Граф коммитов

11955 Коммитов

Автор SHA1 Сообщение Дата
Roman Gushchin 799a34d5b0 Revert "defer call to mem_cgroup_sk_alloc()"
[ Upstream commit edbe69ef2c ]

This patch effectively reverts commit 9f1c2674b3 ("net: memcontrol:
defer call to mem_cgroup_sk_alloc()").

Moving mem_cgroup_sk_alloc() to the inet_csk_accept() completely breaks
memcg socket memory accounting, as packets received before memcg
pointer initialization are not accounted and are causing refcounting
underflow on socket release.

Actually the free-after-use problem was fixed by
commit c0576e3975 ("net: call cgroup_sk_alloc() earlier in
sk_clone_lock()") for the cgroup pointer.

So, let's revert it and call mem_cgroup_sk_alloc() just before
cgroup_sk_alloc(). This is safe, as we hold a reference to the socket
we're cloning, and it holds a reference to the memcg.

Also, let's drop BUG_ON(mem_cgroup_is_root()) check from
mem_cgroup_sk_alloc(). I see no reasons why bumping the root
memcg counter is a good reason to panic, and there are no realistic
ways to hit it.

Signed-off-by: Roman Gushchin <guro@fb.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-02-13 10:19:48 +01:00
Yisheng Xie b2ba0bd346 kmemleak: add scheduling point to kmemleak_scan()
[ Upstream commit bde5f6bc68 ]

kmemleak_scan() will scan struct page for each node and it can be really
large and resulting in a soft lockup.  We have seen a soft lockup when
do scan while compile kernel:

  watchdog: BUG: soft lockup - CPU#53 stuck for 22s! [bash:10287]
 [...]
  Call Trace:
   kmemleak_scan+0x21a/0x4c0
   kmemleak_write+0x312/0x350
   full_proxy_write+0x5a/0xa0
   __vfs_write+0x33/0x150
   vfs_write+0xad/0x1a0
   SyS_write+0x52/0xc0
   do_syscall_64+0x61/0x1a0
   entry_SYSCALL64_slow_path+0x25/0x25

Fix this by adding cond_resched every MAX_SCAN_SIZE.

Link: http://lkml.kernel.org/r/1511439788-20099-1-git-send-email-xieyisheng1@huawei.com
Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com>
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-02-03 17:39:12 +01:00
Vlastimil Babka bd9fa7822f mm, page_alloc: fix potential false positive in __zone_watermark_ok
commit b050e3769c upstream.

Since commit 97a16fc82a ("mm, page_alloc: only enforce watermarks for
order-0 allocations"), __zone_watermark_ok() check for high-order
allocations will shortcut per-migratetype free list checks for
ALLOC_HARDER allocations, and return true as long as there's free page
of any migratetype.  The intention is that ALLOC_HARDER can allocate
from MIGRATE_HIGHATOMIC free lists, while normal allocations can't.

However, as a side effect, the watermark check will then also return
true when there are pages only on the MIGRATE_ISOLATE list, or (prior to
CMA conversion to ZONE_MOVABLE) on the MIGRATE_CMA list.  Since the
allocation cannot actually obtain isolated pages, and might not be able
to obtain CMA pages, this can result in a false positive.

The condition should be rare and perhaps the outcome is not a fatal one.
Still, it's better if the watermark check is correct.  There also
shouldn't be a performance tradeoff here.

Link: http://lkml.kernel.org/r/20171102125001.23708-1-vbabka@suse.cz
Fixes: 97a16fc82a ("mm, page_alloc: only enforce watermarks for order-0 allocations")
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-31 14:03:40 +01:00
Kirill A. Shutemov 3abb4c1103 mm, page_vma_mapped: Drop faulty pointer arithmetics in check_pte()
commit 0d665e7b10 upstream.

Tetsuo reported random crashes under memory pressure on 32-bit x86
system and tracked down to change that introduced
page_vma_mapped_walk().

The root cause of the issue is the faulty pointer math in check_pte().
As ->pte may point to an arbitrary page we have to check that they are
belong to the section before doing math. Otherwise it may lead to weird
results.

