linux.git/mm, branch v5.5-rc4

mm: vmscan: protect shrinker idr replace with CONFIG_MEMCG

2019-12-18T04:59:59+00:00

Since commit 0a432dcbeb32 ("mm: shrinker: make shrinker not depend on
memcg kmem"), shrinkers' idr is protected by CONFIG_MEMCG instead of
CONFIG_MEMCG_KMEM, so it makes no sense to protect shrinker idr replace
with CONFIG_MEMCG_KMEM.

And in the CONFIG_MEMCG && CONFIG_SLOB case, shrinker_idr contains only
shrinker, and it is deferred_split_shrinker.  But it is never actually
called, since idr_replace() is never compiled due to the wrong #ifdef.
The deferred_split_shrinker all the time is staying in half-registered
state, and it's never called for subordinate mem cgroups.

Link: http://lkml.kernel.org/r/1575486978-45249-1-git-send-email-yang.shi@linux.alibaba.com
Fixes: 0a432dcbeb32 ("mm: shrinker: make shrinker not depend on memcg kmem")
Signed-off-by: Yang Shi 
Reviewed-by: Kirill Tkhai 
Acked-by: Michal Hocko 
Cc: Johannes Weiner 
Cc: Shakeel Butt 
Cc: Roman Gushchin 
Cc: 	[5.4+]
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kasan: don't assume percpu shadow allocations will succeed

2019-12-18T04:59:59+00:00

syzkaller and the fault injector showed that I was wrong to assume that
we could ignore percpu shadow allocation failures.

Handle failures properly.  Merge all the allocated areas back into the
free list and release the shadow, then clean up and return NULL.  The
shadow is released unconditionally, which relies upon the fact that the
release function is able to tolerate pages not being present.

Also clean up shadows in the recovery path - currently they are not
released, which leaks a bit of memory.

Link: http://lkml.kernel.org/r/20191205140407.1874-3-dja@axtens.net
Fixes: 3c5c3cfb9ef4 ("kasan: support backing vmalloc space with real shadow memory")
Signed-off-by: Daniel Axtens 
Reported-by: syzbot+82e323920b78d54aaed5@syzkaller.appspotmail.com
Reported-by: syzbot+59b7daa4315e07a994f1@syzkaller.appspotmail.com
Reviewed-by: Andrey Ryabinin 
Cc: Dmitry Vyukov 
Cc: Alexander Potapenko 
Cc: Qian Cai 
Cc: Uladzislau Rezki (Sony) 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kasan: use apply_to_existing_page_range() for releasing vmalloc shadow

2019-12-18T04:59:59+00:00

kasan_release_vmalloc uses apply_to_page_range to release vmalloc
shadow.  Unfortunately, apply_to_page_range can allocate memory to fill
in page table entries, which is not what we want.

Also, kasan_release_vmalloc is called under free_vmap_area_lock, so if
apply_to_page_range does allocate memory, we get a sleep in atomic bug:

	BUG: sleeping function called from invalid context at mm/page_alloc.c:4681
	in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 15087, name:

	Call Trace:
	 __dump_stack lib/dump_stack.c:77 [inline]
	 dump_stack+0x199/0x216 lib/dump_stack.c:118
	 ___might_sleep.cold.97+0x1f5/0x238 kernel/sched/core.c:6800
	 __might_sleep+0x95/0x190 kernel/sched/core.c:6753
	 prepare_alloc_pages mm/page_alloc.c:4681 [inline]
	 __alloc_pages_nodemask+0x3cd/0x890 mm/page_alloc.c:4730
	 alloc_pages_current+0x10c/0x210 mm/mempolicy.c:2211
	 alloc_pages include/linux/gfp.h:532 [inline]
	 __get_free_pages+0xc/0x40 mm/page_alloc.c:4786
	 __pte_alloc_one_kernel include/asm-generic/pgalloc.h:21 [inline]
	 pte_alloc_one_kernel include/asm-generic/pgalloc.h:33 [inline]
	 __pte_alloc_kernel+0x1d/0x200 mm/memory.c:459
	 apply_to_pte_range mm/memory.c:2031 [inline]
	 apply_to_pmd_range mm/memory.c:2068 [inline]
	 apply_to_pud_range mm/memory.c:2088 [inline]
	 apply_to_p4d_range mm/memory.c:2108 [inline]
	 apply_to_page_range+0x77d/0xa00 mm/memory.c:2133
	 kasan_release_vmalloc+0xa7/0xc0 mm/kasan/common.c:970
	 __purge_vmap_area_lazy+0xcbb/0x1f30 mm/vmalloc.c:1313
	 try_purge_vmap_area_lazy mm/vmalloc.c:1332 [inline]
	 free_vmap_area_noflush+0x2ca/0x390 mm/vmalloc.c:1368
	 free_unmap_vmap_area mm/vmalloc.c:1381 [inline]
	 remove_vm_area+0x1cc/0x230 mm/vmalloc.c:2209
	 vm_remove_mappings mm/vmalloc.c:2236 [inline]
	 __vunmap+0x223/0xa20 mm/vmalloc.c:2299
	 __vfree+0x3f/0xd0 mm/vmalloc.c:2356
	 __vmalloc_area_node mm/vmalloc.c:2507 [inline]
	 __vmalloc_node_range+0x5d5/0x810 mm/vmalloc.c:2547
	 __vmalloc_node mm/vmalloc.c:2607 [inline]
	 __vmalloc_node_flags mm/vmalloc.c:2621 [inline]
	 vzalloc+0x6f/0x80 mm/vmalloc.c:2666
	 alloc_one_pg_vec_page net/packet/af_packet.c:4233 [inline]
	 alloc_pg_vec net/packet/af_packet.c:4258 [inline]
	 packet_set_ring+0xbc0/0x1b50 net/packet/af_packet.c:4342
	 packet_setsockopt+0xed7/0x2d90 net/packet/af_packet.c:3695
	 __sys_setsockopt+0x29b/0x4d0 net/socket.c:2117
	 __do_sys_setsockopt net/socket.c:2133 [inline]
	 __se_sys_setsockopt net/socket.c:2130 [inline]
	 __x64_sys_setsockopt+0xbe/0x150 net/socket.c:2130
	 do_syscall_64+0xfa/0x780 arch/x86/entry/common.c:294
	 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Switch to using the apply_to_existing_page_range() helper instead, which
won't allocate memory.

[akpm@linux-foundation.org: s/apply_to_existing_pages/apply_to_existing_page_range/]
Link: http://lkml.kernel.org/r/20191205140407.1874-2-dja@axtens.net
Fixes: 3c5c3cfb9ef4 ("kasan: support backing vmalloc space with real shadow memory")
Signed-off-by: Daniel Axtens 
Reported-by: Dmitry Vyukov 
Reviewed-by: Andrey Ryabinin 
Cc: Alexander Potapenko 
Cc: Qian Cai 
Cc: Uladzislau Rezki (Sony) 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/memory.c: add apply_to_existing_page_range() helper

2019-12-18T04:59:59+00:00

apply_to_page_range() takes an address range, and if any parts of it are
not covered by the existing page table hierarchy, it allocates memory to
fill them in.

In some use cases, this is not what we want - we want to be able to
operate exclusively on PTEs that are already in the tables.

Add apply_to_existing_page_range() for this.  Adjust the walker
functions for apply_to_page_range to take 'create', which switches them
between the old and new modes.

This will be used in KASAN vmalloc.

[akpm@linux-foundation.org: reduce code duplication]
[akpm@linux-foundation.org: s/apply_to_existing_pages/apply_to_existing_page_range/]
[akpm@linux-foundation.org: initialize __apply_to_page_range::err]
Link: http://lkml.kernel.org/r/20191205140407.1874-1-dja@axtens.net
Signed-off-by: Daniel Axtens 
Cc: Dmitry Vyukov 
Cc: Uladzislau Rezki (Sony) 
Cc: Alexander Potapenko 
Cc: Daniel Axtens 
Cc: Qian Cai 
Cc: Andrey Ryabinin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kasan: fix crashes on access to memory mapped by vm_map_ram()

2019-12-18T04:59:59+00:00

With CONFIG_KASAN_VMALLOC=y any use of memory obtained via vm_map_ram()
will crash because there is no shadow backing that memory.

