Re: [PATCH RESEND 1/3] tracing/syscalls: Rename variable 'nr' to 'syscall_nr'
From: Taeung Song
Date: Thu Feb 25 2016 - 11:53:56 EST
Hi, Steven
On 02/26/2016 12:47 AM, Steven Rostedt wrote:
On Fri, 26 Feb 2016 00:24:18 +0900
Taeung Song <treeze.taeung@xxxxxxxxx> wrote:
There is a problem about duplicated variable name
for system call number and a argument of some
system call. I found this problem when I tested
perf-script with python script as below.
# 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
when processing sys_enter_io_getevent() and sys_enter_io_submit().
Because the two system calls have a argument 'nr' as below.
int io_getevents(aio_context_t ctx_id, long min_nr, long nr,
struct io_event *events, struct timespec *timeout);
int io_submit(aio_context_t ctx_id, long nr, struct iocb **iocbpp);
So rename a variable 'nr' to 'syscall_nr' for system call number
in print_syscall_enter().
WTF, how does changing the kernel fix a user space python generation
bug?
The underlying cause of this problem is not because of
the python script. This problem have relevance to tracing/syscalls
as below.
# 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 you see, there are duplicated variable name among fields.
So I renamed the variable name 'nr' to 'syscall_nr' to avoid this
duplication. As you know 'nr' in print_syscall_enter() mean
system call number so, I changed 'nr' to 'syscall_nr'(IMHO).
Thanks,
Taeung
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Lai Jiangshan <jiangshanlai@xxxxxxxxx>
Signed-off-by: Taeung Song <treeze.taeung@xxxxxxxxx>
---
kernel/trace/trace.h | 4 ++--
kernel/trace/trace_syscalls.c | 16 ++++++++--------
2 files changed, 10 insertions(+), 10 deletions(-)
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 8414fa4..beddeb1 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -88,13 +88,13 @@ enum trace_type {
*/
struct syscall_trace_enter {
struct trace_entry ent;
- int nr;
+ int syscall_nr;
unsigned long args[];
};
struct syscall_trace_exit {
struct trace_entry ent;
- int nr;
+ int syscall_nr;
long ret;
};
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 0655afb..956209f 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -118,7 +118,7 @@ print_syscall_enter(struct trace_iterator *iter, int flags,
int i, syscall;
trace = (typeof(trace))ent;
- syscall = trace->nr;
+ syscall = trace->syscall_nr;
entry = syscall_nr_to_meta(syscall);
if (!entry)
@@ -164,7 +164,7 @@ print_syscall_exit(struct trace_iterator *iter, int flags,
struct syscall_metadata *entry;
trace = (typeof(trace))ent;
- syscall = trace->nr;
+ syscall = trace->syscall_nr;
entry = syscall_nr_to_meta(syscall);
if (!entry) {
@@ -261,7 +261,7 @@ 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, syscall_nr), FILTER_OTHER);
if (ret)
return ret;
@@ -281,7 +281,7 @@ 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, syscall_nr), FILTER_OTHER);
if (ret)
return ret;
@@ -332,7 +332,7 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id)
return;
entry = ring_buffer_event_data(event);
- entry->nr = syscall_nr;
+ entry->syscall_nr = syscall_nr;
syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args);
event_trigger_unlock_commit(trace_file, buffer, event, entry,
@@ -378,7 +378,7 @@ static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret)
return;
entry = ring_buffer_event_data(event);
- entry->nr = syscall_nr;
+ entry->syscall_nr = syscall_nr;
entry->ret = syscall_get_return_value(current, regs);
event_trigger_unlock_commit(trace_file, buffer, event, entry,
@@ -579,7 +579,7 @@ static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id)
if (!rec)
return;
- rec->nr = syscall_nr;
+ rec->syscall_nr = syscall_nr;
syscall_get_arguments(current, regs, 0, sys_data->nb_args,
(unsigned long *)&rec->args);
perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head, NULL);
@@ -652,7 +652,7 @@ static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
if (!rec)
return;
- rec->nr = syscall_nr;
+ rec->syscall_nr = syscall_nr;
rec->ret = syscall_get_return_value(current, regs);
perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head, NULL);
}