Re: [PATCH v3] perf sched: fix wrong conversion of task state

[Masami Hiramatsu]

On Fri, 29 Jul 2016 13:00:08 +0900
Tomoki Sekiyama  wrote:

> sched_out_state() converts the prev_state u64 bitmask to a char in
> a wrong way, which may cause invalid memory access.
> TASK_STATE_TO_CHAR_STR should also be fixed to adapt current
> kernel's sched.h.

This still have 2 things...

> 
> Signed-off-by: Tomoki Sekiyama 
> Cc: Jiri Olsa 
> Cc: David Ahern 
> Cc: Namhyung Kim 
> Cc: Peter Zijlstra 
> Cc: Masami Hiramatsu 
> ---
>  tools/perf/builtin-sched.c | 7 ---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
> index 0dfe8df..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,
> @@ -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 

Re: [PATCH v3] perf sched: fix wrong conversion of task state

[Masami Hiramatsu]

On Fri, 29 Jul 2016 13:00:08 +0900
Tomoki Sekiyama  wrote:

> sched_out_state() converts the prev_state u64 bitmask to a char in
> a wrong way, which may cause invalid memory access.
> TASK_STATE_TO_CHAR_STR should also be fixed to adapt current
> kernel's sched.h.

This still have 2 things...

> 
> Signed-off-by: Tomoki Sekiyama 
> Cc: Jiri Olsa 
> Cc: David Ahern 
> Cc: Namhyung Kim 
> Cc: Peter Zijlstra 
> Cc: Masami Hiramatsu 
> ---
>  tools/perf/builtin-sched.c | 7 ---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
> index 0dfe8df..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,
> @@ -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 

Re: [PATCH v3] perf sched: fix wrong conversion of task state

[David Ahern]

On 7/28/16 10:00 PM, Tomoki Sekiyama wrote:

sched_out_state() converts the prev_state u64 bitmask to a char in
a wrong way, which may cause invalid memory access.
TASK_STATE_TO_CHAR_STR should also be fixed to adapt current
kernel's sched.h.


Masami's point is that this should be 2 separate patches -- as suggested 
by the 'also' in the description.




Signed-off-by: Tomoki Sekiyama 
Cc: Jiri Olsa 
Cc: David Ahern 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Masami Hiramatsu 
---
 tools/perf/builtin-sched.c | 7 ---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index 0dfe8df..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"


Patch 1 updates this macro to latest kernel version.



 enum thread_state {
THREAD_SLEEPING = 0,
@@ -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



Patch 2 fixes access to str by treating prev_state as a bitmask and 
adding the Fixes:


Fixes: cdce9d738b91e ("perf sched: Add sched latency profiling")

Re: [PATCH v3] perf sched: fix wrong conversion of task state

[David Ahern]

On 7/28/16 10:00 PM, Tomoki Sekiyama wrote:

sched_out_state() converts the prev_state u64 bitmask to a char in
a wrong way, which may cause invalid memory access.
TASK_STATE_TO_CHAR_STR should also be fixed to adapt current
kernel's sched.h.


Masami's point is that this should be 2 separate patches -- as suggested 
by the 'also' in the description.




Signed-off-by: Tomoki Sekiyama 
Cc: Jiri Olsa 
Cc: David Ahern 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Masami Hiramatsu 
---
 tools/perf/builtin-sched.c | 7 ---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index 0dfe8df..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"


Patch 1 updates this macro to latest kernel version.



 enum thread_state {
THREAD_SLEEPING = 0,
@@ -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



Patch 2 fixes access to str by treating prev_state as a bitmask and 
adding the Fixes:


Fixes: cdce9d738b91e ("perf sched: Add sched latency profiling")

[PATCH v3] perf sched: fix wrong conversion of task state

[Tomoki Sekiyama]

sched_out_state() converts the prev_state u64 bitmask to a char in
a wrong way, which may cause invalid memory access.
TASK_STATE_TO_CHAR_STR should also be fixed to adapt current
kernel's sched.h.

Signed-off-by: Tomoki Sekiyama 
Cc: Jiri Olsa 
Cc: David Ahern 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Masami Hiramatsu 
---
 tools/perf/builtin-sched.c | 7 ---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index 0dfe8df..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,
@@ -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 v3] perf sched: fix wrong conversion of task state

[Tomoki Sekiyama]

sched_out_state() converts the prev_state u64 bitmask to a char in
a wrong way, which may cause invalid memory access.
TASK_STATE_TO_CHAR_STR should also be fixed to adapt current
kernel's sched.h.

Signed-off-by: Tomoki Sekiyama 
Cc: Jiri Olsa 
Cc: David Ahern 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Masami Hiramatsu 
---
 tools/perf/builtin-sched.c | 7 ---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index 0dfe8df..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,
@@ -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