* [PATCH] perf: Fix perf_event_{init,exit}_cpu stubs
@ 2022-11-03 22:43 Florian Fainelli
2022-11-04 13:06 ` Peter Zijlstra
0 siblings, 1 reply; 4+ messages in thread
From: Florian Fainelli @ 2022-11-03 22:43 UTC (permalink / raw)
To: linux-kernel
Cc: anand.gore, william.zhang, Florian Fainelli, Peter Zijlstra,
Ingo Molnar, Arnaldo Carvalho de Melo, Mark Rutland,
Alexander Shishkin, Jiri Olsa, Namhyung Kim, Anna-Maria Gleixner,
Sebastian Siewior, Thomas Gleixner,
open list:PERFORMANCE EVENTS SUBSYSTEM
The original commit that introduced those stubs was already at fault,
but in the absence of a caller of perf_event_{init,exit}_cpu outside of
code that is compiled regardless of CONFIG_PERF_EVENTS, the build
failure cannot be observed. This was observed with the Android kernel to
produce a build failure similar to this:
In file included from ./include/uapi/linux/posix_types.h:5,
from ./include/uapi/linux/types.h:14,
from ./include/linux/types.h:6,
from ./include/linux/limits.h:6,
from ./include/linux/kernel.h:7,
from ./include/linux/sched/mm.h:5,
from kernel/cpu.c:6:
kernel/cpu.c: In function 'random_and_perf_prepare_fusion':
./include/linux/stddef.h:8:14: error: called object is not a function or function pointer
#define NULL ((void *)0)
^
./include/linux/perf_event.h:1607:29: note: in expansion of macro 'NULL'
#define perf_event_init_cpu NULL
^~~~
kernel/cpu.c:1686:2: note: in expansion of macro 'perf_event_init_cpu'
perf_event_init_cpu(cpu);
^~~~~~~~~~~~~~~~~~~
Fixes: 00e16c3d68fc ("perf/core: Convert to hotplug state machine")
Reported-by: Anand Gore <anand.gore@broadcom.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
include/linux/perf_event.h | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 0031f7b4d9ab..592040e2398c 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -1678,8 +1678,15 @@ static struct device_attribute format_attr_##_name = __ATTR_RO(_name)
int perf_event_init_cpu(unsigned int cpu);
int perf_event_exit_cpu(unsigned int cpu);
#else
-#define perf_event_init_cpu NULL
-#define perf_event_exit_cpu NULL
+static inline int perf_event_init_cpu(unsigned int cpu)
+{
+ return 0;
+}
+
+static inline int perf_event_exit_cpu(unsigned int cpu)
+{
+ return 0;
+}
#endif
extern void __weak arch_perf_update_userpage(struct perf_event *event,
--
2.25.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] perf: Fix perf_event_{init,exit}_cpu stubs
2022-11-03 22:43 [PATCH] perf: Fix perf_event_{init,exit}_cpu stubs Florian Fainelli
@ 2022-11-04 13:06 ` Peter Zijlstra
2022-11-04 17:38 ` Florian Fainelli
0 siblings, 1 reply; 4+ messages in thread
From: Peter Zijlstra @ 2022-11-04 13:06 UTC (permalink / raw)
To: Florian Fainelli
Cc: linux-kernel, anand.gore, william.zhang, Ingo Molnar,
Arnaldo Carvalho de Melo, Mark Rutland, Alexander Shishkin,
Jiri Olsa, Namhyung Kim, Anna-Maria Gleixner, Sebastian Siewior,
Thomas Gleixner, open list:PERFORMANCE EVENTS SUBSYSTEM
On Thu, Nov 03, 2022 at 03:43:03PM -0700, Florian Fainelli wrote:
> The original commit that introduced those stubs was already at fault,
> but in the absence of a caller of perf_event_{init,exit}_cpu outside of
> code that is compiled regardless of CONFIG_PERF_EVENTS, the build
> failure cannot be observed. This was observed with the Android kernel to
> produce a build failure similar to this:
>
> In file included from ./include/uapi/linux/posix_types.h:5,
> from ./include/uapi/linux/types.h:14,
> from ./include/linux/types.h:6,
> from ./include/linux/limits.h:6,
> from ./include/linux/kernel.h:7,
> from ./include/linux/sched/mm.h:5,
> from kernel/cpu.c:6:
> kernel/cpu.c: In function 'random_and_perf_prepare_fusion':
> ./include/linux/stddef.h:8:14: error: called object is not a function or function pointer
> #define NULL ((void *)0)
> ^
> ./include/linux/perf_event.h:1607:29: note: in expansion of macro 'NULL'
> #define perf_event_init_cpu NULL
> ^~~~
> kernel/cpu.c:1686:2: note: in expansion of macro 'perf_event_init_cpu'
> perf_event_init_cpu(cpu);
> ^~~~~~~~~~~~~~~~~~~
What is the actual problem reported here? Did you see all the other NULL
assignments in cpuhp_hp_states ?
