kernel_optimize_test/lib
Johannes Weiner ea07b862ac mm: workingset: fix use-after-free in shadow node shrinker
Several people report seeing warnings about inconsistent radix tree
nodes followed by crashes in the workingset code, which all looked like
use-after-free access from the shadow node shrinker.

Dave Jones managed to reproduce the issue with a debug patch applied,
which confirmed that the radix tree shrinking indeed frees shadow nodes
while they are still linked to the shadow LRU:

  WARNING: CPU: 2 PID: 53 at lib/radix-tree.c:643 delete_node+0x1e4/0x200
  CPU: 2 PID: 53 Comm: kswapd0 Not tainted 4.10.0-rc2-think+ #3
  Call Trace:
     delete_node+0x1e4/0x200
     __radix_tree_delete_node+0xd/0x10
     shadow_lru_isolate+0xe6/0x220
     __list_lru_walk_one.isra.4+0x9b/0x190
     list_lru_walk_one+0x23/0x30
     scan_shadow_nodes+0x2e/0x40
     shrink_slab.part.44+0x23d/0x5d0
     shrink_node+0x22c/0x330
     kswapd+0x392/0x8f0

This is the WARN_ON_ONCE(!list_empty(&node->private_list)) placed in the
inlined radix_tree_shrink().

The problem is with 14b468791f ("mm: workingset: move shadow entry
tracking to radix tree exceptional tracking"), which passes an update
callback into the radix tree to link and unlink shadow leaf nodes when
tree entries change, but forgot to pass the callback when reclaiming a
shadow node.

While the reclaimed shadow node itself is unlinked by the shrinker, its
deletion from the tree can cause the left-most leaf node in the tree to
be shrunk.  If that happens to be a shadow node as well, we don't unlink
it from the LRU as we should.

Consider this tree, where the s are shadow entries:

       root->rnode
            |
       [0       n]
        |       |
     [s    ] [sssss]

Now the shadow node shrinker reclaims the rightmost leaf node through
the shadow node LRU:

       root->rnode
            |
       [0        ]
        |
    [s     ]

Because the parent of the deleted node is the first level below the
root and has only one child in the left-most slot, the intermediate
level is shrunk and the node containing the single shadow is put in
its place:

       root->rnode
            |
       [s        ]

The shrinker again sees a single left-most slot in a first level node
and thus decides to store the shadow in root->rnode directly and free
the node - which is a leaf node on the shadow node LRU.

  root->rnode
       |
       s

Without the update callback, the freed node remains on the shadow LRU,
where it causes later shrinker runs to crash.

Pass the node updater callback into __radix_tree_delete_node() in case
the deletion causes the left-most branch in the tree to collapse too.

Also add warnings when linked nodes are freed right away, rather than
wait for the use-after-free when the list is scanned much later.

