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Re: [PATCH v2 4/5] plugins/loader: fix uninitialized variable warning in
From: |
Alex Bennée |
Subject: |
Re: [PATCH v2 4/5] plugins/loader: fix uninitialized variable warning in plugin_reset_uninstall() |
Date: |
Wed, 11 Nov 2020 17:22:53 +0000 |
User-agent: |
mu4e 1.5.7; emacs 28.0.50 |
Chen Qun <kuhn.chenqun@huawei.com> writes:
> After the WITH_QEMU_LOCK_GUARD macro is added, the compiler cannot identify
> that the statements in the macro must be executed. As a result, some
> variables
> assignment statements in the macro may be considered as unexecuted by the
> compiler.
>
> When the -Wmaybe-uninitialized capability is enabled on GCC9,the compiler
> showed warning:
> plugins/loader.c: In function ‘plugin_reset_uninstall’:
> plugins/loader.c:382:15: warning: ‘ctx’ may be used uninitialized in this
> function [-Wmaybe-uninitialized]
> 382 | data->ctx = ctx;
> | ~~~~~~~~~~^~~~~
>
> Add a default value for 'expire_time' to prevented the warning.
>
> Reported-by: Euler Robot <euler.robot@huawei.com>
> Signed-off-by: Chen Qun <kuhn.chenqun@huawei.com>
> ---
> Cc: "Alex Bennée" <alex.bennee@linaro.org>
> ---
> plugins/loader.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/plugins/loader.c b/plugins/loader.c
> index 8ac5dbc20f..88593fe138 100644
> --- a/plugins/loader.c
> +++ b/plugins/loader.c
> @@ -367,7 +367,7 @@ void plugin_reset_uninstall(qemu_plugin_id_t id,
> bool reset)
> {
> struct qemu_plugin_reset_data *data;
> - struct qemu_plugin_ctx *ctx;
> + struct qemu_plugin_ctx *ctx = NULL;
This doesn't really fix anything because you would end up faulting if
you attempted to de-ref a NULL ctx. However...
>
> WITH_QEMU_LOCK_GUARD(&plugin.lock) {
> ctx = plugin_id_to_ctx_locked(id);
...this can't fail. If the lookup failed and returned a NULL plugin then
we would abort(). So why can't the Euler Robot see that?
--
Alex Bennée
- [PATCH v2 0/5] fix uninitialized variable warning, Chen Qun, 2020/11/11
- [PATCH v2 5/5] migration: fix uninitialized variable warning in migrate_send_rp_req_pages(), Chen Qun, 2020/11/11
- [PATCH v2 3/5] util/qemu-timer: fix uninitialized variable warning for expire_time, Chen Qun, 2020/11/11
- [PATCH v2 2/5] util/qemu-timer: fix uninitialized variable warning in timer_mod_anticipate_ns(), Chen Qun, 2020/11/11
- [PATCH v2 4/5] plugins/loader: fix uninitialized variable warning in plugin_reset_uninstall(), Chen Qun, 2020/11/11
- Re: [PATCH v2 4/5] plugins/loader: fix uninitialized variable warning in plugin_reset_uninstall(),
Alex Bennée <=
- [PATCH v2 1/5] hw/rdma/rdma_backend: fix uninitialized variable warning in rdma_poll_cq(), Chen Qun, 2020/11/11