linux-stable.git/mm/slab.c, branch linux-5.0.y

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/slab.c: kmemleak no scan alien caches

2019-04-05T20:34:23+00:00

[ Upstream commit 92d1d07daad65c300c7d0b68bbef8867e9895d54 ]

Kmemleak throws endless warnings during boot due to in
__alloc_alien_cache(),

    alc = kmalloc_node(memsize, gfp, node);
    init_arraycache(&alc->ac, entries, batch);
    kmemleak_no_scan(ac);

Kmemleak does not track the array cache (alc->ac) but the alien cache
(alc) instead, so let it track the latter by lifting kmemleak_no_scan()
out of init_arraycache().

There is another place that calls init_arraycache(), but
alloc_kmem_cache_cpus() uses the percpu allocation where will never be
considered as a leak.

  kmemleak: Found object by alias at 0xffff8007b9aa7e38
  CPU: 190 PID: 1 Comm: swapper/0 Not tainted 5.0.0-rc2+ #2
  Call trace:
   dump_backtrace+0x0/0x168
   show_stack+0x24/0x30
   dump_stack+0x88/0xb0
   lookup_object+0x84/0xac
   find_and_get_object+0x84/0xe4
   kmemleak_no_scan+0x74/0xf4
   setup_kmem_cache_node+0x2b4/0x35c
   __do_tune_cpucache+0x250/0x2d4
   do_tune_cpucache+0x4c/0xe4
   enable_cpucache+0xc8/0x110
   setup_cpu_cache+0x40/0x1b8
   __kmem_cache_create+0x240/0x358
   create_cache+0xc0/0x198
   kmem_cache_create_usercopy+0x158/0x20c
   kmem_cache_create+0x50/0x64
   fsnotify_init+0x58/0x6c
   do_one_initcall+0x194/0x388
   kernel_init_freeable+0x668/0x688
   kernel_init+0x18/0x124
   ret_from_fork+0x10/0x18
  kmemleak: Object 0xffff8007b9aa7e00 (size 256):
  kmemleak:   comm "swapper/0", pid 1, jiffies 4294697137
  kmemleak:   min_count = 1
  kmemleak:   count = 0
  kmemleak:   flags = 0x1
  kmemleak:   checksum = 0
  kmemleak:   backtrace:
       kmemleak_alloc+0x84/0xb8
       kmem_cache_alloc_node_trace+0x31c/0x3a0
       __kmalloc_node+0x58/0x78
       setup_kmem_cache_node+0x26c/0x35c
       __do_tune_cpucache+0x250/0x2d4
       do_tune_cpucache+0x4c/0xe4
       enable_cpucache+0xc8/0x110
       setup_cpu_cache+0x40/0x1b8
       __kmem_cache_create+0x240/0x358
       create_cache+0xc0/0x198
       kmem_cache_create_usercopy+0x158/0x20c
       kmem_cache_create+0x50/0x64
       fsnotify_init+0x58/0x6c
       do_one_initcall+0x194/0x388
       kernel_init_freeable+0x668/0x688
       kernel_init+0x18/0x124
  kmemleak: Not scanning unknown object at 0xffff8007b9aa7e38
  CPU: 190 PID: 1 Comm: swapper/0 Not tainted 5.0.0-rc2+ #2
  Call trace:
   dump_backtrace+0x0/0x168
   show_stack+0x24/0x30
   dump_stack+0x88/0xb0
   kmemleak_no_scan+0x90/0xf4
   setup_kmem_cache_node+0x2b4/0x35c
   __do_tune_cpucache+0x250/0x2d4
   do_tune_cpucache+0x4c/0xe4
   enable_cpucache+0xc8/0x110
   setup_cpu_cache+0x40/0x1b8
   __kmem_cache_create+0x240/0x358
   create_cache+0xc0/0x198
   kmem_cache_create_usercopy+0x158/0x20c
   kmem_cache_create+0x50/0x64
   fsnotify_init+0x58/0x6c
   do_one_initcall+0x194/0x388
   kernel_init_freeable+0x668/0x688
   kernel_init+0x18/0x124
   ret_from_fork+0x10/0x18

Link: http://lkml.kernel.org/r/20190129184518.39808-1-cai@lca.pw
Fixes: 1fe00d50a9e8 ("slab: factor out initialization of array cache")
Signed-off-by: Qian Cai 
Reviewed-by: Andrew Morton 
Cc: Christoph Lameter 
Cc: Pekka Enberg 
Cc: David Rientjes 
Cc: Joonsoo Kim 
Cc: Catalin Marinas 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

mm: add support for kmem caches in DMA32 zone

2019-04-03T04:27:37+00:00

commit 6d6ea1e967a246f12cfe2f5fb743b70b2e608d4a upstream.

