From: Julia Lawall <[email protected]> Find_first_zero_bit considers BITS_PER_LONG bits at a time, and thus may return a larger number than the maximum position argument if that position is not a multiple of BITS_PER_LONG.
The semantic match that finds this problem is as follows: (http://coccinelle.lip6.fr/) // <smpl> @@ expression e1,e2,e3; statement S1,S2; @@ e1 = find_first_zero_bit(e2,e3) ... if (e1 - == + >= e3) S1 else S2 // </smpl> Signed-off-by: Julia Lawall <[email protected]> --- arch/arc/kernel/perf_event.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff -u -p a/arch/arc/kernel/perf_event.c b/arch/arc/kernel/perf_event.c --- a/arch/arc/kernel/perf_event.c +++ b/arch/arc/kernel/perf_event.c @@ -205,7 +205,7 @@ static int arc_pmu_add(struct perf_event if (__test_and_set_bit(idx, arc_pmu->used_mask)) { idx = find_first_zero_bit(arc_pmu->used_mask, arc_pmu->n_counters); - if (idx == arc_pmu->n_counters) + if (idx >= arc_pmu->n_counters) return -EAGAIN; __set_bit(idx, arc_pmu->used_mask); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
