On 10/1/24 18:20, 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/
I hope you can confirm it helps, because the commit added two tests and I've
only skipped one of them, as it's the one using kfree_rcu(), which is
suspected. But the other is responsible for the (now suppressed)
kmem_cache_destroy() warning, and maybe I'm missing something and it was
actually that one causing the lockups.
Since you mentioned the boot lockups happened on some x86_64 too, do you
have a .config of the lockup case? I've tried tweaking some rcu options but
still nothing.
Attachment:
defconfig.gz
Description: application/gzip