In `test_no_sockets` we don't expect any sockets, indeed
check_no_sockets() prints an error and exits if `sockets` list is
not empty, so free_sock_stat() call is unnecessary since it would
only be called when the `sockets` list is empty.
This was discovered by a strange warning printed by gcc v11.2.1:
In file included from ../../include/linux/list.h:7,
from vsock_diag_test.c:18:
vsock_diag_test.c: In function ‘test_no_sockets’:
../../include/linux/kernel.h:35:45: error: array subscript ‘struct vsock_stat[0]’ is partly outside array bound
s of ‘struct list_head[1]’ [-Werror=array-bounds]
35 | const typeof(((type *)0)->member) * __mptr = (ptr); \
| ^~~~~~
../../include/linux/list.h:352:9: note: in expansion of macro ‘container_of’
352 | container_of(ptr, type, member)
| ^~~~~~~~~~~~
../../include/linux/list.h:393:9: note: in expansion of macro ‘list_entry’
393 | list_entry((pos)->member.next, typeof(*(pos)), member)
| ^~~~~~~~~~
../../include/linux/list.h:522:21: note: in expansion of macro ‘list_next_entry’
522 | n = list_next_entry(pos, member); \
| ^~~~~~~~~~~~~~~
vsock_diag_test.c:325:9: note: in expansion of macro ‘list_for_each_entry_safe’
325 | list_for_each_entry_safe(st, next, sockets, list) {
| ^~~~~~~~~~~~~~~~~~~~~~~~
In file included from vsock_diag_test.c:18:
vsock_diag_test.c:333:19: note: while referencing ‘sockets’
333 | LIST_HEAD(sockets);
| ^~~~~~~
../../include/linux/list.h:23:26: note: in definition of macro ‘LIST_HEAD’
23 | struct list_head name = LIST_HEAD_INIT(name)
It seems related to some compiler optimization and assumption
about the empty `sockets` list, since this warning is printed
only with -02 or -O3. Also removing `exit(1)` from
check_no_sockets() makes the warning disappear since in that
case free_sock_stat() can be reached also when the list is
not empty.
Reported-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Link: https://lore.kernel.org/r/20211014152045.173872-1-sgarzare@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
ba95a6225b