linux-stable.git/mm, branch v5.0.17

mm/page_alloc.c: avoid potential NULL pointer dereference

2019-05-16T17:40:26+00:00

[ Upstream commit 8139ad043d632c0e9e12d760068a7a8e91659aa1 ]

ac.preferred_zoneref->zone passed to alloc_flags_nofragment() can be NULL.
'zone' pointer unconditionally derefernced in alloc_flags_nofragment().
Bail out on NULL zone to avoid potential crash.  Currently we don't see
any crashes only because alloc_flags_nofragment() has another bug which
allows compiler to optimize away all accesses to 'zone'.

Link: http://lkml.kernel.org/r/20190423120806.3503-1-aryabinin@virtuozzo.com
Fixes: 6bb154504f8b ("mm, page_alloc: spread allocations across zones before introducing fragmentation")
Signed-off-by: Andrey Ryabinin 
Acked-by: Mel Gorman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

mm/memory_hotplug.c: drop memory device reference after find_memory_block()

2019-05-16T17:40:26+00:00

[ Upstream commit 89c02e69fc5245f8a2f34b58b42d43a737af1a5e ]

Right now we are using find_memory_block() to get the node id for the
pfn range to online.  We are missing to drop a reference to the memory
block device.  While the device still gets unregistered via
device_unregister(), resulting in no user visible problem, the device is
never released via device_release(), resulting in a memory leak.  Fix
that by properly using a put_device().

Link: http://lkml.kernel.org/r/20190411110955.1430-1-david@redhat.com
Fixes: d0dc12e86b31 ("mm/memory_hotplug: optimize memory hotplug")
Signed-off-by: David Hildenbrand 
Reviewed-by: Oscar Salvador 
Reviewed-by: Wei Yang 
Acked-by: Michal Hocko 
Acked-by: Pankaj Gupta 
Cc: David Hildenbrand 
Cc: Pavel Tatashin 
Cc: Qian Cai 
Cc: Arun KS 
Cc: Mathieu Malaterre 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

mm: fix inactive list balancing between NUMA nodes and cgroups

2019-05-16T17:40:21+00:00

[ Upstream commit 3b991208b897f52507168374033771a984b947b1 ]

During !CONFIG_CGROUP reclaim, we expand the inactive list size if it's
thrashing on the node that is about to be reclaimed.  But when cgroups
are enabled, we suddenly ignore the node scope and use the cgroup scope
only.  The result is that pressure bleeds between NUMA nodes depending
on whether cgroups are merely compiled into Linux.  This behavioral
difference is unexpected and undesirable.

When the refault adaptivity of the inactive list was first introduced,
there were no statistics at the lruvec level - the intersection of node
and memcg - so it was better than nothing.

But now that we have that infrastructure, use lruvec_page_state() to
make the list balancing decision always NUMA aware.

[hannes@cmpxchg.org: fix bisection hole]
  Link: http://lkml.kernel.org/r/20190417155241.GB23013@cmpxchg.org
Link: http://lkml.kernel.org/r/20190412144438.2645-1-hannes@cmpxchg.org
Fixes: 2a2e48854d70 ("mm: vmscan: fix IO/refault regression in cache workingset transition")
Signed-off-by: Johannes Weiner 
Reviewed-by: Shakeel Butt 
Cc: Roman Gushchin 
Cc: Michal Hocko 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

mm/hotplug: treat CMA pages as unmovable

2019-05-16T17:40:21+00:00

[ Upstream commit 1a9f219157b22d0ffb340a9c5f431afd02cd2cf3 ]

has_unmovable_pages() is used by allocating CMA and gigantic pages as
well as the memory hotplug.  The later doesn't know how to offline CMA
pool properly now, but if an unused (free) CMA page is encountered, then
has_unmovable_pages() happily considers it as a free memory and
propagates this up the call chain.  Memory offlining code then frees the
page without a proper CMA tear down which leads to an accounting issues.
Moreover if the same memory range is onlined again then the memory never
gets back to the CMA pool.

