Em Thu, Jan 09, 2020 at 05:47:06AM +0000, Martin Lau escreveu: > 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. Thanks for the explanation, I suggest that next time you include it in the cset comment, to help make sense of the patch by having a why + how to match with the actual patch. - Arnaldo > > - 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; > > -- - Arnaldo
