iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity
linux/mm
History
Peter Xu 0f230bc24b mm/hugetlb: fix uffd-wp bit lost when unsharing happens 
When we try to unshare a pinned page for a private hugetlb, uffd-wp bit
can get lost during unsharing.

When above condition met, one can lose uffd-wp bit on the privately mapped
hugetlb page.  It allows the page to be writable even if it should still be
wr-protected.  I assume it can mean data loss.

This should be very rare, only if an unsharing happened on a private
hugetlb page with uffd-wp protected (e.g.  in a child which shares the
same page with parent with UFFD_FEATURE_EVENT_FORK enabled).

When I wrote the reproducer (provided in the last patch) I needed to
use the newest gup_test cmd introduced by David to trigger it because I
don't even know another way to do a proper RO longerm pin.

Besides that, it needs a bunch of other conditions all met:

        (1) hugetlb being mapped privately,
        (2) userfaultfd registered with WP and EVENT_FORK,
        (3) the user app fork()s, then,
        (4) RO longterm pin onto a wr-protected anonymous page.

If it's not impossible to hit in production I'd say extremely rare.

Link: https://lkml.kernel.org/r/20230417195317.898696-3-peterx@redhat.com
Fixes: 166f3ecc0daf ("mm/hugetlb: hook page faults for uffd write protection")
Signed-off-by: Peter Xu <peterx@redhat.com>
Reported-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Mika Penttilä <mpenttil@redhat.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-04-21 14:52:00 -07:00
..
damon
mm/damon/sysfs: make more kobj_type structures constant
2023-04-05 19:42:59 -07:00
kasan
kasan: fix lockdep report invalid wait context
2023-04-21 14:51:59 -07:00
kfence
printk: export console trace point for kcsan/kasan/kfence/kmsan
2023-04-18 16:30:11 -07:00
kmsan
printk: export console trace point for kcsan/kasan/kfence/kmsan
2023-04-18 16:30:11 -07:00
backing-dev.c
mm: backing-dev: set variables dev_attr_min,max_bytes storage-class-specifier to static
2023-04-18 16:29:56 -07:00
balloon_compaction.c
mm: Convert all PageMovable users to movable_operations
2022-08-02 12:34:03 -04:00
bootmem_info.c
bootmem: remove the vmemmap pages from kmemleak in put_page_bootmem
2022-08-28 14:02:45 -07:00
cma_debug.c
mm/cma_debug: show complete cma name in debugfs directories
2022-09-11 20:25:50 -07:00
cma_sysfs.c
mm: cma: make kobj_type structure constant
2023-03-28 16:20:06 -07:00
cma.c
mm: move most of core MM initialization to mm/mm_init.c
2023-04-05 19:42:52 -07:00
cma.h
mm/cma: provide option to opt out from exposing pages on activation failure
2022-03-22 15:57:09 -07:00
compaction.c
mm: compaction: fix the possible deadlock when isolating hugetlb pages
2023-04-05 19:42:50 -07:00
debug_page_ref.c
…
debug_vm_pgtable.c
mm, treewide: redefine MAX_ORDER sanely
2023-04-05 19:42:46 -07:00
debug.c
mm/debug: use %pGt to display page_type in dump_page()
2023-03-28 16:20:09 -07:00
dmapool_test.c
dmapool: add alloc/free performance test
2023-04-05 19:42:38 -07:00
dmapool.c
dmapool: create/destroy cleanup
2023-04-05 19:42:41 -07:00
early_ioremap.c
mm/early_ioremap: declare early_memremap_pgprot_adjust()
2022-03-22 15:57:11 -07:00
fadvise.c
mm: support POSIX_FADV_NOREUSE
2023-01-18 17:12:57 -08:00
failslab.c
