[LTP] [PATCH] accept02: Join the multicast group on lo

[Martin Doucha]

Hi,
I've tested the patch on affected kernel v4.4 and the bug is still 
reproducible. Let's merge it.

Reviewed-by: Martin Doucha <mdoucha@suse.cz>
Tested-by: Martin Doucha <mdoucha@suse.cz>


On 9/28/26 23:27, Anders Roxell wrote:
> The test joins the multicast group with interface 0. Then the kernel
> needs a route to 224.0.0.0 to find a device. When we only have lo,
> like in a QEMU guest with no network, there is no such route and the
> test breaks:
> 
>    accept02.c:52: TBROK: setsockopt(3, 0, 42, ...) failed: ENODEV (19)
> 
> All traffic in the test goes over 127.0.0.1, so join the group on lo.
> 
> Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
> ---
>   testcases/kernel/syscalls/accept/accept02.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/testcases/kernel/syscalls/accept/accept02.c b/testcases/kernel/syscalls/accept/accept02.c
> index 17056625e933..09a1c35e2591 100644
> --- a/testcases/kernel/syscalls/accept/accept02.c
> +++ b/testcases/kernel/syscalls/accept/accept02.c
> @@ -22,6 +22,7 @@
>   #include <errno.h>
>   #include <sys/socket.h>
>   #include "tst_test.h"
> +#include "tst_netdevice.h"
>   #include "tst_safe_net.h"
>   #include "tst_safe_pthread.h"
>   
> @@ -112,7 +113,7 @@ static void setup(void)
>   	client_addr = tst_alloc(sizeof(*client_addr));
>   	mc_group = tst_alloc(sizeof(*mc_group));
>   
> -	mc_group->gr_interface = 0;
> +	mc_group->gr_interface = NETDEV_INDEX_BY_NAME("lo");
>   	mc_group_addr = (struct sockaddr_in *) &mc_group->gr_group;
>   	mc_group_addr->sin_family = AF_INET;
>   	inet_aton(MULTICASTIP, &mc_group_addr->sin_addr);


-- 
Martin Doucha   mdoucha@suse.cz
SW Quality Engineer
SUSE LINUX, s.r.o.
CORSO IIa
Krizikova 148/34
186 00 Prague 8
Czech Republic