On Mon, Jul 30, 2018 at 10:03 AM, xiao jin <jin.xiao@xxxxxxxxx> wrote: > We find the memory use-after-free issue in __blk_drain_queue() > on the kernel 4.14. After read the latest kernel 4.18-rc6 we > think it has the same problem. > > Memory is allocated for q->fq in the blk_init_allocated_queue(). > If the elevator init function called with error return, it will > run into the fail case to free the q->fq. > > Then the __blk_drain_queue() uses the same memory after the free > of the q->fq, it will lead to the unpredictable event. > > The patch is to set q->fq as NULL in the fail case of > blk_init_allocated_queue(). > > Signed-off-by: xiao jin <jin.xiao@xxxxxxxxx> > --- > block/blk-core.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/block/blk-core.c b/block/blk-core.c > index b888175..52635e2 100644 > --- a/block/blk-core.c > +++ b/block/blk-core.c > @@ -1072,6 +1072,7 @@ int blk_init_allocated_queue(struct request_queue *q) > q->exit_rq_fn(q, q->fq->flush_rq); > out_free_flush_queue: > blk_free_flush_queue(q->fq); > + q->fq = NULL; > return -ENOMEM; > } > EXPORT_SYMBOL(blk_init_allocated_queue); > -- > 1.7.9.5 > Reviewed-by: Ming Lei <ming.lei@xxxxxxxxxx> Thanks, Ming Lei
