On Fri, 8 Apr 2022 12:06:20 +0800 Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx> wrote:
>
>
> >>>> Signed-off-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
> >>>
> >>> Are any users affected by this? If so, I think a Fixes tag
> >>> is necessary.
> >>
> >> Looks all current users(blk_pre_runtime_suspend() and set_in_sync()) are
> >> affected by this.
> >>
> >> I see that this patch has been merged into the mm tree, can Andrew help
> >> me add the following Fixes tag?
> >
> > Andrew is helpful ;)
> >
> > Do you see reasons why we should backport this into -stable trees?
> > It's 8 years old, so my uninformed guess is "no"?
>
> Hmm, although the commit 490c79a65708 add wake_up_all(), it is no
> problem for the usage at that time, maybe the correct Fixes tag is the
> following:
>
> Fixes: 210f7cdcf088 ("percpu-refcount: support synchronous switch to
> atomic mode.")
>
> But in fact, there is no problem with it, but all current users expect
> the refcount is stable after percpu_ref_switch_to_atomic_sync() returns.
>
> I have no idea as which Fixes tag to add.
Well the solution to that problem is to add cc:stable and let Greg
figure it out ;)
The more serious question is "should we backport this". What is the
end-user-visible impact of the bug? Do our users need the fix or not?
