[PATCH] nvme: fix admin request_queue lifetime

[Casey Chen]

On Tue, Nov 4, 2025 at 3:00 PM Keith Busch <kbusch at meta.com> wrote:
>
> From: Keith Busch <kbusch at kernel.org>
>
> The namespaces can access the controller's admin request_queue, and
> stale references on the namespaces may exist. Ensure the request_queue
> is active by moving the controller's 'put' after all references on the
> controller have been released to ensure no one is trying to access the
> request_queue. This fixes a reported use-after-free bug:
>
>   BUG: KASAN: slab-use-after-free in blk_queue_enter+0x41c/0x4a0
>   Read of size 8 at addr ffff88c0a53819f8 by task nvme/3287
>   CPU: 67 UID: 0 PID: 3287 Comm: nvme Tainted: G            E       6.13.2-ga1582f1a031e #15
>   Tainted: [E]=UNSIGNED_MODULE
>   Hardware name: Jabil /EGS 2S MB1, BIOS 1.00 06/18/2025
>   Call Trace:
>    <TASK>
>    dump_stack_lvl+0x4f/0x60
>    print_report+0xc4/0x620
>    ? _raw_spin_lock_irqsave+0x70/0xb0
>    ? _raw_read_unlock_irqrestore+0x30/0x30
>    ? blk_queue_enter+0x41c/0x4a0
>    kasan_report+0xab/0xe0
>    ? blk_queue_enter+0x41c/0x4a0
>    blk_queue_enter+0x41c/0x4a0
>    ? __irq_work_queue_local+0x75/0x1d0
>    ? blk_queue_start_drain+0x70/0x70
>    ? irq_work_queue+0x18/0x20
>    ? vprintk_emit.part.0+0x1cc/0x350
>    ? wake_up_klogd_work_func+0x60/0x60
>    blk_mq_alloc_request+0x2b7/0x6b0
>    ? __blk_mq_alloc_requests+0x1060/0x1060
>    ? __switch_to+0x5b7/0x1060
>    nvme_submit_user_cmd+0xa9/0x330
>    nvme_user_cmd.isra.0+0x240/0x3f0
>    ? force_sigsegv+0xe0/0xe0
>    ? nvme_user_cmd64+0x400/0x400
>    ? vfs_fileattr_set+0x9b0/0x9b0
>    ? cgroup_update_frozen_flag+0x24/0x1c0
>    ? cgroup_leave_frozen+0x204/0x330
>    ? nvme_ioctl+0x7c/0x2c0
>    blkdev_ioctl+0x1a8/0x4d0
>    ? blkdev_common_ioctl+0x1930/0x1930
>    ? fdget+0x54/0x380
>    __x64_sys_ioctl+0x129/0x190
>    do_syscall_64+0x5b/0x160
>    entry_SYSCALL_64_after_hwframe+0x4b/0x53
>   RIP: 0033:0x7f765f703b0b
>   Code: ff ff ff 85 c0 79 9b 49 c7 c4 ff ff ff ff 5b 5d 4c 89 e0 41 5c c3 66 0f 1f 84 00 00 00 00 00 f3 0f 1e fa b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d dd 52 0f 00 f7 d8 64 89 01 48
>   RSP: 002b:00007ffe2cefe808 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
>   RAX: ffffffffffffffda RBX: 00007ffe2cefe860 RCX: 00007f765f703b0b
>   RDX: 00007ffe2cefe860 RSI: 00000000c0484e41 RDI: 0000000000000003
>   RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000000
>   R10: 00007f765f611d50 R11: 0000000000000202 R12: 0000000000000003
>   R13: 00000000c0484e41 R14: 0000000000000001 R15: 00007ffe2cefea60
>    </TASK>
>
> Reported-by: Casey Chen <cachen at purestorage.com>
> Signed-off-by: Keith Busch <kbusch at kernel.org>
> ---
>  drivers/nvme/host/core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index fa4181d7de736..0b83d82f67e75 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -4901,7 +4901,6 @@ void nvme_remove_admin_tag_set(struct nvme_ctrl *ctrl)
>          */
>         nvme_stop_keep_alive(ctrl);
>         blk_mq_destroy_queue(ctrl->admin_q);
> -       blk_put_queue(ctrl->admin_q);
>         if (ctrl->ops->flags & NVME_F_FABRICS) {
>                 blk_mq_destroy_queue(ctrl->fabrics_q);
>                 blk_put_queue(ctrl->fabrics_q);
> @@ -5045,6 +5044,7 @@ static void nvme_free_ctrl(struct device *dev)
>                 container_of(dev, struct nvme_ctrl, ctrl_device);
>         struct nvme_subsystem *subsys = ctrl->subsys;
>
> +       blk_put_queue(ctrl->admin_q);

Wait. Do we need to check ctrl->admin_q non-NULL before putting it ?
If nvme_alloc_admin_tag_set() fails, blk_put_queue() would put NULL
and panic kernel.

Casey

>         if (!subsys || ctrl->instance != subsys->instance)
>                 ida_free(&nvme_instance_ida, ctrl->instance);
>         nvme_free_cels(ctrl);
> --
> 2.47.3
>