[PATCH] perf probe: Fix failure to add multiple probes without debuginfo

[PATCH] perf probe: Fix failure to add multiple probes without debuginfo

[He Kuang]

From: hekuang <hekuang@zoho.com>

Perf tries to find probe function addresses from map when debuginfo
could not be found.

To the first added function, the value of ref_reloc_sym was set in
maps__set_kallsyms_ref_reloc_sym() and can be obtained from
host_machine->kmaps->maps. After that, new maps are added to
host_machine->kmaps->maps in dso__load_kcore(), all these new added maps
do not have a valid ref_reloc_sym.

When adding a second function, get_target_map() may get a map without
valid ref_reloc_sym, and raise the error "Relocated base symbol is not
found".

Fix this by getting ref_reloc_sym from machine->vmlinux_maps.

This problem can be reproduced as following:

  $ perf probe --add='sys_write' --add='sys_open'
  Relocated base symbol is not found!
    Error: Failed to add events.

After this patch:

  $ perf probe --add='sys_write' --add='sys_open'
  Added new event:
    probe:sys_write      (on sys_write)

  You can now use it in all perf tools, such as:

      perf record -e probe:sys_write -aR sleep 1

  Added new event:
    probe:sys_open       (on sys_open)

  You can now use it in all perf tools, such as:

      perf record -e probe:sys_open -aR sleep 1

Signed-off-by: He Kuang <hekuang@huawei.com>
---
 tools/perf/util/probe-event.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index c5e1338..75d41ee 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -2540,7 +2540,19 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev,
 	}
 
 	if (!pev->uprobes && !pp->retprobe) {
-		kmap = map__kmap(map);
+		struct machine *machine;
+		struct map *vmlinux_map = NULL;
+
+		if (map->groups && map->groups->machine) {
+			machine = map->groups->machine;
+			vmlinux_map = machine->vmlinux_maps[MAP__FUNCTION];
+		}
+
+		if (vmlinux_map)
+			kmap = map__kmap(vmlinux_map);
+		else
+			kmap = map__kmap(map);
+
 		reloc_sym = kmap->ref_reloc_sym;
 		if (!reloc_sym) {
 			pr_warning("Relocated base symbol is not found!\n");
-- 
2.3.3.220.g9ab698f

[PATCH] perf probe: Fix failure to add multiple probes without debuginfo

[He Kuang]

Perf tries to find probe function addresses from map when debuginfo
could not be found.

To the first added function, the value of ref_reloc_sym was set in
maps__set_kallsyms_ref_reloc_sym() and can be obtained from
host_machine->kmaps->maps. After that, new maps are added to
host_machine->kmaps->maps in dso__load_kcore(), all these new added maps
do not have a valid ref_reloc_sym.

When adding a second function, get_target_map() may get a map without
valid ref_reloc_sym, and raise the error "Relocated base symbol is not
found".

Fix this by getting ref_reloc_sym from machine->vmlinux_maps.

This problem can be reproduced as following:

  $ perf probe --add='sys_write' --add='sys_open'
  Relocated base symbol is not found!
    Error: Failed to add events.

After this patch:

  $ perf probe --add='sys_write' --add='sys_open'
  Added new event:
    probe:sys_write      (on sys_write)

  You can now use it in all perf tools, such as:

      perf record -e probe:sys_write -aR sleep 1

  Added new event:
    probe:sys_open       (on sys_open)

  You can now use it in all perf tools, such as:

      perf record -e probe:sys_open -aR sleep 1

Signed-off-by: He Kuang <hekuang@huawei.com>
---
 tools/perf/util/probe-event.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index c5e1338..75d41ee 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -2540,7 +2540,19 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev,
 	}
 
 	if (!pev->uprobes && !pp->retprobe) {
-		kmap = map__kmap(map);
+		struct machine *machine;
+		struct map *vmlinux_map = NULL;
+
+		if (map->groups && map->groups->machine) {
+			machine = map->groups->machine;
+			vmlinux_map = machine->vmlinux_maps[MAP__FUNCTION];
+		}
+
+		if (vmlinux_map)
+			kmap = map__kmap(vmlinux_map);
+		else
+			kmap = map__kmap(map);
+
 		reloc_sym = kmap->ref_reloc_sym;
 		if (!reloc_sym) {
 			pr_warning("Relocated base symbol is not found!\n");
-- 
2.3.3.220.g9ab698f

