Re: [PATCH 3/3] mm: check for VMA being detached before destroying it

[Suren Baghdasaryan]

On Tue, Jun 20, 2023 at 7:15 PM kernel test robot <lkp@xxxxxxxxx> wrote:
>
> Hi Suren,
>
> kernel test robot noticed the following build errors:
>
> [auto build test ERROR on akpm-mm/mm-everything]
>
> url:    https://github.com/intel-lab-lkp/linux/commits/Suren-Baghdasaryan/mm-change-vma_start_read-to-fail-to-lock-a-detached-VMA/20230621-075833
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
> patch link:    https://lore.kernel.org/r/20230620235726.3873043-3-surenb%40google.com
> patch subject: [PATCH 3/3] mm: check for VMA being detached before destroying it
> config: alpha-allyesconfig (https://download.01.org/0day-ci/archive/20230621/202306211007.hQoEsMrP-lkp@xxxxxxxxx/config)
> compiler: alpha-linux-gcc (GCC) 12.3.0
> reproduce: (https://download.01.org/0day-ci/archive/20230621/202306211007.hQoEsMrP-lkp@xxxxxxxxx/reproduce)
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@xxxxxxxxx>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202306211007.hQoEsMrP-lkp@xxxxxxxxx/
>
> All errors (new ones prefixed by >>):
>
>    scripts/genksyms/parse.y: warning: 9 shift/reduce conflicts [-Wconflicts-sr]
>    scripts/genksyms/parse.y: warning: 5 reduce/reduce conflicts [-Wconflicts-rr]
>    scripts/genksyms/parse.y: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
>    In file included from include/linux/pid_namespace.h:7,
>                     from include/linux/ptrace.h:10,
>                     from arch/alpha/kernel/asm-offsets.c:11:
>    include/linux/mm.h: In function 'vma_init':
> >> include/linux/mm.h:753:12: error: 'struct vm_area_struct' has no member named 'detached'
>      753 |         vma->detached = true;
>          |            ^~

Yep, missed #ifdef CONFIG_PER_VMA_LOCK here. Will fix it in the next
version but will wait a bit for possible feedback.

>    arch/alpha/kernel/asm-offsets.c: At top level:
>    arch/alpha/kernel/asm-offsets.c:15:6: warning: no previous prototype for 'foo' [-Wmissing-prototypes]
>       15 | void foo(void)
>          |      ^~~
>    make[2]: *** [scripts/Makefile.build:114: arch/alpha/kernel/asm-offsets.s] Error 1
>    make[2]: Target 'prepare' not remade because of errors.
>    make[1]: *** [Makefile:1287: prepare0] Error 2
>    make[1]: Target 'prepare' not remade because of errors.
>    make: *** [Makefile:226: __sub-make] Error 2
>    make: Target 'prepare' not remade because of errors.
>
>
> vim +753 include/linux/mm.h
>
>    740
>    741  /*
>    742   * WARNING: vma_init does not initialize vma->vm_lock.
>    743   * Use vm_area_alloc()/vm_area_free() if vma needs locking.
>    744   */
>    745  static inline void vma_init(struct vm_area_struct *vma, struct mm_struct *mm)
>    746  {
>    747          static const struct vm_operations_struct dummy_vm_ops = {};
>    748
>    749          memset(vma, 0, sizeof(*vma));
>    750          vma->vm_mm = mm;
>    751          vma->vm_ops = &dummy_vm_ops;
>    752          INIT_LIST_HEAD(&vma->anon_vma_chain);
>  > 753          vma->detached = true;
>    754          vma_numab_state_init(vma);
>    755  }
>    756
>
> --
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki