averello/linux-stable-mirror
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2026-09-22 09:34:56 +02:00
Code Issues Packages Projects Releases Wiki Activity
847,604 Commits 116 Branches 5,777 Tags
f455c854877dcce5d714b00203ea804bf601fb02
Commit Graph
847604 Commits
This Branch
This Branch
All Branches
Author SHA1 Message Date
Christoph Hellwig f455c85487 mm: use untagged_addr() for get_user_pages_fast addresses 
Patch series "switch the remaining architectures to use generic GUP", v4.

A series to switch mips, sh and sparc64 to use the generic GUP code so
that we only have one codebase to touch for further improvements to this
code.

This patch (of 16):

This will allow sparc64, or any future architecture with memory tagging to
override its tags for get_user_pages and get_user_pages_fast.

Link: http://lkml.kernel.org/r/20190625143715.1689-2-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: David Miller <davem@davemloft.net>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Khalid Aziz <khalid.aziz@oracle.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:44 -07:00
Waiman Long fcf8a1e483 mm, memcg: add a memcg_slabinfo debugfs file 
There are concerns about memory leaks from extensive use of memory cgroups
as each memory cgroup creates its own set of kmem caches.  There is a
possiblity that the memcg kmem caches may remain even after the memory
cgroups have been offlined.  Therefore, it will be useful to show the
status of each of memcg kmem caches.

This patch introduces a new <debugfs>/memcg_slabinfo file which is
somewhat similar to /proc/slabinfo in format, but lists only information
about kmem caches that have child memcg kmem caches.  Information
available in /proc/slabinfo are not repeated in memcg_slabinfo.

A portion of a sample output of the file was:

  # <name> <css_id[:dead]> <active_objs> <num_objs> <active_slabs> <num_slabs>
  rpc_inode_cache   root          13     51      1      1
  rpc_inode_cache     48           0      0      0      0
  fat_inode_cache   root           1     45      1      1
  fat_inode_cache     41           2     45      1      1
  xfs_inode         root         770    816     24     24
  xfs_inode           92          22     34      1      1
  xfs_inode           88:dead      1     34      1      1
  xfs_inode           89:dead     23     34      1      1
  xfs_inode           85           4     34      1      1
  xfs_inode           84           9     34      1      1

The css id of the memcg is also listed. If a memcg is not online,
the tag ":dead" will be attached as shown above.

[longman@redhat.com: memcg: add ":deact" tag for reparented kmem caches in memcg_slabinfo]
  Link: http://lkml.kernel.org/r/20190621173005.31514-1-longman@redhat.com
[longman@redhat.com: set the flag in the common code as suggested by Roman]
  Link: http://lkml.kernel.org/r/20190627184324.5875-1-longman@redhat.com
Link: http://lkml.kernel.org/r/20190619171621.26209-1-longman@redhat.com
Signed-off-by: Waiman Long <longman@redhat.com>
Suggested-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:44 -07:00
Roman Gushchin fb2f2b0adb mm: memcg/slab: reparent memcg kmem_caches on cgroup removal 
Let's reparent non-root kmem_caches on memcg offlining.  This allows us to
release the memory cgroup without waiting for the last outstanding kernel
object (e.g.  dentry used by another application).

Since the parent cgroup is already charged, everything we need to do is to
splice the list of kmem_caches to the parent's kmem_caches list, swap the
memcg pointer, drop the css refcounter for each kmem_cache and adjust the
parent's css refcounter.

Please, note that kmem_cache->memcg_params.memcg isn't a stable pointer
anymore.  It's safe to read it under rcu_read_lock(), cgroup_mutex held,
or any other way that protects the memory cgroup from being released.

We can race with the slab allocation and deallocation paths.  It's not a
big problem: parent's charge and slab global stats are always correct, and
we don't care anymore about the child usage and global stats.  The child
cgroup is already offline, so we don't use or show it anywhere.

Local slab stats (NR_SLAB_RECLAIMABLE and NR_SLAB_UNRECLAIMABLE) aren't
used anywhere except count_shadow_nodes().  But even there it won't break
anything: after reparenting "nodes" will be 0 on child level (because
we're already reparenting shrinker lists), and on parent level page stats
always were 0, and this patch won't change anything.

[guro@fb.com: properly handle kmem_caches reparented to root_mem_cgroup]
  Link: http://lkml.kernel.org/r/20190620213427.1691847-1-guro@fb.com
Link: http://lkml.kernel.org/r/20190611231813.3148843-11-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Waiman Long <longman@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Andrei Vagin <avagin@gmail.com>
Cc: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:44 -07:00
Roman Gushchin 4d96ba3530 mm: memcg/slab: stop setting page->mem_cgroup pointer for slab pages 
Every slab page charged to a non-root memory cgroup has a pointer to the
memory cgroup and holds a reference to it, which protects a non-empty
memory cgroup from being released.  At the same time the page has a
pointer to the corresponding kmem_cache, and also hold a reference to the
kmem_cache.  And kmem_cache by itself holds a reference to the cgroup.

So there is clearly some redundancy, which allows to stop setting the
page->mem_cgroup pointer and rely on getting memcg pointer indirectly via
kmem_cache.  Further it will allow to change this pointer easier, without
a need to go over all charged pages.

So let's stop setting page->mem_cgroup pointer for slab pages, and stop
using the css refcounter directly for protecting the memory cgroup from
going away.  Instead rely on kmem_cache as an intermediate object.

Make sure that vmstats and shrinker lists are working as previously, as
well as /proc/kpagecgroup interface.

Link: http://lkml.kernel.org/r/20190611231813.3148843-10-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Waiman Long <longman@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Andrei Vagin <avagin@gmail.com>
Cc: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:44 -07:00
Roman Gushchin f0a3a24b53 mm: memcg/slab: rework non-root kmem_cache lifecycle management 
Currently each charged slab page holds a reference to the cgroup to which
it's charged.  Kmem_caches are held by the memcg and are released all
together with the memory cgroup.  It means that none of kmem_caches are
released unless at least one reference to the memcg exists, which is very
far from optimal.

Let's rework it in a way that allows releasing individual kmem_caches as
soon as the cgroup is offline, the kmem_cache is empty and there are no
pending allocations.

To make it possible, let's introduce a new percpu refcounter for non-root
kmem caches.  The counter is initialized to the percpu mode, and is
switched to the atomic mode during kmem_cache deactivation.  The counter
is bumped for every charged page and also for every running allocation.
So the kmem_cache can't be released unless all allocations complete.

