* Re: [tip:sched/core 35/37] ld.lld: error: relocation refers to a symbol in a discarded section: __UNIQUE_ID_addressable_overflowuid_553
2026-10-18 7:46 [tip:sched/core 35/37] ld.lld: error: relocation refers to a symbol in a discarded section: __UNIQUE_ID_addressable_overflowuid_553 kernel test robot
@ 2026-10-19 4:00 ` Jemmy Wong
0 siblings, 0 replies; 2+ messages in thread
From: Jemmy Wong @ 2026-10-19 4:00 UTC (permalink / raw)
To: kernel test robot
Cc: Jemmy Wong, llvm, oe-kbuild-all, linux-kernel, x86,
Peter Zijlstra
> On Oct 18, 2026, at 3:46 PM, kernel test robot <lkp@intel.com> wrote:
>
> <Mail Attachment>
Hi,
I reproduced discarded-section relocation errors on tip's sched/core
branch using the reported configuration, adjusted by olddefconfig:
- fcceb7da9465 ("sched/cache: Avoid publishing partial LLC utilization")
- Its parent, 96a494c9cfd8 ("sched/cputime: Don't account idle time twice after dyntick-idle")
- The earlier ancestor 840e23085b03 ("Merge branch 'tip/sched/urgent'")
ALl were tested with Clang/LLD with 23.1.3. It fails similarly.
All tests used separate build directories on macOS, with a host-only
gen_init_cpio compatibility workaround and no kernel source changes.
The generated ELF32 `vmlinux.o` files contain:
fcceb7da9465: 21,371,209 symbols
96a494c9cfd8: 21,370,053 symbols
840e23085b03: 21,370,091 symbols
These exceed the 24-bit symbol-index range of ELF32 relocations. In the
840e23085b03 build, I inspected the relocation for the basic_stm_init
initcall:
Encoded symbol index: 1,427,711 -> unrelated .L0 label
Encoded index plus 2^24: 18,204,927 -> basic_stm_init
This demonstrates symbol-index wrap in the local build, explains
the references to unrelated symbols and suggests a toolchain issue
requiring a fix in ELF32 relocation handling.
The local failure occurs without my scheduler patch.
Thanks,
Jemmy
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