[pve-devel] [PATCH qemu-server 2/3] qmeventd: cancel 'forced cleanup' when normal cleanup succeeds

[Matthias Heiserer]

On 21.09.2022 14:49, Dominik Csapak wrote:
> instead of always sending a SIGKILL to the target pid.
> It was not that much of a problem since the timeout previously was 5
> seconds and we used pifds where possible, thus the chance of killing the
> wrong process was rather slim.
> 
> Now we increased the timeout to 60s which makes the race a bit more likely
> (when not using pidfds), so remove it from the 'forced_cleanups' list when
> the normal cleanup succeeds.
> 
> Signed-off-by: Dominik Csapak <d.csapak at proxmox.com>
> ---
>   qmeventd/qmeventd.c | 20 ++++++++++++++++++++
>   1 file changed, 20 insertions(+)
> 
> diff --git a/qmeventd/qmeventd.c b/qmeventd/qmeventd.c
> index e9ff5b3..de5efd0 100644
> --- a/qmeventd/qmeventd.c
> +++ b/qmeventd/qmeventd.c
> @@ -415,6 +415,25 @@ cleanup_qemu_client(struct Client *client)
>       }
>   }
>   
> +static void
> +remove_cleanup_data(void *ptr, void *client_ptr) {
Not that it really matters, but is there a reason we don't use
remove_cleanup_data(struct CleanupData *ptr, struct Client *client_ptr)
and let the caller deal with types?
> +    struct CleanupData *data = (struct CleanupData *)ptr;
> +    struct Client *client = (struct Client *)client_ptr;
> +
> +    if (data->pid == client->pid) {
> +	forced_cleanups = g_slist_remove(forced_cleanups, ptr);
> +	free(ptr);
> +    }
> +}
> + > +static void
> +remove_from_forced_cleanup(struct Client *client) {
> +    if (g_slist_length(forced_cleanups) > 0) {
> +	VERBOSE_PRINT("removing %s from forced cleanups\n", client->qemu.vmid);
> +	g_slist_foreach(forced_cleanups, remove_cleanup_data, client);
that is, here `(void (*)(void*, void*)) remove_cleanup_data`. Seems a 
bit cleaner to me.
> +    }
> +}
> +
>   void
>   cleanup_client(struct Client *client)
>   {
> @@ -441,6 +460,7 @@ cleanup_client(struct Client *client)
>   	    break;
>       }
>   
> +    remove_from_forced_cleanup(client);
>       free(client);
>   }
>