Messages in this thread | | | Subject | Re: [PATCH v3] perf sched: fix wrong conversion of task state | From | David Ahern <> | Date | Fri, 29 Jul 2016 08:07:54 -0600 |
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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 <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> > --- > 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")
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