On 8/29/22 20:12, Jarkko Sakkinen wrote: > diff --git a/tools/testing/selftests/sgx/alloc-error.bt b/tools/testing/selftests/sgx/alloc-error.bt > new file mode 100644 > index 000000000000..9268d50dea29 > --- /dev/null > +++ b/tools/testing/selftests/sgx/alloc-error.bt > @@ -0,0 +1,7 @@ > +kr:sgx_alloc_epc_page /(uint64)retval >= (uint64)(-4095)/ { > + printf("sgx_alloc_epc_page: retval=%d\n", (int64)retval); > +} > + > +kr:sgx_encl_page_alloc /(uint64)retval >= (uint64)(-4095)/ { > + printf("sgx_encl_page_alloc: retval=%d\n", (int64)retval); > +} I guess this doesn't _hurt_, but it's also not exactly the easiest way to get this done. You need a whole bpf toolchain. You could also just do: perf probe 'sgx_encl_page_alloc%return $retval' Even *that* can be replicated in a few scant lines of shell code echoing into /sys/kernel/debug/tracing.