[PATCH] perf: Fix function pointer case

[PATCH] perf: Fix function pointer case

[Cixi Geng]

From: Peter Zijlstra <peterz@infradead.org>

commit 1af6239d1d3e61d33fd2f0ba53d3d1a67cc50574 upstream.
With the advent of CFI it is no longer acceptible to cast function
pointers.

The robot complains thusly:

  kernel-events-core.c:warning:cast-from-int-(-)(struct-perf_cpu_pmu_context-)-to-remote_function_f-(aka-int-(-)(void-)-)-converts-to-incompatible-function-type

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Cixi Geng <cixi.geng1@unisoc.com>
---
 kernel/events/core.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 97052b2dff7e..c7f13da672c9 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1224,6 +1224,11 @@ static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
 	return 0;
 }
 
+static int perf_mux_hrtimer_restart_ipi(void *arg)
+{
+	return perf_mux_hrtimer_restart(arg);
+}
+
 void perf_pmu_disable(struct pmu *pmu)
 {
 	int *count = this_cpu_ptr(pmu->pmu_disable_count);
@@ -11137,8 +11142,7 @@ perf_event_mux_interval_ms_store(struct device *dev,
 		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
 		cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
 
-		cpu_function_call(cpu,
-			(remote_function_f)perf_mux_hrtimer_restart, cpuctx);
+		cpu_function_call(cpu, perf_mux_hrtimer_restart_ipi, cpuctx);
 	}
 	cpus_read_unlock();
 	mutex_unlock(&mux_interval_mutex);
-- 
2.34.1

Re: [PATCH] perf: Fix function pointer case

[Greg KH]

On Wed, Aug 02, 2023 at 07:40:53PM +0800, Cixi Geng wrote:
> From: Peter Zijlstra <peterz@infradead.org>
> 
> commit 1af6239d1d3e61d33fd2f0ba53d3d1a67cc50574 upstream.
> With the advent of CFI it is no longer acceptible to cast function
> pointers.
> 
> The robot complains thusly:
> 
>   kernel-events-core.c:warning:cast-from-int-(-)(struct-perf_cpu_pmu_context-)-to-remote_function_f-(aka-int-(-)(void-)-)-converts-to-incompatible-function-type
> 
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> Signed-off-by: Cixi Geng <cixi.geng1@unisoc.com>
> ---
>  kernel/events/core.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)

What stable tree(s) is this for?

Re: [PATCH] perf: Fix function pointer case

[cixi.geng]

2023年8月2日 19:47, "Greg KH" <gregkh@linuxfoundation.org> 写到:


> 
> On Wed, Aug 02, 2023 at 07:40:53PM +0800, Cixi Geng wrote:
> 
> > 
> > From: Peter Zijlstra <peterz@infradead.org>
> >  
> >  commit 1af6239d1d3e61d33fd2f0ba53d3d1a67cc50574 upstream.
> >  With the advent of CFI it is no longer acceptible to cast function
> >  pointers.
> >  
> >  The robot complains thusly:
> >  
> >  kernel-events-core.c:warning:cast-from-int-(-)(struct-perf_cpu_pmu_context-)-to-remote_function_f-(aka-int-(-)(void-)-)-converts-to-incompatible-function-type
> >  
> >  Reported-by: kernel test robot <lkp@intel.com>
> >  Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> >  Signed-off-by: Cixi Geng <cixi.geng1@unisoc.com>
> >  ---
> >  kernel/events/core.c | 8 ++++++--
> >  1 file changed, 6 insertions(+), 2 deletions(-)
> > 
> 
> What stable tree(s) is this for?
>
Hi Greg
I want to apply this patch for linux-5.15-y and linux-6.1-y, 
the other stable trees not requred for me, thanks!

Re: [PATCH] perf: Fix function pointer case

[Greg KH]

On Thu, Aug 03, 2023 at 01:28:32AM +0000, cixi.geng@linux.dev wrote:
> 2023年8月2日 19:47, "Greg KH" <gregkh@linuxfoundation.org> 写到:
> 
> 
> > 
> > On Wed, Aug 02, 2023 at 07:40:53PM +0800, Cixi Geng wrote:
> > 
> > > 
> > > From: Peter Zijlstra <peterz@infradead.org>
> > >  
> > >  commit 1af6239d1d3e61d33fd2f0ba53d3d1a67cc50574 upstream.
> > >  With the advent of CFI it is no longer acceptible to cast function
> > >  pointers.
> > >  
> > >  The robot complains thusly:
> > >  
> > >  kernel-events-core.c:warning:cast-from-int-(-)(struct-perf_cpu_pmu_context-)-to-remote_function_f-(aka-int-(-)(void-)-)-converts-to-incompatible-function-type
> > >  
> > >  Reported-by: kernel test robot <lkp@intel.com>
> > >  Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> > >  Signed-off-by: Cixi Geng <cixi.geng1@unisoc.com>
> > >  ---
> > >  kernel/events/core.c | 8 ++++++--
> > >  1 file changed, 6 insertions(+), 2 deletions(-)
> > > 
> > 
> > What stable tree(s) is this for?
> >
> Hi Greg
> I want to apply this patch for linux-5.15-y and linux-6.1-y, 
> the other stable trees not requred for me, thanks!

Now queued up, thanks.

greg k-h