To shutdown non-active empty kmem_caches, let's reuse the work queue,
previously used for the kmem_cache deactivation.  Once the reference
counter reaches 0, let's schedule an asynchronous kmem_cache release.

* I used the following simple approach to test the performance
(stolen from another patchset by T. Harding):

    time find / -name fname-no-exist
    echo 2 > /proc/sys/vm/drop_caches
    repeat 10 times

Results:

        orig		patched

real	0m1.455s	real	0m1.355s
user	0m0.206s	user	0m0.219s
sys	0m0.855s	sys	0m0.807s

real	0m1.487s	real	0m1.699s
user	0m0.221s	user	0m0.256s
sys	0m0.806s	sys	0m0.948s

real	0m1.515s	real	0m1.505s
user	0m0.183s	user	0m0.215s
sys	0m0.876s	sys	0m0.858s

real	0m1.291s	real	0m1.380s
user	0m0.193s	user	0m0.198s
sys	0m0.843s	sys	0m0.786s

real	0m1.364s	real	0m1.374s
user	0m0.180s	user	0m0.182s
sys	0m0.868s	sys	0m0.806s

real	0m1.352s	real	0m1.312s
user	0m0.201s	user	0m0.212s
sys	0m0.820s	sys	0m0.761s

real	0m1.302s	real	0m1.349s
user	0m0.205s	user	0m0.203s
sys	0m0.803s	sys	0m0.792s

real	0m1.334s	real	0m1.301s
user	0m0.194s	user	0m0.201s
sys	0m0.806s	sys	0m0.779s

real	0m1.426s	real	0m1.434s
user	0m0.216s	user	0m0.181s
sys	0m0.824s	sys	0m0.864s

real	0m1.350s	real	0m1.295s
user	0m0.200s	user	0m0.190s
sys	0m0.842s	sys	0m0.811s

So it looks like the difference is not noticeable in this test.

[cai@lca.pw: fix an use-after-free in kmemcg_workfn()]
  Link: http://lkml.kernel.org/r/1560977573-10715-1-git-send-email-cai@lca.pw
Link: http://lkml.kernel.org/r/20190611231813.3148843-9-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Qian Cai <cai@lca.pw>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Waiman Long <longman@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Andrei Vagin <avagin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:44 -07:00
Roman Gushchin 63b02ef7dc mm: memcg/slab: synchronize access to kmem_cache dying flag using a spinlock 
Currently the memcg_params.dying flag and the corresponding workqueue used
for the asynchronous deactivation of kmem_caches is synchronized using the
slab_mutex.

It makes impossible to check this flag from the irq context, which will be
required in order to implement asynchronous release of kmem_caches.

So let's switch over to the irq-save flavor of the spinlock-based
synchronization.

Link: http://lkml.kernel.org/r/20190611231813.3148843-8-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Waiman Long <longman@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Andrei Vagin <avagin@gmail.com>
Cc: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:44 -07:00
Roman Gushchin 570332978e mm: memcg/slab: don't check the dying flag on kmem_cache creation 
There is no point in checking the root_cache->memcg_params.dying flag on
kmem_cache creation path.  New allocations shouldn't be performed using a
dead root kmem_cache, so no new memcg kmem_cache creation can be scheduled
after the flag is set.  And if it was scheduled before,
flush_memcg_workqueue() will wait for it anyway.

So let's drop this check to simplify the code.

Link: http://lkml.kernel.org/r/20190611231813.3148843-7-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Waiman Long <longman@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Andrei Vagin <avagin@gmail.com>
Cc: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:44 -07:00
Roman Gushchin 6cea1d569d mm: memcg/slab: unify SLAB and SLUB page accounting 
Currently the page accounting code is duplicated in SLAB and SLUB
internals.  Let's move it into new (un)charge_slab_page helpers in the
slab_common.c file.  These helpers will be responsible for statistics
(global and memcg-aware) and memcg charging.  So they are replacing direct
memcg_(un)charge_slab() calls.

Link: http://lkml.kernel.org/r/20190611231813.3148843-6-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Waiman Long <longman@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Andrei Vagin <avagin@gmail.com>
Cc: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:44 -07:00
Roman Gushchin 49a18eae2e mm: memcg/slab: introduce __memcg_kmem_uncharge_memcg() 
Let's separate the page counter modification code out of
__memcg_kmem_uncharge() in a way similar to what
__memcg_kmem_charge() and __memcg_kmem_charge_memcg() work.

This will allow to reuse this code later using a new
memcg_kmem_uncharge_memcg() wrapper, which calls
__memcg_kmem_uncharge_memcg() if memcg_kmem_enabled()
check is passed.

Link: http://lkml.kernel.org/r/20190611231813.3148843-5-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Waiman Long <longman@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Andrei Vagin <avagin@gmail.com>
Cc: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:44 -07:00
Roman Gushchin 4348669475 mm: memcg/slab: generalize postponed non-root kmem_cache deactivation 
Currently SLUB uses a work scheduled after an RCU grace period to
deactivate a non-root kmem_cache.  This mechanism can be reused for
kmem_caches release, but requires generalization for SLAB case.

Introduce kmemcg_cache_deactivate() function, which calls
allocator-specific __kmem_cache_deactivate() and schedules execution of
__kmem_cache_deactivate_after_rcu() with all necessary locks in a worker
context after an rcu grace period.

Here is the new calling scheme:
  kmemcg_cache_deactivate()
    __kmemcg_cache_deactivate()                  SLAB/SLUB-specific
    kmemcg_rcufn()                               rcu
      kmemcg_workfn()                            work
        __kmemcg_cache_deactivate_after_rcu()    SLAB/SLUB-specific

instead of:
  __kmemcg_cache_deactivate()                    SLAB/SLUB-specific
    slab_deactivate_memcg_cache_rcu_sched()      SLUB-only
      kmemcg_rcufn()                             rcu
        kmemcg_workfn()                          work
          kmemcg_cache_deact_after_rcu()         SLUB-only

For consistency, all allocator-specific functions start with "__".

Link: http://lkml.kernel.org/r/20190611231813.3148843-4-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Waiman Long <longman@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Andrei Vagin <avagin@gmail.com>
Cc: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:44 -07:00
Roman Gushchin 0b14e8aa68 mm: memcg/slab: rename slab delayed deactivation functions and fields 
The delayed work/rcu deactivation infrastructure of non-root kmem_caches
can be also used for asynchronous release of these objects.  Let's get rid
of the word "deactivation" in corresponding names to make the code look
better after generalization.

It's easier to make the renaming first, so that the generalized code will
look consistent from scratch.