Re: [PATCH] perf probe: Fix failure to add multiple probes without debuginfo

[Arnaldo Carvalho de Melo]

Em Thu, Mar 19, 2015 at 06:02:04PM +0800, He Kuang escreveu:
> Perf tries to find probe function addresses from map when debuginfo
> could not be found.
> 
> To the first added function, the value of ref_reloc_sym was set in
> maps__set_kallsyms_ref_reloc_sym() and can be obtained from
> host_machine->kmaps->maps. After that, new maps are added to
> host_machine->kmaps->maps in dso__load_kcore(), all these new added maps
> do not have a valid ref_reloc_sym.
> 
> When adding a second function, get_target_map() may get a map without
> valid ref_reloc_sym, and raise the error "Relocated base symbol is not
> found".
> 
> Fix this by getting ref_reloc_sym from machine->vmlinux_maps.

Can't this be solved by using the kernel_get_ref_reloc_sym(void) static
function in this same file?

- Arnaldo
 
> This problem can be reproduced as following:
> 
>   $ perf probe --add='sys_write' --add='sys_open'
>   Relocated base symbol is not found!
>     Error: Failed to add events.
> 
> After this patch:
> 
>   $ perf probe --add='sys_write' --add='sys_open'
>   Added new event:
>     probe:sys_write      (on sys_write)
> 
>   You can now use it in all perf tools, such as:
> 
>       perf record -e probe:sys_write -aR sleep 1
> 
>   Added new event:
>     probe:sys_open       (on sys_open)
> 
>   You can now use it in all perf tools, such as:
> 
>       perf record -e probe:sys_open -aR sleep 1
> 
> Signed-off-by: He Kuang <hekuang@huawei.com>
> ---
>  tools/perf/util/probe-event.c | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> index c5e1338..75d41ee 100644
> --- a/tools/perf/util/probe-event.c
> +++ b/tools/perf/util/probe-event.c
> @@ -2540,7 +2540,19 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev,
>  	}
>  
>  	if (!pev->uprobes && !pp->retprobe) {
> -		kmap = map__kmap(map);
> +		struct machine *machine;
> +		struct map *vmlinux_map = NULL;
> +
> +		if (map->groups && map->groups->machine) {
> +			machine = map->groups->machine;
> +			vmlinux_map = machine->vmlinux_maps[MAP__FUNCTION];
> +		}
> +
> +		if (vmlinux_map)
> +			kmap = map__kmap(vmlinux_map);
> +		else
> +			kmap = map__kmap(map);
> +
>  		reloc_sym = kmap->ref_reloc_sym;
>  		if (!reloc_sym) {
>  			pr_warning("Relocated base symbol is not found!\n");
> -- 
> 2.3.3.220.g9ab698f

[PATCHv2] perf probe: Fix failure to add multiple probes without debuginfo

[He Kuang]

Perf tries to find probe function addresses from map when debuginfo
could not be found.

To the first added function, the value of ref_reloc_sym was set in
maps__set_kallsyms_ref_reloc_sym() and can be obtained from
host_machine->kmaps->maps. After that, new maps are added to
host_machine->kmaps->maps in dso__load_kcore(), all these new added maps
do not have a valid ref_reloc_sym.

When adding a second function, get_target_map() may get a map without
valid ref_reloc_sym, and raise the error "Relocated base symbol is not
found".

Fix this by using kernel_get_ref_reloc_sym() to get ref_reloc_sym.

This problem can be reproduced as following:

  $ perf probe --add='sys_write' --add='sys_open'
  Relocated base symbol is not found!
    Error: Failed to add events.

