Received-SPF: pass (google.com: domain of linux-nfs+bounces-2423-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) client-ip=2604:1380:4601:e00::3;
Precedence: bulk
MIME-Version: 1.0
References: <20240307140923.16598-1-npache@redhat.com> <ZfnQoTn-xN72HppD@aion>
In-Reply-To: <ZfnQoTn-xN72HppD@aion>
From: Nico Pache <npache@redhat.com>
Date: Wed, 20 Mar 2024 14:16:03 -0600
Message-ID: <CAA1CXcBqcyXma1kGwvfAQ5T24dmuH_Or9RPrVqxDoVq=N4Se3w@mail.gmail.com>
Subject: Re: [BUG REPORT] not ok 1 Derive Kc subkey for camellia128-cts-cmac
To: Scott Mayhew <smayhew@redhat.com>
Cc: linux-nfs@vger.kernel.org, kunit-dev@googlegroups.com
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

On Tue, Mar 19, 2024 at 11:51=E2=80=AFAM Scott Mayhew <smayhew@redhat.com> =
wrote:
>
> Hi,
>
> On Thu, 07 Mar 2024, Nico Pache wrote:
>
> > Hi,
> >
> > One of the RFC 6803 key derivation kunit subtests is failing.
> >
> > cki-project data warehouse : https://datawarehouse.cki-project.org/issu=
e/2514
> >
> > Arches: X86_64, ARM64, S390x, ppc64le
> > First Appeared: ~6.8.rc2
> >
> > TRACE:
> > # Subtest: RFC 6803 key derivation
> >     # RFC 6803 key derivation: ASSERTION FAILED at net/sunrpc/auth_gss/=
gss_krb5_test.c:63
> >     Expected err =3D=3D 0, but
> >         err =3D=3D -110 (0xffffffffffffff92)
> >         not ok 1 Derive Kc subkey for camellia128-cts-cmac
> >         ok 2 Derive Ke subkey for camellia128-cts-cmac
> >         ok 3 Derive Ki subkey for camellia128-cts-cmac
> >         ok 4 Derive Kc subkey for camellia256-cts-cmac
> >         ok 5 Derive Ke subkey for camellia256-cts-cmac
> >         ok 6 Derive Ki subkey for camellia256-cts-cmac
> >     # RFC 6803 key derivation: pass:5 fail:1 skip:0 total:6
> >     not ok 1 RFC 6803 key derivation
>
> This was broken by:
> c72a870926c2 kunit: add ability to run tests after boot using debugfs
>
> __kunit_test_suites_init() runs any time a kernel module is loaded, via
> the "kunit_mod_nb" notifier_block... even if the kernel module has no
> kunit tests.  But now __kunit_test_suites_init() also locks a mutex,
> which is a problem if a kunit test itself needs to load a kernel module
> (which the gss_krb5_test module does).
>
> This fixes it for me:
>
> ---8<---
> diff --git a/lib/kunit/test.c b/lib/kunit/test.c
> index 088489856db8..18af9453632b 100644
> --- a/lib/kunit/test.c
> +++ b/lib/kunit/test.c
> @@ -707,6 +707,9 @@ int __kunit_test_suites_init(struct kunit_suite * con=
st * const suites, int num_
>  {
>         unsigned int i;
>
> +       if (num_suites =3D=3D 0)
> +               return 0;
> +
>         if (!kunit_enabled() && num_suites > 0) {
>                 pr_info("kunit: disabled\n");
>                 return 0;
> ---8<---
>
Nice find! Would you mind posting a patch?

