kernel_optimize_test/tools
Tony Ambardar a9355b201d bpf: Fix libelf endian handling in resolv_btfids
[ Upstream commit 61e8aeda9398925f8c6fc290585bdd9727d154c4 ]

The vmlinux ".BTF_ids" ELF section is declared in btf_ids.h to hold a list
of zero-filled BTF IDs, which is then patched at link-time with correct
values by resolv_btfids. The section is flagged as "allocable" to preclude
compression, but notably the section contents (BTF IDs) are untyped.

When patching the BTF IDs, resolve_btfids writes in host-native endianness
and relies on libelf for any required translation on reading and updating
vmlinux. However, since the type of the .BTF_ids section content defaults
to ELF_T_BYTE (i.e. unsigned char), no translation occurs. This results in
incorrect patched values when cross-compiling to non-native endianness,
and can manifest as kernel Oops and test failures which are difficult to
troubleshoot [1].

Explicitly set the type of patched data to ELF_T_WORD, the architecture-
neutral ELF type corresponding to the u32 BTF IDs. This enables libelf to
transparently perform any needed endian conversions.

Fixes: fbbb68de80 ("bpf: Add resolve_btfids tool to resolve BTF IDs in ELF object")
Signed-off-by: Tony Ambardar <Tony.Ambardar@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Frank Eigler <fche@redhat.com>
Cc: Mark Wielaard <mark@klomp.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/CAPGftE_eY-Zdi3wBcgDfkz_iOr1KF10n=9mJHm1_a_PykcsoeA@mail.gmail.com [1]
Link: https://lore.kernel.org/bpf/20210618061404.818569-1-Tony.Ambardar@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14 16:56:23 +02:00
..
accounting
arch ia64: tools: remove duplicate definition of ia64_mf() on ia64 2021-04-28 13:40:02 +02:00
bootconfig tools/bootconfig: Fix error return code in apply_xbc() 2021-06-16 12:01:45 +02:00
bpf bpf: Fix libelf endian handling in resolv_btfids 2021-07-14 16:56:23 +02:00
build tools: Factor HOSTCC, HOSTLD, HOSTAR definitions 2021-01-30 13:55:19 +01:00
cgroup tools/cgroup/slabinfo.py: updated to work on current kernel 2021-05-07 11:04:31 +02:00
debugging
edid
firewire
firmware
gpio tools: gpio: fix %llu warning in gpio-watch.c 2021-01-27 11:55:20 +01:00
hv
iio
include tools headers UAPI: Sync linux/in.h copy with the kernel sources 2021-06-23 14:42:54 +02:00
io_uring
kvm/kvm_stat tools/kvm_stat: Add restart delay 2021-04-16 11:43:20 +02:00
laptop
leds
lib libbpf: Fixes incorrect rx_ring_setup_done 2021-06-23 14:42:41 +02:00
memory-model
objtool static_call: Allow module use without exposing static_call_key 2021-03-30 14:31:53 +02:00
pci
pcmcia
perf perf beauty: Update copy of linux/socket.h with the kernel sources 2021-06-23 14:42:54 +02:00
power tweewide: Fix most Shebang lines 2021-05-22 11:40:55 +02:00
scripts tools: Factor HOSTCC, HOSTLD, HOSTAR definitions 2021-01-30 13:55:19 +01:00
spi
testing selftests/bpf: Whitelist test_progs.h from .gitignore 2021-07-14 16:56:23 +02:00
thermal/tmon
time
usb
virtio
vm
wmi
Makefile