Patch series "iommu/io-pgtable-arm-v7s: Use DMA32 zone for page tables",
v6.

This is a followup to the discussion in [1], [2].

IOMMUs using ARMv7 short-descriptor format require page tables (level 1
and 2) to be allocated within the first 4GB of RAM, even on 64-bit
systems.

For L1 tables that are bigger than a page, we can just use
__get_free_pages with GFP_DMA32 (on arm64 systems only, arm would still
use GFP_DMA).

For L2 tables that only take 1KB, it would be a waste to allocate a full
page, so we considered 3 approaches:
 1. This series, adding support for GFP_DMA32 slab caches.
 2. genalloc, which requires pre-allocating the maximum number of L2 page
    tables (4096, so 4MB of memory).
 3. page_frag, which is not very memory-efficient as it is unable to reuse
    freed fragments until the whole page is freed. [3]

This series is the most memory-efficient approach.

stable@ note:
  We confirmed that this is a regression, and IOMMU errors happen on 4.19
  and linux-next/master on MT8173 (elm, Acer Chromebook R13). The issue
  most likely starts from commit ad67f5a6545f ("arm64: replace ZONE_DMA
  with ZONE_DMA32"), i.e. 4.15, and presumably breaks a number of Mediatek
  platforms (and maybe others?).

[1] https://lists.linuxfoundation.org/pipermail/iommu/2018-November/030876.html
[2] https://lists.linuxfoundation.org/pipermail/iommu/2018-December/031696.html
[3] https://patchwork.codeaurora.org/patch/671639/

This patch (of 3):

IOMMUs using ARMv7 short-descriptor format require page tables to be
allocated within the first 4GB of RAM, even on 64-bit systems.  On arm64,
this is done by passing GFP_DMA32 flag to memory allocation functions.

For IOMMU L2 tables that only take 1KB, it would be a waste to allocate
a full page using get_free_pages, so we considered 3 approaches:
 1. This patch, adding support for GFP_DMA32 slab caches.
 2. genalloc, which requires pre-allocating the maximum number of L2
    page tables (4096, so 4MB of memory).
 3. page_frag, which is not very memory-efficient as it is unable
    to reuse freed fragments until the whole page is freed.

This change makes it possible to create a custom cache in DMA32 zone using
kmem_cache_create, then allocate memory using kmem_cache_alloc.

We do not create a DMA32 kmalloc cache array, as there are currently no
users of kmalloc(..., GFP_DMA32).  These calls will continue to trigger a
warning, as we keep GFP_DMA32 in GFP_SLAB_BUG_MASK.

This implies that calls to kmem_cache_*alloc on a SLAB_CACHE_DMA32
kmem_cache must _not_ use GFP_DMA32 (it is anyway redundant and
unnecessary).

Link: http://lkml.kernel.org/r/20181210011504.122604-2-drinkcat@chromium.org
Signed-off-by: Nicolas Boichat 
Acked-by: Vlastimil Babka 
Acked-by: Will Deacon 
Cc: Robin Murphy 
Cc: Joerg Roedel 
Cc: Christoph Lameter 
Cc: Pekka Enberg 
Cc: David Rientjes 
Cc: Joonsoo Kim 
Cc: Michal Hocko 
Cc: Mel Gorman 
Cc: Sasha Levin 
Cc: Huaisheng Ye 
Cc: Mike Rapoport 
Cc: Yong Wu 
Cc: Matthias Brugger 
Cc: Tomasz Figa 
Cc: Yingjoe Chen 
Cc: Christoph Hellwig 
Cc: Matthew Wilcox 
Cc: Hsin-Yi Wang 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

kasan, slab: remove redundant kasan_slab_alloc hooks

2019-02-21T17:01:00+00:00

kasan_slab_alloc() calls in kmem_cache_alloc() and kmem_cache_alloc_node()
are redundant as they are already called via slab_alloc/slab_alloc_node()->
slab_post_alloc_hook()->kasan_slab_alloc().  Remove them.

Link: http://lkml.kernel.org/r/4ca1655cdcfc4379c49c50f7bf80f81c4ad01485.1550602886.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov 
Tested-by: Qian Cai 
Cc: Alexander Potapenko 
Cc: Andrey Ryabinin 
Cc: Catalin Marinas 
Cc: Dmitry Vyukov 
Cc: Evgeniy Stepanov 
Cc: Kostya Serebryany 
Cc: Vincenzo Frascino 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kasan, slab: make freelist stored without tags

2019-02-21T17:01:00+00:00

Similarly to "kasan, slub: move kasan_poison_slab hook before
page_address", move kasan_poison_slab() before alloc_slabmgmt(), which
calls page_address(), to make page_address() return value to be
non-tagged.  This, combined with calling kasan_reset_tag() for off-slab
slab management object, leads to freelist being stored non-tagged.

