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Re: [Qemu-devel] [PATCH] Fix signal handling of SIG_IPI when io-thread i
From: |
Jan Kiszka |
Subject: |
Re: [Qemu-devel] [PATCH] Fix signal handling of SIG_IPI when io-thread is enabled |
Date: |
Wed, 15 Jun 2011 09:38:28 +0200 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 |
On 2011-06-15 07:20, Alexandre Raymond wrote:
> Both the signal thread (via sigwait()) and the cpu thread (via
> a normal signal handler) were attempting to catch SIG_IPI.
Why? Ahh, because of qemu_cpu_kick_self: raise(SIG_IPI)! That should
generate a per-process SIG_IPI. And that may not only affect Darwin.
Looks good.
Acked-by: Jan Kiszka <address@hidden>
>
> This resulted in random freezes under Darwin.
>
> This patch separates SIG_IPI from the rest of the signals handled
> by the signal thread, because it is independently caught by the cpu
> thread.
>
> Signed-off-by: Alexandre Raymond <address@hidden>
> ---
> cpus.c | 10 +++++++++-
> 1 files changed, 9 insertions(+), 1 deletions(-)
>
> diff --git a/cpus.c b/cpus.c
> index 18a1522..84ffd1c 100644
> --- a/cpus.c
> +++ b/cpus.c
> @@ -394,10 +394,18 @@ static int qemu_signal_init(void)
> sigaddset(&set, SIGUSR2);
> pthread_sigmask(SIG_UNBLOCK, &set, NULL);
>
> + /*
> + * SIG_IPI must be blocked in the main thread and must not be caught
> + * by sigwait() in the signal thread. Otherwise, the cpu thread will
> + * not catch it reliably.
> + */
> + sigemptyset(&set);
> + sigaddset(&set, SIG_IPI);
> + pthread_sigmask(SIG_BLOCK, &set, NULL);
> +
> sigemptyset(&set);
> sigaddset(&set, SIGIO);
> sigaddset(&set, SIGALRM);
> - sigaddset(&set, SIG_IPI);
> sigaddset(&set, SIGBUS);
> #else
> sigemptyset(&set);
--
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