[PATCH V4 1/3] tracing: add a possibility of exporting function trace to other places instead of ring buffer only

[Chunyan Zhang]

Hi Fengguang,

On 15 August 2016 at 21:03, kbuild test robot <lkp at intel.com> wrote:
> Hi Chunyan,
>
> [auto build test WARNING on linus/master]
> [also build test WARNING on v4.8-rc2 next-20160815]
> [cannot apply to linux/master]
> [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
>
> url:    https://github.com/0day-ci/linux/commits/Chunyan-Zhang/tracing-add-a-possibility-of-exporting-function-trace-to-other-places-instead-of-ring-buffer-only/20160815-195631
> reproduce:
>         # apt-get install sparse


It may be better to use the latest version of sparse, i.e.

git clone git://git.kernel.org/pub/scm/devel/sparse/sparse.git

and then build the source code according to the direction on the page
https://kernelnewbies.org/Sparse

Otherwise, would get the errors like below if I install sparse using
apt-get install.

-------------------------------------------------------
 CHECK   arch/x86/purgatory/purgatory.c
No such file: asan-stack=1
scripts/Makefile.build:289: recipe for target
'arch/x86/purgatory/purgatory.o' failed
make[1]: *** [arch/x86/purgatory/purgatory.o] Error 1
arch/x86/Makefile:195: recipe for target 'archprepare' failed
make: *** [archprepare] Error 2
-------------------------------------------------------


Thanks,
Chunyan

>         make ARCH=x86_64 allmodconfig
>         make C=1 CF=-D__CHECK_ENDIAN__
>
> sparse warnings: (new ones prefixed by >>)
>
>    include/linux/compiler.h:230:8: sparse: attribute 'no_sanitize_address': unknown attribute
>>> kernel/trace/trace.c:2173:23: sparse: incompatible types in comparison expression (different address spaces)
>    kernel/trace/trace.c:2175:23: sparse: incompatible types in comparison expression (different address spaces)
>
> vim +2173 kernel/trace/trace.c
>
>   2157  static DEFINE_MUTEX(trace_export_lock);
>   2158
>   2159  static struct trace_export trace_export_rb __read_mostly = {
>   2160          .name           = "rb",
>   2161          .commit = trace_rb_commit,
>   2162          .next           = NULL,
>   2163  };
>   2164  static struct trace_export *trace_exports_list __read_mostly = &trace_export_rb;
>   2165
>   2166  inline void
>   2167  trace_exports(struct trace_array *tr, struct ring_buffer_event *event)
>   2168  {
>   2169          struct trace_export *export;
>   2170
>   2171          preempt_disable_notrace();
>   2172
>> 2173          for (export = rcu_dereference_raw_notrace(trace_exports_list);
>   2174               export && export->commit;
>   2175               export = rcu_dereference_raw_notrace(export->next)) {
>   2176                  tr->export = export;
>   2177                  export->commit(tr, event);
>   2178          }
>   2179
>   2180          preempt_enable_notrace();
>   2181  }
>
> ---
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