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a9355b201d
[ 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:
|
||
|---|---|---|
| .. | ||
| bpftool | ||
| resolve_btfids | ||
| runqslower | ||
| .gitignore | ||
| bpf_asm.c | ||
| bpf_dbg.c | ||
| bpf_exp.l | ||
| bpf_exp.y | ||
| bpf_jit_disasm.c | ||
| Makefile | ||
| Makefile.helpers | ||