On Wed, Jan 08, 2020 at 10:06:44PM -0300, Arnaldo Carvalho de Melo wrote: > On January 8, 2020 9:44:24 PM GMT-03:00, Martin KaFai Lau <kafai@xxxxxx> wrote: > >This patch makes the verifier save the PTR_TO_BTF_ID register state > >when > >spilling to the stack. > > You say what it does, but not why that is needed :-/ It is the same as other existing bpf_reg_type (i.e. the above switch cases in is_spillable_regtype()). When a register spills to the stack, the verifier decides if the reg's state can be saved (i.e. what the is_spillable_regtype() is checking). If the state is not saved, the verifier cannot recognize its state later. > > - Arnaldo > > > >Acked-by: Yonghong Song <yhs@xxxxxx> > >Signed-off-by: Martin KaFai Lau <kafai@xxxxxx> > >--- > > kernel/bpf/verifier.c | 1 + > > 1 file changed, 1 insertion(+) > > > >diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c > >index 6f63ae7a370c..d433d70022fd 100644 > >--- a/kernel/bpf/verifier.c > >+++ b/kernel/bpf/verifier.c > >@@ -1916,6 +1916,7 @@ static bool is_spillable_regtype(enum > >bpf_reg_type type) > > case PTR_TO_TCP_SOCK: > > case PTR_TO_TCP_SOCK_OR_NULL: > > case PTR_TO_XDP_SOCK: > >+ case PTR_TO_BTF_ID: > > return true; > > default: > > return false; >
