Unify the "boot" and "mono" tracing clocks and document the new behaviour.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kevin Easton <kevin@guarana.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Salyzyn <salyzyn@android.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20180301165150.489635255@linutronix.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:

    for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
        L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
        for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done
    done

with de-mangling cleanups yet to come.

NOTE! On almost all architectures, the EPOLL* constants have the same
values as the POLL* constants do.  But they keyword here is "almost".
For various bad reasons they aren't the same, and epoll() doesn't
actually work quite correctly in some cases due to this on Sparc et al.

The next patch from Al will sort out the final differences, and we
should be all done.
Scripted-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Always mark the parsed string with a terminated nul '\0' character. This removes
the need for the users to have to append the '\0' before using the parsed string.

Link: http://lkml.kernel.org/r/1516093350-12045-4-git-send-email-changbin.du@intel.comAcked-by: NNamhyung Kim <namhyung@kernel.org>
Signed-off-by: NChangbin Du <changbin.du@intel.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

If only spaces were read while parsing the next string, then parser->idx should be
cleared in order to make trace_parser_loaded() return false.

Link: http://lkml.kernel.org/r/1516093350-12045-3-git-send-email-changbin.du@intel.comAcked-by: NNamhyung Kim <namhyung@kernel.org>
Signed-off-by: NChangbin Du <changbin.du@intel.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

User space can pass in a C nul character '\0' along with its input. The
function trace_get_user() will try to process it as a normal character,
and that will fail to parse.

open("/sys/kernel/debug/tracing//set_ftrace_pid", O_WRONLY|O_TRUNC) = 3
write(3, " \0", 2)                      = -1 EINVAL (Invalid argument)

while parse can handle spaces, so below works.

$ echo "" > set_ftrace_pid
$ echo " " > set_ftrace_pid
$ echo -n " " > set_ftrace_pid

Have the parser stop on '\0' and cease any further parsing. Only process
the characters up to the nul '\0' character and do not process it.

Link: http://lkml.kernel.org/r/1516093350-12045-2-git-send-email-changbin.du@intel.comAcked-by: NNamhyung Kim <namhyung@kernel.org>
Signed-off-by: NChangbin Du <changbin.du@intel.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

With the addition of ORC unwinder and FRAME POINTER unwinder, the stack
trace skipping requirements have changed.

I went through the tracing stack trace dumps with ORC and with frame
pointers and recalculated the proper values.
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

Jing Xia and Chunyan Zhang reported that on failing to allocate part of the
tracing buffer, memory is freed, but the pointers that point to them are not
initialized back to NULL, and later paths may try to free the freed memory
again. Jing and Chunyan fixed one of the locations that does this, but
missed a spot.

Link: http://lkml.kernel.org/r/20171226071253.8968-1-chunyan.zhang@spreadtrum.com

Cc: stable@vger.kernel.org
Fixes: 737223fb ("tracing: Consolidate buffer allocation code")
Reported-by: NJing Xia <jing.xia@spreadtrum.com>
Reported-by: NChunyan Zhang <chunyan.zhang@spreadtrum.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

Double free of the ring buffer happens when it fails to alloc new
ring buffer instance for max_buffer if TRACER_MAX_TRACE is configured.
The root cause is that the pointer is not set to NULL after the buffer
is freed in allocate_trace_buffers(), and the freeing of the ring
buffer is invoked again later if the pointer is not equal to Null,
as:

instance_mkdir()
    |-allocate_trace_buffers()
        |-allocate_trace_buffer(tr, &tr->trace_buffer...)
	|-allocate_trace_buffer(tr, &tr->max_buffer...)

