tg in throtl_select_dispatch is used first and then do check. Since tg may be NULL, it has potential NULL pointer dereference risk. So fix it.
Signed-off-by: Joseph Qi <[email protected]> Reviewed-by: Jiufei Xue <[email protected]> --- block/blk-throttle.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 9052f4e..a0bae2c 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -1228,7 +1228,7 @@ static int throtl_select_dispatch(struct throtl_service_queue *parent_sq) while (1) { struct throtl_grp *tg = throtl_rb_first(parent_sq); - struct throtl_service_queue *sq = &tg->service_queue; + struct throtl_service_queue *sq; if (!tg) break; @@ -1240,6 +1240,7 @@ static int throtl_select_dispatch(struct throtl_service_queue *parent_sq) nr_disp += throtl_dispatch_tg(tg); + sq = &tg->service_queue; if (sq->nr_queued[0] || sq->nr_queued[1]) tg_update_disptime(tg); -- 1.9.4
