It can be a bit hard for driver to avoid request UAF between normal completion and completion via blk_mq_tagset_busy_iter() if async completion is done in blk_mq_tagset_busy_iter(). Cause request->tag is only freed after .mq_ops->complete() is called, and rquest->tag may still be valid after blk_mq_complete_request() is returned from normal completion path, so this request is still visible in blk_mq_tagset_busy_iter(). This patch itself can't avoid such request UAF completely. We will grab a request reference in next patch when walking request via blk_mq_tagset_busy_iter() for fixing such race, that is why we have to convert to blk_mq_complete_request_locally() first. Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx> --- drivers/block/mtip32xx/mtip32xx.c | 2 +- drivers/block/nbd.c | 2 +- drivers/nvme/host/core.c | 2 +- drivers/scsi/scsi_lib.c | 6 +++++- 4 files changed, 8 insertions(+), 4 deletions(-) diff --git a/drivers/block/mtip32xx/mtip32xx.c b/drivers/block/mtip32xx/mtip32xx.c index 3be0dbc674bd..05f5e36ee608 100644 --- a/drivers/block/mtip32xx/mtip32xx.c +++ b/drivers/block/mtip32xx/mtip32xx.c @@ -3748,7 +3748,7 @@ static bool mtip_no_dev_cleanup(struct request *rq, void *data, bool reserv) struct mtip_cmd *cmd = blk_mq_rq_to_pdu(rq); cmd->status = BLK_STS_IOERR; - blk_mq_complete_request(rq); + blk_mq_complete_request_locally(rq); return true; } diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index 4ff71b579cfc..3dcf3288efa8 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -809,7 +809,7 @@ static bool nbd_clear_req(struct request *req, void *data, bool reserved) cmd->status = BLK_STS_IOERR; mutex_unlock(&cmd->lock); - blk_mq_complete_request(req); + blk_mq_complete_request_locally(req); return true; } diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index 0896e21642be..a605954477da 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -381,7 +381,7 @@ bool nvme_cancel_request(struct request *req, void *data, bool reserved) nvme_req(req)->status = NVME_SC_HOST_ABORTED_CMD; nvme_req(req)->flags |= NVME_REQ_CANCELLED; - blk_mq_complete_request(req); + blk_mq_complete_request_locally(req); return true; } EXPORT_SYMBOL_GPL(nvme_cancel_request); diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index c289991ffaed..7cbaee282b6d 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -1568,7 +1568,11 @@ static void scsi_mq_done(struct scsi_cmnd *cmd) if (unlikely(test_and_set_bit(SCMD_STATE_COMPLETE, &cmd->state))) return; trace_scsi_dispatch_cmd_done(cmd); - blk_mq_complete_request(cmd->request); + + if (unlikely(host_byte(cmd->result) != DID_OK)) + blk_mq_complete_request_locally(cmd->request); + else + blk_mq_complete_request(cmd->request); } static void scsi_mq_put_budget(struct request_queue *q) -- 2.29.2