Instead of sprinkling additional kasan_populate_vmalloc() calls all over
the vmalloc code, move it into alloc_vmap_area(). This will fix
vm_map_ram() and simplify the code a bit.

[aryabinin@virtuozzo.com: v2]
  Link: http://lkml.kernel.org/r/20191205095942.1761-1-aryabinin@virtuozzo.comLink: http://lkml.kernel.org/r/20191204204534.32202-1-aryabinin@virtuozzo.com
Fixes: 3c5c3cfb9ef4 ("kasan: support backing vmalloc space with real shadow memory")
Signed-off-by: Andrey Ryabinin 
Reported-by: Dmitry Vyukov 
Reviewed-by: Uladzislau Rezki (Sony) 
Cc: Daniel Axtens 
Cc: Alexander Potapenko 
Cc: Daniel Axtens 
Cc: Qian Cai 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'akpm' (patches from Andrew)

2019-12-05T17:46:26+00:00

Merge more updates from Andrew Morton:
 "Most of the rest of MM and various other things. Some Kconfig rework
  still awaits merges of dependent trees from linux-next.

  Subsystems affected by this patch series: mm/hotfixes, mm/memcg,
  mm/vmstat, mm/thp, procfs, sysctl, misc, notifiers, core-kernel,
  bitops, lib, checkpatch, epoll, binfmt, init, rapidio, uaccess, kcov,
  ubsan, ipc, bitmap, mm/pagemap"

* akpm: (86 commits)
  mm: remove __ARCH_HAS_4LEVEL_HACK and include/asm-generic/4level-fixup.h
  um: add support for folded p4d page tables
  um: remove unused pxx_offset_proc() and addr_pte() functions
  sparc32: use pgtable-nopud instead of 4level-fixup
  parisc/hugetlb: use pgtable-nopXd instead of 4level-fixup
  parisc: use pgtable-nopXd instead of 4level-fixup
  nds32: use pgtable-nopmd instead of 4level-fixup
  microblaze: use pgtable-nopmd instead of 4level-fixup
  m68k: mm: use pgtable-nopXd instead of 4level-fixup
  m68k: nommu: use pgtable-nopud instead of 4level-fixup
  c6x: use pgtable-nopud instead of 4level-fixup
  arm: nommu: use pgtable-nopud instead of 4level-fixup
  alpha: use pgtable-nopud instead of 4level-fixup
  gpio: pca953x: tighten up indentation
  gpio: pca953x: convert to use bitmap API
  gpio: pca953x: use input from regs structure in pca953x_irq_pending()
  gpio: pca953x: remove redundant variable and check in IRQ handler
  lib/bitmap: introduce bitmap_replace() helper
  lib/test_bitmap: fix comment about this file
  lib/test_bitmap: move exp1 and exp2 upper for others to use
  ...

mm: remove __ARCH_HAS_4LEVEL_HACK and include/asm-generic/4level-fixup.h

2019-12-05T03:44:15+00:00

There are no architectures that use include/asm-generic/4level-fixup.h
therefore it can be removed along with __ARCH_HAS_4LEVEL_HACK define.

Link: http://lkml.kernel.org/r/1572938135-31886-14-git-send-email-rppt@kernel.org
Signed-off-by: Mike Rapoport 
Cc: Anatoly Pugachev 
Cc: Anton Ivanov 
Cc: Arnd Bergmann 
Cc: "David S. Miller" 
Cc: Geert Uytterhoeven 
Cc: Greentime Hu 
Cc: Greg Ungerer 
Cc: Helge Deller 
Cc: "James E.J. Bottomley" 
Cc: Jeff Dike 
Cc: "Kirill A. Shutemov" 
Cc: Mark Salter 
Cc: Matt Turner 
Cc: Michal Simek 
Cc: Peter Rosin 
Cc: Richard Weinberger 
Cc: Rolf Eike Beer 
Cc: Russell King 
Cc: Russell King 
Cc: Sam Creasey 
Cc: Vincent Chen 
Cc: Vineet Gupta 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/memory.c: replace is_zero_pfn with is_huge_zero_pmd for thp

2019-12-05T03:44:11+00:00

For hugely mapped thp, we use is_huge_zero_pmd() to check if it's zero
page or not.