Let's rename struct memcg_cache_params fields:
  deact_fn -> work_fn
  deact_rcu_head -> rcu_head
  deact_work -> work

And RCU/delayed work callbacks in slab common code:
  kmemcg_deactivate_rcufn -> kmemcg_rcufn
  kmemcg_deactivate_workfn -> kmemcg_workfn

This patch contains no functional changes, only renamings.

Link: http://lkml.kernel.org/r/20190611231813.3148843-3-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Waiman Long <longman@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Andrei Vagin <avagin@gmail.com>
Cc: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:44 -07:00
Roman Gushchin c03914b7aa mm: memcg/slab: postpone kmem_cache memcg pointer initialization to memcg_link_cache() 
Patch series "mm: reparent slab memory on cgroup removal", v7.

# Why do we need this?

We've noticed that the number of dying cgroups is steadily growing on most
of our hosts in production.  The following investigation revealed an issue
in the userspace memory reclaim code [1], accounting of kernel stacks [2],
and also the main reason: slab objects.

The underlying problem is quite simple: any page charged to a cgroup holds
a reference to it, so the cgroup can't be reclaimed unless all charged
pages are gone.  If a slab object is actively used by other cgroups, it
won't be reclaimed, and will prevent the origin cgroup from being
reclaimed.

Slab objects, and first of all vfs cache, is shared between cgroups, which
are using the same underlying fs, and what's even more important, it's
shared between multiple generations of the same workload.  So if something
is running periodically every time in a new cgroup (like how systemd
works), we do accumulate multiple dying cgroups.

Strictly speaking pagecache isn't different here, but there is a key
difference: we disable protection and apply some extra pressure on LRUs of
dying cgroups, and these LRUs contain all charged pages.  My experiments
show that with the disabled kernel memory accounting the number of dying
cgroups stabilizes at a relatively small number (~100, depends on memory
pressure and cgroup creation rate), and with kernel memory accounting it
grows pretty steadily up to several thousands.

Memory cgroups are quite complex and big objects (mostly due to percpu
stats), so it leads to noticeable memory losses.  Memory occupied by dying
cgroups is measured in hundreds of megabytes.  I've even seen a host with
more than 100Gb of memory wasted for dying cgroups.  It leads to a
degradation of performance with the uptime, and generally limits the usage
of cgroups.

My previous attempt [3] to fix the problem by applying extra pressure on
slab shrinker lists caused a regressions with xfs and ext4, and has been
reverted [4].  The following attempts to find the right balance [5, 6]
were not successful.

So instead of trying to find a maybe non-existing balance, let's do
reparent accounted slab caches to the parent cgroup on cgroup removal.

# Implementation approach

There is however a significant problem with reparenting of slab memory:
there is no list of charged pages.  Some of them are in shrinker lists,
but not all.  Introducing of a new list is really not an option.

But fortunately there is a way forward: every slab page has a stable
pointer to the corresponding kmem_cache.  So the idea is to reparent
kmem_caches instead of slab pages.

It's actually simpler and cheaper, but requires some underlying changes:
1) Make kmem_caches to hold a single reference to the memory cgroup,
   instead of a separate reference per every slab page.
2) Stop setting page->mem_cgroup pointer for memcg slab pages and use
   page->kmem_cache->memcg indirection instead. It's used only on
   slab page release, so performance overhead shouldn't be a big issue.
3) Introduce a refcounter for non-root slab caches. It's required to
   be able to destroy kmem_caches when they become empty and release
   the associated memory cgroup.

There is a bonus: currently we release all memcg kmem_caches all together
with the memory cgroup itself.  This patchset allows individual
kmem_caches to be released as soon as they become inactive and free.

Some additional implementation details are provided in corresponding
commit messages.

# Results

Below is the average number of dying cgroups on two groups of our
production hosts.  They do run some sort of web frontend workload, the
memory pressure is moderate.  As we can see, with the kernel memory
reparenting the number stabilizes in 60s range; however with the original
version it grows almost linearly and doesn't show any signs of plateauing.
The difference in slab and percpu usage between patched and unpatched
versions also grows linearly.  In 7 days it exceeded 200Mb.

day           0    1    2    3    4    5    6    7
original     56  362  628  752 1070 1250 1490 1560
patched      23   46   51   55   60   57   67   69
mem diff(Mb) 22   74  123  152  164  182  214  241

# Links

[1]: commit 68600f623d ("mm: don't miss the last page because of round-off error")
[2]: commit 9b6f7e163c ("mm: rework memcg kernel stack accounting")
[3]: commit 172b06c32b ("mm: slowly shrink slabs with a relatively small number of objects")
[4]: commit a9a238e83f ("Revert "mm: slowly shrink slabs with a relatively small number of objects")
[5]: https://lkml.org/lkml/2019/1/28/1865
[6]: https://marc.info/?l=linux-mm&m=155064763626437&w=2

This patch (of 10):

Initialize kmem_cache->memcg_params.memcg pointer in memcg_link_cache()
rather than in init_memcg_params().

Once kmem_cache will hold a reference to the memory cgroup, it will
simplify the refcounting.

For non-root kmem_caches memcg_link_cache() is always called before the
kmem_cache becomes visible to a user, so it's safe.

Link: http://lkml.kernel.org/r/20190611231813.3148843-2-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrei Vagin <avagin@gmail.com>
Cc: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:43 -07:00
Johannes Weiner c8713d0b23 mm: memcontrol: dump memory.stat during cgroup OOM 
The current cgroup OOM memory info dump doesn't include all the memory
we are tracking, nor does it give insight into what the VM tried to do
leading up to the OOM. All that useful info is in memory.stat.

Furthermore, the recursive printing for every child cgroup can
generate absurd amounts of data on the console for larger cgroup
trees, and it's not like we provide a per-cgroup breakdown during
global OOM kills.

When an OOM kill is triggered, print one set of recursive memory.stat
items at the level whose limit triggered the OOM condition.

