Re: Patch "genirq: GENERIC_IRQ_IPI depends on SMP" has been added to the 5.4-stable tree

Re: Patch "genirq: GENERIC_IRQ_IPI depends on SMP" has been added to the 5.4-stable tree

[Samuel Holland]

Hi Sasha,

On 8/13/22 5:50 PM, Sasha Levin wrote:
> This is a note to let you know that I've just added the patch titled
> 
>     genirq: GENERIC_IRQ_IPI depends on SMP
> 
> to the 5.4-stable tree which can be found at:
>     http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
> 
> The filename of the patch is:
>      genirq-generic_irq_ipi-depends-on-smp.patch
> and it can be found in the queue-5.4 subdirectory.
> 
> If you, or anyone else, feels it should not be added to the stable tree,
> please let <stable@vger.kernel.org> know about it.

This commit should not be backported further than 8190cc572981
("irqchip/mips-gic: Only register IPI domain when SMP is enabled"), which it
depends on. It looks like that commit only went back to 5.10.

Regards,
Samuel

> commit 1ac66168f6a589c3f91104eb692fab83bae9ed73
> Author: Samuel Holland <samuel@sholland.org>
> Date:   Fri Jul 1 15:00:50 2022 -0500
> 
>     genirq: GENERIC_IRQ_IPI depends on SMP
>     
>     [ Upstream commit 0f5209fee90b4544c58b4278d944425292789967 ]
>     
>     The generic IPI code depends on the IRQ affinity mask being allocated
>     and initialized. This will not be the case if SMP is disabled. Fix up
>     the remaining driver that selected GENERIC_IRQ_IPI in a non-SMP config.
>     
>     Reported-by: kernel test robot <lkp@intel.com>
>     Signed-off-by: Samuel Holland <samuel@sholland.org>
>     Signed-off-by: Marc Zyngier <maz@kernel.org>
>     Link: https://lore.kernel.org/r/20220701200056.46555-3-samuel@sholland.org
>     Signed-off-by: Sasha Levin <sashal@kernel.org>
> 
> diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
> index 20f44ef9c4c9..e50b5516bbef 100644
> --- a/drivers/irqchip/Kconfig
> +++ b/drivers/irqchip/Kconfig
> @@ -178,7 +178,7 @@ config MADERA_IRQ
>  config IRQ_MIPS_CPU
>  	bool
>  	select GENERIC_IRQ_CHIP
> -	select GENERIC_IRQ_IPI if SYS_SUPPORTS_MULTITHREADING
> +	select GENERIC_IRQ_IPI if SMP && SYS_SUPPORTS_MULTITHREADING
>  	select IRQ_DOMAIN
>  	select IRQ_DOMAIN_HIERARCHY if GENERIC_IRQ_IPI
>  	select GENERIC_IRQ_EFFECTIVE_AFF_MASK
> diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig
> index 4e11120265c7..3a8a631044f0 100644
> --- a/kernel/irq/Kconfig
> +++ b/kernel/irq/Kconfig
> @@ -81,6 +81,7 @@ config IRQ_FASTEOI_HIERARCHY_HANDLERS
>  # Generic IRQ IPI support
>  config GENERIC_IRQ_IPI
>  	bool
> +	depends on SMP
>  	select IRQ_DOMAIN_HIERARCHY
>  
>  # Generic MSI interrupt support
> 

Re: Patch "genirq: GENERIC_IRQ_IPI depends on SMP" has been added to the 5.4-stable tree

[Marc Zyngier]

On Mon, 15 Aug 2022 05:21:51 +0100,
Samuel Holland <samuel@sholland.org> wrote:
> 
> Hi Sasha,
> 
> On 8/13/22 5:50 PM, Sasha Levin wrote:
> > This is a note to let you know that I've just added the patch titled
> > 
> >     genirq: GENERIC_IRQ_IPI depends on SMP
> > 
> > to the 5.4-stable tree which can be found at:
> >     http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
> > 
> > The filename of the patch is:
> >      genirq-generic_irq_ipi-depends-on-smp.patch
> > and it can be found in the queue-5.4 subdirectory.
> > 
> > If you, or anyone else, feels it should not be added to the stable tree,
> > please let <stable@vger.kernel.org> know about it.
> 
> This commit should not be backported further than 8190cc572981
> ("irqchip/mips-gic: Only register IPI domain when SMP is enabled"), which it
> depends on. It looks like that commit only went back to 5.10.

I also wonder why these commits were backported *at all*. On their
own, they don't fix anything, but allowed further improvements that
are not backport candidates either.

Honestly, if I wanted these backported to stable, I'd have put a 'Cc:
stable' tag. These patches don't even have a 'Fixes:' tag, for the
same reason.

	M.

-- 
Without deviation from the norm, progress is not possible.

Re: Patch "genirq: GENERIC_IRQ_IPI depends on SMP" has been added to the 5.4-stable tree

[Greg KH]

On Mon, Aug 15, 2022 at 09:39:47AM +0100, Marc Zyngier wrote:
> On Mon, 15 Aug 2022 05:21:51 +0100,
> Samuel Holland <samuel@sholland.org> wrote:
> > 
> > Hi Sasha,
> > 
> > On 8/13/22 5:50 PM, Sasha Levin wrote:
> > > This is a note to let you know that I've just added the patch titled
> > > 
> > >     genirq: GENERIC_IRQ_IPI depends on SMP
> > > 
> > > to the 5.4-stable tree which can be found at:
> > >     http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
> > > 
> > > The filename of the patch is:
> > >      genirq-generic_irq_ipi-depends-on-smp.patch
> > > and it can be found in the queue-5.4 subdirectory.
> > > 
> > > If you, or anyone else, feels it should not be added to the stable tree,
> > > please let <stable@vger.kernel.org> know about it.
> > 
> > This commit should not be backported further than 8190cc572981
> > ("irqchip/mips-gic: Only register IPI domain when SMP is enabled"), which it
> > depends on. It looks like that commit only went back to 5.10.
> 
> I also wonder why these commits were backported *at all*. On their
> own, they don't fix anything, but allowed further improvements that
> are not backport candidates either.
> 
> Honestly, if I wanted these backported to stable, I'd have put a 'Cc:
> stable' tag. These patches don't even have a 'Fixes:' tag, for the
> same reason.

Ok, now dropped from everything older than 5.10, thanks.

greg k-h