Guenter Roeck reports that the new slub kunit tests added by commit
4e1c44b3db79 ("kunit, slub: add test_kfree_rcu() and
test_leak_destroy()") cause a lockup on boot on several architectures
when the kunit tests are configured to be built-in and not modules.

These tests invoke kfree_rcu() and kvfree_rcu_barrier() and boot
sequence inspection showed the runner for built-in kunit tests
kunit_run_all_tests() is called before setting system_state to
SYSTEM_RUNNING and calling rcu_end_inkernel_boot(), so this seems like a
likely cause. So while I was unable to reproduce the problem myself,
moving the call to kunit_run_all_tests() a bit later in the boot seems
to have fixed the lockup problem according to Guenter's limited testing.

No kunit tests should be broken by calling the built-in executor a bit
later, as when compiled as modules, they are still executed even later
than this.

Fixes: 4e1c44b3db79 ("kunit, slub: add test_kfree_rcu() and 
test_leak_destroy()")
Reported-by: Guenter Roeck <li...@roeck-us.net>
Closes: 
https://lore.kernel.org/all/6fcb1252-7990-4f0d-8027-5e83f0fb9...@roeck-us.net/
Cc: "Paul E. McKenney" <paul...@kernel.org>
Cc: Boqun Feng <boqun.f...@gmail.com>
Cc: Uladzislau Rezki <ure...@gmail.com>
Cc: r...@vger.kernel.org
Cc: Brendan Higgins <brendanhigg...@google.com>
Cc: David Gow <david...@google.com>
Cc: Rae Moar <rm...@google.com>
Cc: linux-kselft...@vger.kernel.org
Cc: kunit-...@googlegroups.com
Signed-off-by: Vlastimil Babka <vba...@suse.cz>
---
 init/main.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/init/main.c b/init/main.c
index 
c4778edae7972f512d5eefe8400075ac35a70d1c..7890ebb00e84b8bd7bac28923fb1fe571b3e9ee2
 100644
--- a/init/main.c
+++ b/init/main.c
@@ -1489,6 +1489,8 @@ static int __ref kernel_init(void *unused)
 
        rcu_end_inkernel_boot();
 
+       kunit_run_all_tests();
+
        do_sysctl_args();
 
        if (ramdisk_execute_command) {
@@ -1579,8 +1581,6 @@ static noinline void __init kernel_init_freeable(void)
 
        do_basic_setup();
 
-       kunit_run_all_tests();
-
        wait_for_initramfs();
        console_on_rootfs();
 

-- 
2.46.1


Reply via email to