linux-kernel - Re: [PATCH] prevent ia64 from invoking irq handlers on offline CPUs

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Sun, 31 Aug 2008 19:46:33 +0200
From:	"Vegard Nossum" <vegard.nossum@...il.com>
To:	paulmck@...ux.vnet.ibm.com
Cc:	linux-kernel@...r.kernel.org, tony.luck@...el.com, jes@....com,
	manfred@...orfullife.com, akpm@...ux-foundation.org
Subject: Re: [PATCH] prevent ia64 from invoking irq handlers on offline CPUs

On Sun, Aug 31, 2008 at 7:28 PM, Paul E. McKenney
<paulmck@...ux.vnet.ibm.com> wrote:
> Make ia64 refrain from clearing a given to-be-offlined CPU's bit in the
> cpu_online_mask until it has processed pending irqs.  This change
> prevents other CPUs from being blindsided by an apparently offline CPU
> nevertheless changing globally visible state.
>
> Signed-off-by: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
> ---
>
>  smpboot.c |    3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/arch/ia64/kernel/smpboot.c b/arch/ia64/kernel/smpboot.c
> index bcea81e..7a90f42 100644
> --- a/arch/ia64/kernel/smpboot.c
> +++ b/arch/ia64/kernel/smpboot.c
> @@ -741,8 +741,6 @@ int __cpu_disable(void)
>                        return -EBUSY;
>        }
>
> -       cpu_clear(cpu, cpu_online_map);
> -
>        if (migrate_platform_irqs(cpu)) {
>                cpu_set(cpu, cpu_online_map);
>                return (-EBUSY);
> @@ -751,6 +749,7 @@ int __cpu_disable(void)
>        remove_siblinginfo(cpu);
>        cpu_clear(cpu, cpu_online_map);
>        fixup_irqs();
> +       cpu_clear(cpu, cpu_online_map);
>        local_flush_tlb_all();
>        cpu_clear(cpu, cpu_callin_map);
>        return 0;

Hm. Maybe my eyes are going bad. But isn't that now clearing the cpu
both before and after calling fixup_irqs()?


Vegard

-- 
"The animistic metaphor of the bug that maliciously sneaked in while
the programmer was not looking is intellectually dishonest as it
disguises that the error is the programmer's own creation."
	-- E. W. Dijkstra, EWD1036
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/