[PATCH v5] tools lib traceevent: str addresses in heterogeneous arch environments

[PATCH v5] tools lib traceevent: str addresses in heterogeneous arch environments

[Kapileshwar Singh]

When a trace recorded on a 32-bit device is processed with a 64-bit
binary, the higher 32-bits of the address need to ignored

The lack of this results in the output of the 64-bit pointer
value to the trace as the 32-bit address lookup fails in find_printk.

Before:
burn-1778  [003]   548.600305: bputs:   0xc0046db2s: 2cec5c058d98c

After:
burn-1778  [003]   548.600305: bputs:   0xc0046db2s: RT throttling activated

The problem occurs in PRINT_FEILD when the field is recognized as a pointer
to a string (of the type const char *)

Heterogeneous architectures cases below can arise and should be handled:

* Traces recorded using 32-bit addresses processed on a 64-bit machine
* Traces recorded using 64-bit addresses processed on a 32-bit machine

Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Javi Merino <javi.merino@arm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Reported-by: Juri Lelli <juri.lelli@arm.com>
Signed-off-by: Kapileshwar Singh <kapileshwar.singh@arm.com>
---
 tools/lib/traceevent/event-parse.c | 23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
index cc25f059ab3d..a843bee66a4f 100644
--- a/tools/lib/traceevent/event-parse.c
+++ b/tools/lib/traceevent/event-parse.c
@@ -3721,7 +3721,7 @@ static void print_str_arg(struct trace_seq *s, void *data, int size,
 	struct format_field *field;
 	struct printk_map *printk;
 	long long val, fval;
-	unsigned long addr;
+	unsigned long long addr;
 	char *str;
 	unsigned char *hex;
 	int print;
@@ -3754,13 +3754,30 @@ static void print_str_arg(struct trace_seq *s, void *data, int size,
 		 */
 		if (!(field->flags & FIELD_IS_ARRAY) &&
 		    field->size == pevent->long_size) {
-			addr = *(unsigned long *)(data + field->offset);
+
+			/* Handle heterogeneous recording and processing
+			 * architectures
+			 *
+			 * CASE I:
+			 * Traces recorded on 32-bit devices (32-bit
+			 * addressing) and processed on 64-bit devices:
+			 * In this case, only 32 bits should be read.
+			 *
+			 * CASE II:
+			 * Traces recorded on 64 bit devices and processed
+			 * on 32-bit devices:
+			 * In this case, 64 bits must be read.
+			 */
+			addr = (pevent->long_size == 8) ?
+				*(unsigned long long *)(data + field->offset) :
+				(unsigned long long)*(unsigned int *)(data + field->offset);
+
 			/* Check if it matches a print format */
 			printk = find_printk(pevent, addr);
 			if (printk)
 				trace_seq_puts(s, printk->printk);
 			else
-				trace_seq_printf(s, "%lx", addr);
+				trace_seq_printf(s, "%llx", addr);
 			break;
 		}
 		str = malloc(len + 1);
-- 
1.9.1

Re: [PATCH v5] tools lib traceevent: str addresses in heterogeneous arch environments

[Steven Rostedt]

On Tue, 22 Sep 2015 14:22:03 +0100
Kapileshwar Singh <kapileshwar.singh@arm.com> wrote:

>  		if (!(field->flags & FIELD_IS_ARRAY) &&
>  		    field->size == pevent->long_size) {
> -			addr = *(unsigned long *)(data + field->offset);
> +
> +			/* Handle heterogeneous recording and processing
> +			 * architectures
> +			 *
> +			 * CASE I:
> +			 * Traces recorded on 32-bit devices (32-bit
> +			 * addressing) and processed on 64-bit devices:
> +			 * In this case, only 32 bits should be read.
> +			 *
> +			 * CASE II:
> +			 * Traces recorded on 64 bit devices and processed
> +			 * on 32-bit devices:
> +			 * In this case, 64 bits must be read.

Probably should have added a comment about not caring about endianess
and why, but that can be added later. This patch is good enough for now.

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

Arnaldo, want to pick this up?

