mbox series

[bpf-next,v4,0/2] BPF static linker: fix linking duplicate extern functions

Message ID 20241002-libbpf-dup-extern-funcs-v4-0-560eb460ff90@hack3r.moe (mailing list archive)
Headers show
Series BPF static linker: fix linking duplicate extern functions | expand

Message

Eric Long via B4 Relay Oct. 2, 2024, 6:25 a.m. UTC
Currently, if `bpftool gen object` tries to link two objects that
contains the same extern function prototype, libbpf will try to get
their (non-existent) size by calling bpf__resolve_size like extern
variables and fail with:

	libbpf: global 'whatever': failed to resolve size of underlying type: -22

This should not be the case, and this series adds conditions to update
size only when the BTF kind is not function.

Fixes: a46349227cd8 ("libbpf: Add linker extern resolution support for functions and global variables")
Signed-off-by: Eric Long <i@hack3r.moe>
---
Changes in v4:
- Remove redundant FUNC_PROTO check.
- Merge tests into linked_funcs.
- Link to v3: https://lore.kernel.org/r/20241001-libbpf-dup-extern-funcs-v3-0-42f7774efbf3@hack3r.moe

Changes in v3:
- Simplifiy changes and shorten subjects, according to reviews.
- Remove unused includes in selftests.
- Link to v2: https://lore.kernel.org/r/20240929-libbpf-dup-extern-funcs-v2-0-0cc81de3f79f@hack3r.moe

Changes in v2:
- Fix compile errors. Oops!
- Link to v1: https://lore.kernel.org/r/20240929-libbpf-dup-extern-funcs-v1-0-df15fbd6525b@hack3r.moe

---
Eric Long (2):
      libbpf: do not resolve size on duplicate FUNCs
      selftests/bpf: test linking with duplicate extern functions

 tools/lib/bpf/linker.c                            | 4 ++++
 tools/testing/selftests/bpf/progs/linked_funcs1.c | 8 ++++++++
 tools/testing/selftests/bpf/progs/linked_funcs2.c | 8 ++++++++
 3 files changed, 20 insertions(+)
---
base-commit: 93eeaab4563cc7fc0309bc1c4d301139762bbd60
change-id: 20240929-libbpf-dup-extern-funcs-871f4bad2122

Best regards,

Comments

patchwork-bot+netdevbpf@kernel.org Oct. 8, 2024, 3:30 a.m. UTC | #1
Hello:

This series was applied to bpf/bpf-next.git (master)
by Andrii Nakryiko <andrii@kernel.org>:

On Wed, 02 Oct 2024 14:25:05 +0800 you wrote:
> Currently, if `bpftool gen object` tries to link two objects that
> contains the same extern function prototype, libbpf will try to get
> their (non-existent) size by calling bpf__resolve_size like extern
> variables and fail with:
> 
> 	libbpf: global 'whatever': failed to resolve size of underlying type: -22
> 
> [...]

Here is the summary with links:
  - [bpf-next,v4,1/2] libbpf: do not resolve size on duplicate FUNCs
    https://git.kernel.org/bpf/bpf-next/c/4b146e95da87
  - [bpf-next,v4,2/2] selftests/bpf: test linking with duplicate extern functions
    https://git.kernel.org/bpf/bpf-next/c/3c591de28543

You are awesome, thank you!