Re: Regression v6.11 booting cannot mount harddisks (xfs)

[Jesper Dangaard Brouer]

On 10/09/2024 20.30, Linus Torvalds wrote:
> On Tue, 10 Sept 2024 at 10:53, Jesper Dangaard Brouer <hawk@xxxxxxxxxx> wrote:
> > af2814149883e2c1851866ea2afcd8eadc040f79 is the first bad commit
>
> Just for fun - can you test moving the queue freezing *inside* the
> mutex, ie something like
>
>    --- a/block/blk-sysfs.c
>    +++ b/block/blk-sysfs.c
>    @@ -670,11 +670,11 @@ queue_attr_store(struct kobject *kobj, struct
> attribute *attr,
>            if (!entry->store)
>                    return -EIO;
>
>    -       blk_mq_freeze_queue(q);
>            mutex_lock(&q->sysfs_lock);
>    +       blk_mq_freeze_queue(q);
>            res = entry->store(disk, page, length);
>    -       mutex_unlock(&q->sysfs_lock);
>            blk_mq_unfreeze_queue(q);
>    +       mutex_unlock(&q->sysfs_lock);
>            return res;
>     }
>
> (Just do it by hand, my patch is whitespace-damaged on purpose -
> untested and not well thought through).
>
> Because I'm wondering whether maybe some IO is done under the
> sysfs_lock, and then you might have a deadlock?
>
>                Linus

Tested the patch (manually applied change) and it did NOT help.

More likely the patch/fix Jens pointed to is the culprit.

--Jesper