Example output:

    stress invoked oom-killer: gfp_mask=0x100cca(GFP_HIGHUSER_MOVABLE), order=0, oom_score_adj=0
    CPU: 2 PID: 210 Comm: stress Not tainted 5.2.0-rc2-mm1-00247-g47d49835983c #135
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-20181126_142135-anatol 04/01/2014
    Call Trace:
     dump_stack+0x46/0x60
     dump_header+0x4c/0x2d0
     oom_kill_process.cold.10+0xb/0x10
     out_of_memory+0x200/0x270
     ? try_to_free_mem_cgroup_pages+0xdf/0x130
     mem_cgroup_out_of_memory+0xb7/0xc0
     try_charge+0x680/0x6f0
     mem_cgroup_try_charge+0xb5/0x160
     __add_to_page_cache_locked+0xc6/0x300
     ? list_lru_destroy+0x80/0x80
     add_to_page_cache_lru+0x45/0xc0
     pagecache_get_page+0x11b/0x290
     filemap_fault+0x458/0x6d0
     ext4_filemap_fault+0x27/0x36
     __do_fault+0x2f/0xb0
     __handle_mm_fault+0x9c5/0x1140
     ? apic_timer_interrupt+0xa/0x20
     handle_mm_fault+0xc5/0x180
     __do_page_fault+0x1ab/0x440
     ? page_fault+0x8/0x30
     page_fault+0x1e/0x30
    RIP: 0033:0x55c32167fc10
    Code: Bad RIP value.
    RSP: 002b:00007fff1d031c50 EFLAGS: 00010206
    RAX: 000000000dc00000 RBX: 00007fd2db000010 RCX: 00007fd2db000010
    RDX: 0000000000000000 RSI: 0000000010001000 RDI: 0000000000000000
    RBP: 000055c321680a54 R08: 00000000ffffffff R09: 0000000000000000
    R10: 0000000000000022 R11: 0000000000000246 R12: ffffffffffffffff
    R13: 0000000000000002 R14: 0000000000001000 R15: 0000000010000000
    memory: usage 1024kB, limit 1024kB, failcnt 75131
    swap: usage 0kB, limit 9007199254740988kB, failcnt 0
    Memory cgroup stats for /foo:
    anon 0
    file 0
    kernel_stack 36864
    slab 274432
    sock 0
    shmem 0
    file_mapped 0
    file_dirty 0
    file_writeback 0
    anon_thp 0
    inactive_anon 126976
    active_anon 0
    inactive_file 0
    active_file 0
    unevictable 0
    slab_reclaimable 0
    slab_unreclaimable 274432
    pgfault 59466
    pgmajfault 1617
    workingset_refault 2145
    workingset_activate 0
    workingset_nodereclaim 0
    pgrefill 98952
    pgscan 200060
    pgsteal 59340
    pgactivate 40095
    pgdeactivate 96787
    pglazyfree 0
    pglazyfreed 0
    thp_fault_alloc 0
    thp_collapse_alloc 0
    Tasks state (memory values in pages):
    [  pid  ]   uid  tgid total_vm      rss pgtables_bytes swapents oom_score_adj name
    [    200]     0   200     1121      884    53248       29             0 bash
    [    209]     0   209      905      246    45056       19             0 stress
    [    210]     0   210    66442       56   499712    56349             0 stress
    oom-kill:constraint=CONSTRAINT_NONE,nodemask=(null),oom_memcg=/foo,task_memcg=/foo,task=stress,pid=210,uid=0
    Memory cgroup out of memory: Killed process 210 (stress) total-vm:265768kB, anon-rss:0kB, file-rss:224kB, shmem-rss:0kB
    oom_reaper: reaped process 210 (stress), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB

[hannes@cmpxchg.org: s/kvmalloc/kmalloc/ per Michal]
  Link: http://lkml.kernel.org/r/20190605161133.GA12453@cmpxchg.org
Link: http://lkml.kernel.org/r/20190604210509.9744-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:43 -07:00
Shakeel Butt 1e577f970f mm, memcg: introduce memory.events.local 
The memory controller in cgroup v2 exposes memory.events file for each
memcg which shows the number of times events like low, high, max, oom
and oom_kill have happened for the whole tree rooted at that memcg.
Users can also poll or register notification to monitor the changes in
that file.  Any event at any level of the tree rooted at memcg will
notify all the listeners along the path till root_mem_cgroup.  There are
existing users which depend on this behavior.

However there are users which are only interested in the events
happening at a specific level of the memcg tree and not in the events in
the underlying tree rooted at that memcg.  One such use-case is a
centralized resource monitor which can dynamically adjust the limits of
the jobs running on a system.  The jobs can create their sub-hierarchy
for their own sub-tasks.  The centralized monitor is only interested in
the events at the top level memcgs of the jobs as it can then act and
adjust the limits of the jobs.  Using the current memory.events for such
centralized monitor is very inconvenient.  The monitor will keep
receiving events which it is not interested and to find if the received
event is interesting, it has to read memory.event files of the next
level and compare it with the top level one.  So, let's introduce
memory.events.local to the memcg which shows and notify for the events
at the memcg level.

Now, does memory.stat and memory.pressure need their local versions.  IMHO
no due to the no internal process contraint of the cgroup v2.  The
memory.stat file of the top level memcg of a job shows the stats and
vmevents of the whole tree.  The local stats or vmevents of the top level
memcg will only change if there is a process running in that memcg but v2
does not allow that.  Similarly for memory.pressure there will not be any
process in the internal nodes and thus no chance of local pressure.

Link: http://lkml.kernel.org/r/20190527174643.209172-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Chris Down <chris@chrisdown.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:43 -07:00
Shakeel Butt ec16545096 memcg, fsnotify: no oom-kill for remote memcg charging 
Commit d46eb14b73 ("fs: fsnotify: account fsnotify metadata to
kmemcg") added remote memcg charging for fanotify and inotify event
objects.  The aim was to charge the memory to the listener who is
interested in the events but without triggering the OOM killer.
Otherwise there would be security concerns for the listener.

At the time, oom-kill trigger was not in the charging path.  A parallel
work added the oom-kill back to charging path i.e.  commit 29ef680ae7
("memcg, oom: move out_of_memory back to the charge path").  So to not
trigger oom-killer in the remote memcg, explicitly add
__GFP_RETRY_MAYFAIL to the fanotigy and inotify event allocations.

Link: http://lkml.kernel.org/r/20190514212259.156585-2-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Acked-by: Jan Kara <jack@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:43 -07:00
Shakeel Butt 38d384932e memcg, oom: no oom-kill for __GFP_RETRY_MAYFAIL 
The documentation of __GFP_RETRY_MAYFAIL clearly mentioned that the OOM
killer will not be triggered and indeed the page alloc does not invoke OOM
killer for such allocations.  However we do trigger memcg OOM killer for
__GFP_RETRY_MAYFAIL.  Fix that.  This flag will used later to not trigger
oom-killer in the charging path for fanotify and inotify event
allocations.