-- Nico

> More detail below:
>
> Here's the modprobe command where I loaded the gss_krb5_test module.  Thi=
s
> process has the "kunit_run_lock" mutex locked:
>
> PID: 1468     TASK: ffff9aed0ac20000  CPU: 0    COMMAND: "modprobe"
>  #0 [ffffba974196f6f8] __schedule at ffffffff83fd85f5
>  #1 [ffffba974196f7b0] schedule at ffffffff83fd9672
>  #2 [ffffba974196f7c8] schedule_timeout at ffffffff83fe0308
>  #3 [ffffba974196f818] wait_for_completion_timeout at ffffffff83fda3d4
>  #4 [ffffba974196f878] kunit_try_catch_run at ffffffffc0d5e851 [kunit]
>  #5 [ffffba974196f8c8] kunit_run_tests at ffffffffc0d5c0ea [kunit]
>  #6 [ffffba974196fb78] __kunit_test_suites_init at ffffffffc0d5c9af [kuni=
t]
>  #7 [ffffba974196fb98] kunit_module_notify at ffffffffc0d5ba4b [kunit]
>  #8 [ffffba974196fc08] notifier_call_chain at ffffffff8314647a
>  #9 [ffffba974196fc40] blocking_notifier_call_chain_robust at ffffffff831=
46565
> #10 [ffffba974196fc88] load_module at ffffffff831e1935
> #11 [ffffba974196fde8] __do_sys_init_module at ffffffff831e1fba
> #12 [ffffba974196fec0] do_syscall_64 at ffffffff83fc3461
> #13 [ffffba974196fee8] do_user_addr_fault at ffffffff830979df
> #14 [ffffba974196ff28] exc_page_fault at ffffffff83fc9c7f
> #15 [ffffba974196ff50] entry_SYSCALL_64_after_hwframe at ffffffff840000ea
>     RIP: 00007ff1f272b4ae  RSP: 00007ffd45db8f68  RFLAGS: 00000246
>     RAX: ffffffffffffffda  RBX: 000055bf4c0c4b20  RCX: 00007ff1f272b4ae
>     RDX: 000055bf4b204e79  RSI: 0000000000099691  RDI: 000055bf4cbfd130
>     RBP: 00007ffd45db9020   R8: 000055bf4c0c4010   R9: 0000000000000007
>     R10: 0000000000000001  R11: 0000000000000246  R12: 000055bf4b204e79
>     R13: 0000000000040000  R14: 000055bf4c0c4c50  R15: 000055bf4c0c4390
>     ORIG_RAX: 00000000000000af  CS: 0033  SS: 002b
>
> Here's the kunit test case running.  It's trying to allocate "cmac(camell=
ia)"
> via crypto_alloc_shash():
>
> PID: 1508     TASK: ffff9aed155d0000  CPU: 1    COMMAND: "kunit_try_catch=
"
>  #0 [ffffba974194fba0] __schedule at ffffffff83fd85f5
>  #1 [ffffba974194fc58] schedule at ffffffff83fd9672
>  #2 [ffffba974194fc70] schedule_timeout at ffffffff83fe0308
>  #3 [ffffba974194fcc0] wait_for_completion_killable_timeout at ffffffff83=
fda708
>  #4 [ffffba974194fd20] crypto_larval_wait at ffffffff83747fb4
>  #5 [ffffba974194fd38] crypto_alg_mod_lookup at ffffffff83748252
>  #6 [ffffba974194fd70] crypto_alloc_tfm_node at ffffffff83748492
>  #7 [ffffba974194fdb0] krb5_kdf_feedback_cmac at ffffffffc0d76bb2 [rpcsec=
_gss_krb5]
>  #8 [ffffba974194fe30] kdf_case at ffffffffc0d800a8 [gss_krb5_test]
>  #9 [ffffba974194fe80] kunit_try_run_case at ffffffffc0d5bb54 [kunit]
> #10 [ffffba974194fee8] kunit_generic_run_threadfn_adapter at ffffffffc0d5=
e797 [kunit]
> #11 [ffffba974194fef8] kthread at ffffffff8313eda5
> #12 [ffffba974194ff30] ret_from_fork at ffffffff830414a1
> #13 [ffffba974194ff50] ret_from_fork_asm at ffffffff830039ab
>
> Here the crypto manager is trying to modprobe the camellia kernel module =
via a
> usermodehelper call:
>
> PID: 1511     TASK: ffff9aed04630000  CPU: 3    COMMAND: "cryptomgr_probe=
"