>
> Fixes: 00e16c3d68fc ("perf/core: Convert to hotplug state machine")
> Reported-by: Anand Gore <anand.gore@broadcom.com>
> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
> ---
> include/linux/perf_event.h | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
> index 0031f7b4d9ab..592040e2398c 100644
> --- a/include/linux/perf_event.h
> +++ b/include/linux/perf_event.h
> @@ -1678,8 +1678,15 @@ static struct device_attribute format_attr_##_name = __ATTR_RO(_name)
> int perf_event_init_cpu(unsigned int cpu);
> int perf_event_exit_cpu(unsigned int cpu);
> #else
> -#define perf_event_init_cpu NULL
> -#define perf_event_exit_cpu NULL
> +static inline int perf_event_init_cpu(unsigned int cpu)
> +{
> + return 0;
> +}
> +
> +static inline int perf_event_exit_cpu(unsigned int cpu)
> +{
> + return 0;
> +}
> #endif
>
> extern void __weak arch_perf_update_userpage(struct perf_event *event,
> --
> 2.25.1
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] perf: Fix perf_event_{init,exit}_cpu stubs
2022-11-04 13:06 ` Peter Zijlstra
@ 2022-11-04 17:38 ` Florian Fainelli
2022-11-10 19:05 ` Florian Fainelli
0 siblings, 1 reply; 4+ messages in thread
From: Florian Fainelli @ 2022-11-04 17:38 UTC (permalink / raw)
To: Peter Zijlstra
Cc: linux-kernel, anand.gore, william.zhang, Ingo Molnar,
Arnaldo Carvalho de Melo, Mark Rutland, Alexander Shishkin,
Jiri Olsa, Namhyung Kim, Anna-Maria Gleixner, Sebastian Siewior,
Thomas Gleixner, open list:PERFORMANCE EVENTS SUBSYSTEM
On 11/4/2022 6:06 AM, Peter Zijlstra wrote:
> On Thu, Nov 03, 2022 at 03:43:03PM -0700, Florian Fainelli wrote:
>> The original commit that introduced those stubs was already at fault,
>> but in the absence of a caller of perf_event_{init,exit}_cpu outside of
>> code that is compiled regardless of CONFIG_PERF_EVENTS, the build
>> failure cannot be observed. This was observed with the Android kernel to
>> produce a build failure similar to this:
>>
>> In file included from ./include/uapi/linux/posix_types.h:5,
>> from ./include/uapi/linux/types.h:14,
>> from ./include/linux/types.h:6,
>> from ./include/linux/limits.h:6,
>> from ./include/linux/kernel.h:7,
>> from ./include/linux/sched/mm.h:5,
>> from kernel/cpu.c:6:
>> kernel/cpu.c: In function 'random_and_perf_prepare_fusion':
>> ./include/linux/stddef.h:8:14: error: called object is not a function or function pointer
>> #define NULL ((void *)0)
>> ^
>> ./include/linux/perf_event.h:1607:29: note: in expansion of macro 'NULL'
>> #define perf_event_init_cpu NULL
>> ^~~~
>> kernel/cpu.c:1686:2: note: in expansion of macro 'perf_event_init_cpu'
>> perf_event_init_cpu(cpu);
>> ^~~~~~~~~~~~~~~~~~~
>
> What is the actual problem reported here? Did you see all the other NULL
> assignments in cpuhp_hp_states ?
