Re: [PATCH 04/12] bcache: Don't reinvent the wheel but use existing llist API

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On 2017/9/26 下午12:38, Michael Lyle wrote:
> I believe this introduces a critical bug.
> 
> cl->list is used to link together the llists for both things waiting,
> and for things that are being woken.
> 
> If a closure that is woken decides to wait again, it will corrupt the
> llist that __closure_wake_up is using.
> 
> The previous iteration structure gets the next element of the list
> before waking and is therefore safe.
>

Hi Mike,

Good catch! I see llist_del_all() but forget cl->list can be modified in
closure_wait(). Yes there is potential chance to mislead
llist_for_each_entry() to iterate wrong list.
llist_for_each_entry_safe() should be used here. I will send a fix to
Jens, hope to catch up 4.14 still.

Thanks!
-- 
Coly Li



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