On Tue, Sep 29, 2020 at 1:33 PM Tom Zanussi <zanu...@kernel.org> wrote: > > synth_field_size() returns either the size or an error. However, the > code assigns the return val to ssize_t which is unsigned, and then > tests whether it's less than 0, which it isn't so discards the error.
I think the patch is correct, but the commit message is not. field->size is a size_t (unsigned), not an ssize_t (signed). I think this should say instead something like: synth_field_size() returns either a positive size or an error (zero or a negative value). However, the existing code assumes the only error value is 0. It doesn't handle negative error codes, as it assigns directly to field->size (a size_t; unsigned), thereby interpreting the error code as a valid size instead. > > Do the test before assignment to field->size. > > Signed-off-by: Tom Zanussi <zanu...@kernel.org> > --- > kernel/trace/trace_events_synth.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/kernel/trace/trace_events_synth.c > b/kernel/trace/trace_events_synth.c > index a9cd7793f7ea..6e7282c7b530 100644 > --- a/kernel/trace/trace_events_synth.c > +++ b/kernel/trace/trace_events_synth.c > @@ -465,6 +465,7 @@ static struct synth_field *parse_synth_field(int argc, > const char **argv, > struct synth_field *field; > const char *prefix = NULL, *field_type = argv[0], *field_name, *array; > int len, ret = 0; > + int size; Why not make this an ssize_t > > if (field_type[0] == ';') > field_type++; > @@ -520,11 +521,12 @@ static struct synth_field *parse_synth_field(int argc, > const char **argv, > field->type[len - 1] = '\0'; > } > > - field->size = synth_field_size(field->type); > - if (!field->size) { > + size = synth_field_size(field->type); > + if (size < 0) { > ret = -EINVAL; > goto free; > } > + field->size = size; > > if (synth_field_is_string(field->type)) > field->is_string = true; > -- > 2.17.1 >