ACK: [SRU][J][PATCH 0/1] Fix bpf selftests build failure after v5.15.139 update

[Tim Gardner]

On 2/26/24 3:01 AM, Roxana Nicolescu wrote:
> BugLink: https://bugs.launchpad.net/bugs/2054567
> 
> SRU justification
> 
> [Impact]
> Upstream v5.15.139 (#lp2049432) brought commit
> "selftests/bpf: Test tail call counting with bpf2bpf and data on stack"
> that affects one of the bpf kselftests (tailcall_bpf2bpf6).
> because LIBBPF_OPTS macro does not exists, it does not compile. Error below.
> 
> [Fix]
> Initially, I thought cherry-picking commit
> "libbpf: Rename DECLARE_LIBBPF_OPTS into LIBBPF_OPTS" would be the best,
> but upstream stable just reverted the commit that broke it. Hence the fix
> consists of cherry-picking this commit from stable upstream 5.15.49:
> Commit 62900d358c48 (Revert "selftests/bpf: Test tail call counting with bpf2bpf and data on stack")
> 
> [Test]
> This should be solved soon, but compileselftests debian rule does not
> compile bpf selftests.
> I tested it by using our regression testing tooling, but same results can
> be achieved by running:
> $ make -C linux/tools/testing/selftests TARGETS=bpf SKIP_TARGETS= clean all KDIR=/usr/src/linux-headers-5.15.0-<verson>-generic
> from the linux tree directory
> 
> Without the fix, it fails to compile:
>    /root/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests/bpf/prog_tests/tailcalls.c: In function ‘test_tailcall_bpf2bpf_6’:
>    /root/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests/bpf/prog_tests/tailcalls.c:822:9: warning: implicit declaration of function ‘LIBBPF_OPTS’; did you mean ‘LIBBPF_API’? [-Wimplicit-function-declaration]
>      822 | LIBBPF_OPTS(bpf_test_run_opts, topts,
>          | ^~~~~~~~~~~
>          | LIBBPF_API
>    /root/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests/bpf/prog_tests/tailcalls.c:822:21: error: ‘bpf_test_run_opts’ undeclared (first use in this function)
>      822 | LIBBPF_OPTS(bpf_test_run_opts, topts,
>          | ^~~~~~~~~~~~~~~~~
>    /root/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests/bpf/prog_tests/tailcalls.c:822:21: note: each undeclared identifier is reported only once for each function it appears in
>    /root/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests/bpf/prog_tests/tailcalls.c:822:40: error: ‘topts’ undeclared (first use in this function)
>      822 | LIBBPF_OPTS(bpf_test_run_opts, topts,
>          | ^~~~~
>    /root/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests/bpf/prog_tests/tailcalls.c:823:17: error: expected expression before ‘.’ token
>      823 | .data_in = &pkt_v4,
>          | ^
>    make[1]: *** [Makefile:471: /root/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests/bpf/tailcalls.test.o] Error 1
>    make: *** [Makefile:172: all] Error 2
> 
> With the fix, it compiles.
> 
> [Regression potential]
> The only place this is being used is selftests, so the risk is very low.
> 
> Samasth Norway Ananda (1):
>    Revert "selftests/bpf: Test tail call counting with bpf2bpf and data
>      on stack"
> 
>   .../selftests/bpf/prog_tests/tailcalls.c      | 55 -------------------
>   .../selftests/bpf/progs/tailcall_bpf2bpf6.c   | 42 --------------
>   2 files changed, 97 deletions(-)
>   delete mode 100644 tools/testing/selftests/bpf/progs/tailcall_bpf2bpf6.c
> 
Acked-by: Tim Gardner <tim.gardner at canonical.com>
-- 
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Tim Gardner
Canonical, Inc