[PATCH 1/2 v4] perf sched: fix wrong conversion of task state

[PATCH 1/2 v4] perf sched: fix wrong conversion of task state

[Tomoki Sekiyama]

Currently sched_out_state() converts the prev_state u64 bitmask to a char
using the bitmask as an index, which may cause invalid memory access.
This fixes the issue by using the __ffs() returned value as an index.

Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com>
Fixes: cdce9d738b91e ("perf sched: Add sched latency profiling")
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
---
Changes from v3:
  Added Fixes:
  Split the patch into 2 pieces.

 tools/perf/builtin-sched.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index 0dfe8df..ce9bef6 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -897,9 +897,10 @@ static int thread_atoms_insert(struct perf_sched *sched, struct thread *thread)
 
 static char sched_out_state(u64 prev_state)
 {
-	const char *str = TASK_STATE_TO_CHAR_STR;
+	const char str[] = TASK_STATE_TO_CHAR_STR;
+	unsigned int bit = prev_state ? __ffs(prev_state) + 1 : 0;
 
-	return str[prev_state];
+	return bit < ARRAY_SIZE(str) - 1 ? str[bit] : '?';
 }
 
 static int
-- 
2.7.4

[PATCH 2/2 v4] perf sched: adapt TASK_STATE_TO_CHAR_STR to the latest kernel

[Tomoki Sekiyama]

Update TASK_STATE_TO_CHAR_STR macro to one from sched.h in the latest
kernel, where 'N' and 'n' are introduced, 'X' and 'Z' are swapped.

Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com>
Fixes: cdce9d738b91e ("perf sched: Add sched latency profiling")
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
---
Changes from v3:
  Added Fixes:
  Split patch into 2 pieces.

 tools/perf/builtin-sched.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index ce9bef6..5776263 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -70,7 +70,7 @@ struct sched_atom {
 	struct task_desc	*wakee;
 };
 
-#define TASK_STATE_TO_CHAR_STR "RSDTtZXxKWP"
+#define TASK_STATE_TO_CHAR_STR "RSDTtXZxKWPNn"
 
 enum thread_state {
 	THREAD_SLEEPING = 0,
-- 
2.7.4

Re: [PATCH 1/2 v4] perf sched: fix wrong conversion of task state

[David Ahern]

On 7/31/16 10:30 PM, Tomoki Sekiyama wrote:
> Currently sched_out_state() converts the prev_state u64 bitmask to a char
> using the bitmask as an index, which may cause invalid memory access.
> This fixes the issue by using the __ffs() returned value as an index.
>
> Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com>
> Fixes: cdce9d738b91e ("perf sched: Add sched latency profiling")
> Cc: Jiri Olsa <jolsa@kernel.org>
> Cc: David Ahern <dsahern@gmail.com>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
> Cc: Masami Hiramatsu <mhiramat@kernel.org>
> ---
> Changes from v3:
>   Added Fixes:
>   Split the patch into 2 pieces.
>
>  tools/perf/builtin-sched.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
> index 0dfe8df..ce9bef6 100644
> --- a/tools/perf/builtin-sched.c
> +++ b/tools/perf/builtin-sched.c
> @@ -897,9 +897,10 @@ static int thread_atoms_insert(struct perf_sched *sched, struct thread *thread)
>
>  static char sched_out_state(u64 prev_state)
>  {
> -	const char *str = TASK_STATE_TO_CHAR_STR;
> +	const char str[] = TASK_STATE_TO_CHAR_STR;
> +	unsigned int bit = prev_state ? __ffs(prev_state) + 1 : 0;
>
> -	return str[prev_state];
> +	return bit < ARRAY_SIZE(str) - 1 ? str[bit] : '?';
>  }
>
>  static int
>


Acked-by: David Ahern <dsahern@gmail.com>

Re: [PATCH 2/2 v4] perf sched: adapt TASK_STATE_TO_CHAR_STR to the latest kernel

[David Ahern]

On 7/31/16 10:30 PM, Tomoki Sekiyama wrote:
> Update TASK_STATE_TO_CHAR_STR macro to one from sched.h in the latest
> kernel, where 'N' and 'n' are introduced, 'X' and 'Z' are swapped.
>
> Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com>
> Fixes: cdce9d738b91e ("perf sched: Add sched latency profiling")

Wrong Fixes tag for this change.

This is really an update based on kernel changes, the last one being 
7dc603c9028ea.


