Re: [PATCH 1/2 v5] perf sched: fix wrong conversion of task state

[Masami Hiramatsu]

On Tue,  2 Aug 2016 14:35:28 +0900
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 
> Fixes: cdce9d738b91e ("perf sched: Add sched latency profiling")
> Cc: Jiri Olsa 
> Cc: David Ahern 
> Cc: Namhyung Kim 
> Cc: Peter Zijlstra 
> Cc: Masami Hiramatsu 
> Acked-by: David Ahern 

OK, I also give my ack on this version.

Acked-by: Masami Hiramatsu 

Thanks!

> ---
>  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 

Re: [PATCH 1/2 v5] perf sched: fix wrong conversion of task state

[Masami Hiramatsu]

On Tue,  2 Aug 2016 14:35:28 +0900
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 
> Fixes: cdce9d738b91e ("perf sched: Add sched latency profiling")
> Cc: Jiri Olsa 
> Cc: David Ahern 
> Cc: Namhyung Kim 
> Cc: Peter Zijlstra 
> Cc: Masami Hiramatsu 
> Acked-by: David Ahern 

OK, I also give my ack on this version.

Acked-by: Masami Hiramatsu 

Thanks!

> ---
>  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 

[PATCH 1/2 v5] 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 
Fixes: cdce9d738b91e ("perf sched: Add sched latency profiling")
Cc: Jiri Olsa 
Cc: David Ahern 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Masami Hiramatsu 
Acked-by: David Ahern 
---
 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 1/2 v5] 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 
Fixes: cdce9d738b91e ("perf sched: Add sched latency profiling")
Cc: Jiri Olsa 
Cc: David Ahern 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Masami Hiramatsu 
Acked-by: David Ahern 
---
 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