[ Upstream commit 903fad4394 ]
The .BTF_ids section is pre-filled with zeroed BTF ID entries during the
build and afterwards patched by resolve_btfids with correct values.
Since resolve_btfids always writes in host-native endianness, it relies
on libelf to do the translation when the target ELF is cross-compiled to
a different endianness (this was introduced in commit 61e8aeda93
("bpf: Fix libelf endian handling in resolv_btfids")).
Unfortunately, the translation will corrupt the flags fields of SET8
entries because these were written during vmlinux compilation and are in
the correct endianness already. This will lead to numerous selftests
failures such as:
$ sudo ./test_verifier 502 502
#502/p sleepable fentry accept FAIL
Failed to load prog 'Invalid argument'!
bpf_fentry_test1 is not sleepable
verification time 34 usec
stack depth 0
processed 0 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0
Summary: 0 PASSED, 0 SKIPPED, 1 FAILED
Since it's not possible to instruct libelf to translate just certain
values, let's manually bswap the flags (both global and entry flags) in
resolve_btfids when needed, so that libelf then translates everything
correctly.
Fixes: ef2c6f370a ("tools/resolve_btfids: Add support for 8-byte BTF sets")
Signed-off-by: Viktor Malik <vmalik@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/7b6bff690919555574ce0f13d2a5996cacf7bf69.1707223196.git.vmalik@redhat.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
b4907fb68d