* [PATCH] xen/trace: avoid clang warning on function pointers
@ 2019-07-12 8:58 Arnd Bergmann
2019-07-12 9:16 ` Sedat Dilek
2019-07-12 17:41 ` Nathan Chancellor
0 siblings, 2 replies; 5+ messages in thread
From: Arnd Bergmann @ 2019-07-12 8:58 UTC (permalink / raw)
To: Steven Rostedt, Ingo Molnar
Cc: Arnd Bergmann, Jeremy Fitzhardinge, Sakari Ailus, Mike Rapoport,
Petr Mladek, Bjorn Helgaas, linux-kernel, clang-built-linux
clang-9 does not like the way that the is_signed_type() compares
function pointers deep inside of the trace even macros:
In file included from arch/x86/xen/trace.c:21:
In file included from include/trace/events/xen.h:475:
In file included from include/trace/define_trace.h:102:
In file included from include/trace/trace_events.h:467:
include/trace/events/xen.h:69:7: error: ordered comparison of function pointers ('xen_mc_callback_fn_t' (aka 'void (*)(void *)') and 'xen_mc_callback_fn_t') [-Werror,-Wordered-compare-function-pointers]
__field(xen_mc_callback_fn_t, fn)
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/trace/trace_events.h:415:29: note: expanded from macro '__field'
#define __field(type, item) __field_ext(type, item, FILTER_OTHER)
^
include/trace/trace_events.h:401:6: note: expanded from macro '__field_ext'
is_signed_type(type), filter_type); \
^
include/linux/trace_events.h:540:44: note: expanded from macro 'is_signed_type'
#define is_signed_type(type) (((type)(-1)) < (type)1)
^
note: (skipping 1 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
include/trace/trace_events.h:77:16: note: expanded from macro 'TRACE_EVENT'
PARAMS(tstruct), \
~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/tracepoint.h:95:25: note: expanded from macro 'PARAMS'
#define PARAMS(args...) args
^
include/trace/trace_events.h:455:2: note: expanded from macro 'DECLARE_EVENT_CLASS'
tstruct; \
^~~~~~~
I guess the warning is reasonable in principle, though this seems to
be the only instance we get in the entire kernel today.
Shut up the warning by making it a void pointer in the exported
structure.
Fixes: c796f213a693 ("xen/trace: add multicall tracing")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
include/trace/events/xen.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/trace/events/xen.h b/include/trace/events/xen.h
index 9a0e8af21310..f75b77414ac1 100644
--- a/include/trace/events/xen.h
+++ b/include/trace/events/xen.h
@@ -66,7 +66,7 @@ TRACE_EVENT(xen_mc_callback,
TP_PROTO(xen_mc_callback_fn_t fn, void *data),
TP_ARGS(fn, data),
TP_STRUCT__entry(
- __field(xen_mc_callback_fn_t, fn)
+ __field(void *, fn)
__field(void *, data)
),
TP_fast_assign(
--
2.20.0
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH] xen/trace: avoid clang warning on function pointers
2019-07-12 8:58 [PATCH] xen/trace: avoid clang warning on function pointers Arnd Bergmann
@ 2019-07-12 9:16 ` Sedat Dilek
2019-07-12 17:41 ` Nathan Chancellor
1 sibling, 0 replies; 5+ messages in thread
From: Sedat Dilek @ 2019-07-12 9:16 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Steven Rostedt, Ingo Molnar, Jeremy Fitzhardinge, Sakari Ailus,
Mike Rapoport, Petr Mladek, Bjorn Helgaas, linux-kernel,
Clang-Built-Linux ML
On Fri, Jul 12, 2019 at 10:59 AM Arnd Bergmann <arnd@arndb.de> wrote:
>
> clang-9 does not like the way that the is_signed_type() compares
> function pointers deep inside of the trace even macros:
>
> In file included from arch/x86/xen/trace.c:21:
> In file included from include/trace/events/xen.h:475:
> In file included from include/trace/define_trace.h:102:
> In file included from include/trace/trace_events.h:467:
> include/trace/events/xen.h:69:7: error: ordered comparison of function pointers ('xen_mc_callback_fn_t' (aka 'void (*)(void *)') and 'xen_mc_callback_fn_t') [-Werror,-Wordered-compare-function-pointers]
> __field(xen_mc_callback_fn_t, fn)
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> include/trace/trace_events.h:415:29: note: expanded from macro '__field'
> #define __field(type, item) __field_ext(type, item, FILTER_OTHER)
> ^
> include/trace/trace_events.h:401:6: note: expanded from macro '__field_ext'
> is_signed_type(type), filter_type); \
> ^
> include/linux/trace_events.h:540:44: note: expanded from macro 'is_signed_type'
> #define is_signed_type(type) (((type)(-1)) < (type)1)
> ^
> note: (skipping 1 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
> include/trace/trace_events.h:77:16: note: expanded from macro 'TRACE_EVENT'
> PARAMS(tstruct), \
> ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
> include/linux/tracepoint.h:95:25: note: expanded from macro 'PARAMS'
> #define PARAMS(args...) args
> ^
> include/trace/trace_events.h:455:2: note: expanded from macro 'DECLARE_EVENT_CLASS'
> tstruct; \
> ^~~~~~~
>
> I guess the warning is reasonable in principle, though this seems to
> be the only instance we get in the entire kernel today.