          // allocate fail(-ENOMEM),first free
          // and the buffer pointer is not set to null
        |-ring_buffer_free(tr->trace_buffer.buffer)

       // out_free_tr
    |-free_trace_buffers()
        |-free_trace_buffer(&tr->trace_buffer);

	      //if trace_buffer is not null, free again
	    |-ring_buffer_free(buf->buffer)
                |-rb_free_cpu_buffer(buffer->buffers[cpu])
                    // ring_buffer_per_cpu is null, and
                    // crash in ring_buffer_per_cpu->pages

Link: http://lkml.kernel.org/r/20171226071253.8968-1-chunyan.zhang@spreadtrum.com

Cc: stable@vger.kernel.org
Fixes: 737223fb ("tracing: Consolidate buffer allocation code")
Signed-off-by: NJing Xia <jing.xia@spreadtrum.com>
Signed-off-by: NChunyan Zhang <chunyan.zhang@spreadtrum.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

The ring_buffer_read_page() takes care of zeroing out any extra data in the
page that it returns. There's no need to zero it out again from the
consumer. It was removed from one consumer of this function, but
read_buffers_splice_read() did not remove it, and worse, it contained a
nasty bug because of it.

Cc: stable@vger.kernel.org
Fixes: 2711ca23 ("ring-buffer: Move zeroing out excess in page to ring buffer code")
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

By passing an export descriptor to the write function, users don't need to
keep a global static pointer and can rely on container_of() to fetch their
own structure.

Link: http://lkml.kernel.org/r/20170602102025.5140-1-felipe.balbi@linux.intel.comAcked-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: NChunyan Zhang <zhang.chunyan@linaro.org>
Signed-off-by: NFelipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

The default NR_CPUS can be very large, but actual possible nr_cpu_ids
usually is very small. For my x86 distribution, the NR_CPUS is 8192 and
nr_cpu_ids is 4. About 2 pages are wasted.

Most machines don't have so many CPUs, so define a array with NR_CPUS
just wastes memory. So let's allocate the buffer dynamically when need.

With this change, the mutext tracing_cpumask_update_lock also can be
removed now, which was used to protect mask_str.

Link: http://lkml.kernel.org/r/1512013183-19107-1-git-send-email-changbin.du@intel.com

Fixes: 36dfe925 ("ftrace: make use of tracing_cpumask")
Cc: stable@vger.kernel.org
Signed-off-by: NChangbin Du <changbin.du@intel.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

Naming in code comments for tracing_snapshot, tracing_snapshot_alloc
and trace_pid_filter_add_remove_task don't match the real function
names.  And latency_trace has been removed from tracing directory.
Fix them.

Link: http://lkml.kernel.org/r/1508394753-20887-1-git-send-email-chuhu@redhat.com

Fixes: cab50379 ("tracing/ftrace: Enable snapshot function trigger")
Fixes: 886b5b73 ("tracing: remove /debug/tracing/latency_trace")
Signed-off-by: NChunyu Hu <chuhu@redhat.com>
[ Replaced /sys/kernel/debug/tracing with /sys/kerne/tracing ]
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Now that the irq path uses the rcu_nmi_{enter,exit}() algorithm,
rcu_irq_enter() and rcu_irq_exit() may be used from any context.  There is
thus no need for rcu_irq_enter_disabled() and for the checks using it.
This commit therefore eliminates rcu_irq_enter_disabled().
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

traceprobe_probes_write() and traceprobe_command() actually contain
nothing that ties them to kprobes - the code is generically useful for
similar types of parsing elsewhere, so separate it out and move it to
trace.c/trace.h.

Other than moving it, the only change is in naming:
traceprobe_probes_write() becomes trace_parse_run_command() and
traceprobe_command() becomes trace_run_command().

Link: http://lkml.kernel.org/r/ae5c26ea40c196a8986854d921eb6e713ede7e3f.1506105045.git.tom.zanussi@linux.intel.comSigned-off-by: NTom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

In order to make future changes where we need to call
tracing_set_clock() from within an event command, the order of
trace_types_lock and event_mutex must be reversed, as the event command
will hold event_mutex and the trace_types_lock is taken from within
tracing_set_clock().