> Cc: Jiri Olsa <jolsa@kernel.org>
> Cc: David Ahern <dsahern@gmail.com>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
> Cc: Masami Hiramatsu <mhiramat@kernel.org>
> ---
> Changes from v3:
>   Added Fixes:
>   Split patch into 2 pieces.
>
>  tools/perf/builtin-sched.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
> index ce9bef6..5776263 100644
> --- a/tools/perf/builtin-sched.c
> +++ b/tools/perf/builtin-sched.c
> @@ -70,7 +70,7 @@ struct sched_atom {
>  	struct task_desc	*wakee;
>  };
>
> -#define TASK_STATE_TO_CHAR_STR "RSDTtZXxKWP"
> +#define TASK_STATE_TO_CHAR_STR "RSDTtXZxKWPNn"
>
>  enum thread_state {
>  	THREAD_SLEEPING = 0,
>

Acked-by: David Ahern <dsahern@gmail.com>

Re: [PATCH 1/2 v4] perf sched: fix wrong conversion of task state

[Masami Hiramatsu]

On Mon,  1 Aug 2016 13:30:25 +0900
Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com> wrote:

> Currently sched_out_state() converts the prev_state u64 bitmask to a char
> using the bitmask as an index, which may cause invalid memory access.
> This fixes the issue by using the __ffs() returned value as an index.

OK, looks good to me:)

Acked-by: Masami Hiramatsu <mhiramat@kernel.org>

Thanks!

> 
> Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com>
> Fixes: cdce9d738b91e ("perf sched: Add sched latency profiling")
> Cc: Jiri Olsa <jolsa@kernel.org>
> Cc: David Ahern <dsahern@gmail.com>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
> Cc: Masami Hiramatsu <mhiramat@kernel.org>
> ---
> Changes from v3:
>   Added Fixes:
>   Split the patch into 2 pieces.
> 
>  tools/perf/builtin-sched.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
> index 0dfe8df..ce9bef6 100644
> --- a/tools/perf/builtin-sched.c
> +++ b/tools/perf/builtin-sched.c
> @@ -897,9 +897,10 @@ static int thread_atoms_insert(struct perf_sched *sched, struct thread *thread)
>  
>  static char sched_out_state(u64 prev_state)
>  {
> -	const char *str = TASK_STATE_TO_CHAR_STR;
> +	const char str[] = TASK_STATE_TO_CHAR_STR;
> +	unsigned int bit = prev_state ? __ffs(prev_state) + 1 : 0;
>  
> -	return str[prev_state];
> +	return bit < ARRAY_SIZE(str) - 1 ? str[bit] : '?';
>  }
>  
>  static int
> -- 
> 2.7.4
> 


-- 
Masami Hiramatsu <mhiramat@kernel.org>

Re: [PATCH 2/2 v4] perf sched: adapt TASK_STATE_TO_CHAR_STR to the latest kernel

[Masami Hiramatsu]

On Mon, 1 Aug 2016 07:58:19 -0600
David Ahern <dsahern@gmail.com> wrote:

> On 7/31/16 10:30 PM, Tomoki Sekiyama wrote:
> > Update TASK_STATE_TO_CHAR_STR macro to one from sched.h in the latest
> > kernel, where 'N' and 'n' are introduced, 'X' and 'Z' are swapped.
> >
> > Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com>
> > Fixes: cdce9d738b91e ("perf sched: Add sched latency profiling")
> 
> Wrong Fixes tag for this change.
> 
> This is really an update based on kernel changes, the last one being 
> 7dc603c9028ea.

Except for the above mistake, I'm also OK for the code.

Thanks,

> 
> 
> > Cc: Jiri Olsa <jolsa@kernel.org>
> > Cc: David Ahern <dsahern@gmail.com>
> > Cc: Namhyung Kim <namhyung@kernel.org>
> > Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
> > Cc: Masami Hiramatsu <mhiramat@kernel.org>
> > ---
> > Changes from v3:
> >   Added Fixes:
> >   Split patch into 2 pieces.
> >
> >  tools/perf/builtin-sched.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
> > index ce9bef6..5776263 100644
> > --- a/tools/perf/builtin-sched.c
> > +++ b/tools/perf/builtin-sched.c
> > @@ -70,7 +70,7 @@ struct sched_atom {
> >  	struct task_desc	*wakee;
> >  };
> >
> > -#define TASK_STATE_TO_CHAR_STR "RSDTtZXxKWP"
> > +#define TASK_STATE_TO_CHAR_STR "RSDTtXZxKWPNn"
> >
> >  enum thread_state {
> >  	THREAD_SLEEPING = 0,
> >
> 
> Acked-by: David Ahern <dsahern@gmail.com>


-- 
Masami Hiramatsu <mhiramat@kernel.org>