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linux/mm
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Mina Almasry d84cf06e3d mm, hugetlb: fix simple resv_huge_pages underflow on UFFDIO_COPY 
The userfaultfd hugetlb tests cause a resv_huge_pages underflow.  This
happens when hugetlb_mcopy_atomic_pte() is called with !is_continue on
an index for which we already have a page in the cache.  When this
happens, we allocate a second page, double consuming the reservation,
and then fail to insert the page into the cache and return -EEXIST.

To fix this, we first check if there is a page in the cache which
already consumed the reservation, and return -EEXIST immediately if so.

There is still a rare condition where we fail to copy the page contents
AND race with a call for hugetlb_no_page() for this index and again we
will underflow resv_huge_pages.  That is fixed in a more complicated
patch not targeted for -stable.

Test:

  Hacked the code locally such that resv_huge_pages underflows produce a
  warning, then:

  ./tools/testing/selftests/vm/userfaultfd hugetlb_shared 10
	2 /tmp/kokonut_test/huge/userfaultfd_test && echo test success
  ./tools/testing/selftests/vm/userfaultfd hugetlb 10
	2 /tmp/kokonut_test/huge/userfaultfd_test && echo test success

Both tests succeed and produce no warnings.  After the test runs number
of free/resv hugepages is correct.

[mike.kravetz@oracle.com: changelog fixes]

