Re: [PATCH v32 2/6] fs/proc/task_mmu: Implement IOCTL to get and optionally clear info about PTEs

[Philip Li]

On Fri, Aug 18, 2023 at 02:55:36PM +0500, Muhammad Usama Anjum wrote:
> On 8/18/23 12:16 PM, kernel test robot wrote:
> > Hi Muhammad,
> > 
> > kernel test robot noticed the following build errors:
> > 
> > [auto build test ERROR on akpm-mm/mm-everything]
> > [also build test ERROR on next-20230817]
> > [cannot apply to linus/master v6.5-rc6]
> > [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/Muhammad-Usama-Anjum/userfaultfd-UFFD_FEATURE_WP_ASYNC/20230816-193454
> > base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
> > patch link:    https://lore.kernel.org/r/20230816113049.1697849-3-usama.anjum%40collabora.com
> > patch subject: [PATCH v32 2/6] fs/proc/task_mmu: Implement IOCTL to get and optionally clear info about PTEs
> > config: arc-allyesconfig (https://download.01.org/0day-ci/archive/20230818/202308181520.yCq9Z26w-lkp@xxxxxxxxx/config)
> > compiler: arceb-elf-gcc (GCC) 12.3.0
> > reproduce: (https://download.01.org/0day-ci/archive/20230818/202308181520.yCq9Z26w-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/202308181520.yCq9Z26w-lkp@xxxxxxxxx/
> > 
> > All errors (new ones prefixed by >>):
> > 
> >    fs/proc/task_mmu.c: In function 'pagemap_scan_thp_entry':
> >>> fs/proc/task_mmu.c:2077:28: error: 'HPAGE_SIZE' undeclared (first use in this function); did you mean 'PAGE_SIZE'?
> >     2077 |         if (end != start + HPAGE_SIZE) {
> >          |                            ^~~~~~~~~~
> >          |                            PAGE_SIZE
> I've been emailing arc maintainers for resolution of this error from April,
> but nobody replies there:
> https://lore.kernel.org/all/0e6b318a-bbf8-3701-00af-1802c6347897@xxxxxxxxxxxxx

Thanks for the info, we will update the bot to ignore this error
to avoid duplicated reports.

> 
> >    fs/proc/task_mmu.c:2077:28: note: each undeclared identifier is reported only once for each function it appears in
> > 
> > 
> > vim +2077 fs/proc/task_mmu.c
> > 
> >   2044	
> >   2045	static int pagemap_scan_thp_entry(pmd_t *pmd, unsigned long start,
> >   2046					  unsigned long end, struct mm_walk *walk)
> >   2047	{
> >   2048	#ifdef CONFIG_TRANSPARENT_HUGEPAGE
> >   2049		struct pagemap_scan_private *p = walk->private;
> >   2050		struct vm_area_struct *vma = walk->vma;
> >   2051		unsigned long categories;
> >   2052		spinlock_t *ptl;
> >   2053		int ret = 0;
> >   2054	
> >   2055		ptl = pmd_trans_huge_lock(pmd, vma);
> >   2056		if (!ptl)
> >   2057			return -ENOENT;
> >   2058	
> >   2059		categories = p->cur_vma_category | pagemap_thp_category(*pmd);
> >   2060	
> >   2061		if (!pagemap_scan_is_interesting_page(categories, p))
> >   2062			goto out_unlock;
> >   2063	
> >   2064		ret = pagemap_scan_output(categories, p, start, &end);
> >   2065		if (start == end)
> >   2066			goto out_unlock;
> >   2067	
> >   2068		if (~p->arg.flags & PM_SCAN_WP_MATCHING)
> >   2069			goto out_unlock;
> >   2070		if (~categories & PAGE_IS_WRITTEN)
> >   2071			goto out_unlock;
> >   2072	
> >   2073		/*
> >   2074		 * Break huge page into small pages if the WP operation
> >   2075		 * needs to be performed on a portion of the huge page.
> >   2076		 */
> >> 2077		if (end != start + HPAGE_SIZE) {
> >   2078			spin_unlock(ptl);
> >   2079			split_huge_pmd(vma, pmd, start);
> >   2080			pagemap_scan_backout_range(p, start, end);
> >   2081			/* Report as if there was no THP */
> >   2082			return -ENOENT;
> >   2083		}
> >   2084	
> >   2085		make_uffd_wp_pmd(vma, start, pmd);
> >   2086		flush_tlb_range(vma, start, end);
> >   2087	out_unlock:
> >   2088		spin_unlock(ptl);
> >   2089		return ret;
> >   2090	#else /* !CONFIG_TRANSPARENT_HUGEPAGE */
> >   2091		return -ENOENT;
> >   2092	#endif
> >   2093	}
> >   2094	
> > 
> 
> -- 
> BR,
> Muhammad Usama Anjum
>