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Date:   Tue, 14 Apr 2020 14:14:12 +0200
From:   Greg KH <gregkh@linuxfoundation.org>
To:     Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc:     stable@vger.kernel.org, Petr Mladek <pmladek@suse.com>
Subject: Re: printk: queue wake_up_klogd irq_work only if per-CPU areas are
 ready
Message-ID: <20200414121412.GA605766@kroah.com>
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On Tue, Apr 14, 2020 at 09:06:13PM +0900, Sergey Senozhatsky wrote:
> Hello,
> 
> Commit ab6f762f0f53162d41 Linus' HEAD.
> 
> printk_deferred() does not make sure that it's safe to write to
> per-CPU data, which causes problems when printk_deferred() is
> invoked "too early", before per-CPU areas are initialized. There
> are multiple bug reports, e.g.
> https://bugzilla.kernel.org/show_bug.cgi?id=206847
> 
> 	-ss

So where do you want this commit backported to?

thanks,
greg k-h