Re: [PATCH] migration/savevm: release gslist after dump_vmstate_json

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

Correcting Zhang email.

On 2/19/20 10:47 AM, pannengyuan@huawei.com wrote:
> From: Pan Nengyuan <pannengyuan@huawei.com>
> 
> 'list' forgot to free at the end of dump_vmstate_json_to_file(), although it's called only once, but seems like a clean code.
> 
> Fix the leak as follow:
> Direct leak of 16 byte(s) in 1 object(s) allocated from:
>      #0 0x7fb946abd768 in __interceptor_malloc (/lib64/libasan.so.5+0xef768)
>      #1 0x7fb945eca445 in g_malloc (/lib64/libglib-2.0.so.0+0x52445)
>      #2 0x7fb945ee2066 in g_slice_alloc (/lib64/libglib-2.0.so.0+0x6a066)
>      #3 0x7fb945ee3139 in g_slist_prepend (/lib64/libglib-2.0.so.0+0x6b139)
>      #4 0x5585db591581 in object_class_get_list_tramp /mnt/sdb/qemu-new/qemu/qom/object.c:1084
>      #5 0x5585db590f66 in object_class_foreach_tramp /mnt/sdb/qemu-new/qemu/qom/object.c:1028
>      #6 0x7fb945eb35f7 in g_hash_table_foreach (/lib64/libglib-2.0.so.0+0x3b5f7)
>      #7 0x5585db59110c in object_class_foreach /mnt/sdb/qemu-new/qemu/qom/object.c:1038
>      #8 0x5585db5916b6 in object_class_get_list /mnt/sdb/qemu-new/qemu/qom/object.c:1092
>      #9 0x5585db335ca0 in dump_vmstate_json_to_file /mnt/sdb/qemu-new/qemu/migration/savevm.c:638
>      #10 0x5585daa5bcbf in main /mnt/sdb/qemu-new/qemu/vl.c:4420
>      #11 0x7fb941204812 in __libc_start_main ../csu/libc-start.c:308
>      #12 0x5585da29420d in _start (/mnt/sdb/qemu-new/qemu/build/x86_64-softmmu/qemu-system-x86_64+0x27f020d)
> 
> Indirect leak of 7472 byte(s) in 467 object(s) allocated from:
>      #0 0x7fb946abd768 in __interceptor_malloc (/lib64/libasan.so.5+0xef768)
>      #1 0x7fb945eca445 in g_malloc (/lib64/libglib-2.0.so.0+0x52445)
>      #2 0x7fb945ee2066 in g_slice_alloc (/lib64/libglib-2.0.so.0+0x6a066)
>      #3 0x7fb945ee3139 in g_slist_prepend (/lib64/libglib-2.0.so.0+0x6b139)
>      #4 0x5585db591581 in object_class_get_list_tramp /mnt/sdb/qemu-new/qemu/qom/object.c:1084
>      #5 0x5585db590f66 in object_class_foreach_tramp /mnt/sdb/qemu-new/qemu/qom/object.c:1028
>      #6 0x7fb945eb35f7 in g_hash_table_foreach (/lib64/libglib-2.0.so.0+0x3b5f7)
>      #7 0x5585db59110c in object_class_foreach /mnt/sdb/qemu-new/qemu/qom/object.c:1038
>      #8 0x5585db5916b6 in object_class_get_list /mnt/sdb/qemu-new/qemu/qom/object.c:1092
>      #9 0x5585db335ca0 in dump_vmstate_json_to_file /mnt/sdb/qemu-new/qemu/migration/savevm.c:638
>      #10 0x5585daa5bcbf in main /mnt/sdb/qemu-new/qemu/vl.c:4420
>      #11 0x7fb941204812 in __libc_start_main ../csu/libc-start.c:308
>      #12 0x5585da29420d in _start (/mnt/sdb/qemu-new/qemu/build/x86_64-softmmu/qemu-system-x86_64+0x27f020d)
> 
> Reported-by: Euler Robot <euler.robot@huawei.com>
> Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com>
> ---
>   migration/savevm.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/migration/savevm.c b/migration/savevm.c
> index f19cb9ec7a..60e6ea8a8d 100644
> --- a/migration/savevm.c
> +++ b/migration/savevm.c
> @@ -665,6 +665,7 @@ void dump_vmstate_json_to_file(FILE *out_file)
>       }
>       fprintf(out_file, "\n}\n");
>       fclose(out_file);
> +    g_slist_free(list);
>   }
>   
>   static uint32_t calculate_new_instance_id(const char *idstr)
>