Link: http://lkml.kernel.org/r/20190514212259.156585-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:43 -07:00
Huang Ying aeb309b81c mm/mincore.c: fix race between swapoff and mincore 
Via commit 4b3ef9daa4 ("mm/swap: split swap cache into 64MB trunks"),
after swapoff, the address_space associated with the swap device will be
freed.  So swap_address_space() users which touch the address_space need
some kind of mechanism to prevent the address_space from being freed
during accessing.

When mincore processes an unmapped range for swapped shmem pages, it
doesn't hold the lock to prevent swap device from being swapped off.  So
the following race is possible:

CPU1					CPU2
do_mincore()				swapoff()
  walk_page_range()
    mincore_unmapped_range()
      __mincore_unmapped_range
        mincore_page
	  as = swap_address_space()
          ...				  exit_swap_address_space()
          ...				    kvfree(spaces)
	  find_get_page(as)

The address space may be accessed after being freed.

To fix the race, get_swap_device()/put_swap_device() is used to enclose
find_get_page() to check whether the swap entry is valid and prevent the
swap device from being swapoff during accessing.

Link: http://lkml.kernel.org/r/20190611020510.28251-1-ying.huang@intel.com
Fixes: 4b3ef9daa4 ("mm/swap: split swap cache into 64MB trunks")
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Andrea Parri <andrea.parri@amarulasolutions.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:43 -07:00
Aaron Lu 4efaceb1c5 mm, swap: use rbtree for swap_extent 
swap_extent is used to map swap page offset to backing device's block
offset.  For a continuous block range, one swap_extent is used and all
these swap_extents are managed in a linked list.

These swap_extents are used by map_swap_entry() during swap's read and
write path.  To find out the backing device's block offset for a page
offset, the swap_extent list will be traversed linearly, with
curr_swap_extent being used as a cache to speed up the search.

This works well as long as swap_extents are not huge or when the number
of processes that access swap device are few, but when the swap device
has many extents and there are a number of processes accessing the swap
device concurrently, it can be a problem.  On one of our servers, the
disk's remaining size is tight:

  $df -h
  Filesystem      Size  Used Avail Use% Mounted on
  ... ...
  /dev/nvme0n1p1  1.8T  1.3T  504G  72% /home/t4

When creating a 80G swapfile there, there are as many as 84656 swap
extents.  The end result is, kernel spends abou 30% time in
map_swap_entry() and swap throughput is only 70MB/s.

As a comparison, when I used smaller sized swapfile, like 4G whose
swap_extent dropped to 2000, swap throughput is back to 400-500MB/s and
map_swap_entry() is about 3%.

One downside of using rbtree for swap_extent is, 'struct rbtree' takes
24 bytes while 'struct list_head' takes 16 bytes, that's 8 bytes more
for each swap_extent.  For a swapfile that has 80k swap_extents, that
means 625KiB more memory consumed.

Test:

Since it's not possible to reboot that server, I can not test this patch
diretly there.  Instead, I tested it on another server with NVMe disk.

I created a 20G swapfile on an NVMe backed XFS fs.  By default, the
filesystem is quite clean and the created swapfile has only 2 extents.
Testing vanilla and this patch shows no obvious performance difference
when swapfile is not fragmented.

To see the patch's effects, I used some tweaks to manually fragment the
swapfile by breaking the extent at 1M boundary.  This made the swapfile
have 20K extents.

  nr_task=4
  kernel   swapout(KB/s) map_swap_entry(perf)  swapin(KB/s) map_swap_entry(perf)
  vanilla  165191           90.77%             171798          90.21%
  patched  858993 +420%      2.16%             715827 +317%     0.77%

  nr_task=8
  kernel   swapout(KB/s) map_swap_entry(perf)  swapin(KB/s) map_swap_entry(perf)
  vanilla  306783           92.19%             318145          87.76%
  patched  954437 +211%      2.35%            1073741 +237%     1.57%

swapout: the throughput of swap out, in KB/s, higher is better 1st
map_swap_entry: cpu cycles percent sampled by perf swapin: the
throughput of swap in, in KB/s, higher is better.  2nd map_swap_entry:
cpu cycles percent sampled by perf

nr_task=1 doesn't show any difference, this is due to the curr_swap_extent
can be effectively used to cache the correct swap extent for single task
workload.

[akpm@linux-foundation.org: s/BUG_ON(1)/BUG()/]
Link: http://lkml.kernel.org/r/20190523142404.GA181@aaronlu
Signed-off-by: Aaron Lu <ziqian.lzq@antfin.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:43 -07:00
Huang Ying 054f1d1faa mm/swap_state.c: simplify total_swapcache_pages() with get_swap_device() 
total_swapcache_pages() may race with swapper_spaces[] allocation and
freeing.  Previously, this is protected with a swapper_spaces[] specific
RCU mechanism.  To simplify the logic/code complexity, it is replaced with
get/put_swap_device().  The code line number is reduced too.  Although not
so important, the swapoff() performance improves too because one
synchronize_rcu() call during swapoff() is deleted.

[ying.huang@intel.com: fix bad swap file entry warning]
  Link: http://lkml.kernel.org/r/20190531024102.21723-1-ying.huang@intel.com
Link: http://lkml.kernel.org/r/20190527082714.12151-1-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Andrea Parri <andrea.parri@amarulasolutions.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:43 -07:00
Huang Ying eb085574a7 mm, swap: fix race between swapoff and some swap operations 
When swapin is performed, after getting the swap entry information from
the page table, system will swap in the swap entry, without any lock held
to prevent the swap device from being swapoff.  This may cause the race
like below,

CPU 1				CPU 2
-----				-----
				do_swap_page
				  swapin_readahead
				    __read_swap_cache_async
swapoff				      swapcache_prepare
  p->swap_map = NULL		        __swap_duplicate
					  p->swap_map[?] /* !!! NULL pointer access */

Because swapoff is usually done when system shutdown only, the race may
not hit many people in practice.  But it is still a race need to be fixed.

To fix the race, get_swap_device() is added to check whether the specified
swap entry is valid in its swap device.  If so, it will keep the swap
entry valid via preventing the swap device from being swapoff, until
put_swap_device() is called.

Because swapoff() is very rare code path, to make the normal path runs as
fast as possible, rcu_read_lock/unlock() and synchronize_rcu() instead of
reference count is used to implement get/put_swap_device().  >From
get_swap_device() to put_swap_device(), RCU reader side is locked, so
synchronize_rcu() in swapoff() will wait until put_swap_device() is
called.

In addition to swap_map, cluster_info, etc.  data structure in the struct
swap_info_struct, the swap cache radix tree will be freed after swapoff,
so this patch fixes the race between swap cache looking up and swapoff
too.

