Re: [PATCHv2] printk: queue wake_up_klogd irq_work only if per-CPU areas are ready

[Greg Kroah-Hartman]

On Thu, Mar 05, 2020 at 10:30:14AM +0900, Sergey Senozhatsky wrote:
> On (20/03/04 16:21), Petr Mladek wrote:
> [..]
> > > Fix printk_deferred() and do not queue per-CPU irq_work
> > > before per-CPU areas are initialized.
> > >
> > > [0] https://lore.kernel.org/lkml/aa0732c6-5c4e-8a8b-a1c1-75ebe3dca05b@xxxxxxxxxxxxxxxxxxxxxx/
> > >
> > > Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
> > > Reported-by: Lech Perczak <l.perczak@xxxxxxxxxxxxxxxxxxxxxx>
> > > Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> > > Cc: Theodore Ts'o <tytso@xxxxxxx>
> > > Cc: John Ogness <john.ogness@xxxxxxxxxxxxx>
> >
> > Reviewed-by: Petr Mladek <pmladek@xxxxxxxx>
> 
> Thanks!
> 
> > Now, the question is whether to hurry this fix into 5.6 or if
> > it could wait for 5.7.
> >
> > I think that it could wait because 5.6 is not affected by
> > the particular printk_deferred(). This patch fixes a long-term
> > generic problem. But I am open for other opinions.
> 
> Good question. My 5 cents, I would _probably_ push it now. Not
> because it fixes any known issues on 5.6, but because we have
> a number of LTS kernel (4.19, 4.14, 4.9, 4.4, 3.16) that can be
> affected should 1b710b1b10eff9d4 be backported to those kernels.

It was backported there, and now has been reverted.  So no big rush from
what I can tell.

thanks,

greg k-h