linux-next: build warnings after merge of the ftrace tree

linux-next: build warnings after merge of the ftrace tree

[Stephen Rothwell]

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Hi all,

After merging the ftrace tree, today's linux-next build (htmldocs)
produced these warnings:

Documentation/trace/histogram.rst:1969: ERROR: Unexpected indentation.
Documentation/trace/histogram.rst:1970: WARNING: Block quote ends without a blank line; unexpected unindent.
Documentation/trace/histogram.rst:1982: WARNING: Block quote ends without a blank line; unexpected unindent.
Documentation/trace/histogram.rst:2014: WARNING: Definition list ends without a blank line; unexpected unindent.
Documentation/trace/histogram.rst:2016: ERROR: Unexpected indentation.
Documentation/trace/histogram.rst:2028: WARNING: Block quote ends without a blank line; unexpected unindent.
Documentation/trace/histogram.rst:2030: ERROR: Unexpected indentation.
Documentation/trace/histogram.rst:2040: WARNING: Block quote ends without a blank line; unexpected unindent.
Documentation/trace/histogram.rst:2042: ERROR: Unexpected indentation.
Documentation/trace/histogram.rst:2052: WARNING: Block quote ends without a blank line; unexpected unindent.
Documentation/trace/histogram.rst:2055: ERROR: Unexpected indentation.
Documentation/trace/histogram.rst:2065: WARNING: Block quote ends without a blank line; unexpected unindent.

Introduced by commit

  88238513bb26 ("tracing/histogram: Document variable stacktrace")

-- 
Cheers,
Stephen Rothwell

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Re: linux-next: build warnings after merge of the ftrace tree

[Steven Rostedt]

On Mon, 30 Jan 2023 16:51:49 +1100
Stephen Rothwell <sfr@canb.auug.org.au> wrote:

> Hi all,
> 
> After merging the ftrace tree, today's linux-next build (htmldocs)
> produced these warnings:
> 
> Documentation/trace/histogram.rst:1969: ERROR: Unexpected indentation.
> Documentation/trace/histogram.rst:1970: WARNING: Block quote ends without a blank line; unexpected unindent.
> Documentation/trace/histogram.rst:1982: WARNING: Block quote ends without a blank line; unexpected unindent.
> Documentation/trace/histogram.rst:2014: WARNING: Definition list ends without a blank line; unexpected unindent.
> Documentation/trace/histogram.rst:2016: ERROR: Unexpected indentation.
> Documentation/trace/histogram.rst:2028: WARNING: Block quote ends without a blank line; unexpected unindent.
> Documentation/trace/histogram.rst:2030: ERROR: Unexpected indentation.
> Documentation/trace/histogram.rst:2040: WARNING: Block quote ends without a blank line; unexpected unindent.
> Documentation/trace/histogram.rst:2042: ERROR: Unexpected indentation.
> Documentation/trace/histogram.rst:2052: WARNING: Block quote ends without a blank line; unexpected unindent.
> Documentation/trace/histogram.rst:2055: ERROR: Unexpected indentation.
> Documentation/trace/histogram.rst:2065: WARNING: Block quote ends without a blank line; unexpected unindent.
> 
> Introduced by commit
> 
>   88238513bb26 ("tracing/histogram: Document variable stacktrace")
> 

krobot saw this too. I'm thinking this can fix it:

-- Steve

diff --git a/Documentation/trace/histogram.rst b/Documentation/trace/histogram.rst
index 5c391328b9bb..026eef03afe0 100644
--- a/Documentation/trace/histogram.rst
+++ b/Documentation/trace/histogram.rst
@@ -1864,7 +1864,7 @@ A histogram can now be defined for the new synthetic event::
 The above shows the latency "lat" in a power of 2 grouping.
 
 Like any other event, once a histogram is enabled for the event, the
-output can be displayed by reading the event's 'hist' file.
+output can be displayed by reading the event's 'hist' file::
 
   # cat /sys/kernel/debug/tracing/events/synthetic/wakeup_latency/hist
 
@@ -1911,7 +1911,7 @@ output can be displayed by reading the event's 'hist' file.
 
 
 The latency values can also be grouped linearly by a given size with
-the ".buckets" modifier and specify a size (in this case groups of 10).
+the ".buckets" modifier and specify a size (in this case groups of 10)::
 
   # echo 'hist:keys=pid,prio,lat.buckets=10:sort=lat' >> \
         /sys/kernel/debug/tracing/events/synthetic/wakeup_latency/trigger
@@ -1945,7 +1945,7 @@ the ".buckets" modifier and specify a size (in this case groups of 10).
 
