{x86,um}/uapi/ptrace: Guard register offset macros with __ASSEMBLER__ or __FRAME_OFFSETS

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The register offset macros in <asm/ptrace-abi.h> are guarded by
`defined(__ASSEMBLER__) || defined(__FRAME_OFFSETS)` for 64-bit, but
were left unguarded for 32-bit. This causes havoc for userspace that
happens to use identifiers colliding with these short macro names
(e.g., EBX, ECX, EAX, DS, ES, FS, GS, CS, SS). Without this guard,
userspace is forced to be super extra careful with include ordering to
minimize the chance of collision.

Wrap both the 32-bit and 64-bit register definitions under
`#if defined(__ASSEMBLER__) || defined(__FRAME_OFFSETS)`, and ensure
User-Mode Linux (UML) defines `__FRAME_OFFSETS` for 32-bit as well.

Closes: https://github.com/llvm/llvm-project/issues/217413
Assisted-by: LLM
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Tested-by: Elliott Hughes <enh@google.com>
Link: https://patch.msgid.link/20260821-ptrace_uapi-v1-1-3de8638a29f2@google.com

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Nick Desaulniers 2026-08-21 15:45:42 -07:00 • committed by Borislav Petkov (AMD)

parent e3ee38c1bc

commit a661c34fe6

3 changed files with 4 additions and 5 deletions

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4

arch/x86/include/uapi/asm/ptrace-abi.h

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4

arch/x86/um/asm/ptrace.h

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1

arch/x86/um/ptrace_32.c

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