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| author | Kumar Kartikeya Dwivedi <memxor@gmail.com> | 2021-11-22 15:47:40 +0100 |
|---|---|---|
| committer | Andrii Nakryiko <andrii@kernel.org> | 2021-12-02 22:39:46 +0100 |
| commit | d9847eb8be3d895b2b5f514fdf3885d47a0b92a2 (patch) | |
| tree | 7265378e4f5c2cb960c01afc816f15de93b66d12 /lib | |
| parent | mips, bpf: Fix reference to non-existing Kconfig symbol (diff) | |
| download | linux-d9847eb8be3d895b2b5f514fdf3885d47a0b92a2.tar.xz linux-d9847eb8be3d895b2b5f514fdf3885d47a0b92a2.zip | |
bpf: Make CONFIG_DEBUG_INFO_BTF depend upon CONFIG_BPF_SYSCALL
Vinicius Costa Gomes reported [0] that build fails when
CONFIG_DEBUG_INFO_BTF is enabled and CONFIG_BPF_SYSCALL is disabled.
This leads to btf.c not being compiled, and then no symbol being present
in vmlinux for the declarations in btf.h. Since BTF is not useful
without enabling BPF subsystem, disallow this combination.
However, theoretically disabling both now could still fail, as the
symbol for kfunc_btf_id_list variables is not available. This isn't a
problem as the compiler usually optimizes the whole register/unregister
call, but at lower optimization levels it can fail the build in linking
stage.
Fix that by adding dummy variables so that modules taking address of
them still work, but the whole thing is a noop.
[0]: https://lore.kernel.org/bpf/20211110205418.332403-1-vinicius.gomes@intel.com
Fixes: 14f267d95fe4 ("bpf: btf: Introduce helpers for dynamic BTF set registration")
Reported-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20211122144742.477787-2-memxor@gmail.com
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Kconfig.debug | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 9ef7ce18b4f5..596bb5e4790c 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -316,6 +316,7 @@ config DEBUG_INFO_BTF bool "Generate BTF typeinfo" depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST + depends on BPF_SYSCALL help Generate deduplicated BTF type information from DWARF debug info. Turning this on expects presence of pahole tool, which will convert |