linux-kernel - Re: [PATCH] ioapic: fix potential resume deadlock

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Date:	Tue, 10 May 2011 13:32:50 +0800
From:	Daniel J Blueman <daniel.blueman@...il.com>
To:	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>, H Peter Anvin <hpa@...or.com>
Cc:	x86@...nel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ioapic: fix potential resume deadlock

Hi Thomas, Ingo, HPA,

On 9 May 2011 10:40, Daniel J Blueman <daniel.blueman@...il.com> wrote:
> Fix a potential deadlock when resuming; here the calling function
> has disabled interrupts, so we cannot sleep.
>
> Signed-off-by: Daniel J Blueman <daniel.blueman@...il.com>
>
> ---
>  arch/x86/kernel/apic/io_apic.c |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
> index 45fd33d..df63620 100644
> --- a/arch/x86/kernel/apic/io_apic.c
> +++ b/arch/x86/kernel/apic/io_apic.c
> @@ -621,14 +621,14 @@ struct IO_APIC_route_entry **alloc_ioapic_entries(void)
>        struct IO_APIC_route_entry **ioapic_entries;
>
>        ioapic_entries = kzalloc(sizeof(*ioapic_entries) * nr_ioapics,
> -                               GFP_KERNEL);
> +                               GFP_ATOMIC);
>        if (!ioapic_entries)
>                return 0;
>
>        for (apic = 0; apic < nr_ioapics; apic++) {
>                ioapic_entries[apic] =
>                        kzalloc(sizeof(struct IO_APIC_route_entry) *
> -                               nr_ioapic_registers[apic], GFP_KERNEL);
> +                               nr_ioapic_registers[apic], GFP_ATOMIC);
>                if (!ioapic_entries[apic])
>                        goto nomem;
>        }

Any feedback on this? I tested it on 2.6.39-rc6 and it does address
the potential deadlock warning I receive when resuming from suspend.
If positive, it would be good to get into -rc8, as rc7 is released.

Thanks,
  Daniel
-- 
Daniel J Blueman
--
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