State after memory offline:

 # grep cma /proc/vmstat
 nr_free_cma 205824

 # cat /sys/kernel/debug/cma/cma-kvm_cma/count
 209920

Also, kmemleak still think those memory address are reserved below but
have already been used by the buddy allocator after onlining.  This
patch fixes the situation by treating CMA pageblocks as unmovable except
when has_unmovable_pages() is called as part of CMA allocation.

  Offlined Pages 4096
  kmemleak: Cannot insert 0xc000201f7d040008 into the object search tree (overlaps existing)
  Call Trace:
    dump_stack+0xb0/0xf4 (unreliable)
    create_object+0x344/0x380
    __kmalloc_node+0x3ec/0x860
    kvmalloc_node+0x58/0x110
    seq_read+0x41c/0x620
    __vfs_read+0x3c/0x70
    vfs_read+0xbc/0x1a0
    ksys_read+0x7c/0x140
    system_call+0x5c/0x70
  kmemleak: Kernel memory leak detector disabled
  kmemleak: Object 0xc000201cc8000000 (size 13757317120):
  kmemleak:   comm "swapper/0", pid 0, jiffies 4294937297
  kmemleak:   min_count = -1
  kmemleak:   count = 0
  kmemleak:   flags = 0x5
  kmemleak:   checksum = 0
  kmemleak:   backtrace:
       cma_declare_contiguous+0x2a4/0x3b0
       kvm_cma_reserve+0x11c/0x134
       setup_arch+0x300/0x3f8
       start_kernel+0x9c/0x6e8
       start_here_common+0x1c/0x4b0
  kmemleak: Automatic memory scanning thread ended

[cai@lca.pw: use is_migrate_cma_page() and update commit log]
  Link: http://lkml.kernel.org/r/20190416170510.20048-1-cai@lca.pw
Link: http://lkml.kernel.org/r/20190413002623.8967-1-cai@lca.pw
Signed-off-by: Qian Cai 
Acked-by: Michal Hocko 
Acked-by: Vlastimil Babka 
Reviewed-by: Oscar Salvador 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

slab: store tagged freelist for off-slab slabmgmt

2019-05-16T17:40:21+00:00

[ Upstream commit 1a62b18d51e5c5ecc0345c85bb9fef870ab721ed ]

Commit 51dedad06b5f ("kasan, slab: make freelist stored without tags")
calls kasan_reset_tag() for off-slab slab management object leading to
freelist being stored non-tagged.

However, cache_grow_begin() calls alloc_slabmgmt() which calls
kmem_cache_alloc_node() assigns a tag for the address and stores it in
the shadow address.  As the result, it causes endless errors below
during boot due to drain_freelist() -> slab_destroy() ->
kasan_slab_free() which compares already untagged freelist against the
stored tag in the shadow address.

Since off-slab slab management object freelist is such a special case,
just store it tagged.  Non-off-slab management object freelist is still
stored untagged which has not been assigned a tag and should not cause
any other troubles with this inconsistency.

  BUG: KASAN: double-free or invalid-free in slab_destroy+0x84/0x88
  Pointer tag: [ff], memory tag: [99]

  CPU: 0 PID: 1376 Comm: kworker/0:4 Tainted: G        W 5.1.0-rc3+ #8
  Hardware name: HPE Apollo 70             /C01_APACHE_MB         , BIOS L50_5.13_1.0.6 07/10/2018
  Workqueue: cgroup_destroy css_killed_work_fn
  Call trace:
   print_address_description+0x74/0x2a4
   kasan_report_invalid_free+0x80/0xc0
   __kasan_slab_free+0x204/0x208
   kasan_slab_free+0xc/0x18
   kmem_cache_free+0xe4/0x254
   slab_destroy+0x84/0x88
   drain_freelist+0xd0/0x104
   __kmem_cache_shrink+0x1ac/0x224
   __kmemcg_cache_deactivate+0x1c/0x28
   memcg_deactivate_kmem_caches+0xa0/0xe8
   memcg_offline_kmem+0x8c/0x3d4
   mem_cgroup_css_offline+0x24c/0x290
   css_killed_work_fn+0x154/0x618
   process_one_work+0x9cc/0x183c
   worker_thread+0x9b0/0xe38
   kthread+0x374/0x390
   ret_from_fork+0x10/0x18

  Allocated by task 1625:
   __kasan_kmalloc+0x168/0x240
   kasan_slab_alloc+0x18/0x20
   kmem_cache_alloc_node+0x1f8/0x3a0
   cache_grow_begin+0x4fc/0xa24
   cache_alloc_refill+0x2f8/0x3e8
   kmem_cache_alloc+0x1bc/0x3bc
   sock_alloc_inode+0x58/0x334
   alloc_inode+0xb8/0x164
   new_inode_pseudo+0x20/0xec
   sock_alloc+0x74/0x284
   __sock_create+0xb0/0x58c
   sock_create+0x98/0xb8
   __sys_socket+0x60/0x138
   __arm64_sys_socket+0xa4/0x110
   el0_svc_handler+0x2c0/0x47c
   el0_svc+0x8/0xc

  Freed by task 1625:
   __kasan_slab_free+0x114/0x208
   kasan_slab_free+0xc/0x18
   kfree+0x1a8/0x1e0
   single_release+0x7c/0x9c
   close_pdeo+0x13c/0x43c
   proc_reg_release+0xec/0x108
   __fput+0x2f8/0x784
   ____fput+0x1c/0x28
   task_work_run+0xc0/0x1b0
   do_notify_resume+0xb44/0x1278
   work_pending+0x8/0x10

  The buggy address belongs to the object at ffff809681b89e00
   which belongs to the cache kmalloc-128 of size 128
  The buggy address is located 0 bytes inside of
   128-byte region [ffff809681b89e00, ffff809681b89e80)
  The buggy address belongs to the page:
  page:ffff7fe025a06e00 count:1 mapcount:0 mapping:01ff80082000fb00
  index:0xffff809681b8fe04
  flags: 0x17ffffffc000200(slab)
  raw: 017ffffffc000200 ffff7fe025a06d08 ffff7fe022ef7b88 01ff80082000fb00
  raw: ffff809681b8fe04 ffff809681b80000 00000001000000e0 0000000000000000
  page dumped because: kasan: bad access detected
  page allocated via order 0, migratetype Unmovable, gfp_mask
  0x2420c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_COMP|__GFP_THISNODE)
   prep_new_page+0x4e0/0x5e0
   get_page_from_freelist+0x4ce8/0x50d4
   __alloc_pages_nodemask+0x738/0x38b8
   cache_grow_begin+0xd8/0xa24
   ____cache_alloc_node+0x14c/0x268
   __kmalloc+0x1c8/0x3fc
   ftrace_free_mem+0x408/0x1284
   ftrace_free_init_mem+0x20/0x28
   kernel_init+0x24/0x548
   ret_from_fork+0x10/0x18

  Memory state around the buggy address:
   ffff809681b89c00: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
   ffff809681b89d00: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
  >ffff809681b89e00: 99 99 99 99 99 99 99 99 fe fe fe fe fe fe fe fe
                     ^
   ffff809681b89f00: 43 43 43 43 43 fe fe fe fe fe fe fe fe fe fe fe
   ffff809681b8a000: 6d fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe

Link: http://lkml.kernel.org/r/20190403022858.97584-1-cai@lca.pw
Fixes: 51dedad06b5f ("kasan, slab: make freelist stored without tags")
Signed-off-by: Qian Cai 
Reviewed-by: Andrey Konovalov 
Cc: Christoph Lameter 
Cc: Pekka Enberg 
Cc: David Rientjes 
Cc: Joonsoo Kim 
Cc: Andrey Ryabinin 
Cc: Alexander Potapenko 
Cc: Dmitry Vyukov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

slab: fix a crash by reading /proc/slab_allocators

2019-05-10T16:36:09+00:00

[ Upstream commit fcf88917dd435c6a4cb2830cb086ee58605a1d85 ]

The commit 510ded33e075 ("slab: implement slab_root_caches list")
changes the name of the list node within "struct kmem_cache" from "list"
to "root_caches_node", but leaks_show() still use the "list" which
causes a crash when reading /proc/slab_allocators.

You need to have CONFIG_SLAB=y and CONFIG_MEMCG=y to see the problem,
because without MEMCG all slab caches are root caches, and the "list"
node happens to be the right one.

Fixes: 510ded33e075 ("slab: implement slab_root_caches list")
Signed-off-by: Qian Cai 
Reviewed-by: Tobin C. Harding 
Cc: Tejun Heo 
Cc: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

mm/kmemleak.c: fix unused-function warning

2019-05-08T05:23:00+00:00

commit dce5b0bdeec61bdbee56121ceb1d014151d5cab1 upstream.

The only references outside of the #ifdef have been removed, so now we
get a warning in non-SMP configurations:

  mm/kmemleak.c:1404:13: error: unused function 'scan_large_block' [-Werror,-Wunused-function]

Add a new #ifdef around it.

Link: http://lkml.kernel.org/r/20190416123148.3502045-1-arnd@arndb.de
Fixes: 298a32b13208 ("kmemleak: powerpc: skip scanning holes in the .bss section")
Signed-off-by: Arnd Bergmann 
Acked-by: Catalin Marinas 
Cc: Vincent Whitchurch 
Cc: Michael Ellerman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Cc: Nobuhiro Iwamatsu 
Signed-off-by: Greg Kroah-Hartman

kmemleak: powerpc: skip scanning holes in the .bss section

2019-05-08T05:22:54+00:00

[ Upstream commit 298a32b132087550d3fa80641ca58323c5dfd4d9 ]

Commit 2d4f567103ff ("KVM: PPC: Introduce kvm_tmp framework") adds
kvm_tmp[] into the .bss section and then free the rest of unused spaces
back to the page allocator.

kernel_init
  kvm_guest_init
    kvm_free_tmp
      free_reserved_area
        free_unref_page
          free_unref_page_prepare

With DEBUG_PAGEALLOC=y, it will unmap those pages from kernel.  As the
result, kmemleak scan will trigger a panic when it scans the .bss
section with unmapped pages.

This patch creates dedicated kmemleak objects for the .data, .bss and
potentially .data..ro_after_init sections to allow partial freeing via
the kmemleak_free_part() in the powerpc kvm_free_tmp() function.

Link: http://lkml.kernel.org/r/20190321171917.62049-1-catalin.marinas@arm.com
Signed-off-by: Catalin Marinas 
Reported-by: Qian Cai 
Acked-by: Michael Ellerman  (powerpc)
Tested-by: Qian Cai 
Cc: Paul Mackerras 
Cc: Benjamin Herrenschmidt 
Cc: Avi Kivity 
Cc: Paolo Bonzini 
Cc: Radim Krcmar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin (Microsoft)

kasan: fix variable 'tag' set but not used warning

2019-05-04T07:21:22+00:00

[ Upstream commit c412a769d2452161e97f163c4c4f31efc6626f06 ]

set_tag() compiles away when CONFIG_KASAN_SW_TAGS=n, so make
arch_kasan_set_tag() a static inline function to fix warnings below.

  mm/kasan/common.c: In function '__kasan_kmalloc':
  mm/kasan/common.c:475:5: warning: variable 'tag' set but not used [-Wunused-but-set-variable]
    u8 tag;
       ^~~

Link: http://lkml.kernel.org/r/20190307185244.54648-1-cai@lca.pw
Signed-off-by: Qian Cai 
Reviewed-by: Andrey Konovalov 
Cc: Andrey Ryabinin 
Cc: Alexander Potapenko 
Cc: Dmitry Vyukov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin (Microsoft)

mm: prevent get_user_pages() from overflowing page refcount

2019-05-04T07:21:11+00:00

commit 8fde12ca79aff9b5ba951fce1a2641901b8d8e64 upstream.

If the page refcount wraps around past zero, it will be freed while
there are still four billion references to it.  One of the possible
avenues for an attacker to try to make this happen is by doing direct IO
on a page multiple times.  This patch makes get_user_pages() refuse to
take a new page reference if there are already more than two billion
references to the page.

Reported-by: Jann Horn 
Acked-by: Matthew Wilcox 
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman