When the kernel image is finally linked, all the notes are packed into a single .notes section, but these notes may have different alignments. binutils above 2.32 adds a ".note.gnu.property" section to the compiled output, which is 4-byte aligned on 32-bit, but 8-byte aligned on 64-bit. At present, the notes generated by both the ELFNOTE macro and the VDSO linker script are 4-byte aligned. So in a 64-bit kernel, packing segments with different alignments will cause LibElf and tools like readelf to crush or to read wrong values [1][2]. This patch discards ".note.gnu.property" from vmlinux. Note that H.J. Lu has submitted a similar patch in the past[3], but it was not merged. [1] https://lore.kernel.org/bpf/57830c30-cd77-40cf-9cd1-3bb608aa602e@xxxxxxxxxxxxxxxx/ [2] https://lore.kernel.org/linux-arm-kernel/20210428172847.GC4022@xxxxxxx/ [3] https://lore.kernel.org/lkml/20180924201459.35923-1-hjl.tools@xxxxxxxxx/ Signed-off-by: Tianyi Liu <i.pear@xxxxxxxxxxx> --- include/asm-generic/vmlinux.lds.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index d1f57e4868ed..6db0f664c7d6 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -891,9 +891,13 @@ /* * Discard .note.GNU-stack, which is emitted as PROGBITS by the compiler. * Otherwise, the type of .notes section would become PROGBITS instead of NOTES. + * + * Discard .note.gnu.property, which is 8-byte aligned and emitted by the + * compiler. Otherwise, the .notes section will be 8-byte aligned and other + * notes cannot be read. */ #define NOTES \ - /DISCARD/ : { *(.note.GNU-stack) } \ + /DISCARD/ : { *(.note.GNU-stack) *(.note.gnu.property) } \ .notes : AT(ADDR(.notes) - LOAD_OFFSET) { \ BOUNDED_SECTION_BY(.note.*, _notes) \ } NOTES_HEADERS \ -- 2.39.2
