> selftests/bpf: cover the low-32 link for sign-extending movs > > Five programs, mirroring the zero-extending set: > > - sext_mov_wide_src: narrowing the source reaches the destination, and > the value that arrives is sign-extended rather than zero-extended > - sext_self_mov_keeps_link: r0 = (s32)r0 on an already-linked register > stays in its set, the shape a sign-extended int return takes > - sext_self_mov_no_link: the same mov on an unlinked register mints no id > - sext_no_sync_when_base_has_delta: a delta on the base stops propagation > - sext_no_sync_from_subreg_base: narrowing the link does not run > backwards into the rest of the set > - sext_kinds_reach_different_values: the same low half reaches -1 through > a sign extension and 0xffffffff through a zero extension > > Each guards a div by zero that is only unreachable if the propagation > happened, so losing the link is a verification failure rather than a test > that quietly stops checking anything.
This isn't a bug, but should the count read "six programs", and could the closing sentence be scoped to the two __success programs, since sext_self_mov_no_link has no div and the __failure ones expect it to be reachable? > diff --git a/tools/testing/selftests/bpf/progs/bpf_misc.h > b/tools/testing/selftests/bpf/progs/bpf_misc.h > index eb88d9ce6c34..45bfa02a5338 100644 > --- a/tools/testing/selftests/bpf/progs/bpf_misc.h > +++ b/tools/testing/selftests/bpf/progs/bpf_misc.h > @@ -269,6 +269,14 @@ > #define CAN_USE_BPF_ST > #endif > > +#if (defined(__TARGET_ARCH_arm64) || defined(__TARGET_ARCH_x86) || \ > + (defined(__TARGET_ARCH_riscv) && __riscv_xlen == 64) || \ > + defined(__TARGET_ARCH_arm) || defined(__TARGET_ARCH_s390) || \ > + defined(__TARGET_ARCH_loongarch)) && \ > + (__clang_major__ >= 18 || defined(__BPF_FEATURE_MOVSX)) > +#define CAN_USE_MOVSX > +#endif > + This isn't a bug, but now that the gate lives in bpf_misc.h, would it be worth switching verifier_movsx.c's inline #if over to #ifdef CAN_USE_MOVSX so the arch/feature list exists in one place? > diff --git a/tools/testing/selftests/bpf/progs/verifier_linked_scalars.c > b/tools/testing/selftests/bpf/progs/verifier_linked_scalars.c > index 65cb0efd268f..9d060d8b0c1f 100644 [ ... ] --- 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/34506184282