Races between some other swap cache usages and swapoff are fixed too via
calling synchronize_rcu() between clearing PageSwapCache() and freeing
swap cache data structure.

Another possible method to fix this is to use preempt_off() +
stop_machine() to prevent the swap device from being swapoff when its data
structure is being accessed.  The overhead in hot-path of both methods is
similar.  The advantages of RCU based method are,

1. stop_machine() may disturb the normal execution code path on other
   CPUs.

2. File cache uses RCU to protect its radix tree.  If the similar
   mechanism is used for swap cache too, it is easier to share code
   between them.

3. RCU is used to protect swap cache in total_swapcache_pages() and
   exit_swap_address_space() already.  The two mechanisms can be
   merged to simplify the logic.

Link: http://lkml.kernel.org/r/20190522015423.14418-1-ying.huang@intel.com
Fixes: 235b621767 ("mm/swap: add cluster lock")
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Andrea Parri <andrea.parri@amarulasolutions.com>
Not-nacked-by: Hugh Dickins <hughd@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:43 -07:00
Yang Shi a498583388 mm/filemap.c: correct the comment about VM_FAULT_RETRY 
Commit 6b4c9f4469 ("filemap: drop the mmap_sem for all blocking
operations") changed when mmap_sem is dropped during filemap page fault
and when returning VM_FAULT_RETRY.

Correct the comment to reflect the change.

Link: http://lkml.kernel.org/r/1556234531-108228-1-git-send-email-yang.shi@linux.alibaba.com
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:43 -07:00
Christoph Hellwig f053cbd436 9p: pass the correct prototype to read_cache_page 
Fix the callback 9p passes to read_cache_page to actually have the
proper type expected.  Casting around function pointers can easily
hide typing bugs, and defeats control flow protection.

Link: http://lkml.kernel.org/r/20190520055731.24538-5-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:43 -07:00
Christoph Hellwig 265de8ce3d jffs2: pass the correct prototype to read_cache_page 
Fix the callback jffs2 passes to read_cache_page to actually have the
proper type expected.  Casting around function pointers can easily hide
typing bugs, and defeats control flow protection.

Link: http://lkml.kernel.org/r/20190520055731.24538-4-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:43 -07:00
Christoph Hellwig 6c45b45419 mm/filemap: don't cast ->readpage to filler_t for do_read_cache_page 
We can just pass a NULL filler and do the right thing inside of
do_read_cache_page based on the NULL parameter.

Link: http://lkml.kernel.org/r/20190520055731.24538-3-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:43 -07:00
Christoph Hellwig d322a8e5e3 mm/filemap.c: fix an overly long line in read_cache_page 
Patch series "fix filler_t callback type mismatches", v2.

Casting mapping->a_ops->readpage to filler_t causes an indirect call
type mismatch with Control-Flow Integrity checking.  This change fixes
the mismatch in read_cache_page_gfp and read_mapping_page by adding
using a NULL filler argument as an indication to call ->readpage
directly, and by passing the right parameter callbacks in nfs and jffs2.

This patch (of 4):

Code cleanup.

Link: http://lkml.kernel.org/r/20190520055731.24538-2-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:43 -07:00
Vlastimil Babka 3972f6bb1c mm, debug_pagealloc: use a page type instead of page_ext flag 
When debug_pagealloc is enabled, we currently allocate the page_ext
array to mark guard pages with the PAGE_EXT_DEBUG_GUARD flag.  Now that
we have the page_type field in struct page, we can use that instead, as
guard pages are neither PageSlab nor mapped to userspace.  This reduces
memory overhead when debug_pagealloc is enabled and there are no other
features requiring the page_ext array.

Link: http://lkml.kernel.org/r/20190603143451.27353-4-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:43 -07:00
Vlastimil Babka 4462b32c92 mm, page_alloc: more extensive free page checking with debug_pagealloc 
The page allocator checks struct pages for expected state (mapcount,
flags etc) as pages are being allocated (check_new_page()) and freed
(free_pages_check()) to provide some defense against errors in page
allocator users.

Prior commits 479f854a20 ("mm, page_alloc: defer debugging checks of
pages allocated from the PCP") and 4db7548ccb ("mm, page_alloc: defer
debugging checks of freed pages until a PCP drain") this has happened
for order-0 pages as they were allocated from or freed to the per-cpu
caches (pcplists).  Since those are fast paths, the checks are now
performed only when pages are moved between pcplists and global free
lists.  This however lowers the chances of catching errors soon enough.

In order to increase the chances of the checks to catch errors, the
kernel has to be rebuilt with CONFIG_DEBUG_VM, which also enables
multiple other internal debug checks (VM_BUG_ON() etc), which is
suboptimal when the goal is to catch errors in mm users, not in mm code
itself.

To catch some wrong users of the page allocator we have
CONFIG_DEBUG_PAGEALLOC, which is designed to have virtually no overhead
unless enabled at boot time.  Memory corruptions when writing to freed
pages have often the same underlying errors (use-after-free, double free)
as corrupting the corresponding struct pages, so this existing debugging
functionality is a good fit to extend by also perform struct page checks
at least as often as if CONFIG_DEBUG_VM was enabled.

Specifically, after this patch, when debug_pagealloc is enabled on boot,
and CONFIG_DEBUG_VM disabled, pages are checked when allocated from or
freed to the pcplists *in addition* to being moved between pcplists and
free lists.  When both debug_pagealloc and CONFIG_DEBUG_VM are enabled,
pages are checked when being moved between pcplists and free lists *in
addition* to when allocated from or freed to the pcplists.

When debug_pagealloc is not enabled on boot, the overhead in fast paths
should be virtually none thanks to the use of static key.

Link: http://lkml.kernel.org/r/20190603143451.27353-3-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:43 -07:00
Vlastimil Babka 96a2b03f28 mm, debug_pagelloc: use static keys to enable debugging 
Patch series "debug_pagealloc improvements".

I have been recently debugging some pcplist corruptions, where it would be
useful to perform struct page checks immediately as pages are allocated
from and freed to pcplists, which is now only possible by rebuilding the
kernel with CONFIG_DEBUG_VM (details in Patch 2 changelog).

To make this kind of debugging simpler in future on a distro kernel, I
have improved CONFIG_DEBUG_PAGEALLOC so that it has even smaller overhead
when not enabled at boot time (Patch 1) and also when enabled (Patch 3),
and extended it to perform the struct page checks more often when enabled
(Patch 2).  Now it can be configured in when building a distro kernel
without extra overhead, and debugging page use after free or double free
can be enabled simply by rebooting with debug_pagealloc=on.

