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Re: [PATCH] qemu-nbd: Fix a memleak in nbd_client_thread()
From: |
Alex Chen |
Subject: |
Re: [PATCH] qemu-nbd: Fix a memleak in nbd_client_thread() |
Date: |
Wed, 2 Dec 2020 10:02:19 +0800 |
User-agent: |
Mozilla/5.0 (Windows NT 6.2; WOW64; rv:17.0) Gecko/20130509 Thunderbird/17.0.6 |
On 2020/12/2 4:15, Eric Blake wrote:
> On 12/1/20 12:13 AM, Alex Chen wrote:
>> When the qio_channel_socket_connect_sync() fails
>> we should goto 'out_socket' label to free the 'sioc' instead of
>> goto 'out' label.
>> In addition, now the 'out' label is useless, delete it.
>>
>> Reported-by: Euler Robot <euler.robot@huawei.com>
>> Signed-off-by: Alex Chen <alex.chen@huawei.com>
>> ---
>> qemu-nbd.c | 3 +--
>> 1 file changed, 1 insertion(+), 2 deletions(-)
>>
>> diff --git a/qemu-nbd.c b/qemu-nbd.c
>> index 47587a709e..643b0777c0 100644
>> --- a/qemu-nbd.c
>> +++ b/qemu-nbd.c
>> @@ -275,7 +275,7 @@ static void *nbd_client_thread(void *arg)
>> saddr,
>> &local_error) < 0) {
>> error_report_err(local_error);
>> - goto out;
>> + goto out_socket;
>> }
>>
>> ret = nbd_receive_negotiate(NULL, QIO_CHANNEL(sioc),
>> @@ -325,7 +325,6 @@ out_fd:
>> close(fd);
>> out_socket:
>> object_unref(OBJECT(sioc));
>> -out:
>> g_free(info.name);
>> kill(getpid(), SIGTERM);
>> return (void *) EXIT_FAILURE;
>>
>
> While the patch looks correct, we have a lot of duplication. Simpler
> might be a solution with only one exit label altogether:
>
Thanks for your review, I will modify the patch and send patch v2 according to
your suggestion.
BTW, do I need to split this patch into two patches, one to solve the memleak
and the other to optimizes the redundant code?
Thanks,
Alex
> diff --git i/qemu-nbd.c w/qemu-nbd.c
> index a7075c5419d7..d7bdcd0011ba 100644
> --- i/qemu-nbd.c
> +++ w/qemu-nbd.c
> @@ -265,8 +265,8 @@ static void *nbd_client_thread(void *arg)
> char *device = arg;
> NBDExportInfo info = { .request_sizes = false, .name = g_strdup("") };
> QIOChannelSocket *sioc;
> - int fd;
> - int ret;
> + int fd = -1;
> + int ret = EXIT_FAILURE;
> pthread_t show_parts_thread;
> Error *local_error = NULL;
>
> @@ -278,26 +278,24 @@ static void *nbd_client_thread(void *arg)
> goto out;
> }
>
> - ret = nbd_receive_negotiate(NULL, QIO_CHANNEL(sioc),
> - NULL, NULL, NULL, &info, &local_error);
> - if (ret < 0) {
> + if (nbd_receive_negotiate(NULL, QIO_CHANNEL(sioc),
> + NULL, NULL, NULL, &info, &local_error) < 0) {
> if (local_error) {
> error_report_err(local_error);
> }
> - goto out_socket;
> + goto out;
> }
>
> fd = open(device, O_RDWR);
> if (fd < 0) {
> /* Linux-only, we can use %m in printf. */
> error_report("Failed to open %s: %m", device);
> - goto out_socket;
> + goto out;
> }
>
> - ret = nbd_init(fd, sioc, &info, &local_error);
> - if (ret < 0) {
> + if (nbd_init(fd, sioc, &info, &local_error) < 0) {
> error_report_err(local_error);
> - goto out_fd;
> + goto out;
> }
>
> /* update partition table */
> @@ -311,24 +309,18 @@ static void *nbd_client_thread(void *arg)
> dup2(STDOUT_FILENO, STDERR_FILENO);
> }
>
> - ret = nbd_client(fd);
> - if (ret) {
> - goto out_fd;
> + if (nbd_client(fd) == 0) {
> + ret = EXIT_SUCCESS;
> }
> - close(fd);
> - object_unref(OBJECT(sioc));
> - g_free(info.name);
> - kill(getpid(), SIGTERM);
> - return (void *) EXIT_SUCCESS;
>
> -out_fd:
> - close(fd);
> -out_socket:
> + out:
> + if (fd >= 0) {
> + close(fd);
> + }
> object_unref(OBJECT(sioc));
> -out:
> g_free(info.name);
> kill(getpid(), SIGTERM);
> - return (void *) EXIT_FAILURE;
> + return (void *) (intptr_t) ret;
> }
> #endif /* HAVE_NBD_DEVICE */
>