Link: https://lkml.kernel.org/r/20210528004649.85298-1-almasrymina@google.com
Fixes: 8fb5debc5f ("userfaultfd: hugetlbfs: add hugetlb_mcopy_atomic_pte for userfaultfd support")
Signed-off-by: Mina Almasry <almasrymina@google.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-05 08:58:12 -07:00
..
kasan mm/kasan/init.c: fix doc warning 2021-06-05 08:58:11 -07:00
kfence kfence: use TASK_IDLE when awaiting allocation 2021-06-05 08:58:11 -07:00
backing-dev.c mm/backing-dev.c: use might_alloc() 2021-02-26 09:41:01 -08:00
balloon_compaction.c mm: fix typos in comments 2021-05-07 00:26:35 -07:00
cleancache.c
cma_debug.c mm/cma: change cma mutex to irq safe spinlock 2021-05-05 11:27:21 -07:00
cma_sysfs.c mm: cma: support sysfs 2021-05-05 11:27:24 -07:00
cma.c mm: use proper type for cma_[alloc|release] 2021-05-05 11:27:24 -07:00
cma.h mm: cma: support sysfs 2021-05-05 11:27:24 -07:00
compaction.c mm: fix typos in comments 2021-05-07 00:26:35 -07:00
debug_page_ref.c
debug_vm_pgtable.c mm/debug_vm_pgtable: fix alignment for pmd/pud_advanced_tests() 2021-06-05 08:58:11 -07:00
debug.c mm/debug: improve memcg debugging 2021-02-24 13:38:27 -08:00
dmapool.c mm/dmapool: switch from strlcpy to strscpy 2021-04-30 11:20:39 -07:00
early_ioremap.c mm/early_ioremap.c: use __func__ instead of function name 2021-02-26 09:41:02 -08:00
fadvise.c mm, fadvise: improve the expensive remote LRU cache draining after FADV_DONTNEED 2020-10-13 18:38:29 -07:00
failslab.c
filemap.c mm: fix typos in comments 2021-05-07 00:26:35 -07:00
frontswap.c mm/mempool: minor coding style tweaks 2021-05-05 11:27:27 -07:00
gup_test.c selftests/vm: gup_test: test faulting in kernel, and verify pinnable pages 2021-05-05 11:27:26 -07:00
gup_test.h selftests/vm: gup_test: fix test flag 2021-05-05 11:27:26 -07:00
gup.c Revert "mm/gup: check page posion status for coredump." 2021-05-22 15:09:07 -10:00
highmem.c mm: fix typos in comments 2021-05-07 00:26:35 -07:00
hmm.c mm: do page fault accounting in handle_mm_fault 2020-08-12 10:58:02 -07:00
huge_memory.c mm: fix typos in comments 2021-05-07 00:26:35 -07:00
hugetlb_cgroup.c hugetlb: make free_huge_page irq safe 2021-05-05 11:27:22 -07:00
hugetlb.c mm, hugetlb: fix simple resv_huge_pages underflow on UFFDIO_COPY 2021-06-05 08:58:12 -07:00
hwpoison-inject.c mm,hwpoison-inject: don't pin for hwpoison_filter 2020-10-16 11:11:16 -07:00
init-mm.c mm/gup: prevent gup_fast from racing with COW during fork 2020-12-15 12:13:39 -08:00
internal.h Revert "mm/gup: check page posion status for coredump." 2021-05-22 15:09:07 -10:00
interval_tree.c mm/interval_tree: add comments to improve code readability 2021-04-30 11:20:38 -07:00
io-mapping.c mm: add a io_mapping_map_user helper 2021-04-30 11:20:39 -07:00
ioremap.c mm/ioremap: fix iomap_max_page_shift 2021-05-14 19:41:32 -07:00
Kconfig mm,memory_hotplug: allocate memmap from the added memory range 2021-05-05 11:27:26 -07:00
Kconfig.debug mm, page_poison: remove CONFIG_PAGE_POISONING_ZERO 2020-12-15 12:13:46 -08:00
khugepaged.c mm: fix typos in comments 2021-05-07 00:26:35 -07:00
kmemleak.c mm/kmemleak.c: fix a typo 2021-04-30 11:20:36 -07:00
ksm.c ksm: revert "use GET_KSM_PAGE_NOLOCK to get ksm page in remove_rmap_item_from_tree()" 2021-05-14 19:41:32 -07:00
list_lru.c mm: vmscan: consolidate shrinker_maps handling code 2021-05-05 11:27:23 -07:00
maccess.c uaccess: add force_uaccess_{begin,end} helpers 2020-08-12 10:57:59 -07:00
madvise.c mm: fix typos in comments 2021-05-07 00:26:35 -07:00
Makefile mm,memory_hotplug: add kernel boot option to enable memmap_on_memory 2021-05-05 11:27:27 -07:00
mapping_dirty_helpers.c mm/mapping_dirty_helpers: guard hugepage pud's usage 2021-04-16 16:10:37 -07:00
memblock.c memblock: remove return value of memblock_free_all() 2021-02-22 13:01:23 -08:00
memcontrol.c mm: fix typos in comments 2021-05-07 00:26:35 -07:00
memfd.c
memory_hotplug.c mm/mempool: minor coding style tweaks 2021-05-05 11:27:27 -07:00
memory-failure.c mm: fix typos in comments 2021-05-07 00:26:35 -07:00
memory.c Revert "MIPS: make userspace mapping young by default" 2021-06-05 08:58:11 -07:00
mempolicy.c mm: fix typos in comments 2021-05-07 00:26:35 -07:00
mempool.c mm/mempool: minor coding style tweaks 2021-05-05 11:27:27 -07:00
memremap.c mm/memremap.c: fix improper SPDX comment style 2021-04-30 11:20:37 -07:00
memtest.c
migrate.c mm: fix typos in comments 2021-05-07 00:26:35 -07:00
mincore.c inode: make init and permission helpers idmapped mount aware 2021-01-24 14:27:16 +01:00
mlock.c mm/mempool: minor coding style tweaks 2021-05-05 11:27:27 -07:00
mm_init.c include/linux/page-flags-layout.h: cleanups 2021-04-30 11:20:42 -07:00
mmap_lock.c mm: mmap_lock: add tracepoints around lock acquisition 2020-12-15 12:13:41 -08:00
mmap.c mm: fix typos in comments 2021-05-07 00:26:35 -07:00
mmu_gather.c mm: eliminate "expecting prototype" kernel-doc warnings 2021-04-16 16:10:36 -07:00
mmu_notifier.c mm/mmu_notifiers: ensure range_end() is paired with range_start() 2021-03-25 09:22:55 -07:00
