From 1860c2f85922917d8a46f16a6f4bd2298ffa0fb5 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Sun, 10 May 2026 22:48:43 +0800 Subject: [PATCH] ublk: reject max_sectors smaller than PAGE_SECTORS in parameter validation blk_validate_limits() requires max_hw_sectors >= PAGE_SECTORS and fires a WARN_ON_ONCE if this invariant is violated. ublk_validate_params() only checked the upper bound of max_sectors against max_io_buf_bytes, allowing userspace to pass small values (including zero) that trigger the warning when blk_mq_alloc_disk() is called from ublk_ctrl_start_dev(). Before 494ea040bcb5, ublk used blk_queue_max_hw_sectors() which silently clamped small values up to PAGE_SECTORS. The conversion to passing queue_limits directly to blk_mq_alloc_disk() lost that clamping and now hits blk_validate_limits()'s WARN_ON_ONCE instead. Validate that max_sectors is at least PAGE_SECTORS in ublk_validate_params() so invalid values are rejected early with -EINVAL instead of reaching the block layer. Fixes: 494ea040bcb5 ("ublk: pass queue_limits to blk_mq_alloc_disk") Signed-off-by: Ming Lei Link: https://patch.msgid.link/20260510144843.769031-1-tom.leiming@gmail.com Signed-off-by: Jens Axboe --- drivers/block/ublk_drv.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c index 6d13f1481de0..6c041eaebdb9 100644 --- a/drivers/block/ublk_drv.c +++ b/drivers/block/ublk_drv.c @@ -920,6 +920,9 @@ static int ublk_validate_params(const struct ublk_device *ub) if (p->max_sectors > (ub->dev_info.max_io_buf_bytes >> 9)) return -EINVAL; + if (p->max_sectors < PAGE_SECTORS) + return -EINVAL; + if (ublk_dev_is_zoned(ub) && !p->chunk_sectors) return -EINVAL; } else