 To save stacktraces, create a synthetic event with a field of type "unsigned long[]"
 or even just "long[]". For example, to see how long a task is blocked in an
-uninterruptible state:
+uninterruptible state::
 
   # cd /sys/kernel/tracing
   # echo 's:block_lat pid_t pid; u64 delta; unsigned long[] stack;' > dynamic_events
@@ -1990,7 +1990,7 @@ uninterruptible state:
   => kthread+0xe9/0x110
   => ret_from_fork+0x2c/0x50
 
-A synthetic event that has a stacktrace field may use it as a key in histogram:
+A synthetic event that has a stacktrace field may use it as a key in histogram::
 
   # echo 'hist:delta.buckets=100,stack.stacktrace:sort=delta' > events/synthetic/block_lat/trigger
   # cat events/synthetic/block_lat/hist
@@ -2183,7 +2183,7 @@ The following commonly-used handler.action pairs are available:
               wakeup_new_test($testpid) if comm=="cyclictest"' >> \
               /sys/kernel/debug/tracing/events/sched/sched_wakeup_new/trigger
 
-    Or, equivalently, using the 'trace' keyword syntax:
+    Or, equivalently, using the 'trace' keyword syntax::
 
     # echo 'hist:keys=$testpid:testpid=pid:onmatch(sched.sched_wakeup_new).\
             trace(wakeup_new_test,$testpid) if comm=="cyclictest"' >> \
@@ -2320,7 +2320,7 @@ The following commonly-used handler.action pairs are available:
     resulting latency, stored in wakeup_lat, exceeds the current
     maximum latency, a snapshot is taken.  As part of the setup, all
     the scheduler events are also enabled, which are the events that
-    will show up in the snapshot when it is taken at some point:
+    will show up in the snapshot when it is taken at some point::
 
     # echo 1 > /sys/kernel/debug/tracing/events/sched/enable
 
@@ -2339,7 +2339,7 @@ The following commonly-used handler.action pairs are available:
     following the rest of the fields.
 
     If a snapshot was taken, there is also a message indicating that,
-    along with the value and event that triggered the global maximum:
+    along with the value and event that triggered the global maximum::
 
     # cat /sys/kernel/debug/tracing/events/sched/sched_switch/hist
       { next_pid:       2101 } hitcount:        200
@@ -2439,7 +2439,7 @@ The following commonly-used handler.action pairs are available:
     $cwnd variable.  If the value has changed, a snapshot is taken.
     As part of the setup, all the scheduler and tcp events are also
     enabled, which are the events that will show up in the snapshot
-    when it is taken at some point:
+    when it is taken at some point::
 
     # echo 1 > /sys/kernel/debug/tracing/events/sched/enable
     # echo 1 > /sys/kernel/debug/tracing/events/tcp/enable

Re: linux-next: build warnings after merge of the ftrace tree

[Bagas Sanjaya]

