Re: [RFC][PATCH v4 1/2] tracing/syscalls: Rename a field 'nr' to '__syscall_nr' in format

[Taeung Song]

Hi, Steven and Arnaldo

Oh.. Arnaldo already replied :-)

Thank you,
Taeung

On 03/09/2016 04:32 AM, Arnaldo Carvalho de Melo wrote:

Em Tue, Mar 08, 2016 at 04:32:12PM -0300, Arnaldo Carvalho de Melo escreveu:

Em Tue, Mar 08, 2016 at 02:24:34PM -0500, Steven Rostedt escreveu:

On Sun, 28 Feb 2016 01:41:51 +0900
Taeung Song <treeze.tae...@gmail.com> wrote:


Have we decided what we are going to do with this patch? Pull it as is
and see what the fall out is?

That was my understanding, you said somewhere that I could add your
signed-off-by, lemme dig that message...

And this is even already in tip/perf/core

Was there a perf patch with this too?

Yes:

commit c42de706dad3f39c1f65e473a1d165ea33f8b6e8
Author: Taeung Song <treeze.tae...@gmail.com>
Date:   Fri Feb 26 22:14:25 2016 +0900

     perf trace: Check and discard not only 'nr' but also '__syscall_nr'

-- Steve

Some syscalls tracepoint duplicated fields with the same name 'nr' i.e.

     # cat 
/sys/kernel/debug/tracing/events/syscalls/sys_enter_io_getevents/format
     name: sys_enter_io_getevents
     ID: 739
     format:
             field:unsigned short common_type; offset:0;  size:2; signed:0;
             field:unsigned char common_flags; offset:2;  size:1; signed:0;
             field:unsigned char common_preempt_count; offset:3; size:1; 
signed:0;
             field:int common_pid;offset:4;size:4;signed:1;
             field:int nr;                     offset:8;  size:4; signed:1;
             field:aio_context_t ctx_id;       offset:16; size:8; signed:0;
             field:long min_nr;                offset:24; size:8; signed:0;
             field:long nr;                    offset:32; size:8; signed:0;
             field:struct io_event * events;   offset:40; size:8; signed:0;
             field:struct timespec * timeout;  offset:48; size:8; signed:0;

             print fmt: "ctx_id: 0x%08lx, min_nr: 0x%08lx, nr: 0x%08lx,
                         events: 0x%08lx, timeout: 0x%08lx", ((unsigned 
long)(REC->ctx_id)),
                         ((unsigned long)(REC->min_nr)), ((unsigned 
long)(REC->nr)),
                         ((unsigned long)(REC->events)), ((unsigned 
long)(REC->timeout))

As above 'int nr;' and 'long nr;' fields have
duplicated name so problems are occurred in perf-script i.e.

     # perf record -e syscalls:*
     # perf script -g python
     # perf script -s perf-script.py
       File "perf-script.py", line 8694
         def syscalls__sys_enter_io_getevents(event_name, context, common_cpu,
     SyntaxError: duplicate argument 'nr' in function definition
     Error running python script perf-script.py

As above, problems about duplicated argument occurred.
Not only sys_enter_io_getevent() but also sys_enter_io_submit()
have relevevance to this problem.

So rename a field 'nr' to '__syscall_nr' for system call number
without renaming a member 'nr' of two structures 'syscall_trace_enter'
and 'syscall_trace_exit'.

Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Ingo Molnar <mi...@redhat.com>
Cc: Arnaldo Carvalho de Melo <a...@kernel.org>
Cc: Lai Jiangshan <jiangshan...@gmail.com>
Signed-off-by: Taeung Song <treeze.tae...@gmail.com>
Signed-off-by: Steven Rostedt <rost...@goodmis.org>
---
  kernel/trace/trace_syscalls.c | 16 +++++++++-------
  1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 0655afb..d166308 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -186,11 +186,11 @@ print_syscall_exit(struct trace_iterator *iter, int flags,

  extern char *__bad_type_size(void);

-#define SYSCALL_FIELD(type, name)                                      \
-       sizeof(type) != sizeof(trace.name) ?                            \
+#define SYSCALL_FIELD(type, field, name)                               \
+       sizeof(type) != sizeof(trace.field) ?                           \
                __bad_type_size() :                                     \
-               #type, #name, offsetof(typeof(trace), name),            \
-               sizeof(trace.name), is_signed_type(type)
+               #type, #name, offsetof(typeof(trace), field),           \
+               sizeof(trace.field), is_signed_type(type)

  static int __init
  __set_enter_print_fmt(struct syscall_metadata *entry, char *buf, int len)
@@ -261,7 +261,8 @@ static int __init syscall_enter_define_fields(struct 
trace_event_call *call)
        int i;
        int offset = offsetof(typeof(trace), args);

-       ret = trace_define_field(call, SYSCALL_FIELD(int, nr), FILTER_OTHER);
+       ret = trace_define_field(call, SYSCALL_FIELD(int, nr, __syscall_nr),
+                                FILTER_OTHER);
        if (ret)
                return ret;

@@ -281,11 +282,12 @@ static int __init syscall_exit_define_fields(struct 
trace_event_call *call)
        struct syscall_trace_exit trace;
        int ret;

-       ret = trace_define_field(call, SYSCALL_FIELD(int, nr), FILTER_OTHER);
+       ret = trace_define_field(call, SYSCALL_FIELD(int, nr, __syscall_nr),
+                                FILTER_OTHER);
        if (ret)
                return ret;

-       ret = trace_define_field(call, SYSCALL_FIELD(long, ret),
+       ret = trace_define_field(call, SYSCALL_FIELD(long, ret, ret),
                                 FILTER_OTHER);

        return ret;