> Shut up the warning by making it a void pointer in the exported
> structure.
>
Thanks for bringing this up (again), Arnd.
As this is a known CBL issue please add...
Link: https://github.com/ClangBuiltLinux/linux/issues/97
...and...
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
For the sake of completeness see also the comments of Steven Rostedt
and user "Honeybyte" in the above Link - if not known/read.
- Sedat -
P.S.: I am using this patch since 6 months in my
for-5.x/clang-warningfree local Git repository.
> Fixes: c796f213a693 ("xen/trace: add multicall tracing")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> include/trace/events/xen.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/trace/events/xen.h b/include/trace/events/xen.h
> index 9a0e8af21310..f75b77414ac1 100644
> --- a/include/trace/events/xen.h
> +++ b/include/trace/events/xen.h
> @@ -66,7 +66,7 @@ TRACE_EVENT(xen_mc_callback,
> TP_PROTO(xen_mc_callback_fn_t fn, void *data),
> TP_ARGS(fn, data),
> TP_STRUCT__entry(
> - __field(xen_mc_callback_fn_t, fn)
> + __field(void *, fn)
> __field(void *, data)
> ),
> TP_fast_assign(
> --
> 2.20.0
>
> --
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^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] xen/trace: avoid clang warning on function pointers
2019-07-12 8:58 [PATCH] xen/trace: avoid clang warning on function pointers Arnd Bergmann
2019-07-12 9:16 ` Sedat Dilek
@ 2019-07-12 17:41 ` Nathan Chancellor
2019-09-23 22:06 ` Nick Desaulniers
1 sibling, 1 reply; 5+ messages in thread
From: Nathan Chancellor @ 2019-07-12 17:41 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Steven Rostedt, Ingo Molnar, Jeremy Fitzhardinge, Sakari Ailus,
Mike Rapoport, Petr Mladek, Bjorn Helgaas, linux-kernel,
clang-built-linux
On Fri, Jul 12, 2019 at 10:58:48AM +0200, Arnd Bergmann wrote:
> clang-9 does not like the way that the is_signed_type() compares
> function pointers deep inside of the trace even macros:
>
> In file included from arch/x86/xen/trace.c:21:
> In file included from include/trace/events/xen.h:475:
> In file included from include/trace/define_trace.h:102:
> In file included from include/trace/trace_events.h:467:
> include/trace/events/xen.h:69:7: error: ordered comparison of function pointers ('xen_mc_callback_fn_t' (aka 'void (*)(void *)') and 'xen_mc_callback_fn_t') [-Werror,-Wordered-compare-function-pointers]
> __field(xen_mc_callback_fn_t, fn)
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> include/trace/trace_events.h:415:29: note: expanded from macro '__field'
> #define __field(type, item) __field_ext(type, item, FILTER_OTHER)
> ^
> include/trace/trace_events.h:401:6: note: expanded from macro '__field_ext'
> is_signed_type(type), filter_type); \
> ^
> include/linux/trace_events.h:540:44: note: expanded from macro 'is_signed_type'
> #define is_signed_type(type) (((type)(-1)) < (type)1)
> ^
> note: (skipping 1 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
> include/trace/trace_events.h:77:16: note: expanded from macro 'TRACE_EVENT'
> PARAMS(tstruct), \
> ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
> include/linux/tracepoint.h:95:25: note: expanded from macro 'PARAMS'
> #define PARAMS(args...) args
> ^
> include/trace/trace_events.h:455:2: note: expanded from macro 'DECLARE_EVENT_CLASS'
> tstruct; \
> ^~~~~~~
>
> I guess the warning is reasonable in principle, though this seems to
> be the only instance we get in the entire kernel today.
> Shut up the warning by making it a void pointer in the exported
> structure.
>
> Fixes: c796f213a693 ("xen/trace: add multicall tracing")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Nick suggested this as well, I think it's reasonable to work around it
in this one location since this is indeed the only instance of this
warning that I see in the kernel tree across all of my builds.
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] xen/trace: avoid clang warning on function pointers
2019-07-12 17:41 ` Nathan Chancellor
@ 2019-09-23 22:06 ` Nick Desaulniers
2019-09-23 22:07 ` Nick Desaulniers
0 siblings, 1 reply; 5+ messages in thread
From: Nick Desaulniers @ 2019-09-23 22:06 UTC (permalink / raw)
To: Steven Rostedt, Ingo Molnar
Cc: Arnd Bergmann, Jeremy Fitzhardinge, Sakari Ailus, Mike Rapoport,
Petr Mladek, Bjorn Helgaas, LKML, clang-built-linux,
Nathan Chancellor
On Fri, Jul 12, 2019 at 10:41 AM Nathan Chancellor
<natechancellor@gmail.com> wrote:
>
> On Fri, Jul 12, 2019 at 10:58:48AM +0200, Arnd Bergmann wrote:
> > clang-9 does not like the way that the is_signed_type() compares
> > function pointers deep inside of the trace even macros:
> >
> > In file included from arch/x86/xen/trace.c:21:
> > In file included from include/trace/events/xen.h:475:
> > In file included from include/trace/define_trace.h:102:
> > In file included from include/trace/trace_events.h:467:
> > include/trace/events/xen.h:69:7: error: ordered comparison of function pointers ('xen_mc_callback_fn_t' (aka 'void (*)(void *)') and 'xen_mc_callback_fn_t') [-Werror,-Wordered-compare-function-pointers]
> > __field(xen_mc_callback_fn_t, fn)
> > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > include/trace/trace_events.h:415:29: note: expanded from macro '__field'
> > #define __field(type, item) __field_ext(type, item, FILTER_OTHER)
> > ^
> > include/trace/trace_events.h:401:6: note: expanded from macro '__field_ext'
> > is_signed_type(type), filter_type); \
> > ^
> > include/linux/trace_events.h:540:44: note: expanded from macro 'is_signed_type'
> > #define is_signed_type(type) (((type)(-1)) < (type)1)
> > ^
> > note: (skipping 1 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
> > include/trace/trace_events.h:77:16: note: expanded from macro 'TRACE_EVENT'
> > PARAMS(tstruct), \
> > ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > include/linux/tracepoint.h:95:25: note: expanded from macro 'PARAMS'
> > #define PARAMS(args...) args
> > ^
> > include/trace/trace_events.h:455:2: note: expanded from macro 'DECLARE_EVENT_CLASS'
> > tstruct; \
> > ^~~~~~~
> >
> > I guess the warning is reasonable in principle, though this seems to
> > be the only instance we get in the entire kernel today.
> > Shut up the warning by making it a void pointer in the exported
> > structure.
> >
> > Fixes: c796f213a693 ("xen/trace: add multicall tracing")
> > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
>
> Nick suggested this as well, I think it's reasonable to work around it
> in this one location since this is indeed the only instance of this
> warning that I see in the kernel tree across all of my builds.
>
> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Steven, Ingo, would one of you mind picking up this fix, please? See
for multiple reports:
https://github.com/ClangBuiltLinux/linux/issues/216
--
Thanks,
~Nick Desaulniers
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] xen/trace: avoid clang warning on function pointers
2019-09-23 22:06 ` Nick Desaulniers
@ 2019-09-23 22:07 ` Nick Desaulniers
0 siblings, 0 replies; 5+ messages in thread
From: Nick Desaulniers @ 2019-09-23 22:07 UTC (permalink / raw)
To: Steven Rostedt, Ingo Molnar
Cc: Arnd Bergmann, Jeremy Fitzhardinge, Sakari Ailus, Mike Rapoport,
Petr Mladek, Bjorn Helgaas, LKML, clang-built-linux,
Nathan Chancellor
On Mon, Sep 23, 2019 at 3:06 PM Nick Desaulniers
<ndesaulniers@google.com> wrote:
> Steven, Ingo, would one of you mind picking up this fix, please? See
> for multiple reports:
> https://github.com/ClangBuiltLinux/linux/issues/216
Sorry, https://github.com/ClangBuiltLinux/linux/issues/97 is the link.
--
Thanks,
~Nick Desaulniers
^ permalink raw reply [flat|nested] 5+ messages in thread
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2019-07-12 8:58 [PATCH] xen/trace: avoid clang warning on function pointers Arnd Bergmann
2019-07-12 9:16 ` Sedat Dilek
2019-07-12 17:41 ` Nathan Chancellor
2019-09-23 22:06 ` Nick Desaulniers
2019-09-23 22:07 ` Nick Desaulniers
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