mm: fix unexpected changes to {failslab|fail_page_alloc}.attr
2022-11-22 18:50:44 -08:00
filemap.c
mm: return an ERR_PTR from __filemap_get_folio
2023-04-05 19:42:42 -07:00
folio-compat.c
mm: return an ERR_PTR from __filemap_get_folio
2023-04-05 19:42:42 -07:00
frontswap.c
frontswap: don't call ->init if no ops are registered
2022-09-26 12:14:34 -07:00
gup_test.c
mm/gup_test: free memory allocated via kvcalloc() using kvfree()
2022-12-15 16:37:48 -08:00
gup_test.h
mm/gup_test: start/stop/read functionality for PIN LONGTERM test
2022-11-08 17:37:15 -08:00
gup.c
mm/gup.c: fix typo in comments
2023-03-28 16:20:14 -07:00
highmem.c
highmem: fix kmap_to_page() for kmap_local_page() addresses
2022-10-12 18:51:51 -07:00
hmm.c
mm/hugetlb: make walk_hugetlb_range() safe to pmd unshare
2023-01-18 17:12:39 -08:00
huge_memory.c
mm/huge_memory: conditionally call maybe_mkwrite() and drop pte_wrprotect() in __split_huge_pmd_locked()
2023-04-18 16:30:01 -07:00
hugetlb_cgroup.c
mm/hugetlb: increase use of folios in alloc_huge_page()
2023-02-13 15:54:27 -08:00
hugetlb_vmemmap.c
mm, page_alloc: use check_pages_enabled static key to check tail pages
2023-04-18 16:29:54 -07:00
hugetlb_vmemmap.h
mm: hugetlb_vmemmap: improve hugetlb_vmemmap code readability
2022-08-08 18:06:43 -07:00
hugetlb.c
mm/hugetlb: fix uffd-wp bit lost when unsharing happens
2023-04-21 14:52:00 -07:00
hwpoison-inject.c
mm/hwpoison: add __init/__exit annotations to module init/exit funcs
2022-10-03 14:03:05 -07:00
init-mm.c
mm: add per-VMA lock and helper functions to control it
2023-04-05 20:02:57 -07:00
internal.h
mm: apply __must_check to vmap_pages_range_noflush()
2023-04-18 16:30:10 -07:00
interval_tree.c
…
io-mapping.c
…
ioremap.c
mm: ioremap: Add ioremap/iounmap_allowed()
2022-06-27 12:22:31 +01:00
Kconfig
mm/hugetlb_vmemmap: rename ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
2023-04-18 16:30:09 -07:00
Kconfig.debug
kmemleak-test: fix kmemleak_test.c build logic
2023-04-18 16:29:47 -07:00
khugepaged.c
mm/khugepaged: maintain page cache uptodate flag
2023-04-18 16:29:52 -07:00
kmemleak.c
lib/stackdepot, mm: rename stack_depot_want_early_init
2023-02-16 20:43:49 -08:00
ksm.c
mm: ksm: support hwpoison for ksm page
2023-04-18 16:53:52 -07:00
list_lru.c
mm: kmem: make mem_cgroup_from_obj() vmalloc()-safe
2022-06-16 19:48:31 -07:00
maccess.c
maccess: Fix writing offset in case of fault in strncpy_from_kernel_nofault()
2022-11-11 11:44:46 -08:00
madvise.c
mm/madvise: use vma_lookup() instead of find_vma()
2023-04-18 16:29:52 -07:00
Makefile
dmapool: add alloc/free performance test
2023-04-05 19:42:38 -07:00
mapping_dirty_helpers.c
mm/mmu_notifier: remove unused mmu_notifier_range_update_to_read_only export
2023-02-02 22:32:54 -08:00
memblock.c
mm: avoid passing 0 to __ffs()
2023-04-18 16:29:42 -07:00
memcontrol.c
memcg: page_cgroup_ino() get memcg from the page's folio
2023-04-18 16:30:09 -07:00
memfd.c
memfd: pass argument of memfd_fcntl as int
2023-04-18 16:30:11 -07:00
memory_hotplug.c
mm: avoid passing 0 to __ffs()
2023-04-18 16:29:42 -07:00
memory-failure.c
mm: ksm: support hwpoison for ksm page
2023-04-18 16:53:52 -07:00
memory-tiers.c
memory tier: release the new_memtier in find_create_memory_tier()
2023-02-09 16:51:40 -08:00
memory.c
mm: hwpoison: support recovery from HugePage copy-on-write faults
