diff mbox series

[bpf,v3,2/2] bpf: Fix BTF_ID symbol generation collision in tools/

Message ID 20230915-bpf_collision-v3-2-263fc519c21f@google.com (mailing list archive)
State Accepted
Commit c0bb9fb0e52a64601d38b3739b729d9138d4c8a1
Delegated to: BPF
Headers show
Series link to v1: https://lore.kernel.org/bpf/20230915103228.1196234-1-jolsa@kernel.org/ | expand

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netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for bpf
netdev/fixes_present fail Series targets non-next tree, but doesn't contain any Fixes tags
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 9 this patch: 9
netdev/cc_maintainers success CCed 2 of 2 maintainers
netdev/build_clang success Errors and warnings before: 9 this patch: 9
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netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
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netdev/checkpatch warning WARNING: Co-developed-by: must be immediately followed by Signed-off-by: WARNING: Non-standard signature: Debugged-by:
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netdev/source_inline success Was 0 now: 0
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bpf/vmtest-bpf-VM_Test-11 fail Logs for test_progs on s390x with gcc

Commit Message

Nick Desaulniers Sept. 15, 2023, 5:34 p.m. UTC 
Marcus and Satya reported an issue where BTF_ID macro generates same
symbol in separate objects and that breaks final vmlinux link.

  ld.lld: error: ld-temp.o <inline asm>:14577:1: symbol
  '__BTF_ID__struct__cgroup__624' is already defined

This can be triggered under specific configs when __COUNTER__ happens to
be the same for the same symbol in two different translation units,
which is already quite unlikely to happen.

Add __LINE__ number suffix to make BTF_ID symbol more unique, which is
not a complete fix, but it would help for now and meanwhile we can work
on better solution as suggested by Andrii.

Cc: stable@vger.kernel.org
Reported-by: Satya Durga Srinivasu Prabhala <quic_satyap@quicinc.com>
Reported-by: Marcus Seyfarth <m.seyfarth@gmail.com>
Closes: https://github.com/ClangBuiltLinux/linux/issues/1913
Debugged-by: Nathan Chancellor <nathan@kernel.org>
Co-developed-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/CAEf4Bzb5KQ2_LmhN769ifMeSJaWfebccUasQOfQKaOd0nQ51tw@mail.gmail.com/
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
---
 tools/include/linux/btf_ids.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/tools/include/linux/btf_ids.h b/tools/include/linux/btf_ids.h
index 71e54b1e3796..2f882d5cb30f 100644
--- a/tools/include/linux/btf_ids.h
+++ b/tools/include/linux/btf_ids.h
@@ -38,7 +38,7 @@  asm(							\
 	____BTF_ID(symbol)
 
 #define __ID(prefix) \
-	__PASTE(prefix, __COUNTER__)
+	__PASTE(__PASTE(prefix, __COUNTER__), __LINE__)
 
 /*
  * The BTF_ID defines unique symbol for each ID pointing