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Linus Torvalds f6f3732162 Revert "mm: replace p??_write with pte_access_permitted in fault + gup paths" 
This reverts commits 5c9d2d5c26, c7da82b894, and e7fe7b5cae.

We'll probably need to revisit this, but basically we should not
complicate the get_user_pages_fast() case, and checking the actual page
table protection key bits will require more care anyway, since the
protection keys depend on the exact state of the VM in question.

Particularly when doing a "remote" page lookup (ie in somebody elses VM,
not your own), you need to be much more careful than this was.  Dave
Hansen says:

 "So, the underlying bug here is that we now a get_user_pages_remote()
  and then go ahead and do the p*_access_permitted() checks against the
  current PKRU. This was introduced recently with the addition of the
  new p??_access_permitted() calls.

  We have checks in the VMA path for the "remote" gups and we avoid
  consulting PKRU for them. This got missed in the pkeys selftests
  because I did a ptrace read, but not a *write*. I also didn't
  explicitly test it against something where a COW needed to be done"

It's also not entirely clear that it makes sense to check the protection
key bits at this level at all.  But one possible eventual solution is to
make the get_user_pages_fast() case just abort if it sees protection key
bits set, which makes us fall back to the regular get_user_pages() case,
which then has a vma and can do the check there if we want to.

We'll see.

Somewhat related to this all: what we _do_ want to do some day is to
check the PAGE_USER bit - it should obviously always be set for user
pages, but it would be a good check to have back.  Because we have no
generic way to test for it, we lost it as part of moving over from the
architecture-specific x86 GUP implementation to the generic one in
commit e585513b76 ("x86/mm/gup: Switch GUP to the generic
get_user_page_fast() implementation").