On 1/31/23 01:51, Steven Rostedt wrote:
> krobot saw this too. I'm thinking this can fix it:
> 
> -- Steve
> 
> diff --git a/Documentation/trace/histogram.rst b/Documentation/trace/histogram.rst
> index 5c391328b9bb..026eef03afe0 100644
> --- a/Documentation/trace/histogram.rst
> +++ b/Documentation/trace/histogram.rst
> @@ -1864,7 +1864,7 @@ A histogram can now be defined for the new synthetic event::
>  The above shows the latency "lat" in a power of 2 grouping.
>  
>  Like any other event, once a histogram is enabled for the event, the
> -output can be displayed by reading the event's 'hist' file.
> +output can be displayed by reading the event's 'hist' file::
>  
>    # cat /sys/kernel/debug/tracing/events/synthetic/wakeup_latency/hist
>  
> @@ -1911,7 +1911,7 @@ output can be displayed by reading the event's 'hist' file.
>  
>  
>  The latency values can also be grouped linearly by a given size with
> -the ".buckets" modifier and specify a size (in this case groups of 10).
> +the ".buckets" modifier and specify a size (in this case groups of 10)::
>  
>    # echo 'hist:keys=pid,prio,lat.buckets=10:sort=lat' >> \
>          /sys/kernel/debug/tracing/events/synthetic/wakeup_latency/trigger
> @@ -1945,7 +1945,7 @@ the ".buckets" modifier and specify a size (in this case groups of 10).
>  
>  To save stacktraces, create a synthetic event with a field of type "unsigned long[]"
>  or even just "long[]". For example, to see how long a task is blocked in an
> -uninterruptible state:
> +uninterruptible state::
>  
>    # cd /sys/kernel/tracing
>    # echo 's:block_lat pid_t pid; u64 delta; unsigned long[] stack;' > dynamic_events
> @@ -1990,7 +1990,7 @@ uninterruptible state:
>    => kthread+0xe9/0x110
>    => ret_from_fork+0x2c/0x50
>  
> -A synthetic event that has a stacktrace field may use it as a key in histogram:
> +A synthetic event that has a stacktrace field may use it as a key in histogram::
>  
>    # echo 'hist:delta.buckets=100,stack.stacktrace:sort=delta' > events/synthetic/block_lat/trigger
>    # cat events/synthetic/block_lat/hist
> @@ -2183,7 +2183,7 @@ The following commonly-used handler.action pairs are available:
>                wakeup_new_test($testpid) if comm=="cyclictest"' >> \
>                /sys/kernel/debug/tracing/events/sched/sched_wakeup_new/trigger
>  
> -    Or, equivalently, using the 'trace' keyword syntax:
> +    Or, equivalently, using the 'trace' keyword syntax::
>  
>      # echo 'hist:keys=$testpid:testpid=pid:onmatch(sched.sched_wakeup_new).\
>              trace(wakeup_new_test,$testpid) if comm=="cyclictest"' >> \
> @@ -2320,7 +2320,7 @@ The following commonly-used handler.action pairs are available:
>      resulting latency, stored in wakeup_lat, exceeds the current
>      maximum latency, a snapshot is taken.  As part of the setup, all
>      the scheduler events are also enabled, which are the events that
> -    will show up in the snapshot when it is taken at some point:
> +    will show up in the snapshot when it is taken at some point::
>  
>      # echo 1 > /sys/kernel/debug/tracing/events/sched/enable
>  
> @@ -2339,7 +2339,7 @@ The following commonly-used handler.action pairs are available:
>      following the rest of the fields.
>  
>      If a snapshot was taken, there is also a message indicating that,
> -    along with the value and event that triggered the global maximum:
> +    along with the value and event that triggered the global maximum::
>  
>      # cat /sys/kernel/debug/tracing/events/sched/sched_switch/hist
>        { next_pid:       2101 } hitcount:        200
> @@ -2439,7 +2439,7 @@ The following commonly-used handler.action pairs are available:
>      $cwnd variable.  If the value has changed, a snapshot is taken.
>      As part of the setup, all the scheduler and tcp events are also
>      enabled, which are the events that will show up in the snapshot
> -    when it is taken at some point:
> +    when it is taken at some point::
>  
>      # echo 1 > /sys/kernel/debug/tracing/events/sched/enable
>      # echo 1 > /sys/kernel/debug/tracing/events/tcp/enable

Hi Steve,

I had already sent the fix, which also include required indentation changes
to make code blocks alignment nicer at [1].

Thanks.

[1]: https://lore.kernel.org/linux-doc/20230129031402.47420-1-bagasdotme@gmail.com/

-- 
An old man doll... just what I always wanted! - Clara

Re: linux-next: build warnings after merge of the ftrace tree

[Daniel Bristot de Oliveira]

Hi Stephen

On 1/15/22 05:28, Stephen Rothwell wrote:
> Hi all,
> 
> After merging the ftrace tree, today's linux-next build (htmldoc)
> produced these warnings:
> 
> Documentation/tools/rtla/rtla-osnoise-hist.rst: WARNING: document isn't included in any toctree
> Documentation/tools/rtla/rtla-osnoise-top.rst: WARNING: document isn't included in any toctree
> Documentation/tools/rtla/rtla-timerlat.rst: WARNING: document isn't included in any toctree
> Documentation/tools/rtla/rtla-timerlat-hist.rst: WARNING: document isn't included in any toctree
> Documentation/tools/rtla/rtla-timerlat-top.rst: WARNING: document isn't included in any toctree
> 
> Introduced by commits
> 
>   b1be48307de4 ("rtla: Add rtla osnoise top documentation")
>   e7041c6b3c12 ("rtla: Add rtla osnoise hist documentation")
>   29380d4055e5 ("rtla: Add rtla timerlat documentation")
>   df337d014b57 ("rtla: Add rtla timerlat top documentation")
>   5dce5904e3b9 ("rtla: Add rtla timerlat hist documentation")
> 

The Documentation/tools/$tools/ is a new directory to store man pages of the
$tools. The idea seems to be to create a '"book" within the larger documentation 
collection'.

