Pull tracing fixlets from Steven Rostedt:
 "Two updates:

   - A memory fix with left over code from spliting out ftrace_ops and
     function graph tracer, where the function graph tracer could reset
     the trampoline pointer, leaving the old trampoline not to be freed
     (memory leak).

   - The update to Paul's patch that added the unnecessary READ_ONCE().
     This removes the unnecessary READ_ONCE() instead of having to
     rebase the branch to update the patch that added it"

* tag 'trace-v4.14-rc1-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  rcu: Remove extraneous READ_ONCE()s from rcu_irq_{enter,exit}()
  ftrace: Fix kmemleak in unregister_ftrace_graph

The trampoline allocated by function tracer was overwriten by function_graph
tracer, and caused a memory leak. The save_global_trampoline should have
saved the previous trampoline in register_ftrace_graph() and restored it in
unregister_ftrace_graph(). But as it is implemented, save_global_trampoline was
only used in unregister_ftrace_graph as default value 0, and it overwrote the
previous trampoline's value. Causing the previous allocated trampoline to be
lost.

kmmeleak backtrace:
    kmemleak_vmalloc+0x77/0xc0
    __vmalloc_node_range+0x1b5/0x2c0
    module_alloc+0x7c/0xd0
    arch_ftrace_update_trampoline+0xb5/0x290
    ftrace_startup+0x78/0x210
    register_ftrace_function+0x8b/0xd0
    function_trace_init+0x4f/0x80
    tracing_set_tracer+0xe6/0x170
    tracing_set_trace_write+0x90/0xd0
    __vfs_write+0x37/0x170
    vfs_write+0xb2/0x1b0
    SyS_write+0x55/0xc0
    do_syscall_64+0x67/0x180
    return_from_SYSCALL_64+0x0/0x6a

[
  Looking further into this, I found that this was left over from when the
  function and function graph tracers shared the same ftrace_ops. But in
  commit 5f151b2401 ("ftrace: Fix function_profiler and function tracer
  together"), the two were separated, and the save_global_trampoline no
  longer was necessary (and it may have been broken back then too).
  -- Steven Rostedt
]

Link: http://lkml.kernel.org/r/20170912021454.5976-1-shuwang@redhat.com

Cc: stable@vger.kernel.org
Fixes: 5f151b2401 ("ftrace: Fix function_profiler and function tracer together")
Signed-off-by: Shu Wang <shuwang@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Remove yet another task-state char instance.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Pull block fixes from Jens Axboe:

 - Two sets of NVMe pull requests from Christoph:
      - Fixes for the Fibre Channel host/target to fix spec compliance
      - Allow a zero keep alive timeout
      - Make the debug printk for broken SGLs work better
      - Fix queue zeroing during initialization
      - Set of RDMA and FC fixes
      - Target div-by-zero fix

 - bsg double-free fix.

 - ndb unknown ioctl fix from Josef.

 - Buffered vs O_DIRECT page cache inconsistency fix. Has been floating
   around for a long time, well reviewed. From Lukas.

 - brd overflow fix from Mikulas.

 - Fix for a loop regression in this merge window, where using a union
   for two members of the loop_cmd turned out to be a really bad idea.
   From Omar.

 - Fix for an iostat regression fix in this series, using the wrong API
   to get at the block queue. From Shaohua.

 - Fix for a potential blktrace delection deadlock. From Waiman.

* 'for-linus' of git://git.kernel.dk/linux-block: (30 commits)
  nvme-fcloop: fix port deletes and callbacks
  nvmet-fc: sync header templates with comments
  nvmet-fc: ensure target queue id within range.
  nvmet-fc: on port remove call put outside lock
  nvme-rdma: don't fully stop the controller in error recovery
  nvme-rdma: give up reconnect if state change fails
  nvme-core: Use nvme_wq to queue async events and fw activation
  nvme: fix sqhd reference when admin queue connect fails
  block: fix a crash caused by wrong API
  fs: Fix page cache inconsistency when mixing buffered and AIO DIO
  nvmet: implement valid sqhd values in completions
  nvme-fabrics: Allow 0 as KATO value
  nvme: allow timed-out ios to retry
  nvme: stop aer posting if controller state not live
  nvme-pci: Print invalid SGL only once
  nvme-pci: initialize queue memory before interrupts
  nvmet-fc: fix failing max io queue connections
  nvme-fc: use transport-specific sgl format
  nvme: add transport SGL definitions
  nvme.h: remove FC transport-specific error values
  ...