It wasn't noticed until now as mem_map[] is virtually contiguous on
flatmem or vmemmap sparsemem. Pointer arithmetic just works against all
'struct page' pointers. But with classic sparsemem, it doesn't because
each section memap is allocated separately and so consecutive pfns
crossing two sections might have struct pages at completely unrelated
addresses.

Let's restructure code a bit and replace pointer arithmetic with
operations on pfns.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-and-tested-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Acked-by: Michal Hocko <mhocko@suse.com>
Fixes: ace71a19ce ("mm: introduce page_vma_mapped_walk()")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-23 19:58:21 +01:00
Baoquan He c86ee796fe mm/sparse.c: wrong allocation for mem_section
commit d09cfbbfa0 upstream.

In commit 83e3c48729 ("mm/sparsemem: Allocate mem_section at runtime
for CONFIG_SPARSEMEM_EXTREME=y") mem_section is allocated at runtime to
save memory.

It allocates the first dimension of array with sizeof(struct mem_section).

It costs extra memory, should be sizeof(struct mem_section *).

Fix it.

Link: http://lkml.kernel.org/r/1513932498-20350-1-git-send-email-bhe@redhat.com
Fixes: 83e3c48729 ("mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y")
Signed-off-by: Baoquan He <bhe@redhat.com>
Tested-by: Dave Young <dyoung@redhat.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Atsushi Kumagai <ats-kumagai@wm.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-10 09:31:17 +01:00
Anshuman Khandual abcc786278 mm/mprotect: add a cond_resched() inside change_pmd_range()
commit 4991c09c7c upstream.

While testing on a large CPU system, detected the following RCU stall
many times over the span of the workload.  This problem is solved by
adding a cond_resched() in the change_pmd_range() function.

  INFO: rcu_sched detected stalls on CPUs/tasks:
   154-....: (670 ticks this GP) idle=022/140000000000000/0 softirq=2825/2825 fqs=612
   (detected by 955, t=6002 jiffies, g=4486, c=4485, q=90864)
  Sending NMI from CPU 955 to CPUs 154:
  NMI backtrace for cpu 154
  CPU: 154 PID: 147071 Comm: workload Not tainted 4.15.0-rc3+ #3
  NIP:  c0000000000b3f64 LR: c0000000000b33d4 CTR: 000000000000aa18
  REGS: 00000000a4b0fb44 TRAP: 0501   Not tainted  (4.15.0-rc3+)
  MSR:  8000000000009033 <SF,EE,ME,IR,DR,RI,LE>  CR: 22422082  XER: 00000000
  CFAR: 00000000006cf8f0 SOFTE: 1
  GPR00: 0010000000000000 c00003ef9b1cb8c0 c0000000010cc600 0000000000000000
  GPR04: 8e0000018c32b200 40017b3858fd6e00 8e0000018c32b208 40017b3858fd6e00
  GPR08: 8e0000018c32b210 40017b3858fd6e00 8e0000018c32b218 40017b3858fd6e00
  GPR12: ffffffffffffffff c00000000fb25100
  NIP [c0000000000b3f64] plpar_hcall9+0x44/0x7c
  LR [c0000000000b33d4] pSeries_lpar_flush_hash_range+0x384/0x420
  Call Trace:
    flush_hash_range+0x48/0x100
    __flush_tlb_pending+0x44/0xd0
    hpte_need_flush+0x408/0x470
    change_protection_range+0xaac/0xf10
    change_prot_numa+0x30/0xb0
    task_numa_work+0x2d0/0x3e0
    task_work_run+0x130/0x190
    do_notify_resume+0x118/0x120
    ret_from_except_lite+0x70/0x74
  Instruction dump:
  60000000 f8810028 7ca42b78 7cc53378 7ce63b78 7d074378 7d284b78 7d495378
  e9410060 e9610068 e9810070 44000022 <7d806378> e9810028 f88c0000 f8ac0008

Link: http://lkml.kernel.org/r/20171214140551.5794-1-khandual@linux.vnet.ibm.com
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Suggested-by: Nicholas Piggin <npiggin@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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-10 09:31:17 +01:00
Kirill A. Shutemov 7d7545295e mm/sparsemem: Fix ARM64 boot crash when CONFIG_SPARSEMEM_EXTREME=y
commit 629a359bdb upstream.