I moved the documentation to that directory following Corbet's suggestion [1], 
but the "book" was not yet created. I think it deserves the hands of a more 
expert person in Docs.

Thoughts?

[1] https://lore.kernel.org/lkml/5796a3d5-ae98-9d28-138f-981a06dab34b@kernel.org/

-- Daniel

linux-next: build warnings after merge of the ftrace tree

[Stephen Rothwell]

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Hi all,

After merging the ftrace tree, today's linux-next build (htmldoc)
produced these warnings:

Documentation/tools/rtla/rtla-osnoise-hist.rst: WARNING: document isn't included in any toctree
Documentation/tools/rtla/rtla-osnoise-top.rst: WARNING: document isn't included in any toctree
Documentation/tools/rtla/rtla-timerlat.rst: WARNING: document isn't included in any toctree
Documentation/tools/rtla/rtla-timerlat-hist.rst: WARNING: document isn't included in any toctree
Documentation/tools/rtla/rtla-timerlat-top.rst: WARNING: document isn't included in any toctree

Introduced by commits

  b1be48307de4 ("rtla: Add rtla osnoise top documentation")
  e7041c6b3c12 ("rtla: Add rtla osnoise hist documentation")
  29380d4055e5 ("rtla: Add rtla timerlat documentation")
  df337d014b57 ("rtla: Add rtla timerlat top documentation")
  5dce5904e3b9 ("rtla: Add rtla timerlat hist documentation")

-- 
Cheers,
Stephen Rothwell

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Re: linux-next: build warnings after merge of the ftrace tree

[Steven Rostedt]

On Mon, 4 Jul 2016 15:42:07 +1000
Stephen Rothwell <sfr@canb.auug.org.au> wrote:

> Hi Steven,
> 
> After merging the ftrace tree, today's linux-next build (x86_64
> allmodconfig) produced these warnings:

I'm currently running the patch I posted previously and if all goes
well will have that patch added to my ftrace-next repo tonight.
Fengguang Wu's bot caught this, but I was working on something else.
Over the weekend I was wondering why I haven't pushed my repo yet (I
forgot about this), and pushed my branch.

So this doesn't happen again, I added:

 # CONFIG_SECTION_MISMATCH_WARN_ONLY is not set

to one of the configs I use for testing, as my tests didn't die when
a mismatch was added and caught.

-- Steve

Link: http://lkml.kernel.org/r/20160704102139.19cbc0d9@gandalf.local.home

linux-next: build warnings after merge of the ftrace tree

[Stephen Rothwell]

Hi Steven,

After merging the ftrace tree, today's linux-next build (x86_64
allmodconfig) produced these warnings:

WARNING: kernel/trace/libftrace.o(.text+0x9569): Section mismatch in reference from the function ftrace_init_tracefs() to the variable .init.data:function_stats
The function ftrace_init_tracefs() references
the variable __initdata function_stats.
This is often because ftrace_init_tracefs lacks a __initdata 
annotation or the annotation of function_stats is wrong.

WARNING: kernel/trace/libftrace.o(.text+0x9577): Section mismatch in reference from the function ftrace_init_tracefs() to the variable .init.data:function_stats
The function ftrace_init_tracefs() references
the variable __initdata function_stats.
This is often because ftrace_init_tracefs lacks a __initdata 
annotation or the annotation of function_stats is wrong.

WARNING: kernel/trace/libftrace.o(.text+0x9582): Section mismatch in reference from the function ftrace_init_tracefs() to the variable .init.data:function_stats
The function ftrace_init_tracefs() references
the variable __initdata function_stats.
This is often because ftrace_init_tracefs lacks a __initdata 
annotation or the annotation of function_stats is wrong.

WARNING: kernel/trace/libftrace.o(.text+0x958d): Section mismatch in reference from the function ftrace_init_tracefs() to the (unknown reference) .init.data:(unknown)
The function ftrace_init_tracefs() references
the (unknown reference) __initdata (unknown).
This is often because ftrace_init_tracefs lacks a __initdata 
annotation or the annotation of (unknown) is wrong.