We do fill ptes with my_zero_pfn() when we split zero thp pmd, but this
is not what we have in vm_normal_page_pmd() -- pmd_trans_huge_lock()
makes sure of it.

This is a trivial fix for /proc/pid/numa_maps, and AFAIK nobody
complains about it.

Gerald Schaefer asked:
: Maybe the description could also mention the symptom of this bug?
: I would assume that it affects anon/dirty accounting in gather_pte_stats(),
: for huge mappings, if zero page mappings are not correctly recognized.

I came across this while I was looking at the code, so I'm not aware of
any symptom.

Link: http://lkml.kernel.org/r/20191108192629.201556-1-yuzhao@google.com
Signed-off-by: Yu Zhao 
Acked-by: Andrew Morton 
Cc: Matthew Wilcox 
Cc: Ralph Campbell 
Cc: Will Deacon 
Cc: Peter Zijlstra 
Cc: "Aneesh Kumar K . V" 
Cc: Dave Airlie 
Cc: Thomas Hellstrom 
Cc: Souptick Joarder 
Cc: Gerald Schaefer 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/memcontrol: use vmstat names for printing statistics

2019-12-05T03:44:11+00:00

Use common names from vmstat array when possible.  This gives not much
difference in code size for now, but should help in keeping interfaces
consistent.

  add/remove: 0/2 grow/shrink: 2/0 up/down: 70/-72 (-2)
  Function                                     old     new   delta
  memory_stat_format                           984    1050     +66
  memcg_stat_show                              957     961      +4
  memcg1_event_names                            32       -     -32
  mem_cgroup_lru_names                          40       -     -40
  Total: Before=14485337, After=14485335, chg -0.00%

Link: http://lkml.kernel.org/r/157113012508.453.80391533767219371.stgit@buzz
Signed-off-by: Konstantin Khlebnikov 
Acked-by: Andrew Morton 
Cc: Michal Hocko 
Cc: Vladimir Davydov 
Cc: Johannes Weiner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/vmstat: add helpers to get vmstat item names for each enum type

2019-12-05T03:44:11+00:00

Statistics in vmstat is combined from counters with different structure,
but names for them are merged into one array.

This patch adds trivial helpers to get name for each item:

  const char *zone_stat_name(enum zone_stat_item item);
  const char *numa_stat_name(enum numa_stat_item item);
  const char *node_stat_name(enum node_stat_item item);
  const char *writeback_stat_name(enum writeback_stat_item item);
  const char *vm_event_name(enum vm_event_item item);

Names for enum writeback_stat_item are folded in the middle of
vmstat_text so this patch moves declaration into header to calculate
offset of following items.

Also this patch reuses piece of node stat names for lru list names:

  const char *lru_list_name(enum lru_list lru);

This returns common lru list names: "inactive_anon", "active_anon",
"inactive_file", "active_file", "unevictable".

[khlebnikov@yandex-team.ru: do not use size of vmstat_text as count of /proc/vmstat items]
  Link: http://lkml.kernel.org/r/157152151769.4139.15423465513138349343.stgit@buzz
  Link: https://lore.kernel.org/linux-mm/cd1c42ae-281f-c8a8-70ac-1d01d417b2e1@infradead.org/T/#u
Link: http://lkml.kernel.org/r/157113012325.453.562783073839432766.stgit@buzz
Signed-off-by: Konstantin Khlebnikov 
Reviewed-by: Andrew Morton 
Cc: Randy Dunlap 
Cc: Michal Hocko 
Cc: Vladimir Davydov 
Cc: Johannes Weiner 
Cc: YueHaibing 
Cc: Stephen Rothwell 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds