[02/12] trace: Make trace_hwlat timestamp y2038 safe

Submitted by Deepa Dinamani on April 8, 2017, 12:57 a.m.

Details

Message ID 1491613030-11599-3-git-send-email-deepa.kernel@gmail.com
State Not Applicable
Headers show

Commit Message

Deepa Dinamani April 8, 2017, 12:57 a.m.
struct timespec is not y2038 safe on 32 bit machines
and needs to be replaced by struct timespec64
in order to represent times beyond year 2038 on such
machines.

Fix all the timestamp representation in struct trace_hwlat
and all the corresponding implementations.

Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
---
 kernel/trace/trace_entries.h |  6 +++---
 kernel/trace/trace_hwlat.c   | 14 +++++++-------
 kernel/trace/trace_output.c  |  9 ++++-----
 3 files changed, 14 insertions(+), 15 deletions(-)

Comments

Steven Rostedt April 8, 2017, 1:30 a.m.
On Fri,  7 Apr 2017 17:57:00 -0700
Deepa Dinamani <deepa.kernel@gmail.com> wrote:

> struct timespec is not y2038 safe on 32 bit machines
> and needs to be replaced by struct timespec64
> in order to represent times beyond year 2038 on such
> machines.
> 
> Fix all the timestamp representation in struct trace_hwlat
> and all the corresponding implementations.
> 

> diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
> index 02a4aeb..08f9bab 100644
> --- a/kernel/trace/trace_output.c
> +++ b/kernel/trace/trace_output.c
> @@ -4,7 +4,6 @@
>   * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
>   *
>   */
> -
>  #include <linux/module.h>
>  #include <linux/mutex.h>
>  #include <linux/ftrace.h>
> @@ -1161,11 +1160,11 @@ trace_hwlat_print(struct trace_iterator *iter, int flags,
>  
>  	trace_assign_type(field, entry);
>  
> -	trace_seq_printf(s, "#%-5u inner/outer(us): %4llu/%-5llu ts:%ld.%09ld",
> +	trace_seq_printf(s, "#%-5u inner/outer(us): %4llu/%-5llu ts:%lld.%09ld",
>  			 field->seqnum,
>  			 field->duration,
>  			 field->outer_duration,
> -			 field->timestamp.tv_sec,
> +			 (long long)field->timestamp.tv_sec,

Refresh my memory. We need the cast because on 64 bit boxes
timestamp.tv_sec is just a long?

Other than that.

Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

-- Steve

>  			 field->timestamp.tv_nsec);
>  
>  	if (field->nmi_count) {
> @@ -1195,10 +1194,10 @@ trace_hwlat_raw(struct trace_iterator *iter, int flags,
>  
>  	trace_assign_type(field, iter->ent);
>  
> -	trace_seq_printf(s, "%llu %lld %ld %09ld %u\n",
> +	trace_seq_printf(s, "%llu %lld %lld %09ld %u\n",
>  			 field->duration,
>  			 field->outer_duration,
> -			 field->timestamp.tv_sec,
> +			 (long long)field->timestamp.tv_sec,
>  			 field->timestamp.tv_nsec,
>  			 field->seqnum);
>
Deepa Dinamani April 8, 2017, 2:16 a.m.
>> -     trace_seq_printf(s, "#%-5u inner/outer(us): %4llu/%-5llu ts:%ld.%09ld",
>> +     trace_seq_printf(s, "#%-5u inner/outer(us): %4llu/%-5llu ts:%lld.%09ld",
>>                        field->seqnum,
>>                        field->duration,
>>                        field->outer_duration,
>> -                      field->timestamp.tv_sec,
>> +                      (long long)field->timestamp.tv_sec,
>
> Refresh my memory. We need the cast because on 64 bit boxes
> timestamp.tv_sec is just a long?

This is only required until we change the definition of timespec64.
Right now it is defined as

#if __BITS_PER_LONG == 64
# define timespec64 timespec
#else
struct timespec64 {
    time64_t tv_sec;
    long tv_nsec;
};
#endif

And timespec.tv_sec is just long int on 64 bit machines.
This is why we need the cast now.

We will probably change this and only define __kernel_timespec instead
of timespec, leaving only one definition of timespec64.
At that time, we will not need this.

