Subject: Re: "test_ip_fast_csum: ASSERTION FAILED at lib/checksum_kunit.c:589" at boot with CONFIG_CHECKSUM_KUNIT=y enabled on a Talos II, kernel 6.8-rc5

From: Charlie Jenkins <[email-masked]>
Date: Thu, 22 Feb 2024 23:00:46 -0800

On Fri, Feb 23, 2024 at 06:58:14AM +0000, Christophe Leroy wrote:
> 
> 
> Le 23/02/2024 à 07:12, Charlie Jenkins a écrit :
> > On Fri, Feb 23, 2024 at 05:59:07AM +0000, Christophe Leroy wrote:
> >> Hi Erhard, hi Charlie,
> >>
> >> Le 23/02/2024 à 02:26, Erhard Furtner a écrit :
> >>> Greetings!
> >>>
> >>> Looks like my Talos II (running a BE kernel+system) fails some of the kernels internal unit tests. One of the failing tests is checksum_kunit, enabled via CONFIG_CHECKSUM_KUNIT=y:
> >>>
> >>> [...]
> >>>      KTAP version 1
> >>>       # Subtest: checksum
> >>>       # module: checksum_kunit
> >>>       1..5
> >>> entry-flush: disabled on command line.
> >>>       ok 1 test_csum_fixed_random_inputs
> >>>       ok 2 test_csum_all_carry_inputs
> >>>       ok 3 test_csum_no_carry_inputs
> >>>       # test_ip_fast_csum: ASSERTION FAILED at lib/checksum_kunit.c:589
> >>>       Expected ( u64)expected == ( u64)csum_result, but
> >>>           ( u64)expected == 55939 (0xda83)
> >>>           ( u64)csum_result == 33754 (0x83da)
> >>>       not ok 4 test_ip_fast_csum
> >>>       # test_csum_ipv6_magic: ASSERTION FAILED at lib/checksum_kunit.c:617
> >>>       Expected ( u64)expected_csum_ipv6_magic[i] == ( u64)csum_ipv6_magic(saddr, daddr, len, proto, csum), but
> >>>           ( u64)expected_csum_ipv6_magic[i] == 6356 (0x18d4)
> >>>           ( u64)csum_ipv6_magic(saddr, daddr, len, proto, csum) == 43586 (0xaa42)
> >>>       not ok 5 test_csum_ipv6_magic
> >>> # checksum: pass:3 fail:2 skip:0 total:5
> >>> # Totals: pass:3 fail:2 skip:0 total:5
> >>> not ok 4 checksum
> >>> [...]
> >>>
> >>> Full dmesg + kernel .config attached.
> >>
> >> Looks like the same problem as the one I fixed with commit b38460bc463c
> >> ("kunit: Fix checksum tests on big endian CPUs")
> >>
> >> The new tests implemented through commit 6f4c45cbcb00 ("kunit: Add tests
> >> for csum_ipv6_magic and ip_fast_csum") create a lot of type issues as
> >> reported by sparse when built with C=2 (see below).
> >>
> >> Once those issues are fixed, it should work.
> >>
> >> Charlie, can you provide a fix ?
> >>
> >> Thanks,
> >> Christophe
> > 
> > The "lib: checksum: Fix issues with checksum tests" patch should fix all of these issues [1].
> > 
> > [1] https://lore.kernel.org/all/[email-masked]/T/#m189783a9b2a7d12e3c34c4a412e65408658db2c9
> 
> It doesn't fix the issues, I still get the following with your patch 1/2 
> applied:
> 
> [    6.893141] KTAP version 1
> [    6.896118] 1..1
> [    6.897764]     KTAP version 1
> [    6.900800]     # Subtest: checksum
> [    6.904518]     # module: checksum_kunit
> [    6.904601]     1..5
> [    7.139784]     ok 1 test_csum_fixed_random_inputs
> [    7.590056]     ok 2 test_csum_all_carry_inputs
> [    8.064415]     ok 3 test_csum_no_carry_inputs
> [    8.070065]     # test_ip_fast_csum: ASSERTION FAILED at 
> lib/checksum_kunit.c:589
> [    8.070065]     Expected ( u64)expected == ( u64)csum_result, but
> [    8.070065]         ( u64)expected == 55939 (0xda83)
> [    8.070065]         ( u64)csum_result == 33754 (0x83da)
> [    8.075836]     not ok 4 test_ip_fast_csum
> [    8.101039]     # test_csum_ipv6_magic: ASSERTION FAILED at 
> lib/checksum_kunit.c:617
> [    8.101039]     Expected ( u64)( __sum16)expected_csum_ipv6_magic[i] 
> == ( u64)csum_ipv6_magic(saddr, daddr, len, proto, ( __wsum)csum), but
> [    8.101039]         ( u64)( __sum16)expected_csum_ipv6_magic[i] == 
> 6356 (0x18d4)
> [    8.101039]         ( u64)csum_ipv6_magic(saddr, daddr, len, proto, ( 
> __wsum)csum) == 43586 (0xaa42)
> [    8.106446]     not ok 5 test_csum_ipv6_magic
> [    8.143829] # checksum: pass:3 fail:2 skip:0 total:5
> [    8.148334] # Totals: pass:3 fail:2 skip:0 total:5
> [    8.153173] not ok 1 checksum
> 
> All your patch does is to hide the sparse warnings. But forcing a cast 
> doesn't fix byte orders.
> 
> Please have a look at commit b38460bc463c ("kunit: Fix checksum tests on 
> big endian CPUs"), there are helpers to put checksums in the correct 
> byte order.
> 
> Christophe

Well that's what the second patch is for. Is it failing with the second
patch applied?

- Charlie