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

From: Steven Rostedt
Date: Tue Mar 08 2016 - 14:24:59 EST


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


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

Was there a perf patch with this too?

-- 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@xxxxxxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> Cc: Lai Jiangshan <jiangshanlai@xxxxxxxxx>
> Signed-off-by: Taeung Song <treeze.taeung@xxxxxxxxx>
> Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
> ---
> 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;