Pull tracing fixes from Steven Rostedt:
 "Stack tracing and RCU has been having issues with each other and
  lockdep has been pointing out constant problems.

  The changes have been going into the stack tracer, but it has been
  discovered that the problem isn't with the stack tracer itself, but it
  is with calling save_stack_trace() from within the internals of RCU.

  The stack tracer is the one that can trigger the issue the easiest,
  but examining the problem further, it could also happen from a WARN()
  in the wrong place, or even if an NMI happened in this area and it did
  an rcu_read_lock().

  The critical area is where RCU is not watching. Which can happen while
  going to and from idle, or bringing up or taking down a CPU.

  The final fix was to put the protection in kernel_text_address() as it
  is the one that requires RCU to be watching while doing the stack
  trace.

  To make this work properly, Paul had to allow rcu_irq_enter() happen
  after rcu_nmi_enter(). This should have been done anyway, since an NMI
  can page fault (reading vmalloc area), and a page fault triggers
  rcu_irq_enter().

  One patch is just a consolidation of code so that the fix only needed
  to be done in one location"

* tag 'trace-v4.14-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Remove RCU work arounds from stack tracer
  extable: Enable RCU if it is not watching in kernel_text_address()
  extable: Consolidate *kernel_text_address() functions
  rcu: Allow for page faults in NMI handlers

The lockdep code had reported the following unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(s_active#228);
                               lock(&bdev->bd_mutex/1);
                               lock(s_active#228);
  lock(&bdev->bd_mutex);

 *** DEADLOCK ***

The deadlock may happen when one task (CPU1) is trying to delete a
partition in a block device and another task (CPU0) is accessing
tracing sysfs file (e.g. /sys/block/dm-1/trace/act_mask) in that
partition.

The s_active isn't an actual lock. It is a reference count (kn->count)
on the sysfs (kernfs) file. Removal of a sysfs file, however, require
a wait until all the references are gone. The reference count is
treated like a rwsem using lockdep instrumentation code.

The fact that a thread is in the sysfs callback method or in the
ioctl call means there is a reference to the opended sysfs or device
file. That should prevent the underlying block structure from being
removed.

Instead of using bd_mutex in the block_device structure, a new
blk_trace_mutex is now added to the request_queue structure to protect
access to the blk_trace structure.

Suggested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Waiman Long <longman@redhat.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Fix typo in patch subject line, and prune a comment detailing how
the code used to work.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

Currently the stack tracer calls rcu_irq_enter() to make sure RCU
is watching when it records a stack trace. But if the stack tracer
is triggered while tracing inside of a rcu_irq_enter(), calling
rcu_irq_enter() unconditionally can be problematic.

The reason for having rcu_irq_enter() in the first place has been
fixed from within the saving of the stack trace code, and there's no
reason for doing it in the stack tracer itself. Just remove it.

Cc: stable@vger.kernel.org
Fixes: 0be964be0 ("module: Sanitize RCU usage and locking")
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Suggested-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Pull tracing fixes from Steven Rostedt:
 "This includes three minor fixes.

    - Have writing to trace file clear the irqsoff (and friends) tracer

    - trace_pipe behavior for instance buffers was different than top
      buffer

    - Show a message of why mmiotrace doesn't start from commandline"

* tag 'trace-v4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Fix trace_pipe behavior for instance traces
  tracing: Ignore mmiotrace from kernel commandline
  tracing: Erase irqsoff trace with empty write

When reading data from trace_pipe, tracing_wait_pipe() performs a
check to see if tracing has been turned off after some data was read.
Currently, this check always looks at global trace state, but it
should be checking the trace instance where trace_pipe is located at.

Because of this bug, cat instances/i1/trace_pipe in the following
script will immediately exit instead of waiting for data:

cd /sys/kernel/debug/tracing
echo 0 > tracing_on
mkdir -p instances/i1
echo 1 > instances/i1/tracing_on
echo 1 > instances/i1/events/sched/sched_process_exec/enable
cat instances/i1/trace_pipe

Link: http://lkml.kernel.org/r/20170917102348.1615-1-tahsin@google.com

Cc: stable@vger.kernel.org
Fixes: 10246fa35d4f ("tracing: give easy way to clear trace buffer")
Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

The mmiotrace tracer cannot be enabled with ftrace=mmiotrace in kernel
commandline. With this patch, noboot is added to the tracer struct,
and when system boot with a tracer that has noboot=true, it will print
out a warning message and continue booting.

Link: http://lkml.kernel.org/r/1505111195-31942-1-git-send-email-zsun@redhat.com

Signed-off-by: Ziqian SUN (Zamir) <zsun@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>