Re: FAILED: patch "[PATCH] blk-cgroup: hold queue_lock when removing blkg->q_node" failed to apply to 6.1-stable tree

[Ming Lei <ming.lei@redhat.com>]

On Sun, Aug 20, 2023 at 07:54:19PM +0200, gregkh@linuxfoundation.org wrote:
> 
> The patch below does not apply to the 6.1-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@vger.kernel.org>.
> 
> To reproduce the conflict and resubmit, you may use the following commands:
> 
> git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
> git checkout FETCH_HEAD
> git cherry-pick -x c164c7bc9775be7bcc68754bb3431fce5823822e
> # <resolve conflicts, build, test, etc.>
> git commit -s
> git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2023082019-brink-buddhist-4d1b@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
> 
> Possible dependencies:
> 
> c164c7bc9775 ("blk-cgroup: hold queue_lock when removing blkg->q_node")
> a06377c5d01e ("Revert "blk-cgroup: pin the gendisk in struct blkcg_gq"")
> 9a9c261e6b55 ("Revert "blk-cgroup: pass a gendisk to blkg_lookup"")
> 1231039db31c ("Revert "blk-cgroup: move the cgroup information to struct gendisk"")
> dcb522014351 ("Revert "blk-cgroup: simplify blkg freeing from initialization failure paths"")
> 3f13ab7c80fd ("blk-cgroup: move the cgroup information to struct gendisk")
> 479664cee14d ("blk-cgroup: pass a gendisk to blkg_lookup")
> ba91c849fa50 ("blk-rq-qos: store a gendisk instead of request_queue in struct rq_qos")
> 3963d84df797 ("blk-rq-qos: constify rq_qos_ops")
> ce57b558604e ("blk-rq-qos: make rq_qos_add and rq_qos_del more useful")
> b494f9c566ba ("blk-rq-qos: move rq_qos_add and rq_qos_del out of line")
> f05837ed73d0 ("blk-cgroup: store a gendisk to throttle in struct task_struct")
> 84d7d462b16d ("blk-cgroup: pin the gendisk in struct blkcg_gq")
> 180b04d450a7 ("blk-cgroup: remove the !bdi->dev check in blkg_dev_name")
> 27b642b07a4a ("blk-cgroup: simplify blkg freeing from initialization failure paths")
> 0b6f93bdf07e ("blk-cgroup: improve error unwinding in blkg_alloc")
> f1c006f1c685 ("blk-cgroup: synchronize pd_free_fn() from blkg_free_workfn() and blkcg_deactivate_policy()")
> dfd6200a0954 ("blk-cgroup: support to track if policy is online")
> c7241babf085 ("blk-cgroup: dropping parent refcount after pd_free_fn() is done")
> e3ff8887e7db ("blk-cgroup: fix missing pd_online_fn() while activating policy")
> 
> thanks,
> 
> greg k-h
> 
> ------------------ original commit in Linus's tree ------------------
> 
> From c164c7bc9775be7bcc68754bb3431fce5823822e Mon Sep 17 00:00:00 2001
> From: Ming Lei <ming.lei@redhat.com>
> Date: Thu, 17 Aug 2023 22:17:51 +0800
> Subject: [PATCH] blk-cgroup: hold queue_lock when removing blkg->q_node
> 
> When blkg is removed from q->blkg_list from blkg_free_workfn(), queue_lock
> has to be held, otherwise, all kinds of bugs(list corruption, hard lockup,
> ..) can be triggered from blkg_destroy_all().
> 
> Fixes: f1c006f1c685 ("blk-cgroup: synchronize pd_free_fn() from blkg_free_workfn() and blkcg_deactivate_policy()")

The above commit is reverted on 6.1-stable only, so this patch needn't to
backport on 6.1-stable.

Thanks,
Ming