Since commit:

  83e3c48729 ("mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y")

we allocate the mem_section array dynamically in sparse_memory_present_with_active_regions(),
but some architectures, like arm64, don't call the routine to initialize sparsemem.

Let's move the initialization into memory_present() it should cover all
architectures.

Reported-and-tested-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Fixes: 83e3c48729 ("mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y")
Link: http://lkml.kernel.org/r/20171107083337.89952-1-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Dan Rue <dan.rue@linaro.org>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-25 14:26:31 +01:00
Will Deacon 5383f45db3 locking/barriers: Convert users of lockless_dereference() to READ_ONCE()
commit 3382290ed2 upstream.

[ Note, this is a Git cherry-pick of the following commit:

    506458efaf ("locking/barriers: Convert users of lockless_dereference() to READ_ONCE()")

  ... for easier x86 PTI code testing and back-porting. ]

READ_ONCE() now has an implicit smp_read_barrier_depends() call, so it
can be used instead of lockless_dereference() without any change in
semantics.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1508840570-22169-4-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-25 14:26:21 +01:00
Kirill A. Shutemov 4afaf6ea65 mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y
commit 83e3c48729 upstream.

Size of the mem_section[] array depends on the size of the physical address space.

In preparation for boot-time switching between paging modes on x86-64
we need to make the allocation of mem_section[] dynamic, because otherwise
we waste a lot of RAM: with CONFIG_NODE_SHIFT=10, mem_section[] size is 32kB
for 4-level paging and 2MB for 5-level paging mode.

The patch allocates the array on the first call to sparse_memory_present_with_active_regions().

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@suse.de>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20170929140821.37654-2-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-25 14:26:15 +01:00
Michal Hocko 55fe4698d8 mm, oom_reaper: fix memory corruption
commit 4837fe37ad upstream.

David Rientjes has reported the following memory corruption while the
oom reaper tries to unmap the victims address space

  BUG: Bad page map in process oom_reaper  pte:6353826300000000 pmd:00000000
  addr:00007f50cab1d000 vm_flags:08100073 anon_vma:ffff9eea335603f0 mapping:          (null) index:7f50cab1d
  file:          (null) fault:          (null) mmap:          (null) readpage:          (null)
  CPU: 2 PID: 1001 Comm: oom_reaper
  Call Trace:
     unmap_page_range+0x1068/0x1130
     __oom_reap_task_mm+0xd5/0x16b
     oom_reaper+0xff/0x14c
     kthread+0xc1/0xe0

Tetsuo Handa has noticed that the synchronization inside exit_mmap is
insufficient.  We only synchronize with the oom reaper if
tsk_is_oom_victim which is not true if the final __mmput is called from
a different context than the oom victim exit path.  This can trivially
happen from context of any task which has grabbed mm reference (e.g.  to
read /proc/<pid>/ file which requires mm etc.).

The race would look like this

  oom_reaper		oom_victim		task
						mmget_not_zero
			do_exit
			  mmput
  __oom_reap_task_mm				mmput
  						  __mmput
						    exit_mmap
						      remove_vma
    unmap_page_range

Fix this issue by providing a new mm_is_oom_victim() helper which
operates on the mm struct rather than a task.  Any context which
operates on a remote mm struct should use this helper in place of
tsk_is_oom_victim.  The flag is set in mark_oom_victim and never cleared
so it is stable in the exit_mmap path.

Debugged by Tetsuo Handa.

Link: http://lkml.kernel.org/r/20171210095130.17110-1-mhocko@kernel.org
Fixes: 2129258024 ("mm: oom: let oom_reap_task and exit_mmap run concurrently")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: David Rientjes <rientjes@google.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Andrea Argangeli <andrea@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-20 10:10:18 +01:00
Miles Chen 5ca94e0367 slub: fix sysfs duplicate filename creation when slub_debug=O
[ Upstream commit 11066386ef ]

When slub_debug=O is set.  It is possible to clear debug flags for an
"unmergeable" slab cache in kmem_cache_open().  It makes the "unmergeable"
cache became "mergeable" in sysfs_slab_add().