After this patch:

  $ perf probe --add='sys_write' --add='sys_open'
  Added new event:
    probe:sys_write      (on sys_write)

  You can now use it in all perf tools, such as:

      perf record -e probe:sys_write -aR sleep 1

  Added new event:
    probe:sys_open       (on sys_open)

  You can now use it in all perf tools, such as:

      perf record -e probe:sys_open -aR sleep 1

Signed-off-by: He Kuang <hekuang@huawei.com>
---
 tools/perf/util/probe-event.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index c5e1338..c1ccd6a 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -2507,7 +2507,6 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev,
 					    int max_tevs, const char *target)
 {
 	struct map *map = NULL;
-	struct kmap *kmap = NULL;
 	struct ref_reloc_sym *reloc_sym = NULL;
 	struct symbol *sym;
 	struct probe_trace_event *tev;
@@ -2540,8 +2539,7 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev,
 	}
 
 	if (!pev->uprobes && !pp->retprobe) {
-		kmap = map__kmap(map);
-		reloc_sym = kmap->ref_reloc_sym;
+		reloc_sym = kernel_get_ref_reloc_sym();
 		if (!reloc_sym) {
 			pr_warning("Relocated base symbol is not found!\n");
 			ret = -EINVAL;
-- 
2.3.3.220.g9ab698f

Re: [PATCHv2] perf probe: Fix failure to add multiple probes without debuginfo

[Masami Hiramatsu]

(2015/03/20 10:56), He Kuang wrote:
> Perf tries to find probe function addresses from map when debuginfo
> could not be found.
> 
> To the first added function, the value of ref_reloc_sym was set in
> maps__set_kallsyms_ref_reloc_sym() and can be obtained from
> host_machine->kmaps->maps. After that, new maps are added to
> host_machine->kmaps->maps in dso__load_kcore(), all these new added maps
> do not have a valid ref_reloc_sym.
> 
> When adding a second function, get_target_map() may get a map without
> valid ref_reloc_sym, and raise the error "Relocated base symbol is not
> found".
> 
> Fix this by using kernel_get_ref_reloc_sym() to get ref_reloc_sym.
> 
> This problem can be reproduced as following:
> 
>   $ perf probe --add='sys_write' --add='sys_open'
>   Relocated base symbol is not found!
>     Error: Failed to add events.
> 
> After this patch:
> 
>   $ perf probe --add='sys_write' --add='sys_open'
>   Added new event:
>     probe:sys_write      (on sys_write)
> 
>   You can now use it in all perf tools, such as:
> 
>       perf record -e probe:sys_write -aR sleep 1
> 
>   Added new event:
>     probe:sys_open       (on sys_open)
> 
>   You can now use it in all perf tools, such as:
> 
>       perf record -e probe:sys_open -aR sleep 1
> 

OK, I've checked that this solve the problem :)

Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>


Thank you!

> Signed-off-by: He Kuang <hekuang@huawei.com>
> ---
>  tools/perf/util/probe-event.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> index c5e1338..c1ccd6a 100644
> --- a/tools/perf/util/probe-event.c
> +++ b/tools/perf/util/probe-event.c
> @@ -2507,7 +2507,6 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev,
>  					    int max_tevs, const char *target)
>  {
>  	struct map *map = NULL;
> -	struct kmap *kmap = NULL;
>  	struct ref_reloc_sym *reloc_sym = NULL;
>  	struct symbol *sym;
>  	struct probe_trace_event *tev;
> @@ -2540,8 +2539,7 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev,
>  	}
>  
>  	if (!pev->uprobes && !pp->retprobe) {
> -		kmap = map__kmap(map);
> -		reloc_sym = kmap->ref_reloc_sym;
> +		reloc_sym = kernel_get_ref_reloc_sym();
>  		if (!reloc_sym) {
>  			pr_warning("Relocated base symbol is not found!\n");
>  			ret = -EINVAL;
> 


