On 10/22/25 8:33 PM, Jiayuan Chen wrote:
October 22, 2025 at 23:33, "Yonghong Song" <[email protected]
mailto:[email protected]?to=%22Yonghong%20Song%22%20%3Cyonghong.song%40linux.dev%3E >
wrote:
On 10/22/25 12:18 AM, Jiayuan Chen wrote:
When compiling the BPF selftests with Clang versions that do not support
If you are really using llvm18, then I found there are some other
build failures as well, e.g.,
Yes i'm using llvm18
/home/yhs/work/bpf-next/tools/testing/selftests/bpf/bpf_arena_common.h:47:15:
error: conflicting types for 'bpf_arena_alloc_pages'
47 | void __arena* bpf_arena_alloc_pages(void *map, void __arena *addr, __u32
page_cnt,
| ^
/home/yhs/work/bpf-next/tools/testing/selftests/bpf/tools/include/vmlinux.h:160636:48:
note: previous declaration is here
160636 | extern void __attribute__((address_space(1)))
*bpf_arena_alloc_pages(void *p__map, void __attribute__((address_space(1)))
*addr__ign, u32 page_cnt, int node_id, u64 flags) __weak __ksym;
| ^
I hadn't encountered this error before, but it started appearing after I
upgraded LLVM to version 20.
$ make V=1
/home/chenjiayuan/code/upstream/bpf-next/tools/testing/selftests/bpf/tools/sbin/bpftool
btf dump file /home/chenjiayuan/code/upstream/bpf-next/vmlinux format c >
/home/chenjiayuan/code/upstream/bpf-next/tools/testing/selftests/bpf/tools/include/.vmlinux.h.tmp
cmp -s
/home/chenjiayuan/code/upstream/bpf-next/tools/testing/selftests/bpf/tools/include/.vmlinux.h.tmp
/home/chenjiayuan/code/upstream/bpf-next/tools/testing/selftests/bpf/tools/include/vmlinux.h
|| mv
/home/chenjiayuan/code/upstream/bpf-next/tools/testing/selftests/bpf/tools/include/.vmlinux.h.tmp
/home/chenjiayuan/code/upstream/bpf-next/tools/testing/selftests/bpf/tools/include/vmlinux.h
clang -g -Wall -Werror -D__TARGET_ARCH_x86 -mlittle-endian
-I/home/chenjiayuan/code/upstream/bpf-next/tools/testing/selftests/bpf/tools/include
-I/home/chenjiayuan/code/upstream/bpf-next/tools/testing/selftests/bpf
-I/home/chenjiayuan/code/upstream/bpf-next/tools/include/uapi
-I/home/chenjiayuan/code/upstream/bpf-next/tools/testing/selftests/usr/include
-std=gnu11 -fno-strict-aliasing -Wno-compare-distinct-pointer-types -idirafter
/usr/lib/llvm-20/lib/clang/20/include -idirafter /usr/local/include -idirafter
/usr/include/x86_64-linux-gnu -idirafter /usr/include -DENABLE_ATOMICS_TESTS
-O2 --target=bpfel -c progs/stream.c -mcpu=v3 -o
/home/chenjiayuan/code/upstream/bpf-next/tools/testing/selftests/bpf/stream.bpf.o
In file included from progs/stream.c:8:
/home/chenjiayuan/code/upstream/bpf-next/tools/testing/selftests/bpf/bpf_arena_common.h:47:15:
error: conflicting types for 'bpf_arena_alloc_pages'
47 | void __arena* bpf_arena_alloc_pages(void *map, void __arena *addr,
__u32 page_cnt,
| ^
/home/chenjiayuan/code/upstream/bpf-next/tools/testing/selftests/bpf/tools/include/vmlinux.h:152158:14:
note: previous declaration is here
152158 | extern void *bpf_arena_alloc_pages(void *p__map, void *addr__ign,
u32 page_cnt, int node_id, u64 flags) __weak __ksym;
| ^
In file included from progs/stream.c:8:
/home/chenjiayuan/code/upstream/bpf-next/tools/testing/selftests/bpf/bpf_arena_common.h:49:5:
error: conflicting types for 'bpf_arena_reserve_pages'
49 | int bpf_arena_reserve_pages(void *map, void __arena *addr, __u32
page_cnt) __ksym __weak;
| ^
/home/chenjiayuan/code/upstream/bpf-next/tools/testing/selftests/bpf/tools/include/vmlinux.h:152160:12:
note: previous declaration is here
152160 | extern int bpf_arena_reserve_pages(void *p__map, void *ptr__ign, u32
page_cnt) __weak __ksym;
| ^
In file included from progs/stream.c:8:
/home/chenjiayuan/code/upstream/bpf-next/tools/testing/selftests/bpf/bpf_arena_common.h:50:6:
error: conflicting types for 'bpf_arena_free_pages'
50 | void bpf_arena_free_pages(void *map, void __arena *ptr, __u32
page_cnt) __ksym __weak;
| ^
/home/chenjiayuan/code/upstream/bpf-next/tools/testing/selftests/bpf/tools/include/vmlinux.h:152159:13:
note: previous declaration is here
152159 | extern void bpf_arena_free_pages(void *p__map, void *ptr__ign, u32
page_cnt) __weak __ksym;
| ^
3 errors generated.
make: *** [Makefile:761:
/home/chenjiayuan/code/upstream/bpf-next/tools/testing/selftests/bpf/stream.bpf.o]
Error 1
$ clang --version
Ubuntu clang version 20.1.8
(++20250804090239+87f0227cb601-1~exp1~20250804210352.139)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/lib/llvm-20/bin
$ pahole --version
v1.29
Please try pahole version 1.30.
I updated LLVM via https://apt.llvm.org/. Could this be caused by some binaries
or libraries still using LLVM 18?
