Re: linux-next: build failure after merge of the tip tree

peterz
2020-09-08T11:03:48Z

On Tue, Sep 08, 2020 at 07:12:23PM +1000, Stephen Rothwell wrote:
> Hi all,
>
> After merging the tip tree, today's linux-next build (powerpc
> allyesconfig) failed like this:
>
> ERROR: modpost: too long symbol ".__tracepoint_iter_pnfs_mds_fallback_pg_get_mirror_count" [fs/nfs/flexfilelayout/nfs_layout_flexfiles.ko]
>
> Caused by commit
>
> d25e37d89dd2 ("tracepoint: Optimize using static_call()")
>
> Exported symbols need to be <= (64 - sizeof(Elf_Addr)) long. This is
> presumably 56 on 64 bit arches and the above symbol (including the '.')
> is 56 characters long.

I suppose something like the below ought to cure that. Still, stupid
long tracename that.

---

diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index 3722a10fc46d..81fa0b2f271e 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -154,7 +154,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
#ifdef CONFIG_HAVE_STATIC_CALL
#define __DO_TRACE_CALL(name) static_call(tp_func_##name)
#else
-#define __DO_TRACE_CALL(name) __tracepoint_iter_##name
+#define __DO_TRACE_CALL(name) __traceiter_##name
#endif /* CONFIG_HAVE_STATIC_CALL */

/*
@@ -232,8 +232,8 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
* poking RCU a bit.
*/
#define __DECLARE_TRACE(name, proto, args, cond, data_proto, data_args) \
- extern int __tracepoint_iter_##name(data_proto); \
- DECLARE_STATIC_CALL(tp_func_##name, __tracepoint_iter_##name); \
+ extern int __traceiter_##name(data_proto); \
+ DECLARE_STATIC_CALL(tp_func_##name, __traceiter_##name); \
extern struct tracepoint __tracepoint_##name; \
static inline void trace_##name(proto) \
{ \
@@ -288,19 +288,19 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
static const char __tpstrtab_##_name[] \
__section(__tracepoints_strings) = #_name; \
extern struct static_call_key STATIC_CALL_KEY(tp_func_##_name); \
- int __tracepoint_iter_##_name(void *__data, proto); \
+ int __traceiter_##_name(void *__data, proto); \
struct tracepoint __tracepoint_##_name __used \
__section(__tracepoints) = { \
.name = __tpstrtab_##_name, \
.key = STATIC_KEY_INIT_FALSE, \
.static_call_key = &STATIC_CALL_KEY(tp_func_##_name), \
.static_call_tramp = STATIC_CALL_TRAMP_ADDR(tp_func_##_name), \
- .iterator = &__tracepoint_iter_##_name, \
+ .iterator = &__traceiter_##_name, \
.regfunc = _reg, \
.unregfunc = _unreg, \
.funcs = NULL }; \
__TRACEPOINT_ENTRY(_name); \
- int __tracepoint_iter_##_name(void *__data, proto) \
+ int __traceiter_##_name(void *__data, proto) \
{ \
struct tracepoint_func *it_func_ptr; \
void *it_func; \
@@ -314,18 +314,18 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
} while ((++it_func_ptr)->func); \
return 0; \
} \
- DEFINE_STATIC_CALL(tp_func_##_name, __tracepoint_iter_##_name);
+ DEFINE_STATIC_CALL(tp_func_##_name, __traceiter_##_name);

#define DEFINE_TRACE(name, proto, args) \
DEFINE_TRACE_FN(name, NULL, NULL, PARAMS(proto), PARAMS(args));

#define EXPORT_TRACEPOINT_SYMBOL_GPL(name) \
EXPORT_SYMBOL_GPL(__tracepoint_##name); \
- EXPORT_SYMBOL_GPL(__tracepoint_iter_##name); \
+ EXPORT_SYMBOL_GPL(__traceiter_##name); \
EXPORT_STATIC_CALL_GPL(tp_func_##name)
#define EXPORT_TRACEPOINT_SYMBOL(name) \
EXPORT_SYMBOL(__tracepoint_##name); \
- EXPORT_SYMBOL(__tracepoint_iter_##name); \
+ EXPORT_SYMBOL(__traceiter_##name); \
EXPORT_STATIC_CALL(tp_func_##name)