PR11599: update STAPCONF_TRACEPOINT_HAS_DATA to work with kernel 5.7.0+

PR11599: update STAPCONF_TRACEPOINT_HAS_DATA to work with kernel 5.7.0+

[Torsten Polle]

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Hi Serhei,

Your patch introduces a new source for the definition of STAPCONF_TRACEPOINT_HAS_DATA in the files generated by autoconf, which conflicts with the original definition stp_tracepoints.h.

The following patch remedies this situation at least in my environment. But I wonder whether the definition in stp_tracepoints.h could be simply removed.

Kind Regards,
Torsten

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From ec0017bf86606f87703a2b8345f49dc0eebf363c Mon Sep 17 00:00:00 2001
From: Torsten Polle <Torsten.Polle@gmx.de>
Date: Sun, 24 May 2020 10:49:35 +0200
Subject: [PATCH] PR11599: Fix: STAPCONF_TRACEPOINT_HAS_DATA already defined.

---
 runtime/linux/stp_tracepoint.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/runtime/linux/stp_tracepoint.h b/runtime/linux/stp_tracepoint.h
index cb8d335..e66cd4f 100644
--- a/runtime/linux/stp_tracepoint.h
+++ b/runtime/linux/stp_tracepoint.h
@@ -21,7 +21,9 @@
  * Since NOARGS was removed in 5.7.0, this configuration is now also
  * checked with autoconf-tracepoint-has-data.c. */
 #ifdef DECLARE_TRACE_NOARGS
-#define STAPCONF_TRACEPOINT_HAS_DATA
+#  ifndef STAPCONF_TRACEPOINT_HAS_DATA
+#    define STAPCONF_TRACEPOINT_HAS_DATA
+#  endif
 #endif
 
 
-- 
2.7.4

Re: PR11599: update STAPCONF_TRACEPOINT_HAS_DATA to work with kernel 5.7.0+

[Serhei Makarov]

Hello Torsten,

Thank you very much for testing the change! I went to apply your patch this morning and saw that Frank also caught the same problem and fixed it with commit 823a77ab03c3. If that approach to fix it still generates a warning, I'll apply your patch.

In answer to your question, to remove the definition of stp_tracepoints.h, the autoconf file must compile correctly on every prior kernel version where DECLARE_TRACE_NOARGS was defined.
I have not verified this, so I can only be certain the autoconf check is appropriate for kernel 5.7+.
For earlier versions, we continue to check for DECLARE_TRACE_NOARGS.

All the best,
      Serhei

On Sun, May 24, 2020, at 10:07 AM, Torsten Polle wrote:
> Hi Serhei,
> 
> Your patch introduces a new source for the definition of 
> STAPCONF_TRACEPOINT_HAS_DATA in the files generated by autoconf, which 
> conflicts with the original definition stp_tracepoints.h.
> 
> The following patch remedies this situation at least in my environment. 
> But I wonder whether the definition in stp_tracepoints.h could be 
> simply removed.
> 
> Kind Regards,
> Torsten
> 
> Attachments:
> * PR11599-Fix-STAPCONF_TRACEPOINT_HAS_DATA-already-def.patch