On Tue, Jan 05, 2021 at 01:15:39PM -0800, Andrii Nakryiko wrote:
> On Tue, Jan 5, 2021 at 7:41 AM Jiri Olsa <[email protected]> wrote:
> >
> > The kernel image can contain multiple types (structs/unions)
> > with the same name. This causes distinct type hierarchies in
> > BTF data and makes resolve_btfids fail with error like:
> >
> > BTFIDS vmlinux
> > FAILED unresolved symbol udp6_sock
> >
> > as reported by Qais Yousef [1].
> >
> > This change adds warning when multiple types of the same name
> > are detected:
> >
> > BTFIDS vmlinux
> > WARN: multiple IDs found for 'file' (526, 113351)
> > WARN: multiple IDs found for 'sk_buff' (2744, 113958)
> >
> > We keep the lower ID for the given type instance and let the
> > build continue.
> >
> > [1]
> > https://lore.kernel.org/lkml/20201229151352.6hzmjvu3qh6p2qgg@e107158-lin/
> > Reported-by: Qais Yousef <[email protected]>
> > Signed-off-by: Jiri Olsa <[email protected]>
> > ---
>
> see comments below, but otherwise lgtm
>
> Acked-by: Andrii Nakryiko <[email protected]>
>
> > tools/bpf/resolve_btfids/main.c | 11 +++++++++--
> > 1 file changed, 9 insertions(+), 2 deletions(-)
> >
> > diff --git a/tools/bpf/resolve_btfids/main.c
> > b/tools/bpf/resolve_btfids/main.c
> > index e3ea569ee125..36a3b1024cdc 100644
> > --- a/tools/bpf/resolve_btfids/main.c
> > +++ b/tools/bpf/resolve_btfids/main.c
> > @@ -139,6 +139,8 @@ int eprintf(int level, int var, const char *fmt, ...)
> > #define pr_debug2(fmt, ...) pr_debugN(2, pr_fmt(fmt), ##__VA_ARGS__)
> > #define pr_err(fmt, ...) \
> > eprintf(0, verbose, pr_fmt(fmt), ##__VA_ARGS__)
> > +#define pr_info(fmt, ...) \
> > + eprintf(0, verbose, pr_fmt(fmt), ##__VA_ARGS__)
>
> how is it different from pr_err? Did you forget to update verboseness
> levels or it's intentional?
intentional, I'm using pr_err to print in error paths,
so I wanted to add new one for other 'info' messages without -v
>
> >
> > static bool is_btf_id(const char *name)
> > {
> > @@ -526,8 +528,13 @@ static int symbols_resolve(struct object *obj)
> >
> > id = btf_id__find(root, str);
> > if (id) {
> > - id->id = type_id;
> > - (*nr)--;
> > + if (id->id) {
> > + pr_info("WARN: multiple IDs found for '%s'
> > (%d, %d)\n",
> > + str, id->id, type_id);
> > + } else {
> > + id->id = type_id;
> > + (*nr)--;
>
> btw, there is a nasty shadowing of nr variable, which is used both for
> the for() loop condition (as int) and as `int *` inside the loop body.
> It's better to rename inner (or outer) nr, it's extremely confusing as
> is.
nice, I'll change that
thanks,
jirka
>
> > + }
> > }
> > }
> >
> > --
> > 2.26.2
> >
>