-- 
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com

Re: [PATCHv2] perf probe: Fix failure to add multiple probes without debuginfo

[Arnaldo Carvalho de Melo]

Em Fri, Mar 20, 2015 at 04:42:46PM +0900, Masami Hiramatsu escreveu:
> (2015/03/20 10:56), He Kuang wrote:
> > Perf tries to find probe function addresses from map when debuginfo
> > could not be found.
> > 
> > To the first added function, the value of ref_reloc_sym was set in
> > maps__set_kallsyms_ref_reloc_sym() and can be obtained from
> > host_machine->kmaps->maps. After that, new maps are added to
> > host_machine->kmaps->maps in dso__load_kcore(), all these new added maps
> > do not have a valid ref_reloc_sym.
> > 
> > When adding a second function, get_target_map() may get a map without
> > valid ref_reloc_sym, and raise the error "Relocated base symbol is not
> > found".
> > 
> > Fix this by using kernel_get_ref_reloc_sym() to get ref_reloc_sym.
> > 
> > This problem can be reproduced as following:
> > 
> >   $ perf probe --add='sys_write' --add='sys_open'
> >   Relocated base symbol is not found!
> >     Error: Failed to add events.
> > 
> > After this patch:
> > 
> >   $ perf probe --add='sys_write' --add='sys_open'
> >   Added new event:
> >     probe:sys_write      (on sys_write)
> > 
> >   You can now use it in all perf tools, such as:
> > 
> >       perf record -e probe:sys_write -aR sleep 1
> > 
> >   Added new event:
> >     probe:sys_open       (on sys_open)
> > 
> >   You can now use it in all perf tools, such as:
> > 
> >       perf record -e probe:sys_open -aR sleep 1
> > 
> 
> OK, I've checked that this solve the problem :)
> 
> Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

Ok, next time, please consider sending a Tested-by: tag instead, if what
you did was to apply the patch, check that it fixes the problem, that
provides a stronger patch endorsement.

- Arnaldo
 
> 
> Thank you!
> 
> > Signed-off-by: He Kuang <hekuang@huawei.com>
> > ---
> >  tools/perf/util/probe-event.c | 4 +---
> >  1 file changed, 1 insertion(+), 3 deletions(-)
> > 
> > diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> > index c5e1338..c1ccd6a 100644
> > --- a/tools/perf/util/probe-event.c
> > +++ b/tools/perf/util/probe-event.c
> > @@ -2507,7 +2507,6 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev,
> >  					    int max_tevs, const char *target)
> >  {
> >  	struct map *map = NULL;
> > -	struct kmap *kmap = NULL;
> >  	struct ref_reloc_sym *reloc_sym = NULL;
> >  	struct symbol *sym;
> >  	struct probe_trace_event *tev;
> > @@ -2540,8 +2539,7 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev,
> >  	}
> >  
> >  	if (!pev->uprobes && !pp->retprobe) {
> > -		kmap = map__kmap(map);
> > -		reloc_sym = kmap->ref_reloc_sym;
> > +		reloc_sym = kernel_get_ref_reloc_sym();
> >  		if (!reloc_sym) {
> >  			pr_warning("Relocated base symbol is not found!\n");
> >  			ret = -EINVAL;
> > 
> 
> 
> -- 
> Masami HIRAMATSU
> Software Platform Research Dept. Linux Technology Research Center
> Hitachi, Ltd., Yokohama Research Laboratory
> E-mail: masami.hiramatsu.pt@hitachi.com
> 

Re: [PATCHv2] perf probe: Fix failure to add multiple probes without debuginfo

[Masami Hiramatsu]