mmzone.c mm/lru: replace pgdat lru_lock with lruvec lock 2020-12-15 14:48:04 -08:00
mprotect.c mm: fix typos in comments 2021-05-07 00:26:35 -07:00
mremap.c mm: fix typos in comments 2021-05-07 00:26:35 -07:00
msync.c mm/msync: exit early when the flags is an MS_ASYNC and start < vm_start 2021-04-30 11:20:37 -07:00
nommu.c mm/vmalloc: remove vwrite() 2021-05-07 00:26:34 -07:00
oom_kill.c mm: fix typos in comments 2021-05-07 00:26:35 -07:00
page_alloc.c mm/page_alloc: fix counting of free pages after take off from buddy 2021-06-05 08:58:11 -07:00
page_counter.c mm: page_counter: mitigate consequences of a page_counter underflow 2021-04-30 11:20:38 -07:00
page_ext.c mm: fix some spelling mistakes in comments 2020-12-15 22:46:19 -08:00
page_idle.c mm: page_idle_get_page() does not need lru_lock 2020-12-15 14:48:03 -08:00
page_io.c swap: fix swapfile read/write offset 2021-03-02 17:25:46 -07:00
page_isolation.c mm/page_isolation: do not isolate the max order page 2020-12-15 12:13:45 -08:00
page_owner.c mm: fix typos in comments 2021-05-07 00:26:35 -07:00
page_poison.c mm: page_poison: print page info when corruption is caught 2021-04-30 11:20:36 -07:00
page_reporting.c mm/page_reporting: use list_entry_is_head() in page_reporting_cycle() 2021-02-24 13:38:30 -08:00
page_reporting.h mm: introduce include/linux/pgtable.h 2020-06-09 09:39:13 -07:00
page_vma_mapped.c mm: fix typos in comments 2021-05-07 00:26:35 -07:00
page-writeback.c mm: fix typos in comments 2021-05-07 00:26:35 -07:00
pagewalk.c mmap locking API: convert mmap_sem comments 2020-06-09 09:39:14 -07:00
percpu-internal.h mm: fix typos in comments 2021-05-07 00:26:35 -07:00
percpu-km.c mm: memcg/percpu: account percpu memory to memory cgroups 2020-08-12 10:57:55 -07:00
percpu-stats.c percpu: make pcpu_nr_empty_pop_pages per chunk type 2021-04-09 13:58:38 +00:00
percpu-vm.c mm/vmalloc: remove unmap_kernel_range 2021-04-30 11:20:40 -07:00
percpu.c mm: fix typos in comments 2021-05-07 00:26:35 -07:00
pgalloc-track.h mm: fix typos in comments 2021-05-07 00:26:35 -07:00
pgtable-generic.c mm/pgtable-generic.c: optimize the VM_BUG_ON condition in pmdp_huge_clear_flush() 2021-02-24 13:38:30 -08:00
process_vm_access.c mm/process_vm_access.c: remove duplicate include 2021-05-05 11:27:27 -07:00
ptdump.c mm: ptdump: fix build failure 2021-04-16 16:10:37 -07:00
readahead.c mm: Implement readahead_control pageset expansion 2021-04-23 10:14:29 +01:00
rmap.c mm: fix some typos and code style problems 2021-05-07 00:26:33 -07:00
rodata_test.c mm/rodata_test.c: fix missing function declaration 2020-08-21 09:52:53 -07:00
shmem.c userfaultfd: release page in error path to avoid BUG_ON 2021-05-14 19:41:32 -07:00
shuffle.c mm: eliminate "expecting prototype" kernel-doc warnings 2021-04-16 16:10:36 -07:00
shuffle.h mm/shuffle: fix section mismatch warning 2021-05-22 15:09:07 -10:00
slab_common.c mm, slub: move slub_debug static key enabling outside slab_mutex 2021-05-14 19:41:32 -07:00
slab.c mm: fix typos in comments 2021-05-07 00:26:35 -07:00
slab.h kasan, mm: integrate slab init_on_alloc with HW_TAGS 2021-04-30 11:20:41 -07:00
slob.c mm: Don't build mm_dump_obj() on CONFIG_PRINTK=n kernels 2021-03-08 14:18:46 -08:00
slub.c kasan: slab: always reset the tag in get_freepointer_safe() 2021-05-22 15:09:07 -10:00
sparse-vmemmap.c mm/sparse: only sub-section aligned range would be populated 2020-08-07 11:33:27 -07:00
sparse.c mm/mempool: minor coding style tweaks 2021-05-05 11:27:27 -07:00
swap_cgroup.c mm: memcontrol: make swap tracking an integral part of memory control 2020-06-03 20:09:48 -07:00
swap_slots.c mm: fix typos in comments 2021-05-07 00:26:35 -07:00
swap_state.c mm: fix some typos and code style problems 2021-05-07 00:26:33 -07:00
swap.c mm: fix some typos and code style problems 2021-05-07 00:26:33 -07:00
swapfile.c mm/mempool: minor coding style tweaks 2021-05-05 11:27:27 -07:00
truncate.c mm: stop accounting shadow entries 2021-05-05 11:27:19 -07:00
usercopy.c mm/usercopy.c: delete duplicated word 2020-08-12 10:57:58 -07:00
userfaultfd.c userfaultfd: hugetlbfs: fix new flag usage in error path 2021-05-22 15:09:07 -10:00
util.c mm/util.c: fix typo 2021-05-05 11:27:25 -07:00
vmacache.c kernel: better document the use_mm/unuse_mm API contract 2020-06-10 19:14:18 -07:00
vmalloc.c mm: fix typos in comments 2021-05-07 00:26:35 -07:00
vmpressure.c
vmscan.c mm/mempool: minor coding style tweaks 2021-05-05 11:27:27 -07:00
vmstat.c mm: fix typos in comments 2021-05-07 00:26:35 -07:00
workingset.c mm: stop accounting shadow entries 2021-05-05 11:27:19 -07:00
z3fold.c mm: fix some typos and code style problems 2021-05-07 00:26:33 -07:00
zbud.c mm: set the sleep_mapped to true for zbud and z3fold 2021-02-26 09:41:01 -08:00
zpool.c mm: fix typos in comments 2021-05-07 00:26:35 -07:00
zsmalloc.c mm: fix typos in comments 2021-05-07 00:26:35 -07:00
zswap.c mm/zswap.c: switch from strlcpy to strscpy 2021-05-05 11:27:27 -07:00