhost-user sockets.
+
+config UML_RTC
+	bool "UML RTC driver"
+	depends on RTC_CLASS
+	# there's no use in this if PM_SLEEP isn't enabled ...
+	depends on PM_SLEEP
+	help
+	  When PM_SLEEP is configured, it may be desirable to wake up using
+	  rtcwake, especially in time-travel mode. This driver enables that
+	  by providing a fake RTC clock that causes a wakeup at the right
+	  time.
+
+config UML_PCI
+	bool
+	select FORCE_PCI
+	select IRQ_MSI_LIB
+	select UML_IOMEM_EMULATION
+	select UML_DMA_EMULATION
+	select PCI_MSI
+	select PCI_LOCKLESS_CONFIG
+
+config UML_PCI_OVER_VIRTIO
+	bool "Enable PCI over VIRTIO device simulation"
+	# in theory, just VIRTIO is enough, but that causes recursion
+	depends on VIRTIO_UML
+	select UML_PCI
+
+config UML_PCI_OVER_VIRTIO_DEVICE_ID
+	int "set the virtio device ID for PCI emulation"
+	default -1
+	depends on UML_PCI_OVER_VIRTIO
+	help
+	  There's no official device ID assigned (yet), set the one you
+	  wish to use for experimentation here. The default of -1 is
+	  not valid and will cause the driver to fail at probe.
+
+config UML_PCI_OVER_VFIO
+	bool "Enable VFIO-based PCI passthrough"
+	select UML_PCI
+	help
+	  This driver provides support for VFIO-based PCI passthrough.
+	  Currently, only MSI-X capable devices are supported, and it
+	  is assumed that drivers will use MSI-X.