(2015/03/20 22:50), Arnaldo Carvalho de Melo wrote:
> Em Fri, Mar 20, 2015 at 04:42:46PM +0900, Masami Hiramatsu escreveu:
>> (2015/03/20 10:56), He Kuang wrote:
>>> Perf tries to find probe function addresses from map when debuginfo
>>> could not be found.
>>>
>>> To the first added function, the value of ref_reloc_sym was set in
>>> maps__set_kallsyms_ref_reloc_sym() and can be obtained from
>>> host_machine->kmaps->maps. After that, new maps are added to
>>> host_machine->kmaps->maps in dso__load_kcore(), all these new added maps
>>> do not have a valid ref_reloc_sym.
>>>
>>> When adding a second function, get_target_map() may get a map without
>>> valid ref_reloc_sym, and raise the error "Relocated base symbol is not
>>> found".
>>>
>>> Fix this by using kernel_get_ref_reloc_sym() to get ref_reloc_sym.
>>>
>>> This problem can be reproduced as following:
>>>
>>>   $ perf probe --add='sys_write' --add='sys_open'
>>>   Relocated base symbol is not found!
>>>     Error: Failed to add events.
>>>
>>> After this patch:
>>>
>>>   $ perf probe --add='sys_write' --add='sys_open'
>>>   Added new event:
>>>     probe:sys_write      (on sys_write)
>>>
>>>   You can now use it in all perf tools, such as:
>>>
>>>       perf record -e probe:sys_write -aR sleep 1
>>>
>>>   Added new event:
>>>     probe:sys_open       (on sys_open)
>>>
>>>   You can now use it in all perf tools, such as:
>>>
>>>       perf record -e probe:sys_open -aR sleep 1
>>>
>>
>> OK, I've checked that this solve the problem :)
>>
>> Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
> 
> Ok, next time, please consider sending a Tested-by: tag instead, if what
> you did was to apply the patch, check that it fixes the problem, that
> provides a stronger patch endorsement.

I see. :)

Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

BTW, I've found another bug in perf probe for these sys_XXX functions.

----
# ./perf probe -vfn --add="sys_write" --add="sys_open"
probe-definition(0): sys_write
symbol:sys_write file:(null) line:0 offset:0 return:0 lazy:(null)
0 arguments
probe-definition(1): sys_open
symbol:sys_open file:(null) line:0 offset:0 return:0 lazy:(null)
0 arguments
symsrc__init: cannot get elf header.
Looking at the vmlinux_path (7 entries long)
Using /usr/lib/debug/lib/modules/3.10.0-123.13.2.el7.x86_64/vmlinux for symbols
Open Debuginfo file: /usr/lib/debug/lib/modules/3.10.0-123.13.2.el7.x86_64/vmlinux
Try to find probe point from debuginfo.
Symbol sys_write address found : 3b0100
Failed to find debug information for address 3b0100
Probe point 'sys_write' not found.
  Error: Failed to add events. Reason: No such file or directory (Code: -2)
----

Something went wrong... :-( I'll check that.


Thank you,
> 
> - Arnaldo
>  
>>
>> Thank you!
>>
>>> Signed-off-by: He Kuang <hekuang@huawei.com>
>>> ---
>>>  tools/perf/util/probe-event.c | 4 +---
>>>  1 file changed, 1 insertion(+), 3 deletions(-)
>>>
>>> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
>>> index c5e1338..c1ccd6a 100644
>>> --- a/tools/perf/util/probe-event.c
>>> +++ b/tools/perf/util/probe-event.c
>>> @@ -2507,7 +2507,6 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev,
>>>  					    int max_tevs, const char *target)
>>>  {
>>>  	struct map *map = NULL;
>>> -	struct kmap *kmap = NULL;
>>>  	struct ref_reloc_sym *reloc_sym = NULL;
>>>  	struct symbol *sym;
>>>  	struct probe_trace_event *tev;
>>> @@ -2540,8 +2539,7 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev,
>>>  	}
>>>  
>>>  	if (!pev->uprobes && !pp->retprobe) {
>>> -		kmap = map__kmap(map);
>>> -		reloc_sym = kmap->ref_reloc_sym;
>>> +		reloc_sym = kernel_get_ref_reloc_sym();
>>>  		if (!reloc_sym) {
>>>  			pr_warning("Relocated base symbol is not found!\n");
>>>  			ret = -EINVAL;
>>>
>>
>>
>> -- 
>> Masami HIRAMATSU
>> Software Platform Research Dept. Linux Technology Research Center
>> Hitachi, Ltd., Yokohama Research Laboratory
>> E-mail: masami.hiramatsu.pt@hitachi.com
>>
> 