Anand reported to me that the following downstream commit in the Android
common kernel repository:
https://android.googlesource.com/kernel/common/+/ca927bd22ad8bd26fd8dcebf3c7f2a093385d8ea
was resulting in the build failure above.
While this is an Android inflicted change and I still intend to get a
fix there, upon closer look, the build failure could be experienced
upstream as well with any code calling perf_event_{init,exit}_cpu() as a
regular function call as opposed to being used as a function pointer.
This felt worthy of fixing in the upstream kernel, hence this patch.
--
Florian
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] perf: Fix perf_event_{init,exit}_cpu stubs
2022-11-04 17:38 ` Florian Fainelli
@ 2022-11-10 19:05 ` Florian Fainelli
0 siblings, 0 replies; 4+ messages in thread
From: Florian Fainelli @ 2022-11-10 19:05 UTC (permalink / raw)
To: Peter Zijlstra
Cc: linux-kernel, anand.gore, william.zhang, Ingo Molnar,
Arnaldo Carvalho de Melo, Mark Rutland, Alexander Shishkin,
Jiri Olsa, Namhyung Kim, Anna-Maria Gleixner, Sebastian Siewior,
Thomas Gleixner, open list:PERFORMANCE EVENTS SUBSYSTEM
On 11/4/22 10:38, Florian Fainelli wrote:
>
>
> On 11/4/2022 6:06 AM, Peter Zijlstra wrote:
>> On Thu, Nov 03, 2022 at 03:43:03PM -0700, Florian Fainelli wrote:
>>> The original commit that introduced those stubs was already at fault,
>>> but in the absence of a caller of perf_event_{init,exit}_cpu outside of
>>> code that is compiled regardless of CONFIG_PERF_EVENTS, the build
>>> failure cannot be observed. This was observed with the Android kernel to
>>> produce a build failure similar to this:
>>>
>>> In file included from ./include/uapi/linux/posix_types.h:5,
>>> from ./include/uapi/linux/types.h:14,
>>> from ./include/linux/types.h:6,
>>> from ./include/linux/limits.h:6,
>>> from ./include/linux/kernel.h:7,
>>> from ./include/linux/sched/mm.h:5,
>>> from kernel/cpu.c:6:
>>> kernel/cpu.c: In function 'random_and_perf_prepare_fusion':
>>> ./include/linux/stddef.h:8:14: error: called object is not a
>>> function or function pointer
>>> #define NULL ((void *)0)
>>> ^
>>> ./include/linux/perf_event.h:1607:29: note: in expansion of
>>> macro 'NULL'
>>> #define perf_event_init_cpu NULL
>>> ^~~~
>>> kernel/cpu.c:1686:2: note: in expansion of macro
>>> 'perf_event_init_cpu'
>>> perf_event_init_cpu(cpu);
>>> ^~~~~~~~~~~~~~~~~~~
>>
>> What is the actual problem reported here? Did you see all the other NULL
>> assignments in cpuhp_hp_states ?
>
> Anand reported to me that the following downstream commit in the Android
> common kernel repository:
>
> https://android.googlesource.com/kernel/common/+/ca927bd22ad8bd26fd8dcebf3c7f2a093385d8ea
>
> was resulting in the build failure above.
>
> While this is an Android inflicted change and I still intend to get a
> fix there, upon closer look, the build failure could be experienced
> upstream as well with any code calling perf_event_{init,exit}_cpu() as a
> regular function call as opposed to being used as a function pointer.
>
> This felt worthy of fixing in the upstream kernel, hence this patch.
No response meaning it's a don't care because upstream is not (yet?)
impacted?
--
Florian
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-11-10 19:07 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-11-03 22:43 [PATCH] perf: Fix perf_event_{init,exit}_cpu stubs Florian Fainelli
2022-11-04 13:06 ` Peter Zijlstra
2022-11-04 17:38 ` Florian Fainelli
2022-11-10 19:05 ` Florian Fainelli
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).