On Sun, 26 May 2024 14:27:56 +0200 Carlos López <clo...@suse.de> wrote:
> > Hi, > > On 26/5/24 12:17, Masami Hiramatsu (Google) wrote: > > On Sat, 25 May 2024 20:21:32 +0200 > > Carlos López <clo...@suse.de> wrote: > > > >> btf_find_struct_member() might return NULL or an error via the > >> ERR_PTR() macro. However, its caller in parse_btf_field() only checks > >> for the NULL condition. Fix this by using IS_ERR() and returning the > >> error up the stack. > >> > > > > Thanks for finding it! > > I think this requires new error message for error_log file. > > Can you add the log as > > > > trace_probe_log_err(ctx->offset, BTF_ERROR); > > > > And define BTF_ERROR in ERRORS@kernel/trace/trace_probe.h ? > > Sounds good, but should we perhaps reuse BAD_BTF_TID? > > ``` > C(BAD_BTF_TID, "Failed to get BTF type info."),\ > ``` > > `btf_find_struct_member()` fails if `type` is not a struct or if it runs > OOM while allocating the anon stack, so it seems appropriate. Good point, it sounds reasonable. Thanks! > > Best, > Carlos > > > Thank you, > > > >> Fixes: c440adfbe3025 ("tracing/probes: Support BTF based data structure > >> field access") > >> Signed-off-by: Carlos López <clo...@suse.de> > >> --- > >> kernel/trace/trace_probe.c | 2 ++ > >> 1 file changed, 2 insertions(+) > >> > >> diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c > >> index 5e263c141574..5417e9712157 100644 > >> --- a/kernel/trace/trace_probe.c > >> +++ b/kernel/trace/trace_probe.c > >> @@ -554,6 +554,8 @@ static int parse_btf_field(char *fieldname, const > >> struct btf_type *type, > >> anon_offs = 0; > >> field = btf_find_struct_member(ctx->btf, type, > >> fieldname, > >> &anon_offs); > >> + if (IS_ERR(field)) > >> + return PTR_ERR(field); > >> if (!field) { > >> trace_probe_log_err(ctx->offset, NO_BTF_FIELD); > >> return -ENOENT; > >> -- > >> 2.35.3 > >> > > > > > > -- > Carlos López > Security Engineer > SUSE Software Solutions -- Masami Hiramatsu (Google) <mhira...@kernel.org>