This patch (of 3):

CONFIG_DEBUG_PAGEALLOC has been redesigned by 031bc5743f
("mm/debug-pagealloc: make debug-pagealloc boottime configurable") to
allow being always enabled in a distro kernel, but only perform its
expensive functionality when booted with debug_pagelloc=on.  We can
further reduce the overhead when not boot-enabled (including page
allocator fast paths) using static keys.  This patch introduces one for
debug_pagealloc core functionality, and another for the optional guard
page functionality (enabled by booting with debug_guardpage_minorder=X).

Link: http://lkml.kernel.org/r/20190603143451.27353-2-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:43 -07:00
Nicolas Boichat a9659476d4 mm/failslab.c: by default, do not fail allocations with direct reclaim only 
When failslab was originally written, the intention of the
"ignore-gfp-wait" flag default value ("N") was to fail GFP_ATOMIC
allocations.  Those were defined as (__GFP_HIGH), and the code would test
for __GFP_WAIT (0x10u).

However, since then, __GFP_WAIT was replaced by __GFP_RECLAIM
(___GFP_DIRECT_RECLAIM|___GFP_KSWAPD_RECLAIM), and GFP_ATOMIC is now
defined as (__GFP_HIGH|__GFP_ATOMIC|__GFP_KSWAPD_RECLAIM).

This means that when the flag is false, almost no allocation ever fails
(as even GFP_ATOMIC allocations contain ___GFP_KSWAPD_RECLAIM).

Restore the original intent of the code, by ignoring calls that directly
reclaim only (__GFP_DIRECT_RECLAIM), and thus, failing GFP_ATOMIC calls
again by default.

Link: http://lkml.kernel.org/r/20190520214514.81360-1-drinkcat@chromium.org
Fixes: 71baba4b92 ("mm, page_alloc: rename __GFP_WAIT to __GFP_RECLAIM")
Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
Reviewed-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:43 -07:00
Andrew Morton f445884562 include/linux/pagemap.h: document trylock_page() return value 
Cc: Henry Burns <henryburns@google.com>
Cc: Jonathan Adams <jwadams@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Vitaly Wool <vitalywool@gmail.com>
Cc: Xidong Wang <wangxidong_97@163.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:43 -07:00
Denis Efremov 98ef2046f2 mm: remove the exporting of totalram_pages 
Previously totalram_pages was the global variable.  Currently,
totalram_pages is the static inline function from the include/linux/mm.h
However, the function is also marked as EXPORT_SYMBOL, which is at best an
odd combination.  Because there is no point for the static inline function
from a public header to be exported, this commit removes the
EXPORT_SYMBOL() marking.  It will be still possible to use the function in
modules because all the symbols it depends on are exported.

Link: http://lkml.kernel.org/r/20190710141031.15642-1-efremov@linux.com
Fixes: ca79b0c211 ("mm: convert totalram_pages and totalhigh_pages variables to atomic")
Signed-off-by: Denis Efremov <efremov@linux.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:43 -07:00
Sebastian Andrzej Siewior 51b1762904 include/linux/vmpressure.h: use spinlock_t instead of struct spinlock 
For spinlocks the type spinlock_t should be used instead of "struct
spinlock".

Use spinlock_t for spinlock's definition.

Link: http://lkml.kernel.org/r/20190704153803.12739-3-bigeasy@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:43 -07:00
Pingfan Liu 1fcf0a561c mm/page_isolation.c: change the prototype of undo_isolate_page_range() 
undo_isolate_page_range() never fails, so no need to return value.

Link: http://lkml.kernel.org/r/1562075604-8979-1-git-send-email-kernelfans@gmail.com
Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:43 -07:00
Christoph Hellwig ac1c3e49a9 mm: remove the account_page_dirtied export 
account_page_dirtied() is only used by our set_page_dirty() helpers and
should not be used anywhere else.

Link: http://lkml.kernel.org/r/20190605183702.30572-1-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:42 -07:00
Alexey Dobriyan 219f8a2e25 include/linux/mm_types.h: ifdef struct vm_area_struct::swap_readahead_info 
The field is only used in swap code.

Link: http://lkml.kernel.org/r/20190503190500.GA30589@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:42 -07:00
Jason Gunthorpe 442a5a9a92 mm: make !CONFIG_HUGE_PAGE wrappers into static inlines 
Instead of using defines, which loses type safety and provokes unused
variable warnings from gcc, put the constants into static inlines.

Link: http://lkml.kernel.org/r/20190522235102.GA15370@mellanox.com
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:42 -07:00
Miklos Szeredi 465fc3a9b3 mm/memory.c: trivial clean up in insert_page() 
Make the success case use the same cleanup path as the failure case.

Link: http://lkml.kernel.org/r/20190523134024.GC24093@localhost.localdomain
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:42 -07:00
Bharath Vedartham a7030aea20 mm/gup.c: make follow_page_mask() static 
follow_page_mask() is only used in gup.c, make it static.

Link: http://lkml.kernel.org/r/20190510190831.GA4061@bharath12345-Inspiron-5559
Signed-off-by: Bharath Vedartham <linux.bhar@gmail.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:42 -07:00
Mike Rapoport 4456760717 sparc: remove ARCH_SELECT_MEMORY_MODEL 
The ARCH_SELECT_MEMORY_MODEL option is enabled only for 64-bit.  However,
64-bit configuration also enables ARCH_SPARSEMEM_DEFAULT and there is no
ARCH_FLATMEM_ENABLE in arch/sparc/Kconfig.

With such settings, the dependencies in mm/Kconfig are always evaluated to
SPARSEMEM=y for 64-bit and to FLATMEM=y for 32-bit.

The ARCH_SELECT_MEMORY_MODEL option in arch/sparc/Kconfig does not affect
anything and can be removed.

Link: http://lkml.kernel.org/r/1556740577-4140-4-git-send-email-rppt@linux.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Russell King <linux@armlinux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:42 -07:00
Mike Rapoport a9d8777e39 s390: remove ARCH_SELECT_MEMORY_MODEL 
The only reason s390 has ARCH_SELECT_MEMORY_MODEL option in
arch/s390/Kconfig is an ancient compile error with allnoconfig which was
fixed by commit 97195d6b41 ("[S390] fix sparsemem related compile error
with allnoconfig on s390") by adding the ARCH_SELECT_MEMORY_MODEL option.

Since then a lot have changed and now allnoconfig builds just fine without
ARCH_SELECT_MEMORY_MODEL, so it can be removed.

