On 7/31/16 10:30 PM, 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 <[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
Acked-by: David Ahern <[email protected]>
