kunit: Fix missed memory release in kunit_free_suite_set()

kunit: Fix missed memory release in kunit_free_suite_set()

[ Upstream commit a6074cf0126b0bee51ab77a15930dc24a4d5db90 ]

modprobe cpumask_kunit and rmmod cpumask_kunit, kmemleak detect
a suspected memory leak as below.

If kunit_filter_suites() in kunit_module_init() succeeds, the
suite_set.start will not be NULL and the kunit_free_suite_set() in
kunit_module_exit() should free all the memory which has not
been freed. However the test_cases in suites is left out.

unreferenced object 0xffff54ac47e83200 (size 512):
  comm "modprobe", pid 592, jiffies 4294913238 (age 1367.612s)
  hex dump (first 32 bytes):
    84 13 1a f0 d3 b6 ff ff 30 68 1a f0 d3 b6 ff ff  ........0h......
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<000000008dec63a2>] slab_post_alloc_hook+0xb8/0x368
    [<00000000ec280d8e>] __kmem_cache_alloc_node+0x174/0x290
    [<00000000896c7740>] __kmalloc+0x60/0x2c0
    [<000000007a50fa06>] kunit_filter_suites+0x254/0x5b8
    [<0000000078cc98e2>] kunit_module_notify+0xf4/0x240
    [<0000000033cea952>] notifier_call_chain+0x98/0x17c
    [<00000000973d05cc>] notifier_call_chain_robust+0x4c/0xa4
    [<000000005f95895f>] blocking_notifier_call_chain_robust+0x4c/0x74
    [<0000000048e36fa7>] load_module+0x1a2c/0x1c40
    [<0000000004eb8a91>] init_module_from_file+0x94/0xcc
    [<0000000037dbba28>] idempotent_init_module+0x184/0x278
    [<00000000161b75cb>] __arm64_sys_finit_module+0x68/0xa8
    [<000000006dc1669b>] invoke_syscall+0x44/0x100
    [<00000000fa87e304>] el0_svc_common.constprop.1+0x68/0xe0
    [<000000009d8ad866>] do_el0_svc+0x1c/0x28
    [<000000005b83c607>] el0_svc+0x3c/0xc4

Fixes: a127b154a8f2 ("kunit: tool: allow filtering test cases via glob")
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Reviewed-by: Rae Moar <rmoar@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>