-- Steve

> +			 */
> +			addr = (pevent->long_size == 8) ?
> +				*(unsigned long long *)(data + field->offset) :
> +				(unsigned long long)*(unsigned int *)(data + field->offset);
> +
>  			/* Check if it matches a print format */
>  			printk = find_printk(pevent, addr);
>  			if (printk)
>  				trace_seq_puts(s, printk->printk);
>  			else
> -				trace_seq_printf(s, "%lx", addr);
> +				trace_seq_printf(s, "%llx", addr);
>  			break;
>  		}
>  		str = malloc(len + 1);

Re: [PATCH v5] tools lib traceevent: str addresses in heterogeneous arch environments

[Arnaldo Carvalho de Melo]

Em Tue, Sep 22, 2015 at 09:46:18AM -0400, Steven Rostedt escreveu:
> On Tue, 22 Sep 2015 14:22:03 +0100
> Kapileshwar Singh <kapileshwar.singh@arm.com> wrote:
> 
> >  		if (!(field->flags & FIELD_IS_ARRAY) &&
> >  		    field->size == pevent->long_size) {
> > -			addr = *(unsigned long *)(data + field->offset);
> > +
> > +			/* Handle heterogeneous recording and processing
> > +			 * architectures
> > +			 *
> > +			 * CASE I:
> > +			 * Traces recorded on 32-bit devices (32-bit
> > +			 * addressing) and processed on 64-bit devices:
> > +			 * In this case, only 32 bits should be read.
> > +			 *
> > +			 * CASE II:
> > +			 * Traces recorded on 64 bit devices and processed
> > +			 * on 32-bit devices:
> > +			 * In this case, 64 bits must be read.
> 
> Probably should have added a comment about not caring about endianess
> and why, but that can be added later. This patch is good enough for now.
> 
> Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
> 
> Arnaldo, want to pick this up?

Sure, I'm adding it to perf/core, i.e. for 4.4, or do you think this
needs to go into 4.3?

- Arnaldo

Re: [PATCH v5] tools lib traceevent: str addresses in heterogeneous arch environments

[Steven Rostedt]

On Tue, 22 Sep 2015 11:04:43 -0300
Arnaldo Carvalho de Melo <acme@redhat.com> wrote:
 
> Sure, I'm adding it to perf/core, i.e. for 4.4, or do you think this
> needs to go into 4.3?
> 

Well, it does fix a bug. Probably should. Maybe even mark it for stable?

-- Steve

Re: [PATCH v5] tools lib traceevent: str addresses in heterogeneous arch environments

[Arnaldo Carvalho de Melo]

Em Tue, Sep 22, 2015 at 10:19:39AM -0400, Steven Rostedt escreveu:
> On Tue, 22 Sep 2015 11:04:43 -0300
> Arnaldo Carvalho de Melo <acme@redhat.com> wrote:
> > Sure, I'm adding it to perf/core, i.e. for 4.4, or do you think this
> > needs to go into 4.3?
> > 
> 
> Well, it does fix a bug. Probably should. Maybe even mark it for stable?

Right, its not something that affects that many people, but indeed fixes
a bug, queuing it in perf/urgent.

BTW, I changed the patch summary to:

  "tools lib traceevent: Fix string handling in heterogeneous arch environments"

Ok?

- Arnaldo

Re: [PATCH v5] tools lib traceevent: str addresses in heterogeneous arch environments

[Kapileshwar Singh]

Thanks for reviewing this Steve and Arnaldo!

On 22/09/15 15:37, Arnaldo Carvalho de Melo wrote:
> Em Tue, Sep 22, 2015 at 10:19:39AM -0400, Steven Rostedt escreveu:
>> On Tue, 22 Sep 2015 11:04:43 -0300
>> Arnaldo Carvalho de Melo <acme@redhat.com> wrote:
>>> Sure, I'm adding it to perf/core, i.e. for 4.4, or do you think this
>>> needs to go into 4.3?
>>>
>>
>> Well, it does fix a bug. Probably should. Maybe even mark it for stable?
> 
> Right, its not something that affects that many people, but indeed fixes
> a bug, queuing it in perf/urgent.
> 
> BTW, I changed the patch summary to:
> 
>   "tools lib traceevent: Fix string handling in heterogeneous arch environments"

Looks fine to me.

