On Tue, Jun 18, 2024 at 5:43 AM Jiri Olsa <olsajiri@xxxxxxxxx> wrote: > > On Mon, Jun 17, 2024 at 03:25:53PM -0700, Andrii Nakryiko wrote: > > On Mon, Jun 10, 2024 at 6:04 AM Jiri Olsa <olsajiri@xxxxxxxxx> wrote: > > > > > > On Sat, Jun 08, 2024 at 03:16:02PM -0600, Daniel Xu wrote: > > > > The prototype defined in bpf_kfuncs.h was not in line with how the > > > > actual kfunc was defined. This causes compilation errors when kfunc > > > > prototypes are generated from BTF. > > > > > > > > Fix by aligning with actual kfunc definition. > > > > > > > > Signed-off-by: Daniel Xu <dxu@xxxxxxxxx> > > > > --- > > > > tools/testing/selftests/bpf/bpf_kfuncs.h | 2 +- > > > > tools/testing/selftests/bpf/progs/kprobe_multi_session_cookie.c | 2 +- > > > > 2 files changed, 2 insertions(+), 2 deletions(-) > > > > > > > > diff --git a/tools/testing/selftests/bpf/bpf_kfuncs.h b/tools/testing/selftests/bpf/bpf_kfuncs.h > > > > index be91a6919315..3b6675ab4086 100644 > > > > --- a/tools/testing/selftests/bpf/bpf_kfuncs.h > > > > +++ b/tools/testing/selftests/bpf/bpf_kfuncs.h > > > > @@ -77,5 +77,5 @@ extern int bpf_verify_pkcs7_signature(struct bpf_dynptr *data_ptr, > > > > struct bpf_key *trusted_keyring) __ksym; > > > > > > > > extern bool bpf_session_is_return(void) __ksym __weak; > > > > -extern long *bpf_session_cookie(void) __ksym __weak; > > > > +extern __u64 *bpf_session_cookie(void) __ksym __weak; > > > > > > the original intent was to expose long instead of __u64 :-\ > > > > > > > Cookies internally are always u64 (8 byte values). Marking them > > internally in the kernel as long could lead to problems on 32-bit > > architectures, potentially (it still needs to be 64-bit value > > according to BPF contract, but we'll allocate only 4 bytes for them). > > > > It seems better and safer to be explicit with __u64/u64 for cookies everywhere. > > hum, I based that on what we did for kprobe session, > but I guess it makes sense just for bpf side: yep, exactly, long is 64-bit only for BPF "architecture", but internally it will be 4 bytes for 32-bit architectures, which will potentially lead to problems. With recent kfunc vmlinux.h generation, it's probably better to stick to explicitly sized types. > > https://lore.kernel.org/bpf/CAEf4BzbyQpKvZS-mUECLRq3gyBJbsqQghOKyAbutoB76mJM8xw@xxxxxxxxxxxxxx/ > > jirka > > > > > What am I missing? > > > > > could we rather change the bpf_session_cookie function to return long? > > > should be just return value type change > > > > > > thanks, > > > jirka > > > > > > > > > > #endif > > > > diff --git a/tools/testing/selftests/bpf/progs/kprobe_multi_session_cookie.c b/tools/testing/selftests/bpf/progs/kprobe_multi_session_cookie.c > > > > index d49070803e22..0835b5edf685 100644 > > > > --- a/tools/testing/selftests/bpf/progs/kprobe_multi_session_cookie.c > > > > +++ b/tools/testing/selftests/bpf/progs/kprobe_multi_session_cookie.c > > > > @@ -25,7 +25,7 @@ int BPF_PROG(trigger) > > > > > > > > static int check_cookie(__u64 val, __u64 *result) > > > > { > > > > - long *cookie; > > > > + __u64 *cookie; > > > > > > > > if (bpf_get_current_pid_tgid() >> 32 != pid) > > > > return 1; > > > > -- > > > > 2.44.0 > > > >
