> diff --git a/tools/testing/selftests/bpf/usdt.h
> b/tools/testing/selftests/bpf/usdt.h
> index c71e21df38b3..75687f50f4e2 100644
> --- a/tools/testing/selftests/bpf/usdt.h
> +++ b/tools/testing/selftests/bpf/usdt.h
> @@ -313,7 +313,7 @@ struct usdt_sema { volatile unsigned short active; };
> #if defined(__ia64__) || defined(__s390__) || defined(__s390x__)
> #define USDT_NOP nop 0
> #elif defined(__x86_64__)
> -#define USDT_NOP .byte 0x90, 0x0f, 0x1f, 0x44, 0x00,
> 0x0 /* nop, nop5 */
> +#define USDT_NOP .byte 0x90, 0x66, 0x2e, 0x0f, 0x1f,
> 0x84, 0x00, 0x00, 0x00, 0x00, 0x00 /* nop, nop10 */
> #else
> #define USDT_NOP nop
> #endif
Does this change break the USDT selftest? Multiple reviewers raised
concerns across v1 through v4 that subtest_optimized_attach() in
prog_tests/usdt.c searches for the old 6-byte nop1_nop5_combo sequence.
When usdt_2.c emits the new 11-byte nop,nop10 instead, find_instr() will
return NULL and fail the ASSERT_OK_PTR check.
You mentioned in v1/v2 that the test would be updated in a following commit,
preferring to keep changes separated for easier review. However, this creates
a git bisect regression where the test breaks at this commit. Should the test
update be squashed in to avoid breaking bisectability?
The commit message contains a placeholder reference:
> Syncing latest usdt.h change [1].
>
> Now that we have nop10 optimization support in kernel, let's emit
> nop,nop10 for usdt probe. We leave it up to the library to use
> desirable nop instruction.
>
> [1] TBD
This isn't a bug, but the "[1] TBD" should either be filled in or removed.
---
AI reviewed your patch. Please fix the bug or email reply why it's not a bug.
See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md
CI run summary: https://github.com/kernel-patches/bpf/actions/runs/26475828601
