On Thu, Jul 13, 2023 at 09:53:58AM +0000, Tage Johansson wrote:
> Apologize if resending, but I'm not sure my previous email was
> actually delivered.
>
>
> On 7/12/2023 10:33 PM, Eric Blake wrote:
>
>
> >On Wed, Jul 12, 2023 at 03:19:59PM +0000, Tage Johansson wrote:
> >>Hello,
> >>
> >>
> >>While writing some tests for the Rust bindings, I discovered a
> >>memory leak
> >>with Valgrind due to a completion callback not being freed. More
> >>specificly,
> >>the completion callback of `aio_opt_info()` doesn't seem to be if
> >>`aio_opt_info()` failes. In this case, `aio_opt_info()` was called in the
> >>connected state, so it should indeed fail, but it should perhaps
> >>also call
> >>the free function associated with the callback.
> >Can you paste the valgrind output showing the leak?
>
>
> The Valgrind output is very Rust specific and only shows the Rust
> allocations which goes into the completion callback and are lost.
>
>
> But if you apply the following patch (which modifies
> tests/opt-info.c) you shall see that the completion callback is not
> called.
>
> I have replaced a call to `nbd_opt_info()` with a call to
> `nbd_aio_opt_info()` and passed in a completion callback which just
> calls `exit(EXIT_FAILURE)`. So if the completion callback is called
> the test should fail, which it doesn't, at least not on my machine.
Isn't that OK? Only .free is required to be called.
Rich.
>
> diff --git a/tests/opt-info.c b/tests/opt-info.c
> index 86a0608..ba5c72b 100644
> --- a/tests/opt-info.c
> +++ b/tests/opt-info.c
> @@ -30,6 +30,12 @@
>
> #include <libnbd.h>
>
> +int
> +my_completion_cb(void *_user_data, int *_err)
> +{
> + exit(EXIT_FAILURE);
> +}
> +
> int
> main (int argc, char *argv[])
> {
> @@ -201,7 +207,10 @@ main (int argc, char *argv[])
> fprintf (stderr, "expecting export name 'good', got '%s'\n", s);
> exit (EXIT_FAILURE);
> }
> - if (nbd_opt_info (nbd) != -1) {
> + if (nbd_aio_opt_info (
> + nbd,
> + (nbd_completion_callback) { .callback = my_completion_cb }
> + ) != -1) {
> fprintf (stderr, "expecting error for opt_info\n");
> exit (EXIT_FAILURE);
> }
>
> Best regards,
>
> Tage
>
>
--
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