Link: http://lkml.kernel.org/r/dfb53b44a4d00de3879a05a9f04c1f55e584f7a1.1550602886.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov 
Tested-by: Qian Cai 
Cc: Alexander Potapenko 
Cc: Andrey Ryabinin 
Cc: Catalin Marinas 
Cc: Dmitry Vyukov 
Cc: Evgeniy Stepanov 
Cc: Kostya Serebryany 
Cc: Vincenzo Frascino 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kasan, slab: fix conflicts with CONFIG_HARDENED_USERCOPY

2019-02-21T17:01:00+00:00

Similarly to commit 96fedce27e13 ("kasan: make tag based mode work with
CONFIG_HARDENED_USERCOPY"), we need to reset pointer tags in
__check_heap_object() in mm/slab.c before doing any pointer math.

Link: http://lkml.kernel.org/r/9a5c0f958db10e69df5ff9f2b997866b56b7effc.1550602886.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov 
Tested-by: Qian Cai 
Cc: Alexander Potapenko 
Cc: Andrey Ryabinin 
Cc: Catalin Marinas 
Cc: Dmitry Vyukov 
Cc: Evgeniy Stepanov 
Cc: Kostya Serebryany 
Cc: Vincenzo Frascino 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

slab: alien caches must not be initialized if the allocation of the alien cache failed

2019-01-09T01:15:11+00:00

Callers of __alloc_alien() check for NULL.  We must do the same check in
__alloc_alien_cache to avoid NULL pointer dereferences on allocation
failures.

Link: http://lkml.kernel.org/r/010001680f42f192-82b4e12e-1565-4ee0-ae1f-1e98974906aa-000000@email.amazonses.com
Fixes: 49dfc304ba241 ("slab: use the lock on alien_cache, instead of the lock on array_cache")
Fixes: c8522a3a5832b ("Slab: introduce alloc_alien")
Signed-off-by: Christoph Lameter 
Reported-by: syzbot+d6ed4ec679652b4fd4e4@syzkaller.appspotmail.com
Reviewed-by: Andrew Morton 
Cc: Pekka Enberg 
Cc: David Rientjes 
Cc: Joonsoo Kim 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: convert totalram_pages and totalhigh_pages variables to atomic

2018-12-28T20:11:47+00:00

totalram_pages and totalhigh_pages are made static inline function.

Main motivation was that managed_page_count_lock handling was complicating
things.  It was discussed in length here,
https://lore.kernel.org/patchwork/patch/995739/#1181785 So it seemes
better to remove the lock and convert variables to atomic, with preventing
poteintial store-to-read tearing as a bonus.

[akpm@linux-foundation.org: coding style fixes]
Link: http://lkml.kernel.org/r/1542090790-21750-4-git-send-email-arunks@codeaurora.org
Signed-off-by: Arun KS 
Suggested-by: Michal Hocko 
Suggested-by: Vlastimil Babka 
Reviewed-by: Konstantin Khlebnikov 
Reviewed-by: Pavel Tatashin 
Acked-by: Michal Hocko 
Acked-by: Vlastimil Babka 
Cc: David Hildenbrand 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kasan, mm, arm64: tag non slab memory allocated via pagealloc

2018-12-28T20:11:44+00:00

Tag-based KASAN doesn't check memory accesses through pointers tagged with
0xff.  When page_address is used to get pointer to memory that corresponds
to some page, the tag of the resulting pointer gets set to 0xff, even
though the allocated memory might have been tagged differently.

For slab pages it's impossible to recover the correct tag to return from
page_address, since the page might contain multiple slab objects tagged
with different values, and we can't know in advance which one of them is
going to get accessed.  For non slab pages however, we can recover the tag
in page_address, since the whole page was marked with the same tag.

This patch adds tagging to non slab memory allocated with pagealloc.  To
set the tag of the pointer returned from page_address, the tag gets stored
to page->flags when the memory gets allocated.

Link: http://lkml.kernel.org/r/d758ddcef46a5abc9970182b9137e2fbee202a2c.1544099024.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov 
Reviewed-by: Andrey Ryabinin 
Reviewed-by: Dmitry Vyukov 
Acked-by: Will Deacon 
Cc: Christoph Lameter 
Cc: Mark Rutland 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds