Re: [PATCH v6 00/12] mm/debug_vm_pgtable: Enhancements

[Gavin Shan]

Hi Anshuman and Vineet,

On 8/12/21 9:11 PM, Anshuman Khandual wrote:
> On 8/9/21 2:56 PM, Gavin Shan wrote:
> > There are couple of issues with current implementations and this series
> > tries to resolve the issues:
> >
> >    (a) All needed information are scattered in variables, passed to various
> >        test functions. The code is organized in pretty much relaxed fashion.
> >
> >    (b) The page isn't allocated from buddy during page table entry modifying
> >        tests. The page can be invalid, conflicting to the implementations
> >        of set_xxx_at() on ARM64. The target page is accessed so that the
> >        iCache can be flushed when execution permission is given on ARM64.
> >        Besides, the target page can be unmapped and accessing to it causes
> >        kernel crash.
> >
> > "struct pgtable_debug_args" is introduced to address issue (a). For issue
> > (b), the used page is allocated from buddy in page table entry modifying
> > tests. The corresponding tets will be skipped if we fail to allocate the
> > (huge) page. For other test cases, the original page around to kernel
> > symbol (@start_kernel) is still used.
> >
> > The patches are organized as below. PATCH[2-10] could be combined to one
> > patch, but it will make the review harder:
> >
> >    PATCH[1] introduces "struct pgtable_debug_args" as place holder of all
> >             needed information. With it, the old and new implementation
> >             can coexist.
> >    PATCH[2-10] uses "struct pgtable_debug_args" in various test functions.
> >    PATCH[11] removes the unused code for old implementation.
> >    PATCH[12] fixes the issue of corrupted page flag for ARM64
> >
> > Changelog
> > =========
> > v6:
> >     * Populate saved page table entry pointers after
> >       they're allocated in init_args()                        (Anshuman)
> >     * Fix imbalanced preemption count issue by replacing
> >       pte_alloc_mmap() with pte_alloc() in init_args()        (syzbot)
>
> + vgupta@xxxxxxxxxx
>
> Hello Gavin/Vineet,
>
> This series still need to be tested on ARC ?

Yes, I'm unable to test ARC as it's not supported by QEMU yet.
It would great if Vineet can give it a try on ARC :)

Thanks,
Gavin