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

[Arnaldo Carvalho de Melo <acme@kernel.org>]

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.taeung@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.taeung@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 <tglx@linutronix.de>
> > > Cc: Peter Zijlstra <peterz@infradead.org>
> > > Cc: Ingo Molnar <mingo@redhat.com>
> > > Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
> > > Cc: Lai Jiangshan <jiangshanlai@gmail.com>
> > > Signed-off-by: Taeung Song <treeze.taeung@gmail.com>
> > > Signed-off-by: Steven Rostedt <rostedt@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;