WARNING: kernel/trace/libftrace.o(.text+0x9598): Section mismatch in reference from the function ftrace_init_tracefs() to the (unknown reference) .init.data:(unknown)
The function ftrace_init_tracefs() references
the (unknown reference) __initdata (unknown).
This is often because ftrace_init_tracefs lacks a __initdata 
annotation or the annotation of (unknown) is wrong.

WARNING: kernel/trace/libftrace.o(.text+0x95a3): Section mismatch in reference from the function ftrace_init_tracefs() to the (unknown reference) .init.data:(unknown)
The function ftrace_init_tracefs() references
the (unknown reference) __initdata (unknown).
This is often because ftrace_init_tracefs lacks a __initdata 
annotation or the annotation of (unknown) is wrong.

WARNING: kernel/trace/libftrace.o(.text+0x95ae): Section mismatch in reference from the function ftrace_init_tracefs() to the variable .init.data:ftrace_filter_param
The function ftrace_init_tracefs() references
the variable __initdata ftrace_filter_param.
This is often because ftrace_init_tracefs lacks a __initdata 
annotation or the annotation of ftrace_filter_param is wrong.

WARNING: kernel/trace/built-in.o(.text+0x9789): Section mismatch in reference from the function ftrace_init_tracefs() to the variable .init.data:function_stats
The function ftrace_init_tracefs() references
the variable __initdata function_stats.
This is often because ftrace_init_tracefs lacks a __initdata 
annotation or the annotation of function_stats is wrong.

WARNING: kernel/trace/built-in.o(.text+0x9797): Section mismatch in reference from the function ftrace_init_tracefs() to the variable .init.data:function_stats
The function ftrace_init_tracefs() references
the variable __initdata function_stats.
This is often because ftrace_init_tracefs lacks a __initdata 
annotation or the annotation of function_stats is wrong.

WARNING: kernel/trace/built-in.o(.text+0x97a2): Section mismatch in reference from the function ftrace_init_tracefs() to the variable .init.data:function_stats
The function ftrace_init_tracefs() references
the variable __initdata function_stats.
This is often because ftrace_init_tracefs lacks a __initdata 
annotation or the annotation of function_stats is wrong.

WARNING: kernel/trace/built-in.o(.text+0x97ad): Section mismatch in reference from the function ftrace_init_tracefs() to the (unknown reference) .init.data:(unknown)
The function ftrace_init_tracefs() references
the (unknown reference) __initdata (unknown).
This is often because ftrace_init_tracefs lacks a __initdata 
annotation or the annotation of (unknown) is wrong.

WARNING: kernel/trace/built-in.o(.text+0x97b8): Section mismatch in reference from the function ftrace_init_tracefs() to the (unknown reference) .init.data:(unknown)
The function ftrace_init_tracefs() references
the (unknown reference) __initdata (unknown).
This is often because ftrace_init_tracefs lacks a __initdata 
annotation or the annotation of (unknown) is wrong.

WARNING: kernel/trace/built-in.o(.text+0x97c3): Section mismatch in reference from the function ftrace_init_tracefs() to the (unknown reference) .init.data:(unknown)
The function ftrace_init_tracefs() references
the (unknown reference) __initdata (unknown).
This is often because ftrace_init_tracefs lacks a __initdata 
annotation or the annotation of (unknown) is wrong.

WARNING: kernel/trace/built-in.o(.text+0x97ce): Section mismatch in reference from the function ftrace_init_tracefs() to the variable .init.data:ftrace_filter_param
The function ftrace_init_tracefs() references
the variable __initdata ftrace_filter_param.
This is often because ftrace_init_tracefs lacks a __initdata 
annotation or the annotation of ftrace_filter_param is wrong.

WARNING: kernel/built-in.o(.text+0x18bbb9): Section mismatch in reference from the function ftrace_init_tracefs() to the variable .init.data:function_stats
The function ftrace_init_tracefs() references
the variable __initdata function_stats.
This is often because ftrace_init_tracefs lacks a __initdata 
annotation or the annotation of function_stats is wrong.

WARNING: kernel/built-in.o(.text+0x18bbc7): Section mismatch in reference from the function ftrace_init_tracefs() to the variable .init.data:function_stats
The function ftrace_init_tracefs() references
the variable __initdata function_stats.
This is often because ftrace_init_tracefs lacks a __initdata 
annotation or the annotation of function_stats is wrong.

