kernel_optimize_test/mm
Linus Torvalds 6b3a707736 Merge branch 'page-refs' (page ref overflow)
Merge page ref overflow branch.

Jann Horn reported that he can overflow the page ref count with
sufficient memory (and a filesystem that is intentionally extremely
slow).

Admittedly it's not exactly easy.  To have more than four billion
references to a page requires a minimum of 32GB of kernel memory just
for the pointers to the pages, much less any metadata to keep track of
those pointers.  Jann needed a total of 140GB of memory and a specially
crafted filesystem that leaves all reads pending (in order to not ever
free the page references and just keep adding more).

Still, we have a fairly straightforward way to limit the two obvious
user-controllable sources of page references: direct-IO like page
references gotten through get_user_pages(), and the splice pipe page
duplication.  So let's just do that.

* branch page-refs:
  fs: prevent page refcount overflow in pipe_buf_get
  mm: prevent get_user_pages() from overflowing page refcount
  mm: add 'try_get_page()' helper function
  mm: make page ref count overflow check tighter and more explicit
2019-04-14 15:09:40 -07:00
..
kasan kasan: fix variable 'tag' set but not used warning 2019-03-29 10:01:36 -07:00
backing-dev.c writeback: synchronize sync(2) against cgroup writeback membership switches 2019-01-22 14:39:38 -07:00
balloon_compaction.c
cleancache.c
cma_debug.c mm/cma_debug.c: remove static scoped cma_debugfs_root 2019-03-05 21:07:20 -08:00
cma.c memblock: emphasize that memblock_alloc_range() returns a physical address 2019-03-12 10:04:01 -07:00
cma.h
compaction.c mm/compaction.c: abort search if isolation fails 2019-04-04 11:56:15 +01:00
debug_page_ref.c
debug.c mm/debug.c: fix __dump_page when mapping->host is not set 2019-03-29 10:01:37 -07:00
dmapool.c docs/core-api/mm: fix return value descriptions in mm/ 2019-03-05 21:07:20 -08:00
early_ioremap.c
fadvise.c
failslab.c mm: no need to check return value of debugfs_create functions 2019-03-05 21:07:17 -08:00
filemap.c filemap: add a comment about FAULT_FLAG_RETRY_NOWAIT behavior 2019-03-15 11:26:07 -07:00
frame_vector.c
frontswap.c
gup_benchmark.c mm: no need to check return value of debugfs_create functions 2019-03-05 21:07:17 -08:00
gup.c Merge branch 'page-refs' (page ref overflow) 2019-04-14 15:09:40 -07:00
highmem.c mm: convert totalram_pages and totalhigh_pages variables to atomic 2018-12-28 12:11:47 -08:00
hmm.c mm/hmm: convert to use vm_fault_t 2019-03-12 10:04:00 -07:00
huge_memory.c mm/huge_memory.c: fix modifying of page protection by insert_pfn_pmd() 2019-04-05 16:02:31 -10:00
hugetlb_cgroup.c
hugetlb.c Merge branch 'page-refs' (page ref overflow) 2019-04-14 15:09:40 -07:00
hwpoison-inject.c
init-mm.c
internal.h mm, compaction: capture a page under direct compaction 2019-03-05 21:07:17 -08:00
interval_tree.c
Kconfig ksm: replace jhash2 with xxhash 2018-12-28 12:11:46 -08:00
Kconfig.debug mm/page_owner: move config option to mm/Kconfig.debug 2019-03-05 21:07:18 -08:00
khugepaged.c mm: memcontrol: expose THP events on a per-memcg basis 2019-03-05 21:07:19 -08:00
kmemleak-test.c
kmemleak.c kmemleak: powerpc: skip scanning holes in the .bss section 2019-04-05 16:02:30 -10:00
ksm.c mm: ksm: do not block on page lock when searching stable tree 2019-03-05 21:07:19 -08:00
list_lru.c numa: make "nr_node_ids" unsigned int 2019-03-05 21:07:19 -08:00
maccess.c Revert "x86/fault: BUG() when uaccess helpers fault on kernel addresses" 2019-02-25 09:10:51 -08:00
madvise.c mm/mmu_notifier: use structure for invalidate_range_start/end calls v2 2018-12-28 12:11:50 -08:00
Makefile mm: remove nobootmem 2018-10-31 08:54:16 -07:00
memblock.c mm: memblock: update comments and kernel-doc 2019-03-12 10:04:02 -07:00
memcontrol.c mm: writeback: use exact memcg dirty counts 2019-04-05 16:02:31 -10:00
memfd.c mm/memfd: add an F_SEAL_FUTURE_WRITE seal to memfd 2019-03-05 21:07:19 -08:00
memory_hotplug.c mm/memory_hotplug.c: fix notification in offline error path 2019-03-29 10:01:37 -07:00
memory-failure.c mm: hwpoison: fix thp split handing in soft_offline_in_use_page() 2019-03-05 21:07:13 -08:00
memory.c mm/memory.c: fix modifying of page protection by insert_pfn() 2019-03-29 10:01:37 -07:00
mempolicy.c mm: mempolicy: make mbind() return -EIO when MPOL_MF_STRICT is specified 2019-03-29 10:01:37 -07:00
mempool.c docs/core-api/mm: fix return value descriptions in mm/ 2019-03-05 21:07:20 -08:00
