From: Michael Ellerman <patch-notifications@ellerman.id.au>
To: Nicholas Piggin <npiggin@gmail.com>, linuxppc-dev@lists.ozlabs.org
Cc: Nicholas Piggin <npiggin@gmail.com>
Subject: Re: [v2] powerpc: NMI IPI make NMI IPIs fully sychronous
Date: Tue, 24 Jul 2018 23:59:47 +1000 (AEST) [thread overview]
Message-ID: <41Zg372DMxz9s29@ozlabs.org> (raw)
In-Reply-To: <20180425051759.9474-1-npiggin@gmail.com>
On Wed, 2018-04-25 at 05:17:59 UTC, Nicholas Piggin wrote:
> There is an asynchronous aspect to smp_send_nmi_ipi. The caller waits
> for all CPUs to call in to the handler, but it does not wait for
> completion of the handler. This is a needless complication, so remove
> it and always wait synchronously.
>
> The synchronous wait allows the caller to easily time out and clear
> the wait for completion (zero nmi_ipi_busy_count) in the case of badly
> behaved handlers. This would have prevented the recent smp_send_stop
> NMI IPI bug from causing the system to hang.
>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Applied to powerpc next, thanks.
https://git.kernel.org/powerpc/c/5b73151fff63fb019db8171cb81c6c
cheers
prev parent reply other threads:[~2018-07-24 13:59 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-25 5:17 [PATCH v2] powerpc: NMI IPI make NMI IPIs fully sychronous Nicholas Piggin
2018-07-24 13:59 ` Michael Ellerman [this message]
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