WARNING: kernel/built-in.o(.text+0x18bbd2): Section mismatch in reference from the function ftrace_init_tracefs() to the variable .init.data:function_stats
The function ftrace_init_tracefs() references
the variable __initdata function_stats.
This is often because ftrace_init_tracefs lacks a __initdata 
annotation or the annotation of function_stats is wrong.

WARNING: kernel/built-in.o(.text+0x18bbdd): Section mismatch in reference from the function ftrace_init_tracefs() to the (unknown reference) .init.data:(unknown)
The function ftrace_init_tracefs() references
the (unknown reference) __initdata (unknown).
This is often because ftrace_init_tracefs lacks a __initdata 
annotation or the annotation of (unknown) is wrong.

WARNING: kernel/built-in.o(.text+0x18bbe8): Section mismatch in reference from the function ftrace_init_tracefs() to the (unknown reference) .init.data:(unknown)
The function ftrace_init_tracefs() references
the (unknown reference) __initdata (unknown).
This is often because ftrace_init_tracefs lacks a __initdata 
annotation or the annotation of (unknown) is wrong.

WARNING: kernel/built-in.o(.text+0x18bbf3): Section mismatch in reference from the function ftrace_init_tracefs() to the (unknown reference) .init.data:(unknown)
The function ftrace_init_tracefs() references
the (unknown reference) __initdata (unknown).
This is often because ftrace_init_tracefs lacks a __initdata 
annotation or the annotation of (unknown) is wrong.

WARNING: kernel/built-in.o(.text+0x18bbfe): Section mismatch in reference from the function ftrace_init_tracefs() to the variable .init.data:ftrace_filter_param
The function ftrace_init_tracefs() references
the variable __initdata ftrace_filter_param.
This is often because ftrace_init_tracefs lacks a __initdata 
annotation or the annotation of ftrace_filter_param is wrong.

WARNING: vmlinux.o(.text+0x2636f9): Section mismatch in reference from the function ftrace_init_tracefs() to the variable .init.data:function_stats
The function ftrace_init_tracefs() references
the variable __initdata function_stats.
This is often because ftrace_init_tracefs lacks a __initdata 
annotation or the annotation of function_stats is wrong.

WARNING: vmlinux.o(.text+0x263707): Section mismatch in reference from the function ftrace_init_tracefs() to the variable .init.data:function_stats
The function ftrace_init_tracefs() references
the variable __initdata function_stats.
This is often because ftrace_init_tracefs lacks a __initdata 
annotation or the annotation of function_stats is wrong.

WARNING: vmlinux.o(.text+0x263712): Section mismatch in reference from the function ftrace_init_tracefs() to the variable .init.data:function_stats
The function ftrace_init_tracefs() references
the variable __initdata function_stats.
This is often because ftrace_init_tracefs lacks a __initdata 
annotation or the annotation of function_stats is wrong.

WARNING: vmlinux.o(.text+0x26371d): Section mismatch in reference from the function ftrace_init_tracefs() to the (unknown reference) .init.data:(unknown)
The function ftrace_init_tracefs() references
the (unknown reference) __initdata (unknown).
This is often because ftrace_init_tracefs lacks a __initdata 
annotation or the annotation of (unknown) is wrong.

WARNING: vmlinux.o(.text+0x263728): Section mismatch in reference from the function ftrace_init_tracefs() to the (unknown reference) .init.data:(unknown)
The function ftrace_init_tracefs() references
the (unknown reference) __initdata (unknown).
This is often because ftrace_init_tracefs lacks a __initdata 
annotation or the annotation of (unknown) is wrong.

WARNING: vmlinux.o(.text+0x263733): Section mismatch in reference from the function ftrace_init_tracefs() to the (unknown reference) .init.data:(unknown)
The function ftrace_init_tracefs() references
the (unknown reference) __initdata (unknown).
This is often because ftrace_init_tracefs lacks a __initdata 
annotation or the annotation of (unknown) is wrong.

WARNING: vmlinux.o(.text+0x26373e): Section mismatch in reference from the function ftrace_init_tracefs() to the variable .init.data:ftrace_filter_param
The function ftrace_init_tracefs() references
the variable __initdata ftrace_filter_param.
This is often because ftrace_init_tracefs lacks a __initdata 
annotation or the annotation of ftrace_filter_param is wrong.

Introduced (I assume) by commit

  345ddcc882d8 ("ftrace: Have set_ftrace_pid use the bitmap like events do")

-- 
Cheers,
Stephen Rothwell