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, 207 insertions, 0 deletions

diff --git a/Documentation/admin-guide/blockdev/paride.rst b/Documentation/admin-guide/blockdev/paride.rst
new file mode 100644
index 000000000..b2f627d4c
--- /dev/null
+++ b/Documentation/admin-guide/blockdev/paride.rst
@@ -0,0 +1,207 @@
+===================================
+Linux and parallel port IDE devices
+===================================
+
+PARIDE v1.03   (c) 1997-8  Grant Guenther <grant@torque.net>
+PATA_PARPORT   (c) 2023 Ondrej Zary
+
+1. Introduction
+===============
+
+Owing to the simplicity and near universality of the parallel port interface
+to personal computers, many external devices such as portable hard-disk,
+CD-ROM, LS-120 and tape drives use the parallel port to connect to their
+host computer.  While some devices (notably scanners) use ad-hoc methods
+to pass commands and data through the parallel port interface, most
+external devices are actually identical to an internal model, but with
+a parallel-port adapter chip added in.  Some of the original parallel port
+adapters were little more than mechanisms for multiplexing a SCSI bus.
+(The Iomega PPA-3 adapter used in the ZIP drives is an example of this
+approach).  Most current designs, however, take a different approach.
+The adapter chip reproduces a small ISA or IDE bus in the external device
+and the communication protocol provides operations for reading and writing
+device registers, as well as data block transfer functions.  Sometimes,
+the device being addressed via the parallel cable is a standard SCSI
+controller like an NCR 5380.  The "ditto" family of external tape
+drives use the ISA replicator to interface a floppy disk controller,
+which is then connected to a floppy-tape mechanism.  The vast majority
+of external parallel port devices, however, are now based on standard
+IDE type devices, which require no intermediate controller.  If one
+were to open up a parallel port CD-ROM drive, for instance, one would
+find a standard ATAPI CD-ROM drive, a power supply, and a single adapter
+that interconnected a standard PC parallel port cable and a standard
+IDE cable.  It is usually possible to exchange the CD-ROM device with
+any other device using the IDE interface.
+
+The document describes the support in Linux for parallel port IDE
+devices.  It does not cover parallel port SCSI devices, "ditto" tape
+drives or scanners.  Many different devices are supported by the
+parallel port IDE subsystem, including:
+
+	- MicroSolutions backpack CD-ROM
+	- MicroSolutions backpack PD/CD
+	- MicroSolutions backpack hard-drives
+	- MicroSolutions backpack 8000t tape drive
+	- SyQuest EZ-135, EZ-230 & SparQ drives
+	- Avatar Shark
+	- Imation Superdisk LS-120
+	- Maxell Superdisk LS-120
+	- FreeCom Power CD
+	- Hewlett-Packard 5GB and 8GB tape drives
+	- Hewlett-Packard 7100 and 7200 CD-RW drives
+
+as well as most of the clone and no-name products on the market.
+
+To support such a wide range of devices, pata_parport is actually structured
+in two parts. There is a base pata_parport module which provides an interface
+to kernel libata subsystem, registry and some common methods for accessing
+the parallel ports.
+
+The second component is a set of low-level protocol drivers for each of the
+parallel port IDE adapter chips.  Thanks to the interest and encouragement of
+Linux users from many parts of the world, support is available for almost all
+known adapter protocols:
+
+	====    ====================================== ====
+        aten    ATEN EH-100                            (HK)
+        bpck    Microsolutions backpack                (US)
+        comm    DataStor (old-type) "commuter" adapter (TW)
+        dstr    DataStor EP-2000                       (TW)
+        epat    Shuttle EPAT                           (UK)
+        epia    Shuttle EPIA                           (UK)
+	fit2    FIT TD-2000			       (US)
+	fit3    FIT TD-3000			       (US)
+	friq    Freecom IQ cable                       (DE)
+        frpw    Freecom Power                          (DE)
+        kbic    KingByte KBIC-951A and KBIC-971A       (TW)
+	ktti    KT Technology PHd adapter              (SG)
+        on20    OnSpec 90c20                           (US)
+        on26    OnSpec 90c26                           (US)
+	====    ====================================== ====
+
+
+2. Using pata_parport subsystem
+===============================
+
+While configuring the Linux kernel, you may choose either to build
+the pata_parport drivers into your kernel, or to build them as modules.
