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linux/mm
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Lars Persson d2b2c6dd22 mm/migrate.c: add missing flush_dcache_page for non-mapped page migrate 
Our MIPS 1004Kc SoCs were seeing random userspace crashes with SIGILL
and SIGSEGV that could not be traced back to a userspace code bug.  They
had all the magic signs of an I/D cache coherency issue.

Now recently we noticed that the /proc/sys/vm/compact_memory interface
was quite efficient at provoking this class of userspace crashes.

Studying the code in mm/migrate.c there is a distinction made between
migrating a page that is mapped at the instant of migration and one that
is not mapped.  Our problem turned out to be the non-mapped pages.

For the non-mapped page the code performs a copy of the page content and
all relevant meta-data of the page without doing the required D-cache
maintenance.  This leaves dirty data in the D-cache of the CPU and on
the 1004K cores this data is not visible to the I-cache.  A subsequent
page-fault that triggers a mapping of the page will happily serve the
process with potentially stale code.

What about ARM then, this bug should have seen greater exposure? Well
ARM became immune to this flaw back in 2010, see commit c01778001a
("ARM: 6379/1: Assume new page cache pages have dirty D-cache").

My proposed fix moves the D-cache maintenance inside move_to_new_page to
make it common for both cases.

Link: http://lkml.kernel.org/r/20190315083502.11849-1-larper@axis.com
Fixes: 97ee052461 ("flush cache before installing new page at migraton")
Signed-off-by: Lars Persson <larper@axis.com>
Reviewed-by: Paul Burton <paul.burton@mips.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-29 10:01:37 -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: pass pgdat to too_many_isolated() instead of zone 2019-03-05 21:07:21 -08:00
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 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-03-07 17:43:58 -08:00
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 "orig_pud" set but not used 2019-03-05 21:07:21 -08:00
hugetlb_cgroup.c
hugetlb.c mm: update get_user_pages_longterm to migrate pages allocated from CMA region 2019-03-05 21:07:19 -08:00
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: account for tagged pointers when calculating pointer range 2019-02-21 09:01:00 -08:00
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
memblock.c mm: memblock: update comments and kernel-doc 2019-03-12 10:04:02 -07:00
memcontrol.c mm/memcontrol.c: fix bad line in comment 2019-03-05 21:07:21 -08:00
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
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
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 mm: add support for kmem caches in DMA32 zone 2019-03-29 10:01:37 -07:00
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 docs/core-api/mm: fix return value descriptions in mm/ 2019-03-05 21:07:20 -08:00
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
zswap.c mm: convert totalram_pages and totalhigh_pages variables to atomic 2018-12-28 12:11:47 -08:00