Messages in this thread | | | Subject | Re: [PATCH] MIPS: fix pmd_mkinvalid | From | Hongchen Zhang <> | Date | Tue, 12 Jul 2022 18:01:08 +0800 |
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On 2022/7/7 下午7:12, Hongchen Zhang wrote: > On 2022/7/7 下午5:22, Thomas Bogendoerfer wrote: >> On Thu, Jul 07, 2022 at 04:11:35PM +0800, Hongchen Zhang wrote: >>> When a pmd entry is invalidated by pmd_mkinvalid,pmd_present should >>> return true. >>> So introduce a _PMD_PRESENT_INVALID_SHIFT bit to check if a pmd is >>> present but invalidated by pmd_mkinvalid. >> >> What problem are you trying to fix ? What are the symptoms ? >> >>> Reported-by: kernel test robot <lkp@intel.com> >> >> the test robot showed problems with your last version of the patch, >> which hasn't been integrated into at least the MIPS tree, so no >> need to that. >> >> Thomas. >> > > Hi Thomas, > The idea come from the commit: > b65399f6111b(arm64/mm: Change THP helpers to comply with generic MM > semantics). > There is an problem now: > CPU 0 CPU 1 > pmdp_invalidate do_page_fault > ... __handle_mm_fault > is_swap_pmd == true > trigger VM_BUG_ON() ? > set_pmd_at > the reason is that pmd_present return true,after this commit > pmd_present will return false,and the VM_BUG_ON will not be triggered. > Like arm64 does,we can introduce a new bit to fix this. > > Thanks. Hi Thomas, Is there problem of this patch? What's your opinion of this patch?
Thanks
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