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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Josef Bacik <jbacik@fb.com>,
        "Steven Rostedt (VMware)" <rostedt@goodmis.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.14 050/166] tracing: Set kernel_stacks caller size properly
Date:   Tue, 29 Sep 2020 12:59:22 +0200
Message-Id: <20200929105937.701380697@linuxfoundation.org>
In-Reply-To: <20200929105935.184737111@linuxfoundation.org>
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From: Josef Bacik <jbacik@fb.com>

[ 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>
---
 kernel/trace/trace_entries.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace_entries.h b/kernel/trace/trace_entries.h
index e3a658bac10fe..ff91acff72946 100644
--- a/kernel/trace/trace_entries.h
+++ b/kernel/trace/trace_entries.h
@@ -179,7 +179,7 @@ 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"
-- 
2.25.1