Fixes crashes due to ubd requeue logic conflicting with the block-mq logic. Crash is reproducible in 5.0 - 5.3.

Fixes: 53766defb8c860a47e2a965f5b4b05ed2848e2d0 Signed-off-by: Anton Ivanov anton.ivanov@cambridgegreys.com --- arch/um/drivers/ubd_kern.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c index 33c1cd6a12ac..40ab9ad7aa96 100644 --- a/arch/um/drivers/ubd_kern.c +++ b/arch/um/drivers/ubd_kern.c @@ -1403,8 +1403,12 @@ static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx,

spin_unlock_irq(&ubd_dev->lock);

- if (ret < 0) - blk_mq_requeue_request(req, true); + if (ret < 0) { + if (ret == -ENOMEM) + res = BLK_STS_RESOURCE; + else + res = BLK_STS_DEV_RESOURCE; + }

return res; }