These caches will generate their "unique IDs" by create_unique_id(), but
it is possible to create identical unique IDs.  In my experiment,
sgpool-128, names_cache, biovec-256 generate the same ID ":Ft-0004096" and
the kernel reports "sysfs: cannot create duplicate filename
'/kernel/slab/:Ft-0004096'".

To repeat my experiment, set disable_higher_order_debug=1,
CONFIG_SLUB_DEBUG_ON=y in kernel-4.14.

Fix this issue by setting unmergeable=1 if slub_debug=O and the the
default slub_debug contains any no-merge flags.

call path:
kmem_cache_create()
  __kmem_cache_alias()	-> we set SLAB_NEVER_MERGE flags here
  create_cache()
    __kmem_cache_create()
      kmem_cache_open()	-> clear DEBUG_METADATA_FLAGS
      sysfs_slab_add()	-> the slab cache is mergeable now

  sysfs: cannot create duplicate filename '/kernel/slab/:Ft-0004096'
  ------------[ cut here ]------------
  WARNING: CPU: 0 PID: 1 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x60/0x7c
  Modules linked in:
  CPU: 0 PID: 1 Comm: swapper/0 Tainted: G        W       4.14.0-rc7ajb-00131-gd4c2e9f-dirty #123
  Hardware name: linux,dummy-virt (DT)
  task: ffffffc07d4e0080 task.stack: ffffff8008008000
  PC is at sysfs_warn_dup+0x60/0x7c
  LR is at sysfs_warn_dup+0x60/0x7c
  pc :  lr :  pstate: 60000145
  Call trace:
   sysfs_warn_dup+0x60/0x7c
   sysfs_create_dir_ns+0x98/0xa0
   kobject_add_internal+0xa0/0x294
   kobject_init_and_add+0x90/0xb4
   sysfs_slab_add+0x90/0x200
   __kmem_cache_create+0x26c/0x438
   kmem_cache_create+0x164/0x1f4
   sg_pool_init+0x60/0x100
   do_one_initcall+0x38/0x12c
   kernel_init_freeable+0x138/0x1d4
   kernel_init+0x10/0xfc
   ret_from_fork+0x10/0x18

Link: http://lkml.kernel.org/r/1510365805-5155-1-git-send-email-miles.chen@mediatek.com
Signed-off-by: Miles Chen <miles.chen@mediatek.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-14 09:53:10 +01:00
Sergey Senozhatsky 1238334082 zsmalloc: calling zs_map_object() from irq is a bug
[ Upstream commit 1aedcafbf3 ]

Use BUG_ON(in_interrupt()) in zs_map_object().  This is not a new
BUG_ON(), it's always been there, but was recently changed to
VM_BUG_ON().  There are several problems there.  First, we use use
per-CPU mappings both in zsmalloc and in zram, and interrupt may easily
corrupt those buffers.  Second, and more importantly, we believe it's
possible to start leaking sensitive information.  Consider the following
case:

-> process P
	swap out
	 zram
	  per-cpu mapping CPU1
	   compress page A
-> IRQ

	swap out
	 zram
	  per-cpu mapping CPU1
	   compress page B
	    write page from per-cpu mapping CPU1 to zsmalloc pool
	iret

-> process P
	    write page from per-cpu mapping CPU1 to zsmalloc pool  [*]
	return

* so we store overwritten data that actually belongs to another
  page (task) and potentially contains sensitive data. And when
  process P will page fault it's going to read (swap in) that
  other task's data.

Link: http://lkml.kernel.org/r/20170929045140.4055-1-sergey.senozhatsky@gmail.com
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-14 09:53:10 +01:00
Kirill A. Shutemov 342ee87758 mm, x86/mm: Fix performance regression in get_user_pages_fast()
[ Upstream commit 5b65c4677a ]

The 0-day test bot found a performance regression that was tracked down to
switching x86 to the generic get_user_pages_fast() implementation:

  http://lkml.kernel.org/r/20170710024020.GA26389@yexl-desktop

The regression was caused by the fact that we now use local_irq_save() +
local_irq_restore() in get_user_pages_fast() to disable interrupts.
In x86 implementation local_irq_disable() + local_irq_enable() was used.