>  #0 [ffffba974195fb88] __schedule at ffffffff83fd85f5
>  #1 [ffffba974195fc40] schedule at ffffffff83fd9672
>  #2 [ffffba974195fc58] schedule_timeout at ffffffff83fe03c1
>  #3 [ffffba974195fca8] wait_for_completion_state at ffffffff83fdb06d
>  #4 [ffffba974195fd18] call_usermodehelper_exec at ffffffff83130313
>  #5 [ffffba974195fd68] __request_module at ffffffff831e325d
>  #6 [ffffba974195fe28] crypto_alg_mod_lookup at ffffffff83748220
>  #7 [ffffba974195fe60] crypto_grab_spawn at ffffffff83749ff7
>  #8 [ffffba974195fe98] cmac_create at ffffffff8375c2f0
>  #9 [ffffba974195fed8] cryptomgr_probe at ffffffff83754a93
> #10 [ffffba974195fef8] kthread at ffffffff8313eda5
> #11 [ffffba974195ff30] ret_from_fork at ffffffff830414a1
> #12 [ffffba974195ff50] ret_from_fork_asm at ffffffff830039ab
>
> And here's the resulting modprobe command, which is stuck waiting on the
> "kunit_run_lock" mutex:
>
> PID: 1512     TASK: ffff9aed143fafc0  CPU: 2    COMMAND: "modprobe"
>  #0 [ffffba9741957990] __schedule at ffffffff83fd85f5
>  #1 [ffffba9741957a48] schedule at ffffffff83fd9672
>  #2 [ffffba9741957a60] schedule_preempt_disabled at ffffffff83fd9cb5
>  #3 [ffffba9741957a68] __mutex_lock.constprop.0 at ffffffff83fdc57a
>  #4 [ffffba9741957ae8] __kunit_test_suites_init at ffffffffc0d5c95a [kuni=
t]
>  #5 [ffffba9741957b08] kunit_module_notify at ffffffffc0d5ba4b [kunit]
>  #6 [ffffba9741957b78] notifier_call_chain at ffffffff8314647a
>  #7 [ffffba9741957bb0] blocking_notifier_call_chain_robust at ffffffff831=
46565
>  #8 [ffffba9741957bf8] load_module at ffffffff831e1935
>  #9 [ffffba9741957d58] __do_sys_init_module at ffffffff831e1fba
> #10 [ffffba9741957e30] do_syscall_64 at ffffffff83fc3461
> #11 [ffffba9741957e48] __vm_munmap at ffffffff833bcdeb
> #12 [ffffba9741957ee8] do_syscall_64 at ffffffff83fc3470
> #13 [ffffba9741957f50] entry_SYSCALL_64_after_hwframe at ffffffff840000ea
>     RIP: 00007f8ba092b4ae  RSP: 00007ffc771e0378  RFLAGS: 00000246
>     RAX: ffffffffffffffda  RBX: 00005572137e6e40  RCX: 00007f8ba092b4ae
>     RDX: 0000557211c4de79  RSI: 0000000000080451  RDI: 00007f8b9ff90010
>     RBP: 00007ffc771e0430   R8: 00005572137e6010   R9: 0000000000000007
>     R10: 0000000000000001  R11: 0000000000000246  R12: 0000557211c4de79
>     R13: 0000000000040000  R14: 00005572137e73b0  R15: 00005572137e6400
>     ORIG_RAX: 00000000000000af  CS: 0033  SS: 002b
>
> The camellia module doesn't even have any kunit tests, so __kunit_test_su=
ites_init()
> is waiting to lock the "kunit_run_lock" mutex for nothing:
>
> crash> module -o | grep num_kunit
>   [0x478] int num_kunit_init_suites;
>   [0x488] int num_kunit_suites;
> crash> mod | grep camellia
> ffffffffc0da15c0  camellia_x86_64                ffffffffc0d99000    5734=
4  (not loaded)  [CONFIG_KALLSYMS]
> crash> px 0xffffffffc0da15c0+0x478
> $1 =3D 0xffffffffc0da1a38
> crash> px 0xffffffffc0da15c0+0x488
> $2 =3D 0xffffffffc0da1a48
> crash> rd 0xffffffffc0da1a38
> ffffffffc0da1a38:  0000000000000000                    ........
> crash> rd 0xffffffffc0da1a48
> ffffffffc0da1a48:  0000000000000000                    ........
>
> -Scott
> > --
> > 2.44.0
> >
> >
>