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

Posted by Tomoki Sekiyama 
Tomoki Sekiyama
[PATCH 1/2 v5] perf sched: fix wrong conversion of task state
December 13, 2016 05:58AM
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>
Acked-by: David Ahern <dsahern@gmail.com>
---
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
Update TASK_STATE_TO_CHAR_STR macro to one from sched.h in the latest
kernel.

Related kernel commits:
- commit ad86622b478e ("wait: swap EXIT_ZOMBIE and EXIT_DEAD to hide
EXIT_TRACE from user-space"):
'Z' and 'X' are swapped

- commit 80ed87c8a9ca ("sched/wait: Introduce TASK_NOLOAD and TASK_IDLE"):
Introduces new state 'N'

- commit 7dc603c9028e ("sched/fair: Fix PELT integrity for new tasks"):
Introduces new state 'n'

Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com>
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 v4:
Removed 'Fixes:' tag and added related commits in the commit message

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
On 8/1/16 11:35 PM, Tomoki Sekiyama wrote:
> Update TASK_STATE_TO_CHAR_STR macro to one from sched.h in the latest
> kernel.
>
> Related kernel commits:
> - commit ad86622b478e ("wait: swap EXIT_ZOMBIE and EXIT_DEAD to hide
> EXIT_TRACE from user-space"):
> 'Z' and 'X' are swapped
>
> - commit 80ed87c8a9ca ("sched/wait: Introduce TASK_NOLOAD and TASK_IDLE"):
> Introduces new state 'N'
>
> - commit 7dc603c9028e ("sched/fair: Fix PELT integrity for new tasks"):
> Introduces new state 'n'
>
> Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com>
> 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 v4:
> Removed 'Fixes:' tag and added related commits in the commit message

Acked-by: David Ahern <dsahern@gmail.com>
On Tue, 2 Aug 2016 14:35:29 +0900
Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com> wrote:

> Update TASK_STATE_TO_CHAR_STR macro to one from sched.h in the latest
> kernel.
>
> Related kernel commits:
> - commit ad86622b478e ("wait: swap EXIT_ZOMBIE and EXIT_DEAD to hide
> EXIT_TRACE from user-space"):
> 'Z' and 'X' are swapped
>
> - commit 80ed87c8a9ca ("sched/wait: Introduce TASK_NOLOAD and TASK_IDLE"):
> Introduces new state 'N'
>
> - commit 7dc603c9028e ("sched/fair: Fix PELT integrity for new tasks"):
> Introduces new state 'n'
>

Ah, here is the newer one :)

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

Thanks!

> Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com>
> 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 v4:
> Removed 'Fixes:' tag and added related commits in the commit message
>
> 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
>


--
Masami Hiramatsu <mhiramat@kernel.org>
Masami Hiramatsu
Re: [PATCH 1/2 v5] perf sched: fix wrong conversion of task state
December 13, 2016 05:59AM
On Tue, 2 Aug 2016 14:35:28 +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.
>
> 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>
> Acked-by: David Ahern <dsahern@gmail.com>

OK, I also give my ack on this version.

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

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 <mhiramat@kernel.org>
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