[bug report] kmemleak observed during blktests nvme/fc

[Ming Lei]

On Thu, Jan 15, 2026 at 05:24:58PM +0800, Yi Zhang wrote:
> Hi Justin and Chaitanya
> 
> It turns out that the kmemleak was caused by nvme-loop. It was
> observed during the stress nvme loop/tcp/fc[1] test, but the kmemleak
> log was reported during the nvme/fc test. That's why I didn't
> reproduce it with the stress nvme/fc test before.
> 
> [1]
> nvme_trtype=loop ./check nvme/
> nvme_trtype=tcp ./check nvme/
> nvme_trtype=fc ./check nvme/
> 
> unreferenced object 0xffff8881295fd000 (size 1024):
>   comm "nvme", pid 101335, jiffies 4299282670
>   hex dump (first 32 bytes):
>     00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00  .....N..........
>     ff ff ff ff ff ff ff ff e0 3c 57 af ff ff ff ff  .........<W.....
>   backtrace (crc 414bcfcd):
>     __kmalloc_cache_node_noprof+0x5f9/0x840
>     blk_mq_alloc_hctx+0x52/0x810
>     blk_mq_alloc_and_init_hctx+0x5b9/0x840
>     __blk_mq_realloc_hw_ctxs+0x20a/0x610
>     blk_mq_init_allocated_queue+0x2e9/0x1210
>     blk_mq_alloc_queue+0x17f/0x230
>     nvme_alloc_admin_tag_set+0x352/0x670 [nvme_core]
>     nvme_loop_configure_admin_queue+0xdf/0x2d0 [nvme_loop]
>     nvme_loop_create_ctrl+0x428/0xb13 [nvme_loop]
>     nvmf_create_ctrl+0x2ec/0x620 [nvme_fabrics]
>     nvmf_dev_write+0xd5/0x180 [nvme_fabrics]
>     vfs_write+0x1d0/0xfd0
>     ksys_write+0xf9/0x1d0
>     do_syscall_64+0x95/0x520
>     entry_SYSCALL_64_after_hwframe+0x76/0x7e

It seems regression from 03b3bcd319b3 ("nvme: fix admin request_queue
lifetime"), can you try the following fix?


diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 19b67cf5d550..64db8e3d8fd8 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -4848,6 +4848,15 @@ int nvme_alloc_admin_tag_set(struct nvme_ctrl *ctrl, struct blk_mq_tag_set *set,
 	struct queue_limits lim = {};
 	int ret;
 
+	/*
+	 * If a previous admin queue exists (e.g., from before a reset),
+	 * put it now before allocating a new one to avoid orphaning it.
+	 */
+	if (ctrl->admin_q) {
+		blk_put_queue(ctrl->admin_q);
+		ctrl->admin_q = NULL;
+	}
+
 	memset(set, 0, sizeof(*set));
 	set->ops = ops;
 	set->queue_depth = NVME_AQ_MQ_TAG_DEPTH;




Thanks,
Ming