ublk_ch_uring_cmd_local() may jump to the out label before initialising the io pointer. This will cause trouble if DEBUG is defined, because the pr_devel() call dereferences io. Clang reports: drivers/block/ublk_drv.c:2403:6: error: variable 'io' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized] 2403 | if (tag >= ub->dev_info.queue_depth) | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/block/ublk_drv.c:2492:32: note: uninitialized use occurs here 2492 | __func__, cmd_op, tag, ret, io->flags); | Fix this by initialising io to NULL and checking it before dereferencing it. Signed-off-by: Kevin Brodsky --- Cc: Ali Utku Selen Cc: Ming Lei Cc: Jens Axboe --- drivers/block/ublk_drv.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c index 0c74a41a6753..359564c40cb5 100644 --- a/drivers/block/ublk_drv.c +++ b/drivers/block/ublk_drv.c @@ -2367,7 +2367,7 @@ static int ublk_ch_uring_cmd_local(struct io_uring_cmd *cmd, u16 buf_idx = UBLK_INVALID_BUF_IDX; struct ublk_device *ub = cmd->file->private_data; struct ublk_queue *ubq; - struct ublk_io *io; + struct ublk_io *io = NULL; u32 cmd_op = cmd->cmd_op; u16 q_id = READ_ONCE(ub_src->q_id); u16 tag = READ_ONCE(ub_src->tag); @@ -2488,7 +2488,7 @@ static int ublk_ch_uring_cmd_local(struct io_uring_cmd *cmd, out: pr_devel("%s: complete: cmd op %d, tag %d ret %x io_flags %x\n", - __func__, cmd_op, tag, ret, io->flags); + __func__, cmd_op, tag, ret, io ? io->flags : 0); return ret; } base-commit: ac3fd01e4c1efce8f2c054cdeb2ddd2fc0fb150d -- 2.51.2