memtest.c
migrate.c mm/migrate.c: add missing flush_dcache_page for non-mapped page migrate 2019-03-29 10:01:37 -07:00
mincore.c Revert "Change mincore() to count "mapped" pages rather than "cached" pages" 2019-01-24 09:04:37 +13:00
mlock.c mm: remove zone_lru_lock() function, access ->lru_lock directly 2019-03-05 21:07:21 -08:00
mm_init.c mm: convert totalram_pages and totalhigh_pages variables to atomic 2018-12-28 12:11:47 -08:00
mmap.c mm: fix some typos in mm directory 2019-03-05 21:07:18 -08:00
mmu_context.c
mmu_gather.c mm: Replace call_rcu_sched() with call_rcu() 2018-11-27 09:21:46 -08:00
mmu_notifier.c mm/mmu_notifier: use structure for invalidate_range_start/end calls v2 2018-12-28 12:11:50 -08:00
mmzone.c
mprotect.c mm: update ptep_modify_prot_commit to take old pte value as arg 2019-03-05 21:07:18 -08:00
mremap.c mm,mremap: bail out earlier in mremap_to under map pressure 2019-03-05 21:07:21 -08:00
msync.c
nommu.c mm/gup: cache dev_pagemap while pinning pages 2018-10-26 16:38:15 -07:00
oom_kill.c mm,oom: don't kill global init via memory.oom.group 2019-03-05 21:07:19 -08:00
page_alloc.c mm/hotplug: fix offline undo_isolate_page_range() 2019-03-29 10:01:37 -07:00
page_counter.c
page_ext.c memblock: drop memblock_alloc_*_nopanic() variants 2019-03-12 10:04:02 -07:00
page_idle.c mm: remove zone_lru_lock() function, access ->lru_lock directly 2019-03-05 21:07:21 -08:00
page_io.c mm/page_io.c: fix polled swap page in 2019-01-04 13:13:48 -08:00
page_isolation.c mm/page_isolation.c: fix a wrong flag in set_migratetype_isolate() 2019-03-29 10:01:37 -07:00
page_owner.c mm: no need to check return value of debugfs_create functions 2019-03-05 21:07:17 -08:00
page_poison.c page_poison: play nicely with KASAN 2019-03-05 21:07:13 -08:00
page_vma_mapped.c mm/rmap: map_pte() was not handling private ZONE_DEVICE page properly 2018-10-31 08:54:11 -07:00
page-writeback.c docs/core-api/mm: fix return value descriptions in mm/ 2019-03-05 21:07:20 -08:00
pagewalk.c
percpu-internal.h
percpu-km.c percpu: km: no need to consider pcpu_group_offsets[0] 2019-02-26 13:47:58 -08:00
percpu-stats.c
percpu-vm.c
percpu.c memblock: drop memblock_alloc_*_nopanic() variants 2019-03-12 10:04:02 -07:00
pgtable-generic.c
process_vm_access.c
quicklist.c
readahead.c docs/core-api/mm: fix return value descriptions in mm/ 2019-03-05 21:07:20 -08:00
rmap.c mm: remove zone_lru_lock() function, access ->lru_lock directly 2019-03-05 21:07:21 -08:00
rodata_test.c
shmem.c mm/memfd: add an F_SEAL_FUTURE_WRITE seal to memfd 2019-03-05 21:07:19 -08:00
slab_common.c mm: add support for kmem caches in DMA32 zone 2019-03-29 10:01:37 -07:00
slab.c slab: fix a crash by reading /proc/slab_allocators 2019-04-07 19:23:12 -10:00
slab.h mm: add support for kmem caches in DMA32 zone 2019-03-29 10:01:37 -07:00
slob.c
slub.c mm: add support for kmem caches in DMA32 zone 2019-03-29 10:01:37 -07:00
sparse-vmemmap.c mm: remove include/linux/bootmem.h 2018-10-31 08:54:16 -07:00
sparse.c mm/hotplug: fix offline undo_isolate_page_range() 2019-03-29 10:01:37 -07:00
swap_cgroup.c
swap_slots.c
swap_state.c mm: swap: add comment for swap_vma_readahead 2019-03-05 21:07:16 -08:00
swap.c mm: remove zone_lru_lock() function, access ->lru_lock directly 2019-03-05 21:07:21 -08:00
swapfile.c mm/swapfile.c: use struct_size() in kvzalloc() 2019-03-05 21:07:21 -08:00
truncate.c docs/core-api/mm: fix return value descriptions in mm/ 2019-03-05 21:07:20 -08:00
usercopy.c mm/usercopy.c: no check page span for stack objects 2019-01-08 17:15:11 -08:00
userfaultfd.c hugetlbfs: revert "use i_mmap_rwsem for more pmd sharing synchronization" 2019-01-08 17:15:11 -08:00
util.c mm/util.c: fix strndup_user() comment 2019-04-05 16:02:31 -10:00
vmacache.c
vmalloc.c docs/core-api/mm: fix return value descriptions in mm/ 2019-03-05 21:07:20 -08:00
vmpressure.c
vmscan.c mm: remove zone_lru_lock() function, access ->lru_lock directly 2019-03-05 21:07:21 -08:00
vmstat.c mm: no need to check return value of debugfs_create functions 2019-03-05 21:07:17 -08:00
workingset.c mm/workingset: remove unused @mapping argument in workingset_eviction() 2019-03-05 21:07:21 -08:00
z3fold.c z3fold: fix possible reclaim races 2018-11-18 10:15:09 -08:00
zbud.c
zpool.c
zsmalloc.c mm/zsmalloc.c: fix fall-through annotation 2018-10-26 16:26:35 -07:00
zswap.c mm: convert totalram_pages and totalhigh_pages variables to atomic 2018-12-28 12:11:47 -08:00