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| author | Alexander Potapenko <glider@google.com> | 2025-11-28 13:29:28 +0100 |
|---|---|---|
| committer | Alexander Potapenko <glider@google.com> | 2025-11-28 13:15:13 +0000 |
| commit | 01c07bfe113aa2369bbff34c8f845108a2273e1f (patch) | |
| tree | e03a9e26dd5faffc8def529849fb6eb06c8536d3 | |
| parent | d1b870e1003b52891d2196c1e2ee42fe905010ba (diff) | |
executor: apply optnone to guest_handle_nested_vmentry_intel()
Florent Revest reported ThinLTO builds failing with the following error:
<inline asm>:2:1: error: symbol 'after_vmentry_label' is already defined
after_vmentry_label:
^
error: cannot compile inline asm
, which turned out to be caused by the compiler not respecting `noinline`.
Adding __attribute__((optnone)) (or optimize("O0") on GCC) fixes the issue.
| -rw-r--r-- | executor/common_kvm_amd64_syzos.h | 5 | ||||
| -rw-r--r-- | executor/common_kvm_syzos.h | 11 |
2 files changed, 14 insertions, 2 deletions
diff --git a/executor/common_kvm_amd64_syzos.h b/executor/common_kvm_amd64_syzos.h index baabbef7e..df1f63ad5 100644 --- a/executor/common_kvm_amd64_syzos.h +++ b/executor/common_kvm_amd64_syzos.h @@ -1151,7 +1151,10 @@ guest_handle_nested_load_code(struct api_call_nested_load_code* cmd, uint64 cpu_ } } -GUEST_CODE static noinline void +// Clang's LTO may ignore noinline and attempt to inline this function into both callers, +// which results in duplicate declaration of after_vmentry_label. +// Applying __optnone should prevent this behavior. +GUEST_CODE static noinline __optnone void guest_handle_nested_vmentry_intel(uint64 vm_id, uint64 cpu_id, bool is_launch) { uint64 vmx_error_code = 0; diff --git a/executor/common_kvm_syzos.h b/executor/common_kvm_syzos.h index 5fe513ab1..923284efe 100644 --- a/executor/common_kvm_syzos.h +++ b/executor/common_kvm_syzos.h @@ -35,10 +35,19 @@ #define __addrspace_guest #endif +// Disable optimizations for a particular function. +#if defined(__clang__) +#define __optnone __attribute__((optnone)) +#elif defined(__GNUC__) +#define __optnone __attribute__((optimize("O0"))) +#else +#define __optnone +#endif + // Host will map the code in this section into the guest address space. #define GUEST_CODE __attribute__((section("guest"))) __no_stack_protector __addrspace_guest // Start/end of the guest section. extern char *__start_guest, *__stop_guest; -#endif // EXECUTOR_COMMON_KVM_SYZOS_H
\ No newline at end of file +#endif // EXECUTOR_COMMON_KVM_SYZOS_H |