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References: <20190102141603.3681-1-lvivier@redhat.com>
From: =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= <philmd@redhat.com>
Message-ID: <c976232a-47a6-966d-4ab9-807e20525e31@redhat.com>
Date: Wed, 2 Jan 2019 15:28:06 +0100
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Subject: Re: [Qemu-devel] [PATCH] cpus: ignore ESRCH in
 qemu_cpu_kick_thread()
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To: Laurent Vivier <lvivier@redhat.com>, qemu-devel@nongnu.org
Cc: Paolo Bonzini <pbonzini@redhat.com>, Peter Crosthwaite <crosthwaite.peter@gmail.com>, Richard Henderson <rth@twiddle.net>

On 1/2/19 3:16 PM, Laurent Vivier wrote:
> We can have a race condition between qemu_cpu_kick_thread() and
> qemu_kvm_cpu_thread_fn() when we hotunplug a CPU. In this case,
> qemu_cpu_kick_thread() can try to kick a thread that is exiting.
> pthread_kill() returns an error and qemu is stopped by an exit(1).
> 
>    qemu:qemu_cpu_kick_thread: No such process
> 
> We can ignore safely this error.
> 
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

> ---
>  cpus.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/cpus.c b/cpus.c
> index 0ddeeefc14..4717490bd0 100644
> --- a/cpus.c
> +++ b/cpus.c
> @@ -1778,7 +1778,7 @@ static void qemu_cpu_kick_thread(CPUState *cpu)
>      }
>      cpu->thread_kicked = true;
>      err = pthread_kill(cpu->thread->thread, SIG_IPI);
> -    if (err) {
> +    if (err && err != ESRCH) {
>          fprintf(stderr, "qemu:%s: %s", __func__, strerror(err));
>          exit(1);
>      }
>