-Deepa

Patch hide | download patch | download mbox

diff --git a/kernel/trace/trace_entries.h b/kernel/trace/trace_entries.h
index c203ac4..adcdbbe 100644
--- a/kernel/trace/trace_entries.h
+++ b/kernel/trace/trace_entries.h
@@ -348,14 +348,14 @@  FTRACE_ENTRY(hwlat, hwlat_entry,
 		__field(	u64,			duration	)
 		__field(	u64,			outer_duration	)
 		__field(	u64,			nmi_total_ts	)
-		__field_struct( struct timespec,	timestamp	)
-		__field_desc(	long,	timestamp,	tv_sec		)
+		__field_struct( struct timespec64,	timestamp	)
+		__field_desc(	s64,	timestamp,	tv_sec		)
 		__field_desc(	long,	timestamp,	tv_nsec		)
 		__field(	unsigned int,		nmi_count	)
 		__field(	unsigned int,		seqnum		)
 	),
 
-	F_printk("cnt:%u\tts:%010lu.%010lu\tinner:%llu\touter:%llunmi-ts:%llu\tnmi-count:%u\n",
+	F_printk("cnt:%u\tts:%010llu.%010lu\tinner:%llu\touter:%llunmi-ts:%llu\tnmi-count:%u\n",
 		 __entry->seqnum,
 		 __entry->tv_sec,
 		 __entry->tv_nsec,
diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c
index 21ea6ae..d7c8e4e 100644
--- a/kernel/trace/trace_hwlat.c
+++ b/kernel/trace/trace_hwlat.c
@@ -79,12 +79,12 @@  static u64 last_tracing_thresh = DEFAULT_LAT_THRESHOLD * NSEC_PER_USEC;
 
 /* Individual latency samples are stored here when detected. */
 struct hwlat_sample {
-	u64		seqnum;		/* unique sequence */
-	u64		duration;	/* delta */
-	u64		outer_duration;	/* delta (outer loop) */
-	u64		nmi_total_ts;	/* Total time spent in NMIs */
-	struct timespec	timestamp;	/* wall time */
-	int		nmi_count;	/* # NMIs during this sample */
+	u64			seqnum;		/* unique sequence */
+	u64			duration;	/* delta */
+	u64			outer_duration;	/* delta (outer loop) */
+	u64			nmi_total_ts;	/* Total time spent in NMIs */
+	struct timespec64	timestamp;	/* wall time */
+	int			nmi_count;	/* # NMIs during this sample */
 };
 
 /* keep the global state somewhere. */
@@ -250,7 +250,7 @@  static int get_sample(void)
 		s.seqnum = hwlat_data.count;
 		s.duration = sample;
 		s.outer_duration = outer_sample;
-		s.timestamp = CURRENT_TIME;
+		ktime_get_real_ts64(&s.timestamp);
 		s.nmi_total_ts = nmi_total_ts;
 		s.nmi_count = nmi_count;
 		trace_hwlat_sample(&s);
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 02a4aeb..08f9bab 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -4,7 +4,6 @@ 
  * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
  *
  */
-
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/ftrace.h>
@@ -1161,11 +1160,11 @@  trace_hwlat_print(struct trace_iterator *iter, int flags,
 
 	trace_assign_type(field, entry);
 
-	trace_seq_printf(s, "#%-5u inner/outer(us): %4llu/%-5llu ts:%ld.%09ld",
+	trace_seq_printf(s, "#%-5u inner/outer(us): %4llu/%-5llu ts:%lld.%09ld",
 			 field->seqnum,
 			 field->duration,
 			 field->outer_duration,
-			 field->timestamp.tv_sec,
+			 (long long)field->timestamp.tv_sec,
 			 field->timestamp.tv_nsec);
 
 	if (field->nmi_count) {
@@ -1195,10 +1194,10 @@  trace_hwlat_raw(struct trace_iterator *iter, int flags,
 
 	trace_assign_type(field, iter->ent);
 
-	trace_seq_printf(s, "%llu %lld %ld %09ld %u\n",
+	trace_seq_printf(s, "%llu %lld %lld %09ld %u\n",
 			 field->duration,
 			 field->outer_duration,
-			 field->timestamp.tv_sec,
+			 (long long)field->timestamp.tv_sec,
 			 field->timestamp.tv_nsec,
 			 field->seqnum);