Re: [PATCH v2] plugins/hotblocks: Fix potential deadlock in plugin_exit() function

[Philippe Mathieu-Daudé]

On 21/9/23 11:23, Cong Liu wrote:
> This patch fixes a potential deadlock in the plugin_exit() function of QEMU.
> The original code does not release the lock mutex if it is NULL. This patch
> adds a check for it being NULL and releases the mutex in that case.
>
> Signed-off-by: Cong Liu <liucong2@kylinos.cn>
> Suggested-by: Philippe Mathieu-Daudé <philmd@linaro.org>

Not really suggested, just reviewed ;)

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

> ---
>   contrib/plugins/hotblocks.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/contrib/plugins/hotblocks.c b/contrib/plugins/hotblocks.c
> index 6b74d25fead6..b99b93ad8dc7 100644
> --- a/contrib/plugins/hotblocks.c
> +++ b/contrib/plugins/hotblocks.c
> @@ -69,9 +69,9 @@ static void plugin_exit(qemu_plugin_id_t id, void *p)
>           }
>   
>           g_list_free(it);
> -        g_mutex_unlock(&lock);
>       }
>   
> +    g_mutex_unlock(&lock);
>       qemu_plugin_outs(report->str);
>   }
>