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 		2017-12-15 18:53:22 -08:00
..
kasan kasan: use %px to print addresses instead of %p 2017-11-29 12:13:16 +11:00
Kconfig mm: add infrastructure for get_user_pages_fast() benchmarking 2017-11-17 16:10:04 -08:00
Kconfig.debug kmemcheck: rip it out 2017-11-15 18:21:05 -08:00
Makefile mm: add infrastructure for get_user_pages_fast() benchmarking 2017-11-17 16:10:04 -08:00
backing-dev.c bdi: add error handle for bdi_debug_register 2017-11-19 11:02:13 -07:00
balloon_compaction.c virtio_balloon: fix deadlock on OOM 2017-11-14 23:57:38 +02:00
bootmem.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
cleancache.c
…
cma.c mm/cma.c: change pr_info to pr_err for cma_alloc fail log 2017-11-15 18:21:03 -08:00
cma.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
cma_debug.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
compaction.c mm, compaction: remove unneeded pageblock_skip_persistent() checks 2017-11-17 16:10:00 -08:00
debug.c mm: consolidate page table accounting 2017-11-15 18:21:04 -08:00
debug_page_ref.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dmapool.c
…
early_ioremap.c mm/early_ioremap: Fix boot hang with earlyprintk=efi,keep 2017-12-11 14:54:44 +01:00
fadvise.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
failslab.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
filemap.c AFS development 2017-11-16 11:41:22 -08:00
frame_vector.c mm/frame_vector.c: release a semaphore in 'get_vaddr_frames()' 2017-12-14 16:00:48 -08:00
frontswap.c
…
gup.c Revert "mm: replace p??_write with pte_access_permitted in fault + gup paths" 2017-12-15 18:53:22 -08:00
gup_benchmark.c mm: add infrastructure for get_user_pages_fast() benchmarking 2017-11-17 16:10:04 -08:00
highmem.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
hmm.c Revert "mm: replace p??_write with pte_access_permitted in fault + gup paths" 2017-12-15 18:53:22 -08:00
huge_memory.c Revert "mm: replace p??_write with pte_access_permitted in fault + gup paths" 2017-12-15 18:53:22 -08:00
hugetlb.c mm/hugetlb: fix NULL-pointer dereference on 5-level paging machine 2017-11-29 18:40:43 -08:00
hugetlb_cgroup.c
…
hwpoison-inject.c
…
init-mm.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
internal.h Revert "mm, thp: Do not make pmd/pud dirty without a reason" 2017-11-29 09:01:01 -08:00
interval_tree.c
…
khugepaged.c Revert "mm, thp: Do not make pmd/pud dirty without a reason" 2017-11-29 09:01:01 -08:00
kmemleak-test.c
…
kmemleak.c mm/kmemleak.c: make cond_resched() rate-limiting more efficient 2017-12-14 16:00:48 -08:00
ksm.c mm/mmu_notifier: avoid double notification when it is useless 2017-11-15 18:21:03 -08:00
list_lru.c mm/list_lru.c: mark expected switch fall-through 2017-11-15 18:21:07 -08:00
maccess.c
…
madvise.c mm/madvise.c: fix madvise() infinite loop under special circumstances 2017-11-29 18:40:43 -08:00
memblock.c mm: define memblock_virt_alloc_try_nid_raw 2017-11-15 18:21:05 -08:00
memcontrol.c mm, memcg: fix mem_cgroup_swapout() for THPs 2017-11-29 18:40:43 -08:00
memory-failure.c mm, soft_offline: improve hugepage soft offlining error log 2017-11-15 18:21:05 -08:00
memory.c Revert "mm: replace p??_write with pte_access_permitted in fault + gup paths" 2017-12-15 18:53:22 -08:00
memory_hotplug.c memory hotplug: fix comments when adding section 2017-11-15 18:21:07 -08:00
mempolicy.c mm, sysctl: make NUMA stats configurable 2017-11-15 18:21:07 -08:00
mempool.c mm/mempool.c: use kmalloc_array_node() 2017-11-15 18:21:02 -08:00
memtest.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
migrate.c Revert "mm, thp: Do not make pmd/pud dirty without a reason" 2017-11-29 09:01:01 -08:00
mincore.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mlock.c mm: mlock: remove lru_add_drain_all() 2017-11-15 18:21:07 -08:00
mm_init.c
…
mmap.c mm, oom_reaper: fix memory corruption 2017-12-14 16:00:49 -08:00
mmu_context.c
…
mmu_notifier.c mm/mmu_notifier: avoid call to invalidate_range() in range_end() 2017-11-15 18:21:03 -08:00
mmzone.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mprotect.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mremap.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
msync.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
nobootmem.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
nommu.c
…
oom_kill.c mm, oom_reaper: fix memory corruption 2017-12-14 16:00:49 -08:00
page-writeback.c Revert "mm/page-writeback.c: print a warning if the vm dirtiness settings are illogical" 2017-11-29 18:40:43 -08:00
page_alloc.c mm/page_alloc.c: avoid excessive IRQ disabled times in free_unref_page_list() 2017-12-14 16:00:48 -08:00
page_counter.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
page_ext.c mm/page_ext.c: check if page_ext is not prepared 2017-11-15 18:21:07 -08:00
page_idle.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
page_io.c mm, swap: skip swapcache for swapin of synchronous device 2017-11-15 18:21:02 -08:00
page_isolation.c mm: distinguish CMA and MOVABLE isolation in has_unmovable_pages() 2017-11-15 18:21:02 -08:00
page_owner.c mm/page_owner.c: reduce page_owner structure size 2017-11-15 18:21:03 -08:00
page_poison.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
page_vma_mapped.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pagewalk.c mm/pagewalk.c: report holes in hugetlb ranges 2017-11-15 13:12:08 -08:00
percpu-internal.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
percpu-km.c
…
percpu-stats.c
…
percpu-vm.c mm: remove __GFP_COLD 2017-11-15 18:21:06 -08:00
percpu.c percpu: hack to let the CRIS architecture to boot until they clean up 2017-11-27 12:53:12 -08:00
pgtable-generic.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
process_vm_access.c
…
quicklist.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
readahead.c
…
rmap.c mm: remove cold parameter from free_hot_cold_page* 2017-11-15 18:21:06 -08:00
rodata_test.c
…
shmem.c Rename superblock flags (MS_xyz -> SB_xyz) 2017-11-27 13:05:09 -08:00
slab.c mm/slab.c: do not hash pointers when debugging slab 2017-12-14 16:00:48 -08:00
slab.h kmemcheck: stop using GFP_NOTRACK and SLAB_NOTRACK 2017-11-15 18:21:04 -08:00
slab_common.c kmemcheck: stop using GFP_NOTRACK and SLAB_NOTRACK 2017-11-15 18:21:04 -08:00
slob.c slab, slub, slob: add slab_flags_t 2017-11-15 18:21:01 -08:00
slub.c kmemcheck: rip it out 2017-11-15 18:21:05 -08:00
sparse-vmemmap.c mm, sparse: do not swamp log with huge vmemmap allocation failures 2017-11-15 18:21:07 -08:00
sparse.c mm: stop zeroing memory during allocation in vmemmap 2017-11-15 18:21:05 -08:00
swap.c mm, pagevec: rename pagevec drained field 2017-11-15 18:21:06 -08:00
swap_cgroup.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
swap_slots.c mm/swap_slots.c: fix race conditions in swap_slots cache init 2017-11-15 18:21:03 -08:00
swap_state.c mm: remove cold parameter for release_pages 2017-11-15 18:21:06 -08:00
swapfile.c mm: swap: SWP_SYNCHRONOUS_IO: skip swapcache only if swapped page has no other reference 2017-11-15 18:21:02 -08:00
truncate.c mm, pagevec: remove cold parameter for pagevecs 2017-11-15 18:21:06 -08:00
usercopy.c
…
userfaultfd.c
…
util.c
…
vmacache.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
vmalloc.c
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vmpressure.c
…
vmscan.c mm: remove cold parameter from free_hot_cold_page* 2017-11-15 18:21:06 -08:00
vmstat.c mm, sysctl: make NUMA stats configurable 2017-11-15 18:21:07 -08:00
workingset.c mm, truncate: do not check mapping for every page being truncated 2017-11-15 18:21:06 -08:00
z3fold.c mm/z3fold.c: use kref to prevent page free/compact race 2017-11-17 16:10:00 -08:00
zbud.c
…
zpool.c
…
zsmalloc.c zsmalloc: calling zs_map_object() from irq is a bug 2017-11-15 18:21:03 -08:00
zswap.c
…