2023-04-18 16:30:09 -07:00
mempolicy.c
mm/mempolicy: fix use-after-free of VMA iterator
2023-04-16 10:41:25 -07:00
mempool.c
mempool: do not use ksize() for poisoning
2022-11-30 15:58:41 -08:00
memremap.c
mm/memremap.c: fix outdated comment in devm_memremap_pages
2023-02-09 16:51:46 -08:00
memtest.c
mm/memtest: add results of early memtest to /proc/meminfo
2023-04-05 19:42:55 -07:00
migrate_device.c
mm: change to return bool for isolate_lru_page()
2023-02-20 12:46:17 -08:00
migrate.c
mm/migrate: revert "mm/migrate: fix wrongly apply write bit after mkdirty on sparc64"
2023-04-18 16:30:01 -07:00
mincore.c
mm: return an ERR_PTR from __filemap_get_folio
2023-04-05 19:42:42 -07:00
mlock.c
mm: mlock: use folios_put() in mlock_folio_batch()
2023-04-18 16:29:53 -07:00
mm_init.c
mm/vmemmap/devdax: fix kernel crash when probing devdax devices
2023-04-18 16:30:09 -07:00
mm_slot.h
mm: introduce common struct mm_slot
2022-10-03 14:02:43 -07:00
mmap_lock.c
…
mmap.c
sync mm-stable with mm-hotfixes-stable to pick up depended-upon upstream changes
2023-04-18 14:53:49 -07:00
mmu_gather.c
mm: prefer xxx_page() alloc/free functions for order-0 pages
2023-03-28 16:20:16 -07:00
mmu_notifier.c
mm/mmu_notifier: remove unused mmu_notifier_range_update_to_read_only export
2023-02-02 22:32:54 -08:00
mmzone.c
mm: multi-gen LRU: groundwork
2022-09-26 19:46:09 -07:00
mprotect.c
mm/userfaultfd: don't consider uffd-wp bit of writable migration entries
2023-04-18 16:29:53 -07:00
mremap.c
mm/mremap: write-lock VMA while remapping it to a new address range
2023-04-05 20:02:58 -07:00
msync.c
mm/msync: use vma_find() instead of vma linked list
2022-09-26 19:46:25 -07:00
nommu.c
mm: vmalloc: convert vread() to vread_iter()
2023-04-05 19:42:57 -07:00
oom_kill.c
mm/mmu_notifier: remove unused mmu_notifier_range_update_to_read_only export
2023-02-02 22:32:54 -08:00
page_alloc.c
mm, page_alloc: use check_pages_enabled static key to check tail pages
2023-04-18 16:29:54 -07:00
page_counter.c
mm: page_counter: remove unneeded atomic ops for low/min
2022-09-11 20:26:01 -07:00
page_ext.c
mm/page_ext: init page_ext early if there are no deferred struct pages
2023-02-02 22:33:22 -08:00
page_idle.c
mm: page_idle: convert page idle to use a folio
2023-01-18 17:12:52 -08:00
page_io.c
- Daniel Verkamp has contributed a memfd series ("mm/memfd: add
2023-02-23 17:09:35 -08:00
page_isolation.c
mm, treewide: redefine MAX_ORDER sanely
2023-04-05 19:42:46 -07:00
page_owner.c
mm, treewide: redefine MAX_ORDER sanely
2023-04-05 19:42:46 -07:00
page_poison.c
…
page_reporting.c
mm, treewide: redefine MAX_ORDER sanely
2023-04-05 19:42:46 -07:00
page_reporting.h
…
page_table_check.c
mm/page_ext: do not allocate space for page_ext->flags if not needed
2023-02-02 22:33:11 -08:00
page_vma_mapped.c
mm/hugetlb: introduce hugetlb_walk()
2023-01-18 17:12:39 -08:00
page-writeback.c
mm,jfs: move write_one_page/folio_write_one to jfs
2023-03-28 16:20:14 -07:00
pagewalk.c
mm/hugetlb: introduce hugetlb_walk()
2023-01-18 17:12:39 -08:00
percpu-internal.h
mm: percpu: fix incorrect size in pcpu_obj_full_size()
2023-02-16 20:43:55 -08:00
percpu-km.c
…
percpu-stats.c
…
percpu-vm.c
…
percpu.c
mm: memcontrol: rename memcg_kmem_enabled()
2023-02-16 20:43:56 -08:00
pgalloc-track.h
…
pgtable-generic.c
