Re: [PATCH 4/7] mm/vmalloc: Use a trace_alloc_vmap_area event

[Uladzislau Rezki <urezki@gmail.com>]

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On Tue, Oct 18, 2022 at 12:44:12PM -0400, Steven Rostedt wrote:
> On Tue, 18 Oct 2022 18:17:55 +0200
> Uladzislau Rezki <urezki@gmail.com> wrote:
> 
> > Hello, Steven.
> > 
> > > 
> > > [auto build test ERROR on akpm-mm/mm-everything]
> > > [also build test ERROR on linus/master v6.1-rc1 next-20221017]
> > > [If your patch is applied to the wrong git tree, kindly drop us a note.
> > > And when submitting patch, we suggest to use '--base' as documented in
> > > https://git-scm.com/docs/git-format-patch#_base_tree_information]
> > > 
> > > url:    https://github.com/intel-lab-lkp/linux/commits/Uladzislau-Rezki-Sony/Add-basic-trace-events-for-vmap-vmalloc/20221018-000544
> > > base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
> > > patch link:    https://lore.kernel.org/r/20221017160233.16582-7-urezki%40gmail.com
> > > patch subject: [PATCH 4/7] mm/vmalloc: Use a trace_alloc_vmap_area event
> > > config: um-i386_defconfig
> > > compiler: gcc-11 (Debian 11.3.0-8) 11.3.0
> > > reproduce (this is a W=1 build):
> > >         # https://github.com/intel-lab-lkp/linux/commit/fbc853c689b29d3bb9fe250b2653fd2dd8046fc7
> > >         git remote add linux-review https://github.com/intel-lab-lkp/linux
> > >         git fetch --no-tags linux-review Uladzislau-Rezki-Sony/Add-basic-trace-events-for-vmap-vmalloc/20221018-000544
> > >         git checkout fbc853c689b29d3bb9fe250b2653fd2dd8046fc7
> > >         # save the config file
> > >         mkdir build_dir && cp config build_dir/.config
> > >         make W=1 O=build_dir ARCH=um SUBARCH=i386 SHELL=/bin/bash
> > > 
> > > If you fix the issue, kindly add following tag where applicable
> > > | Reported-by: kernel test robot <lkp@intel.com>
> > > 
> > > All errors (new ones prefixed by >>):
> > > 
> > >    In file included from include/trace/events/vmap.h:123,
> > >                     from mm/vmalloc.c:47:  
> > > >> include/trace/define_trace.h:84:34: fatal error: trace/events/kernel_vmap.h: No such file or directory  
> > >       84 | # define __TRACE_INCLUDE(system) <trace/events/system.h>
> > >          |                                  ^
> > >    compilation terminated.
> > >  
> > I can reproduce it. It seems it happens so far only on the ARCH=um case.
> > For regular arm/x86 i do not see such build error.
> > 
> > If i rename the TRACE_SYSTEM macro to something different then "vmap"
> > it compiles fine. In case of:
> > 
> > #define TRACE_SYSTEM vmap
> > 
> > the prefix "kernel_" is added, thus the header name becomes as kernel_vmap.h
> > 
> > Steven can you give some indications? Or any thoughts about it?
> > 
> > Thank you in advance!
> 
> It comes from this:
> 
>    arch/um/Makefile:# -Dvmap=kernel_vmap prevents anything from referencing the libpcap.o symbol so
>    arch/um/Makefile:       $(ARCH_INCLUDE) $(MODE_INCLUDE) -Dvmap=kernel_vmap      \
> 
> 
> It defines "vmap" to "kernel_vmap" which will change the above
> TRACE_SYSTEM Define to:
> 
>   #define TRACE_SYSTEM kernel_vmap
> 
> and that will confuse everything else.
> 
Hm... Right then it goes completely crazy. So there is only one option
it is to rename the trace header defined by the TRACE_SYSTEM.

Thank you for your help :)

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Uladzislau Rezki