Re: [syzbot] [mm?] WARNING in __folio_rmap_sanity_checks

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



vm_normal_page() works on these mappings, so we'd also have to skip rmap
code when unmapping these pages etc. Maybe that's the whole reason we
have the rmap handling here: to not special-case the unmap path.

vm_insert_page() will set VM_MIXEDMAP and vm_normal_page() will skip
the page if CONFIG_ARCH_HAS_PTE_SPECIAL is enabled (it's enabled for
x86).  So the unmap path will skip these kind of folios?

I think we run into the
	if (likely(!pte_special(pte)))
		goto check_pfn;

first and return these folios. That also matches the comment of vm_normal_page: "VM_MIXEDMAP mappings can likewise contain memory with or without ... _all_ pages with a struct page (that is, those where pfn_valid is true) are refcounted and considered normal pages by the VM."

--
Cheers,

David / dhildenb





[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Bugtraq]     [Linux OMAP]     [Linux MIPS]     [eCos]     [Asterisk Internet PBX]     [Linux API]

  Powered by Linux