The fix is to make get_user_pages_fast() use local_irq_disable(),
leaving local_irq_save() for __get_user_pages_fast() that can be called
with interrupts disabled.

Numbers for pinning a gigabyte of memory, one page a time, 20 repeats:

  Before:  Average: 14.91 ms, stddev: 0.45 ms
  After:   Average: 10.76 ms, stddev: 0.18 ms

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thorsten Leemhuis <regressions@leemhuis.info>
Cc: linux-mm@kvack.org
Fixes: e585513b76 ("x86/mm/gup: Switch GUP to the generic get_user_page_fast() implementation")
Link: http://lkml.kernel.org/r/20170908215603.9189-3-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-10 13:40:43 +01:00
Kirill A. Shutemov be75ad849b mm/hugetlb: fix NULL-pointer dereference on 5-level paging machine
commit f4f0a3d85b upstream.

I made a mistake during converting hugetlb code to 5-level paging: in
huge_pte_alloc() we have to use p4d_alloc(), not p4d_offset().

Otherwise it leads to crash -- NULL-pointer dereference in pud_alloc()
if p4d table is not yet allocated.

It only can happen in 5-level paging mode.  In 4-level paging mode
p4d_offset() always returns pgd, so we are fine.

Link: http://lkml.kernel.org/r/20171122121921.64822-1-kirill.shutemov@linux.intel.com
Fixes: c2febafc67 ("mm: convert generic code to 5-level paging")
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-05 11:26:30 +01:00
Shakeel Butt d983b6251c mm, memcg: fix mem_cgroup_swapout() for THPs
commit d08afa149a upstream.

Commit d6810d7300 ("memcg, THP, swap: make mem_cgroup_swapout()
support THP") changed mem_cgroup_swapout() to support transparent huge
page (THP).

However the patch missed one location which should be changed for
correctly handling THPs.  The resulting bug will cause the memory
cgroups whose THPs were swapped out to become zombies on deletion.

Link: http://lkml.kernel.org/r/20171128161941.20931-1-shakeelb@google.com
Fixes: d6810d7300 ("memcg, THP, swap: make mem_cgroup_swapout() support THP")
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Greg Thelen <gthelen@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-12-05 11:26:29 +01:00
chenjie 8a0bb9ebaa mm/madvise.c: fix madvise() infinite loop under special circumstances
commit 6ea8d958a2 upstream.

MADVISE_WILLNEED has always been a noop for DAX (formerly XIP) mappings.
Unfortunately madvise_willneed() doesn't communicate this information
properly to the generic madvise syscall implementation.  The calling
convention is quite subtle there.  madvise_vma() is supposed to either
return an error or update &prev otherwise the main loop will never
advance to the next vma and it will keep looping for ever without a way
to get out of the kernel.

It seems this has been broken since introduction.  Nobody has noticed
because nobody seems to be using MADVISE_WILLNEED on these DAX mappings.

[mhocko@suse.com: rewrite changelog]
Link: http://lkml.kernel.org/r/20171127115318.911-1-guoxuenan@huawei.com
Fixes: fe77ba6f4f ("[PATCH] xip: madvice/fadvice: execute in place")
Signed-off-by: chenjie <chenjie6@huawei.com>
Signed-off-by: guoxuenan <guoxuenan@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: zhangyi (F) <yi.zhang@huawei.com>
Cc: Miao Xie <miaoxie@huawei.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Shaohua Li <shli@fb.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Carsten Otte <cotte@de.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-05 11:26:29 +01:00
Dan Williams daac045736 mm: fail get_vaddr_frames() for filesystem-dax mappings
commit b7f0554a56 upstream.

Until there is a solution to the dma-to-dax vs truncate problem it is
not safe to allow V4L2, Exynos, and other frame vector users to create
long standing / irrevocable memory registrations against filesytem-dax
vmas.