Fixes: 14b468791f ("mm: workingset: move shadow entry tracking to radix tree exceptional tracking")
Reported-by: Dave Chinner <david@fromorbit.com>
Reported-by: Hugh Dickins <hughd@google.com>
Reported-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-and-tested-by: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chris Leech <cleech@redhat.com>
Cc: Lee Duncan <lduncan@suse.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@linuxonhyperv.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-01-07 18:22:40 -08:00
..
842
fonts
lz4
lzo
mpi mpi: Fix NULL ptr dereference in mpi_powm() [ver #3] 2016-11-25 12:57:50 +11:00
raid6 lib/raid6: Add AVX2 optimized xor_syndrome functions 2016-11-07 15:08:20 -08:00
reed_solomon
xz
zlib_deflate
zlib_inflate
.gitignore
argv_split.c
asn1_decoder.c
assoc_array.c
atomic64_test.c atomic64: no need for CONFIG_ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE 2016-10-07 18:46:30 -07:00
atomic64.c
audit.c
bcd.c
bch.c
bitmap.c lib/bitmap.c: enhance bitmap syntax 2016-10-11 15:06:30 -07:00
bitrev.c
bsearch.c
btree.c
bug.c
build_OID_registry
bust_spinlocks.c
chacha20.c
check_signature.c
checksum.c
clz_ctz.c
clz_tab.c
cmdline.c
compat_audit.c
cordic.c
cpu_rmap.c
cpumask.c
crc-ccitt.c
crc-itu-t.c
crc-t10dif.c
crc7.c
crc8.c
crc16.c
crc32.c
crc32defs.h
ctype.c
debug_info.c
debug_locks.c
debugobjects.c Merge branch 'for-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq 2016-12-13 12:59:57 -08:00
dec_and_lock.c
decompress_bunzip2.c
decompress_inflate.c
decompress_unlz4.c
decompress_unlzma.c
decompress_unlzo.c
decompress_unxz.c
decompress.c
devres.c
digsig.c
div64.c
dma-debug.c dmaengine updates for 4.8-rc1 2016-10-06 17:13:54 -07:00
dma-noop.c
dump_stack.c
dynamic_debug.c
dynamic_queue_limits.c
earlycpio.c
extable.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
fault-inject.c
fdt_empty_tree.c
fdt_ro.c
fdt_rw.c
fdt_strerror.c
fdt_sw.c
fdt_wip.c
fdt.c
find_bit.c
flex_array.c
flex_proportions.c
gcd.c
gen_crc32table.c
genalloc.c lib/genalloc.c: start search from start of chunk 2016-10-27 18:43:43 -07:00
glob.c
halfmd4.c
hexdump.c
hweight.c
idr.c lib/ida: document locking requirements a bit better 2016-12-12 18:55:09 -08:00
inflate.c
int_sqrt.c
interval_tree_test.c
interval_tree.c
iomap_copy.c
iomap.c
iommu-common.c
iommu-helper.c
ioremap.c
iov_iter.c [iov_iter] fix iterate_all_kinds() on empty iterators 2016-12-22 23:00:22 -05:00
irq_poll.c This adds a new gcc plugin named "latent_entropy". It is designed to 2016-10-15 10:03:15 -07:00
irq_regs.c
is_single_threaded.c
jedec_ddr_data.c
kasprintf.c
Kconfig Merge branch 'akpm' (patches from Andrew) 2016-10-07 21:38:00 -07:00
Kconfig.debug cpu/hotplug: Remove obsolete cpu hotplug register/unregister functions 2016-12-25 10:47:43 +01:00
Kconfig.kasan
Kconfig.kgdb
Kconfig.kmemcheck
Kconfig.ubsan Kconfig: lib/Kconfig.ubsan fix reference to ubsan documentation 2016-12-14 16:04:08 -08:00
kfifo.c
klist.c
kobject_uevent.c kobject: improve function-level documentation 2016-10-28 02:42:10 -04:00
kobject.c
kstrtox.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
kstrtox.h
lcm.c
libcrc32c.c
list_debug.c bug: Provide toggle for BUG on data corruption 2016-10-31 13:01:58 -07:00
list_sort.c
llist.c
locking-selftest-hardirq.h
locking-selftest-mutex.h
locking-selftest-rlock-hardirq.h
locking-selftest-rlock-softirq.h
locking-selftest-rlock.h
locking-selftest-rsem.h
locking-selftest-softirq.h
locking-selftest-spin-hardirq.h
locking-selftest-spin-softirq.h
locking-selftest-spin.h
locking-selftest-wlock-hardirq.h
locking-selftest-wlock-softirq.h
locking-selftest-wlock.h
locking-selftest-wsem.h
locking-selftest.c locking/selftest: Fix output since KERN_CONT changes 2016-11-25 07:12:19 +01:00
lockref.c locking/core: Remove cpu_relax_lowlatency() users 2016-11-16 10:15:10 +01:00
lru_cache.c
Makefile cpu/hotplug: Remove obsolete cpu hotplug register/unregister functions 2016-12-25 10:47:43 +01:00
md5.c
memory-notifier-error-inject.c
memweight.c
net_utils.c
netdev-notifier-error-inject.c
nlattr.c netlink: smaller nla_attr_minlen table 2016-11-19 22:11:25 -05:00
nmi_backtrace.c nmi_backtrace: generate one-line reports for idle cpus 2016-10-07 18:46:30 -07:00
nodemask.c
notifier-error-inject.c
notifier-error-inject.h
of-reconfig-notifier-error-inject.c
oid_registry.c
once.c
parser.c parser: add u64 number parser 2016-12-06 10:17:03 +02:00
pci_iomap.c
percpu_counter.c lib/percpu_counter: Convert to hotplug state machine 2016-11-09 23:45:26 +01:00
percpu_ida.c
percpu_test.c
percpu-refcount.c
plist.c
pm-notifier-error-inject.c
radix-tree.c mm: workingset: fix use-after-free in shadow node shrinker 2017-01-07 18:22:40 -08:00
random32.c This adds a new gcc plugin named "latent_entropy". It is designed to 2016-10-15 10:03:15 -07:00
ratelimit.c
rational.c
rbtree_test.c
rbtree.c lib/rbtree.c: fix typo in comment of ____rb_erase_color 2016-12-12 18:55:09 -08:00
reciprocal_div.c
rhashtable.c
sbitmap.c
scatterlist.c
seq_buf.c
sg_pool.c
sg_split.c
sha1.c
show_mem.c
smp_processor_id.c
sort.c
stackdepot.c lib/stackdepot: export save/fetch stack for drivers 2016-11-11 08:12:37 -08:00
stmp_device.c
string_helpers.c
string.c
strncpy_from_user.c lib: harden strncpy_from_user 2016-10-11 15:06:30 -07:00
strnlen_user.c
swiotlb.c swiotlb: Export swiotlb_max_segment to users 2017-01-06 13:00:01 -05:00
syscall.c
test_bitmap.c
test_bpf.c bpf, test: fix ld_abs + vlan push/pop stress test 2016-10-20 14:39:06 -04:00
test_firmware.c
test_hash.c
test_hexdump.c
test_kasan.c kasan: support use-after-scope detection 2016-11-30 16:32:52 -08:00
test_module.c
test_printf.c
test_rhashtable.c
test_static_key_base.c
test_static_keys.c
test_user_copy.c
test_uuid.c
test-kstrtox.c
test-string_helpers.c
textsearch.c
timerqueue.c ktime: Get rid of the union 2016-12-25 17:21:22 +01:00
ts_bm.c
ts_fsm.c
ts_kmp.c
ubsan.c
ubsan.h
ucs2_string.c
uuid.c
vsprintf.c
win_minmax.c