Link: http://lkml.kernel.org/r/20170921162249.0dde3dca@gandalf.local.homeRequested-by: NTom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

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: 10246fa3 ("tracing: give easy way to clear trace buffer")
Signed-off-by: NTahsin Erdogan <tahsin@google.com>
Signed-off-by: NSteven 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.comSigned-off-by: NZiqian SUN (Zamir) <zsun@redhat.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

One convenient way to erase trace is "echo > trace". However, this
is currently broken if the current tracer is irqsoff tracer. This
is because irqsoff tracer use max_buffer as the default trace
buffer.

Set the max_buffer as the one to be cleared when it's the trace
buffer currently in use.

Link: http://lkml.kernel.org/r/1505754215-29411-1-git-send-email-byan@nvidia.com

Cc: <mingo@redhat.com>
Cc: stable@vger.kernel.org
Fixes: 4acd4d00 ("tracing: give easy way to clear trace buffer")
Signed-off-by: NBo Yan <byan@nvidia.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

Currently trace_clock timestamps are applied to both regular and max
buffers only for global trace. For instance trace, trace_clock
timestamps are applied only to regular buffer. But, regular and max
buffers can be swapped, for example, following a snapshot. So, for
instance trace, bad timestamps can be seen following a snapshot.
Let's apply trace_clock timestamps to instance max buffer as well.

Link: http://lkml.kernel.org/r/ebdb168d0be042dcdf51f81e696b17fabe3609c1.1504642143.git.tom.zanussi@linux.intel.com

Cc: stable@vger.kernel.org
Fixes: 277ba044 ("tracing: Add interface to allow multiple trace buffers")
Signed-off-by: NBaohong Liu <baohong.liu@intel.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

trace_printk() uses 4 buffers, one for each context (normal, softirq, irq
and NMI), such that it does not need to worry about one context preempting
the other. There's a nesting counter that gets incremented to figure out
which buffer to use. If the context gets preempted by another context which
calls trace_printk() it will increment the counter and use the next buffer,
and restore the counter when it is finished.

The problem is that gcc may optimize the modification of the buffer nesting
counter and it may not be incremented in memory before the buffer is used.
If this happens, and the context gets interrupted by another context, it
could pick the same buffer and corrupt the one that is being used.

Compiler barriers need to be added after the nesting variable is incremented
and before it is decremented to prevent usage of the context buffers by more
than one context at the same time.

Cc: Andy Lutomirski <luto@kernel.org>
Cc: stable@vger.kernel.org
Fixes: e2ace001 ("tracing: Choose static tp_printk buffer by explicit nesting count")
Hat-tip-to: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

Currently, when a module event is enabled, when that module is removed, it
clears all ring buffers. This is to prevent another module from being loaded
and having one of its trace event IDs from reusing a trace event ID of the
removed module. This could cause undesirable effects as the trace event of
the new module would be using its own processing algorithms to process raw
data of another event. To prevent this, when a module is loaded, if any of
its events have been used (signified by the WAS_ENABLED event call flag,
which is never cleared), all ring buffers are cleared, just in case any one
of them contains event data of the removed event.

The problem is, there's no reason to clear all ring buffers if only one (or
less than all of them) uses one of the events. Instead, only clear the ring
buffers that recorded the events of a module that is being removed.

To do this, instead of keeping the WAS_ENABLED flag with the trace event
call, move it to the per instance (per ring buffer) event file descriptor.
The event file descriptor maps each event to a separate ring buffer
instance. Then when the module is removed, only the ring buffers that
activated one of the module's events get cleared. The rest are not touched.
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

Chunyu Hu reported:
  "per_cpu trace directories and files are created for all possible cpus,
   but only the cpus which have ever been on-lined have their own per cpu
   ring buffer (allocated by cpuhp threads). While trace_buffers_open, the
   open handler for trace file 'trace_pipe_raw' is always trying to access
   field of ring_buffer_per_cpu, and would panic with the NULL pointer.

   Align the behavior of trace_pipe_raw with trace_pipe, that returns -NODEV
   when openning it if that cpu does not have trace ring buffer.