Regards, 
KP

> 
> Ok?
> 
> - Arnaldo
> 

Re: [PATCH v5] tools lib traceevent: str addresses in heterogeneous arch environments

[Steven Rostedt]

On Tue, 22 Sep 2015 11:37:14 -0300
Arnaldo Carvalho de Melo <acme@redhat.com> wrote:

> Em Tue, Sep 22, 2015 at 10:19:39AM -0400, Steven Rostedt escreveu:
> > On Tue, 22 Sep 2015 11:04:43 -0300
> > Arnaldo Carvalho de Melo <acme@redhat.com> wrote:
> > > Sure, I'm adding it to perf/core, i.e. for 4.4, or do you think this
> > > needs to go into 4.3?
> > > 
> > 
> > Well, it does fix a bug. Probably should. Maybe even mark it for stable?
> 
> Right, its not something that affects that many people, but indeed fixes
> a bug, queuing it in perf/urgent.
> 
> BTW, I changed the patch summary to:
> 
>   "tools lib traceevent: Fix string handling in heterogeneous arch environments"
> 
> Ok?
> 

Looks fine to me.

-- Steve

[tip:perf/core] tools lib traceevent: Fix string handling in heterogeneous arch environments

[tip-bot for Kapileshwar Singh]

Commit-ID:  c2e4b24ff848bb180f9b9cd873a38327cd219ad2
Gitweb:     http://git.kernel.org/tip/c2e4b24ff848bb180f9b9cd873a38327cd219ad2
Author:     Kapileshwar Singh <kapileshwar.singh@arm.com>
AuthorDate: Tue, 22 Sep 2015 14:22:03 +0100
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Tue, 22 Sep 2015 11:57:04 -0300

tools lib traceevent: Fix string handling in heterogeneous arch environments

When a trace recorded on a 32-bit device is processed with a 64-bit
binary, the higher 32-bits of the address need to ignored.

The lack of this results in the output of the 64-bit pointer
value to the trace as the 32-bit address lookup fails in find_printk().

Before:

  burn-1778  [003]   548.600305: bputs:   0xc0046db2s: 2cec5c058d98c

After:

  burn-1778  [003]   548.600305: bputs:   0xc0046db2s: RT throttling activated

The problem occurs in PRINT_FIELD when the field is recognized as a
pointer to a string (of the type const char *)

Heterogeneous architectures cases below can arise and should be handled:

* Traces recorded using 32-bit addresses processed on a 64-bit machine
* Traces recorded using 64-bit addresses processed on a 32-bit machine

Reported-by: Juri Lelli <juri.lelli@arm.com>
Signed-off-by: Kapileshwar Singh <kapileshwar.singh@arm.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Javi Merino <javi.merino@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1442928123-13824-1-git-send-email-kapileshwar.singh@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/lib/traceevent/event-parse.c | 23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
index 4d88593..cf42b09 100644
--- a/tools/lib/traceevent/event-parse.c
+++ b/tools/lib/traceevent/event-parse.c
@@ -3795,7 +3795,7 @@ static void print_str_arg(struct trace_seq *s, void *data, int size,
 	struct format_field *field;
 	struct printk_map *printk;
 	long long val, fval;
-	unsigned long addr;
+	unsigned long long addr;
 	char *str;
 	unsigned char *hex;
 	int print;
@@ -3828,13 +3828,30 @@ static void print_str_arg(struct trace_seq *s, void *data, int size,
 		 */
 		if (!(field->flags & FIELD_IS_ARRAY) &&
 		    field->size == pevent->long_size) {
-			addr = *(unsigned long *)(data + field->offset);
+
+			/* Handle heterogeneous recording and processing
+			 * architectures
+			 *
+			 * CASE I:
+			 * Traces recorded on 32-bit devices (32-bit
+			 * addressing) and processed on 64-bit devices:
+			 * In this case, only 32 bits should be read.
+			 *
+			 * CASE II:
+			 * Traces recorded on 64 bit devices and processed
+			 * on 32-bit devices:
+			 * In this case, 64 bits must be read.
+			 */
+			addr = (pevent->long_size == 8) ?
+				*(unsigned long long *)(data + field->offset) :
+				(unsigned long long)*(unsigned int *)(data + field->offset);
+
 			/* Check if it matches a print format */
 			printk = find_printk(pevent, addr);
 			if (printk)
 				trace_seq_puts(s, printk->printk);
 			else
-				trace_seq_printf(s, "%lx", addr);
+				trace_seq_printf(s, "%llx", addr);
 			break;
 		}
 		str = malloc(len + 1);