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 <[email protected]> Fixes: cdce9d738b91e ("perf sched: Add sched latency profiling") Cc: Jiri Olsa <[email protected]> Cc: David Ahern <[email protected]> Cc: Namhyung Kim <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Masami Hiramatsu <[email protected]> --- 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