+
+In either case, you will need to select "Parallel port IDE device support"
+and at least one of the parallel port communication protocols.
+If you do not know what kind of parallel port adapter is used in your drive,
+you could begin by checking the file names and any text files on your DOS
+installation floppy.  Alternatively, you can look at the markings on
+the adapter chip itself.  That's usually sufficient to identify the
+correct device.
+
+You can actually select all the protocol modules, and allow the pata_parport
+subsystem to try them all for you.
+
+For the "brand-name" products listed above, here are the protocol
+and high-level drivers that you would use:
+
+	================	============	========
+	Manufacturer		Model		Protocol
+	================	============	========
+	MicroSolutions		CD-ROM		bpck
+	MicroSolutions		PD drive	bpck
+	MicroSolutions		hard-drive	bpck
+	MicroSolutions          8000t tape      bpck
+	SyQuest			EZ, SparQ	epat
+	Imation			Superdisk	epat
+	Maxell                  Superdisk       friq
+	Avatar			Shark		epat
+	FreeCom			CD-ROM		frpw
+	Hewlett-Packard		5GB Tape	epat
+	Hewlett-Packard		7200e (CD)	epat
+	Hewlett-Packard		7200e (CD-R)	epat
+	================	============	========
+
+All parports and all protocol drivers are probed automatically unless probe=0
+parameter is used. So just "modprobe epat" is enough for an Imation SuperDisk
+drive to work.
+
+Manual device creation::
+
+	# echo "port protocol mode unit delay" >/sys/bus/pata_parport/new_device
+
+where:
+
+	======== ================================================
+	port	 parport name (or "auto" for all parports)
+	protocol protocol name (or "auto" for all protocols)
+	mode	 mode number (protocol-specific) or -1 for probe
+	unit	 unit number (for backpack only, see below)
+	delay	 I/O delay (see troubleshooting section below)
+	======== ================================================
+
+If you happen to be using a MicroSolutions backpack device, you will
+also need to know the unit ID number for each drive.  This is usually
+the last two digits of the drive's serial number (but read MicroSolutions'
+documentation about this).
+
+If you omit the parameters from the end, defaults will be used, e.g.:
+
+Probe all parports with all protocols::
+
+	# echo auto >/sys/bus/pata_parport/new_device
+
+Probe parport0 using protocol epat and mode 4 (EPP-16)::
+
+	# echo "parport0 epat 4" >/sys/bus/pata_parport/new_device
+
+Probe parport0 using all protocols::
+
+	# echo "parport0 auto" >/sys/bus/pata_parport/new_device
+
+Probe all parports using protoocol epat::
+
+	# echo "auto epat" >/sys/bus/pata_parport/new_device
+
+Deleting devices::
+
+	# echo pata_parport.0 >/sys/bus/pata_parport/delete_device
+
+
+3. Troubleshooting
+==================
+
+3.1  Use EPP mode if you can
+----------------------------
+
+The most common problems that people report with the pata_parport drivers
+concern the parallel port CMOS settings.  At this time, none of the
+protocol modules support ECP mode, or any ECP combination modes.
+If you are able to do so, please set your parallel port into EPP mode
+using your CMOS setup procedure.
+
+3.2  Check the port delay
+-------------------------
+
+Some parallel ports cannot reliably transfer data at full speed.  To
+offset the errors, the protocol modules introduce a "port
+delay" between each access to the i/o ports.  Each protocol sets
+a default value for this delay.  In most cases, the user can override
+the default and set it to 0 - resulting in somewhat higher transfer
+rates.  In some rare cases (especially with older 486 systems) the
+default delays are not long enough.  if you experience corrupt data
+transfers, or unexpected failures, you may wish to increase the
+port delay.
+
+3.3  Some drives need a printer reset
+-------------------------------------
+
+There appear to be a number of "noname" external drives on the market
+that do not always power up correctly.  We have noticed this with some
+drives based on OnSpec and older Freecom adapters.  In these rare cases,
+the adapter can often be reinitialised by issuing a "printer reset" on
+the parallel port.  As the reset operation is potentially disruptive in
+multiple device environments, the pata_parport drivers will not do it
+automatically.  You can however, force a printer reset by doing::
+
+	insmod lp reset=1
+	rmmod lp
+
+If you have one of these marginal cases, you should probably build
+your pata_parport drivers as modules, and arrange to do the printer reset
+before loading the pata_parport drivers.