   Reproduce:
   cat /sys/kernel/debug/tracing/per_cpu/cpu31/trace_pipe_raw
   (cpu31 is never on-lined, this is a 16 cores x86_64 box)

   Tested with:
   1) boot with maxcpus=14, read trace_pipe_raw of cpu15.
      Got -NODEV.
   2) oneline cpu15, read trace_pipe_raw of cpu15.
      Get the raw trace data.

   Call trace:
   [ 5760.950995] RIP: 0010:ring_buffer_alloc_read_page+0x32/0xe0
   [ 5760.961678]  tracing_buffers_read+0x1f6/0x230
   [ 5760.962695]  __vfs_read+0x37/0x160
   [ 5760.963498]  ? __vfs_read+0x5/0x160
   [ 5760.964339]  ? security_file_permission+0x9d/0xc0
   [ 5760.965451]  ? __vfs_read+0x5/0x160
   [ 5760.966280]  vfs_read+0x8c/0x130
   [ 5760.967070]  SyS_read+0x55/0xc0
   [ 5760.967779]  do_syscall_64+0x67/0x150
   [ 5760.968687]  entry_SYSCALL64_slow_path+0x25/0x25"

This was introduced by the addition of the feature to reuse reader pages
instead of re-allocating them. The problem is that the allocation of a
reader page (which is per cpu) does not check if the cpu is online and set
up for the ring buffer.

Link: http://lkml.kernel.org/r/1500880866-1177-1-git-send-email-chuhu@redhat.com

Cc: stable@vger.kernel.org
Fixes: 73a757e6 ("ring-buffer: Return reader page back into existing ring buffer")
Reported-by: NChunyu Hu <chuhu@redhat.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

If ring_buffer_alloc() or one of the next couple function calls fail
then we should return -ENOMEM but the current code returns success.

Link: http://lkml.kernel.org/r/20170801110201.ajdkct7vwzixahvx@mwanda

Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: stable@vger.kernel.org
Fixes: b32614c0 ('tracing/rb: Convert to hotplug state machine')
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

The clear_boot_tracer function is used to reset the default_bootup_tracer
string to prevent it from being accessed after boot, as it originally points
to init data. But since clear_boot_tracer() is called via the
init_lateinit() call, it races with the initcall for registering the hwlat
tracer. If someone adds "ftrace=hwlat" to the kernel command line, depending
on how the linker sets up the text, the saved command line may be cleared,
and the hwlat tracer never is initialized.

Simply have the clear_boot_tracer() be called by initcall_lateinit_sync() as
that's for tasks to be called after lateinit.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=196551

Cc: stable@vger.kernel.org
Fixes: e7c15cd8 ("tracing: Added hardware latency tracer")
Reported-by: NZamir SUN <sztsian@gmail.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

Hit the kmemleak when executing instance_rmdir, it forgot releasing
mem of tracing_cpumask. With this fix, the warn does not appear any
more.

unreferenced object 0xffff93a8dfaa7c18 (size 8):
  comm "mkdir", pid 1436, jiffies 4294763622 (age 9134.308s)
  hex dump (first 8 bytes):
    ff ff ff ff ff ff ff ff                          ........
  backtrace:
    [<ffffffff88b6567a>] kmemleak_alloc+0x4a/0xa0
    [<ffffffff8861ea41>] __kmalloc_node+0xf1/0x280
    [<ffffffff88b505d3>] alloc_cpumask_var_node+0x23/0x30
    [<ffffffff88b5060e>] alloc_cpumask_var+0xe/0x10
    [<ffffffff88571ab0>] instance_mkdir+0x90/0x240
    [<ffffffff886e5100>] tracefs_syscall_mkdir+0x40/0x70
    [<ffffffff886565c9>] vfs_mkdir+0x109/0x1b0
    [<ffffffff8865b1d0>] SyS_mkdir+0xd0/0x100
    [<ffffffff88403857>] do_syscall_64+0x67/0x150
    [<ffffffff88b710e7>] return_from_SYSCALL_64+0x0/0x6a
    [<ffffffffffffffff>] 0xffffffffffffffff

