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Date: Mon, 01 Apr 2019 17:11:42 +0800
From: Wei Wang <wei.w.wang@intel.com>
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Subject: Re: [Qemu-devel] [PATCH] migration/ram.c: Fix codes conflict about
 bitmap_mutex
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To: Zhang Chen <chen.zhang@intel.com>, Zhang Chen <zhangckid@gmail.com>, "Dr. David Alan Gilbert" <dgilbert@redhat.com>, Juan Quintela <quintela@redhat.com>, qemu-dev <qemu-devel@nongnu.org>

On 03/30/2019 06:29 AM, Zhang Chen wrote:
> From: Zhang Chen <chen.zhang@intel.com>
>
> I found upstream codes conflict with COLO and lead to crash,
> and I located to this patch:
>
> commit 386a907b37a9321bc5d699bc37104d6ffba1b34d
> Author: Wei Wang <wei.w.wang@intel.com>
> Date:   Tue Dec 11 16:24:49 2018 +0800
>
> migration: use bitmap_mutex in migration_bitmap_clear_dirty
>
> My colleague Wei's patch add bitmap_mutex in migration_bitmap_clear_dirty,
> but COLO didn't initialize the bitmap_mutex. So we always get an error
> when COLO start up. like that:
> qemu-system-x86_64: util/qemu-thread-posix.c:64: qemu_mutex_lock_impl: Assertion `mutex->initialized' failed.
>
> This patch add the bitmap_mutex initialize and destroy in COLO
> lifecycle.
>
> Signed-off-by: Zhang Chen <chen.zhang@intel.com>
> ---
>   migration/ram.c | 2 ++
>   1 file changed, 2 insertions(+)
>
> diff --git a/migration/ram.c b/migration/ram.c
> index d7f8fe45a8..f68beeeeff 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -3918,6 +3918,7 @@ int colo_init_ram_cache(void)
>       }
>       ram_state = g_new0(RAMState, 1);
>       ram_state->migration_dirty_pages = 0;
> +    qemu_mutex_init(&ram_state->bitmap_mutex);
>       memory_global_dirty_log_start();
>   
>       return 0;
> @@ -3956,6 +3957,7 @@ void colo_release_ram_cache(void)
>       }
>   
>       rcu_read_unlock();
> +    qemu_mutex_destroy(&ram_state->bitmap_mutex);
>       g_free(ram_state);
>       ram_state = NULL;
>   }

Reviewed-by: Wei Wang <wei.w.wang@intel.com>

Best,
Wei