[PATCH 2/2] qemuBuildInterfaceConnect: Initialize @tapfd array

[Michal Prívozník]

On 6/13/22 16:04, Peter Krempa wrote:
> On Mon, Jun 13, 2022 at 15:18:14 +0200, Michal Privoznik wrote:
>> When creating a TAP interface we can end up with multiple FDs,
>> each representing one queue. However, these FDs must be
>> relabelled as they are then passed to QEMU. In case of
>> qemuBuildInterfaceConnect() we allocate the array for the FDs and
>> then let function corresponding to the <interface/> type to fill
>> the array with FDs. When any of the functions meets an error,
>> it's also responsible for closing previously opened FDs. However,
>> the functions take a shortcut: iterate through each member of the
>> array and close it (if it's non-negative). This assumes that the
>> array is initialized to negative values, which use to be the case
>> before rewrite in v8.4.0-rc1~170 but after it it's no longer the
>> case. Subsequently, "random" FDs are closed (okay, not that
>> random since the array is allocated via g_new0(), but hey - FD 0
>> is still valid FD and might be valuable, actually).
>>
>> Fixes: 7a38d3946bc1a7ef0206f36dfe3dbf422fb8d578
>> Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
>> ---
>>  src/qemu/qemu_command.c | 2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
>> index be20053c0d..ecfe6020f3 100644
>> --- a/src/qemu/qemu_command.c
>> +++ b/src/qemu/qemu_command.c
>> @@ -8736,6 +8736,8 @@ qemuBuildInterfaceConnect(virDomainObj *vm,
>>      size_t tapfdSize = net->driver.virtio.queues;
>>      g_autofree int *tapfd = g_new0(int, tapfdSize + 1);
>>  
>> +    memset(tapfd, -1, (tapfdSize + 1) * sizeof(*tapfd));
>> +
> 
> Reviewed-by: Peter Krempa <pkrempa at redhat.com>
> 
> but I'm adding to my todo list to fix the offending functions :)
> 

Yeah, that might be worth fixing. Pushed thanks.

Michal