Re: [PATCH 5.10] tracing: Add tracing_reset_all_online_cpus_unlocked() function

[Zheng Yejian]

On 2023/6/19 16:26, Greg KH wrote:
> On Fri, Jun 16, 2023 at 04:49:31AM +0800, Zheng Yejian wrote:
> > From: "Steven Rostedt (Google)" <rostedt@xxxxxxxxxxx>
> >
> > commit e18eb8783ec4949adebc7d7b0fdb65f65bfeefd9 upstream.
> >
> > Currently the tracing_reset_all_online_cpus() requires the
> > trace_types_lock held. But only one caller of this function actually has
> > that lock held before calling it, and the other just takes the lock so
> > that it can call it. More users of this function is needed where the lock
> > is not held.
> >
> > Add a tracing_reset_all_online_cpus_unlocked() function for the one use
> > case that calls it without being held, and also add a lockdep_assert to
> > make sure it is held when called.
> >
> > Then have tracing_reset_all_online_cpus() take the lock internally, such
> > that callers do not need to worry about taking it.
> >
> > Link: https://lkml.kernel.org/r/20221123192741.658273220@xxxxxxxxxxx
> >
> > Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> > Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> > Cc: Zheng Yejian <zhengyejian1@xxxxxxxxxx>
> > Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
> > [this patch is pre-depended by be111ebd8868d4b7c041cb3c6102e1ae27d6dc1d
> > due to tracing_reset_all_online_cpus() should be called after taking lock]
> > Fixes: be111ebd8868 ("tracing: Free buffers when a used dynamic event is removed")
> > Signed-off-by: Zheng Yejian <zhengyejian1@xxxxxxxxxx>
> > ---
>
>
> What about for 5.15.y?  You can't apply a fix to just an older tree as
> you will then have a regression when you update.
>
> I'll drop this one from my queue, please resend a backport for all
> relevent stable releases.

Hi, greg,

I have resend the patch to relevent stable releases:
5.15.y: 
https://lore.kernel.org/all/20230620013052.1127047-1-zhengyejian1@xxxxxxxxxx/
5.10.y: 
https://lore.kernel.org/all/20230620013104.1127100-1-zhengyejian1@xxxxxxxxxx/
5.4.y: 
https://lore.kernel.org/all/20230620013113.1127152-1-zhengyejian1@xxxxxxxxxx/

---

Thanks,
Zheng Yejian

> thanks,
>
> greg k-h