On 10/1/24 09:20, Vlastimil Babka wrote:
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.
The test_kfree_rcu test invokes kfree_rcu() 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, skipping the test when the
slub_kunit module is built-in should avoid the issue.
An alternative fix that was moving the call to kunit_run_all_tests() a
bit later in the boot was tried, but has broken tests with functions
marked as __init due to free_initmem() already being done.
Fixes: 4e1c44b3db79 ("kunit, slub: add test_kfree_rcu() and test_leak_destroy()")
Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Closes: https://lore.kernel.org/all/6fcb1252-7990-4f0d-8027-5e83f0fb9409@xxxxxxxxxxxx/
Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxx>
Cc: Boqun Feng <boqun.feng@xxxxxxxxx>
Cc: Uladzislau Rezki <urezki@xxxxxxxxx>
Cc: rcu@xxxxxxxxxxxxxxx
Cc: Brendan Higgins <brendanhiggins@xxxxxxxxxx>
Cc: David Gow <davidgow@xxxxxxxxxx>
Cc: Rae Moar <rmoar@xxxxxxxxxx>
Cc: linux-kselftest@xxxxxxxxxxxxxxx
Cc: kunit-dev@xxxxxxxxxxxxxxxx
Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
This results in:
KTAP version 1
# Subtest: slub_test
# module: slub_kunit
1..8
# test_clobber_zone: pass:1 fail:0 skip:0 total:1
ok 1 test_clobber_zone
# test_next_pointer: pass:1 fail:0 skip:0 total:1
ok 2 test_next_pointer
# test_first_word: pass:1 fail:0 skip:0 total:1
ok 3 test_first_word
# test_clobber_50th_byte: pass:1 fail:0 skip:0 total:1
ok 4 test_clobber_50th_byte
# test_clobber_redzone_free: pass:1 fail:0 skip:0 total:1
ok 5 test_clobber_redzone_free
# test_kmalloc_redzone_access: pass:1 fail:0 skip:0 total:1
ok 6 test_kmalloc_redzone_access
# test_kfree_rcu: pass:0 fail:0 skip:1 total:1
ok 7 test_kfree_rcu # SKIP can't do kfree_rcu() when test is built-in
# test_leak_destroy: pass:1 fail:0 skip:0 total:1
ok 8 test_leak_destroy
# slub_test: pass:7 fail:0 skip:1 total:8
Tested-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Thanks,
Guenter