Link: http://lkml.kernel.org/r/1556740577-4140-3-git-send-email-rppt@linux.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Russell King <linux@armlinux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:42 -07:00
Mike Rapoport 03069bb0b1 arm: remove ARCH_SELECT_MEMORY_MODEL 
Patch series "remove ARCH_SELECT_MEMORY_MODEL where it has no effect".

For several architectures the ARCH_SELECT_MEMORY_MODEL has no real effect
because the dependencies for the memory model are always evaluated to a
single value.

Remove the ARCH_SELECT_MEMORY_MODEL from the Kconfigs for these
architectures.

This patch (of 3):

The ARCH_SELECT_MEMORY_MODEL in arch/arm/Kconfig is enabled only when
ARCH_SPARSEMEM_ENABLE=y.  But in this case, ARCH_SPARSEMEM_DEFAULT is also
enabled and this in turn enables SPARSEMEM_MANUAL.

Since there is no definition of ARCH_FLATMEM_ENABLE in arch/arm/Kconfig,
SPARSEMEM_MANUAL is the only enabled memory model, hence the final
selection will evaluate to SPARSEMEM=y.

Since ARCH_SPARSEMEM_ENABLE is set to 'y' only by several sub-arch
configurations, the default for must sub-arches would be the falback to
FLATMEM regardless of ARCH_SELECT_MEMORY_MODEL.

Link: http://lkml.kernel.org/r/1556740577-4140-2-git-send-email-rppt@linux.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Russell King <linux@armlinux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:42 -07:00
Andrew Morton 2236b99d6a include/linux/pfn_t.h: remove pfn_t_to_virt() 
It has no callers and there is no virt_to_pfn_t().

Reported-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:42 -07:00
Marco Elver 0d4ca4c9ba mm/kasan: add object validation in ksize() 
ksize() has been unconditionally unpoisoning the whole shadow memory
region associated with an allocation.  This can lead to various undetected
bugs, for example, double-kzfree().

Specifically, kzfree() uses ksize() to determine the actual allocation
size, and subsequently zeroes the memory.  Since ksize() used to just
unpoison the whole shadow memory region, no invalid free was detected.

This patch addresses this as follows:

1. Add a check in ksize(), and only then unpoison the memory region.

2. Preserve kasan_unpoison_slab() semantics by explicitly unpoisoning
   the shadow memory region using the size obtained from __ksize().

Tested:
1. With SLAB allocator: a) normal boot without warnings; b) verified the
   added double-kzfree() is detected.
2. With SLUB allocator: a) normal boot without warnings; b) verified the
   added double-kzfree() is detected.

[elver@google.com: s/BUG_ON/WARN_ON_ONCE/, per Kees]
  Link: http://lkml.kernel.org/r/20190627094445.216365-6-elver@google.com
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=199359
Link: http://lkml.kernel.org/r/20190626142014.141844-6-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:42 -07:00
Marco Elver 10d1f8cb39 mm/slab: refactor common ksize KASAN logic into slab_common.c 
This refactors common code of ksize() between the various allocators into
slab_common.c: __ksize() is the allocator-specific implementation without
instrumentation, whereas ksize() includes the required KASAN logic.

Link: http://lkml.kernel.org/r/20190626142014.141844-5-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Acked-by: Christoph Lameter <cl@linux.com>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:42 -07:00
Marco Elver bb104ed785 lib/test_kasan: Add test for double-kzfree detection 
Add a simple test that checks if double-kzfree is being detected
correctly.

Link: http://lkml.kernel.org/r/20190626142014.141844-4-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:42 -07:00
Marco Elver b5f6e0fc7d mm/kasan: change kasan_check_{read,write} to return boolean 
This changes {,__}kasan_check_{read,write} functions to return a boolean
denoting if the access was valid or not.

[sfr@canb.auug.org.au: include types.h for "bool"]
  Link: http://lkml.kernel.org/r/20190705184949.13cdd021@canb.auug.org.au
Link: http://lkml.kernel.org/r/20190626142014.141844-3-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:42 -07:00
Marco Elver 7d8ad890da mm/kasan: introduce __kasan_check_{read,write} 
Patch series "mm/kasan: Add object validation in ksize()", v3.

This patch (of 5):

This introduces __kasan_check_{read,write}.  __kasan_check functions may
be used from anywhere, even compilation units that disable instrumentation
selectively.

This change eliminates the need for the __KASAN_INTERNAL definition.

[elver@google.com: v5]
  Link: http://lkml.kernel.org/r/20190708170706.174189-2-elver@google.com
Link: http://lkml.kernel.org/r/20190626142014.141844-2-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:42 -07:00
Marco Elver 751ad98d5f asm-generic, x86: add bitops instrumentation for KASAN 
This adds a new header to asm-generic to allow optionally instrumenting
architecture-specific asm implementations of bitops.

This change includes the required change for x86 as reference and
changes the kernel API doc to point to bitops-instrumented.h instead.
Rationale: the functions in x86's bitops.h are no longer the kernel API
functions, but instead the arch_ prefixed functions, which are then
instrumented via bitops-instrumented.h.

Other architectures can similarly add support for asm implementations of
bitops.

The documentation text was derived from x86 and existing bitops
asm-generic versions: 1) references to x86 have been removed; 2) as a
result, some of the text had to be reworded for clarity and consistency.

Tested using lib/test_kasan with bitops tests (pre-requisite patch).
Bugzilla ref: https://bugzilla.kernel.org/show_bug.cgi?id=198439

Link: http://lkml.kernel.org/r/20190613125950.197667-4-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:42 -07:00
Marco Elver ff66135015 x86: use static_cpu_has in uaccess region to avoid instrumentation 
This patch is a pre-requisite for enabling KASAN bitops instrumentation;
using static_cpu_has instead of boot_cpu_has avoids instrumentation of
test_bit inside the uaccess region.  With instrumentation, the KASAN
check would otherwise be flagged by objtool.

For consistency, kernel/signal.c was changed to mirror this change,
however, is never instrumented with KASAN (currently unsupported under
x86 32bit).

Link: http://lkml.kernel.org/r/20190613125950.197667-3-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Suggested-by: H. Peter Anvin <hpa@zytor.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:42 -07:00
Marco Elver 19a33ca6c2 lib/test_kasan: add bitops tests 
Patch series "Bitops instrumentation for KASAN", v5.

This patch (of 3):

This adds bitops tests to the test_kasan module.  In a follow-up patch,
support for bitops instrumentation will be added.

Link: http://lkml.kernel.org/r/20190613125950.197667-2-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2019-07-12 11:05:42 -07:00