tracing: Set kernel_stack's caller size properly

[ Upstream commit cbc3b92ce037f5e7536f6db157d185cd8b8f615c ]

I noticed when trying to use the trace-cmd python interface that reading the raw
buffer wasn't working for kernel_stack events.  This is because it uses a
stubbed version of __dynamic_array that doesn't do the __data_loc trick and
encode the length of the array into the field.  Instead it just shows up as a
size of 0.  So change this to __array and set the len to FTRACE_STACK_ENTRIES
since this is what we actually do in practice and matches how user_stack_trace
works.

Link: http://lkml.kernel.org/r/1411589652-1318-1-git-send-email-jbacik@fb.com
Signed-off-by: Josef Bacik <jbacik@fb.com>
[ Pulled from the archeological digging of my INBOX ]
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/kernel/trace/trace_entries.h b/kernel/trace/trace_entries.h
index d1cc37e78f9975ca38c48635b3bd377065685e32..1430f6bbb1a077367a4d23ded4159baed276c6f1 100644 (file)
--- a/kernel/trace/trace_entries.h
+++ b/kernel/trace/trace_entries.h
@@ -178,7 +178,7 @@ FTRACE_ENTRY(kernel_stack, stack_entry,
 
        F_STRUCT(
                __field(        int,            size    )
-               __dynamic_array(unsigned long,  caller  )
+               __array(        unsigned long,  caller, FTRACE_STACK_ENTRIES    )
        ),
 
        F_printk("\t=> (" IP_FMT ")\n\t=> (" IP_FMT ")\n\t=> (" IP_FMT ")\n"