Link: http://lkml.kernel.org/r/1500546969-12594-1-git-send-email-chuhu@redhat.com

Cc: stable@vger.kernel.org
Fixes: ccfe9e42 ("tracing: Make tracing_cpumask available for all instances")
Signed-off-by: NChunyu Hu <chuhu@redhat.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

The addition of TGID to the tracing header added a check to see if TGID
shoudl be displayed or not, and updated the header accordingly.
Unfortunately, it broke the default header.

Also add constant strings to use for spacing. This does remove the
visibility of the header a bit, but cuts it down from the extended lines
much greater than 80 characters.

Before this change:

 # tracer: function
 #
 #                            _-----=> irqs-off
 #                           / _----=> need-resched
 #                          | / _---=> hardirq/softirq
 #                          || / _--=> preempt-depth
 #                          ||| /     delay
 #           TASK-PID   CPU#||||    TIMESTAMP  FUNCTION
 #              | |       | ||||       |         |
        swapper/0-1     [000] ....     0.277830: migration_init <-do_one_initcall
        swapper/0-1     [002] d...    13.861967: Unknown type 1201
        swapper/0-1     [002] d..1    13.861970: Unknown type 1202

After this change:

 # tracer: function
 #
 #                              _-----=> irqs-off
 #                             / _----=> need-resched
 #                            | / _---=> hardirq/softirq
 #                            || / _--=> preempt-depth
 #                            ||| /     delay
 #           TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION
 #              | |       |   ||||       |         |
        swapper/0-1     [000] ....     0.278245: migration_init <-do_one_initcall
        swapper/0-1     [003] d...    13.861189: Unknown type 1201
        swapper/0-1     [003] d..1    13.861192: Unknown type 1202

Cc: Joel Fernandes <joelaf@google.com>
Fixes: 441dae8f ("tracing: Add support for display of tgid in trace output")
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

In recent patches where we record comm and tgid at the same time, we skip
continuing to record if any fail. Fix that by trying to record as many things
as we can even if some couldn't be recorded. If any information isn't recorded,
then we don't set trace_taskinfo_save as before.

Link: http://lkml.kernel.org/r/20170706230023.17942-3-joelaf@google.com

Cc: kernel-team@android.com
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: NJoel Fernandes <joelaf@google.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

Currently we stop recording tgid for non-idle tasks when switching from/to idle
task since we treat that as a record failure. Fix that by treat recording of
tgid for idle task as a success.

Link: http://lkml.kernel.org/r/20170706230023.17942-2-joelaf@google.com

Cc: kernel-team@android.com
Cc: Ingo Molnar <mingo@redhat.com>
Reported-by: NMichael Sartain <mikesart@gmail.com>
Signed-off-by: NJoel Fernandes <joelaf@google.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

Currently we stop recording comm for non-idle tasks when switching from/to idle
task since we treat that as a record failure. Fix that by treat recording of
comm for idle task as a success.

Link: http://lkml.kernel.org/r/20170706230023.17942-1-joelaf@google.com

Cc: kernel-team@android.com
Cc: Ingo Molnar <mingo@redhat.com>
Reported-by: NMichael Sartain <mikesart@gmail.com>
Signed-off-by: NJoel Fernandes <joelaf@google.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

Export the cached pid / tgid mappings in debugfs tracing saved_tgids file.
This allows user apps to translate the pids from a trace to their respective
thread group.

Example saved_tgids file with pid / tgid values separated by ' ':

  # cat saved_tgids
  1048 1048
  1047 1047
  7 7
  1049 1047
  1054 1047
  1053 1047

Link: http://lkml.kernel.org/r/20170630004023.064965233@goodmis.org
Link: http://lkml.kernel.org/r/20170706040713.unwkumbta5menygi@mikesart-cosReviewed-by: NJoel Fernandes <joelaf@google.com>
Signed-off-by: NMichael Sartain <mikesart@fastmail.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

When doing the following command:

 # echo ":mod:kvm_intel" > /sys/kernel/tracing/stack_trace_filter

it triggered a crash.

