On Wed, Dec 31, 2025 at 10:04 AM <[email protected]> wrote: > > > diff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c > > b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c > > index 90c4b1a51de6..5e460b1dbdb6 100644 > > --- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c > > +++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c > > [ ... ] > > > @@ -1275,7 +1275,7 @@ bpf_testmod_ops__test_return_ref_kptr(int dummy, > > struct task_struct *task__ref, > > return NULL; > > } > > > > -static struct bpf_testmod_ops __bpf_testmod_ops = { > > +static const struct bpf_testmod_ops __bpf_testmod_ops = { > > .test_1 = bpf_testmod_test_1, > > .test_2 = bpf_testmod_test_2, > > Is it safe to make __bpf_testmod_ops const here? In bpf_testmod_init(), > this struct is modified at runtime: > > tramp = (void **)&__bpf_testmod_ops.tramp_1; > while (tramp <= (void **)&__bpf_testmod_ops.tramp_40) > *tramp++ = bpf_testmod_tramp; > > Writing to a const-qualified object is undefined behavior and may cause a > protection fault when the compiler places this in read-only memory. Would > the module fail to load on systems where .rodata is actually read-only?
Yup, that's indeed the bug caught by KASAN. Missed this mutation at init time, I'll leave __bpf_testmod_ops as mutable. Thanks, Caleb > > > --- > 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/20624206229