-- 
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com

Re: [PATCHv2] perf probe: Fix failure to add multiple probes without debuginfo

[Arnaldo Carvalho de Melo]

Em Sat, Mar 21, 2015 at 09:19:21PM +0900, Masami Hiramatsu escreveu:
> (2015/03/20 22:50), Arnaldo Carvalho de Melo wrote:
> > Em Fri, Mar 20, 2015 at 04:42:46PM +0900, Masami Hiramatsu escreveu:
> >> OK, I've checked that this solve the problem :)

> >> Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

> > Ok, next time, please consider sending a Tested-by: tag instead, if what
> > you did was to apply the patch, check that it fixes the problem, that
> > provides a stronger patch endorsement.

> I see. :)
> 
> Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

Thanks!
 
> BTW, I've found another bug in perf probe for these sys_XXX functions.

Ooops, 

<SNIP>
 
> Something went wrong... :-( I'll check that.

Thanks again!

- Arnaldo

[tip:perf/core] perf probe: Fix failure to add multiple probes without debuginfo

[tip-bot for He Kuang]

Commit-ID:  0560a0c4a12a45def9700e7ec3215da102cf914b
Gitweb:     http://git.kernel.org/tip/0560a0c4a12a45def9700e7ec3215da102cf914b
Author:     He Kuang <hekuang@huawei.com>
AuthorDate: Fri, 20 Mar 2015 09:56:56 +0800
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Sat, 21 Mar 2015 14:53:21 -0300

perf probe: Fix failure to add multiple probes without debuginfo

Perf tries to find probe function addresses from map when debuginfo
could not be found.

To the first added function, the value of ref_reloc_sym was set in
maps__set_kallsyms_ref_reloc_sym() and can be obtained from
host_machine->kmaps->maps. After that, new maps are added to
host_machine->kmaps->maps in dso__load_kcore(), all these new added maps
do not have a valid ref_reloc_sym.

When adding a second function, get_target_map() may get a map without
valid ref_reloc_sym, and raise the error "Relocated base symbol is not
found".

Fix this by using kernel_get_ref_reloc_sym() to get ref_reloc_sym.

This problem can be reproduced as following:

  $ perf probe --add='sys_write' --add='sys_open'
  Relocated base symbol is not found!
    Error: Failed to add events.

After this patch:

  $ perf probe --add='sys_write' --add='sys_open'
  Added new event:
    probe:sys_write      (on sys_write)

  You can now use it in all perf tools, such as:

      perf record -e probe:sys_write -aR sleep 1

  Added new event:
    probe:sys_open       (on sys_open)

  You can now use it in all perf tools, such as:

      perf record -e probe:sys_open -aR sleep 1

Signed-off-by: He Kuang <hekuang@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1426816616-2394-1-git-send-email-hekuang@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/probe-event.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index f272a71..6b95985 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -2507,7 +2507,6 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev,
 					    int max_tevs, const char *target)
 {
 	struct map *map = NULL;
-	struct kmap *kmap = NULL;
 	struct ref_reloc_sym *reloc_sym = NULL;
 	struct symbol *sym;
 	struct probe_trace_event *tev;
@@ -2540,8 +2539,7 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev,
 	}
 
 	if (!pev->uprobes && !pp->retprobe) {
-		kmap = map__kmap(map);
-		reloc_sym = kmap->ref_reloc_sym;
+		reloc_sym = kernel_get_ref_reloc_sym();
 		if (!reloc_sym) {
 			pr_warning("Relocated base symbol is not found!\n");
 			ret = -EINVAL;