This happened with the clean up of probes. It required all callers to the
regex function (doing ftrace filtering) to have ops->private be a pointer to
a trace_array. But for the stack tracer, that is not the case.

Allow for the ops->private to be NULL, and change the function command
callbacks to handle the trace_array pointer being NULL as well.

Fixes: d2afd57a ("tracing/ftrace: Allow instances to have their own function probes")
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

Earlier patches introduced ability to record the tgid using the 'record-tgid'
option. Here we read the tgid and output it if the option is enabled.

Link: http://lkml.kernel.org/r/20170626053844.5746-3-joelaf@google.com

Cc: kernel-team@android.com
Cc: Ingo Molnar <mingo@redhat.com>
Tested-by: NMichael Sartain <mikesart@gmail.com>
Signed-off-by: NJoel Fernandes <joelaf@google.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

Inorder to support recording of tgid, the following changes are made:

* Introduce a new API (tracing_record_taskinfo) to additionally record the tgid
  along with the task's comm at the same time. This has has the benefit of not
  setting trace_cmdline_save before all the information for a task is saved.
* Add a new API tracing_record_taskinfo_sched_switch to record task information
  for 2 tasks at a time (previous and next) and use it from sched_switch probe.
* Preserve the old API (tracing_record_cmdline) and create it as a wrapper
  around the new one so that existing callers aren't affected.
* Reuse the existing sched_switch and sched_wakeup probes to record tgid
  information and add a new option 'record-tgid' to enable recording of tgid

When record-tgid option isn't enabled to being with, we take care to make sure
that there's isn't memory or runtime overhead.

Link: http://lkml.kernel.org/r/20170627020155.5139-1-joelaf@google.com

Cc: kernel-team@android.com
Cc: Ingo Molnar <mingo@redhat.com>
Tested-by: NMichael Sartain <mikesart@gmail.com>
Signed-off-by: NJoel Fernandes <joelaf@google.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

ftrace_arch_read_dyn_info() was used so that archs could add its own debug
information into the dyn_ftrace_total_info in the tracefs file system. That
file is for debugging usage of dynamic ftrace. No arch uses that function
anymore, so just get rid of it.

This also allows for tracing_read_dyn_info() to be cleaned up a bit.
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

The enum_map file is used to display a list of symbol
to name conversions. As its now used to resolve sizeof
lets update the name and description.

Link: http://lkml.kernel.org/r/20170531215653.3240-13-jeremy.linton@arm.comSigned-off-by: NJeremy Linton <jeremy.linton@arm.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

Rename the core trace enum routines to use eval, to
reflect their use by more than just enum to value mapping.

Link: http://lkml.kernel.org/r/20170531215653.3240-8-jeremy.linton@arm.comSigned-off-by: NJeremy Linton <jeremy.linton@arm.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

Rename the init and trace_enum_jmp_to_tail() routines
to reflect their use by more than enumerated types.

Link: http://lkml.kernel.org/r/20170531215653.3240-7-jeremy.linton@arm.comSigned-off-by: NJeremy Linton <jeremy.linton@arm.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

There is a lock protecting the trace_enum_map, rename
it to reflect the use by more than enums.

Link: http://lkml.kernel.org/r/20170531215653.3240-6-jeremy.linton@arm.comSigned-off-by: NJeremy Linton <jeremy.linton@arm.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

The enum map entries can be exported to userspace
via a sys enum_map file. Rename those functions
and structures to reflect the fact that we are using
them for more than enums.

Link: http://lkml.kernel.org/r/20170531215653.3240-5-jeremy.linton@arm.comSigned-off-by: NJeremy Linton <jeremy.linton@arm.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>