[PATCH 2/2] nvme-tcp: remove tag set when second admin queue config fails

[Chaitanya Kulkarni]

On 6/1/25 21:35, Shin'ichiro Kawasaki wrote:
> Commit 104d0e2f6222 ("nvme-fabrics: reset admin connection for secure
> concatenation") modified nvme_tcp_setup_ctrl() to call
> nvme_tcp_configure_admin_queue() twice. The first call prepares for
> DH-CHAP negotitation, and the second call is required for secure
> concatenation. However, this change triggered BUG KASAN slab-use-after-
> free in blk_mq_queue_tag_busy_iter(). This BUG can be recreated by
> repeating the blktests test case nvme/063 a few times [1].
>
> When the BUG happens, nvme_tcp_create_ctrl() fails in the call chain
> below:
>
> nvme_tcp_create_ctrl()
>   nvme_tcp_alloc_ctrl() new=true             ... Alloc nvme_tcp_ctrl and admin_tag_set
>   nvme_tcp_setup_ctrl() new=true
>    nvme_tcp_configure_admin_queue() new=true ... Succeed
>     nvme_alloc_admin_tag_set()               ... Alloc the tag set for admin_tag_set
>    nvme_stop_keep_alive()
>    nvme_tcp_teardown_admin_queue() remove=false
>    nvme_tcp_configure_admin_queue() new=false
>     nvme_tcp_alloc_admin_queue()             ... Fail, but do not call nvme_remove_admin_tag_set()
>   nvme_uninit_ctrl()
>   nvme_put_ctrl()                            ... Free up the nvme_tcp_ctrl and admin_tag_set
>
> The first call of nvme_tcp_configure_admin_queue() succeeds with
> new=true argument. The second call fails with new=false argument. This
> second call does not call nvme_remove_admin_tag_set() on failure, due to
> the new=false argument. Then the admin tag set is not removed. However,
> nvme_tcp_create_ctrl() assumes that nvme_tcp_setup_ctrl() would call
> nvme_remove_admin_tag_set(). Then it frees up struct nvme_tcp_ctrl which
> has admin_tag_set field. Later on, the timeout handler accesses the
> admin_tag_set field and causes the BUG KASAN slab-use-after-free.
>
> To not leave the admin tag set, call nvme_remove_admin_tag_set() when
> the second nvme_tcp_configure_admin_queue() call fails. Do not return
> from nvme_tcp_setup_ctrl() on failure. Instead, jump to "destroy_admin"
> go-to label to call nvme_tcp_teardown_admin_queue() which calls
> nvme_remove_admin_tag_set().
>
> Fixes: 104d0e2f6222 ("nvme-fabrics: reset admin connection for secure concatenation")
> Cc:stable at vger.kernel.org
> Link:https://lore.kernel.org/linux-nvme/6mhxskdlbo6fk6hotsffvwriauurqky33dfb3s44mqtr5dsxmf@gywwmnyh3twm/ [1]
> Signed-off-by: Shin'ichiro Kawasaki<shinichiro.kawasaki at wdc.com>

Thanks for the really good commit log, it made reviewing both the
patches easier. Looks good.

Reviewed-by: Chaitanya Kulkarni <kch at nvidia.com>

-ck