mm: add PTE pointer parameter to flush_tlb_fix_spurious_fault()
2023-03-28 16:20:12 -07:00
process_vm_access.c
use less confusing names for iov_iter direction initializers
2022-11-25 13:01:55 -05:00
ptdump.c
mm: pagewalk: Fix race between unmap and page walker
2022-09-03 10:13:13 -07:00
readahead.c
readahead: convert readahead_expand() to use a folio
2023-02-02 22:33:21 -08:00
rmap.c
mm/khugepaged: write-lock VMA while collapsing a huge page
2023-04-05 20:02:58 -07:00
rodata_test.c
mm/rodata_test: use PAGE_ALIGNED() helper
2022-10-03 14:03:05 -07:00
secretmem.c
- Daniel Verkamp has contributed a memfd series ("mm/memfd: add
2023-02-23 17:09:35 -08:00
shmem.c
userfaultfd: convert mfill_atomic() to use a folio
2023-04-18 16:29:55 -07:00
shrinker_debug.c
mm: shrinkers: convert shrinker_rwsem to mutex
2023-03-28 16:20:17 -07:00
shuffle.c
mm/shuffle: convert module_param_call to module_param_cb
2022-10-03 14:03:07 -07:00
shuffle.h
mm, treewide: redefine MAX_ORDER sanely
2023-04-05 19:42:46 -07:00
slab_common.c
mm/kasan: simplify and refine kasan_cache code
2023-01-18 17:12:55 -08:00
slab.c
mm: vmscan: refactor updating current->reclaim_state
2023-04-18 16:30:10 -07:00
slab.h
mm: move kmem_cache_init() declaration to mm/slab.h
2023-04-05 19:42:54 -07:00
slob.c
mm: vmscan: refactor updating current->reclaim_state
2023-04-18 16:30:10 -07:00
slub.c
mm: vmscan: refactor updating current->reclaim_state
2023-04-18 16:30:10 -07:00
sparse-vmemmap.c
mm/vmemmap/devdax: fix kernel crash when probing devdax devices
2023-04-18 16:30:09 -07:00
sparse.c
mm/sparse: fix "unused function 'pgdat_to_phys'" warning
2023-02-02 22:33:29 -08:00
swap_cgroup.c
mm: memcontrol: don't allocate cgroup swap arrays when memcg is disabled
2022-10-03 14:03:36 -07:00
swap_slots.c
mm/swap: convert put_swap_page() to put_swap_folio()
2022-10-03 14:02:46 -07:00
swap_state.c
mm: return an ERR_PTR from __filemap_get_folio
2023-04-05 19:42:42 -07:00
swap.c
mm: swap: fix performance regression on sparsetruncate-tiny
2023-04-16 10:41:24 -07:00
swap.h
mm: remove the __swap_writepage return value
2023-02-02 22:33:33 -08:00
swapfile.c
sync mm-stable with mm-hotfixes-stable to pick up depended-upon upstream changes
2023-04-16 12:31:58 -07:00
truncate.c
mm: return an ERR_PTR from __filemap_get_folio
2023-04-05 19:42:42 -07:00
usercopy.c
mm: use kstrtobool() instead of strtobool()
2022-11-30 15:58:45 -08:00
userfaultfd.c
userfaultfd: convert mfill_atomic() to use a folio
2023-04-18 16:29:55 -07:00
util.c
mm: fix typo in __vm_enough_memory warning
2023-02-13 15:54:33 -08:00
vmalloc.c
mm: vmalloc: rename addr_to_vb_xarray() function
2023-04-18 16:29:48 -07:00
vmpressure.c
…
vmscan.c
mm: Multi-gen LRU: remove wait_event_killable()
2023-04-18 16:30:11 -07:00
vmstat.c
mm: introduce per-VMA lock statistics
2023-04-05 20:03:01 -07:00
workingset.c
mm: workingset: update description of the source file
2023-04-18 16:30:11 -07:00
z3fold.c
mm: remove PageMovable export
2023-01-18 17:12:57 -08:00
zbud.c
zpool: clean out dead code
2022-12-11 18:12:10 -08:00
zpool.c
zpool: clean out dead code
2022-12-11 18:12:10 -08:00
zsmalloc.c
zsmalloc: reset compaction source zspage pointer after putback_zspage()
2023-04-18 16:29:42 -07:00
zswap.c
mm/zswap: delay the initialization of zswap
2023-04-18 16:29:48 -07:00