On 8/19/20 2:23 AM, Jiri Olsa wrote:
The data of compressed section should be aligned to 4
(for 32bit) or 8 (for 64 bit) bytes.
The binutils ld sets sh_addralign to 1, which makes libelf
fail with misaligned section error during the update as
reported by Jesper:
FAILED elf_update(WRITE): invalid section alignment
While waiting for ld fix, we can fix compressed sections
sh_addralign value manually.
Adding warning in -vv mode when the fix is triggered:
$ ./tools/bpf/resolve_btfids/resolve_btfids -vv vmlinux
...
section(36) .comment, size 44, link 0, flags 30, type=1
section(37) .debug_aranges, size 45684, link 0, flags 800, type=1
- fixing wrong alignment sh_addralign 16, expected 8
section(38) .debug_info, size 129104957, link 0, flags 800, type=1
- fixing wrong alignment sh_addralign 1, expected 8
section(39) .debug_abbrev, size 1152583, link 0, flags 800, type=1
- fixing wrong alignment sh_addralign 1, expected 8
section(40) .debug_line, size 7374522, link 0, flags 800, type=1
- fixing wrong alignment sh_addralign 1, expected 8
section(41) .debug_frame, size 702463, link 0, flags 800, type=1
section(42) .debug_str, size 1017571, link 0, flags 830, type=1
- fixing wrong alignment sh_addralign 1, expected 8
section(43) .debug_loc, size 3019453, link 0, flags 800, type=1
- fixing wrong alignment sh_addralign 1, expected 8
section(44) .debug_ranges, size 1744583, link 0, flags 800, type=1
- fixing wrong alignment sh_addralign 16, expected 8
section(45) .symtab, size 2955888, link 46, flags 0, type=2
section(46) .strtab, size 2613072, link 0, flags 0, type=3
...
update ok for vmlinux
Another workaround is to disable compressed debug info data
CONFIG_DEBUG_INFO_COMPRESSED kernel option.
Fixes: fbbb68de80a4 ("bpf: Add resolve_btfids tool to resolve BTF IDs in ELF object")
Cc: Mark Wielaard <mjw@xxxxxxxxxx>
Cc: Nick Clifton <nickc@xxxxxxxxxx>
Reported-by: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Acked-by: Yonghong Song <yhs@xxxxxx>