[dan.j.williams@intel.com: add comment for vma_is_fsdax() check in get_vaddr_frames(), per Jan]
  Link: http://lkml.kernel.org/r/151197874035.26211.4061781453123083667.stgit@dwillia2-desk3.amr.corp.intel.com
Link: http://lkml.kernel.org/r/151068939985.7446.15684639617389154187.stgit@dwillia2-desk3.amr.corp.intel.com
Fixes: 3565fce3a6 ("mm, x86: get_user_pages() for dax mappings")
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Inki Dae <inki.dae@samsung.com>
Cc: Seung-Woo Kim <sw0312.kim@samsung.com>
Cc: Joonyoung Shim <jy0922.shim@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Doug Ledford <dledford@redhat.com>
Cc: Hal Rosenstock <hal.rosenstock@gmail.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-05 11:26:28 +01:00
Dan Williams 40aa9d2998 mm: introduce get_user_pages_longterm
commit 2bb6d28370 upstream.

Patch series "introduce get_user_pages_longterm()", v2.

Here is a new get_user_pages api for cases where a driver intends to
keep an elevated page count indefinitely.  This is distinct from usages
like iov_iter_get_pages where the elevated page counts are transient.
The iov_iter_get_pages cases immediately turn around and submit the
pages to a device driver which will put_page when the i/o operation
completes (under kernel control).

In the longterm case userspace is responsible for dropping the page
reference at some undefined point in the future.  This is untenable for
filesystem-dax case where the filesystem is in control of the lifetime
of the block / page and needs reasonable limits on how long it can wait
for pages in a mapping to become idle.

Fixing filesystems to actually wait for dax pages to be idle before
blocks from a truncate/hole-punch operation are repurposed is saved for
a later patch series.

Also, allowing longterm registration of dax mappings is a future patch
series that introduces a "map with lease" semantic where the kernel can
revoke a lease and force userspace to drop its page references.

I have also tagged these for -stable to purposely break cases that might
assume that longterm memory registrations for filesystem-dax mappings
were supported by the kernel.  The behavior regression this policy
change implies is one of the reasons we maintain the "dax enabled.
Warning: EXPERIMENTAL, use at your own risk" notification when mounting
a filesystem in dax mode.

It is worth noting the device-dax interface does not suffer the same
constraints since it does not support file space management operations
like hole-punch.

This patch (of 4):

Until there is a solution to the dma-to-dax vs truncate problem it is
not safe to allow long standing memory registrations against
filesytem-dax vmas.  Device-dax vmas do not have this problem and are
explicitly allowed.

This is temporary until a "memory registration with layout-lease"
mechanism can be implemented for the affected sub-systems (RDMA and
V4L2).

[akpm@linux-foundation.org: use kcalloc()]
Link: http://lkml.kernel.org/r/151068939435.7446.13560129395419350737.stgit@dwillia2-desk3.amr.corp.intel.com
Fixes: 3565fce3a6 ("mm, x86: get_user_pages() for dax mappings")
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Suggested-by: Christoph Hellwig <hch@lst.de>
Cc: Doug Ledford <dledford@redhat.com>
Cc: Hal Rosenstock <hal.rosenstock@gmail.com>
Cc: Inki Dae <inki.dae@samsung.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Joonyoung Shim <jy0922.shim@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Sean Hefty <sean.hefty@intel.com>
Cc: Seung-Woo Kim <sw0312.kim@samsung.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-05 11:26:28 +01:00
Dan Williams c6c78a1d45 mm, hugetlbfs: introduce ->split() to vm_operations_struct
commit 31383c6865 upstream.

Patch series "device-dax: fix unaligned munmap handling"

When device-dax is operating in huge-page mode we want it to behave like
hugetlbfs and fail attempts to split vmas into unaligned ranges.  It
would be messy to teach the munmap path about device-dax alignment
constraints in the same (hstate) way that hugetlbfs communicates this
constraint.  Instead, these patches introduce a new ->split() vm
operation.

This patch (of 2):

The device-dax interface has similar constraints as hugetlbfs in that it
requires the munmap path to unmap in huge page aligned units.  Rather
than add more custom vma handling code in __split_vma() introduce a new
vm operation to perform this vma specific check.

Link: http://lkml.kernel.org/r/151130418135.4029.6783191281930729710.stgit@dwillia2-desk3.amr.corp.intel.com
Fixes: dee4107924 ("/dev/dax, core: file operations and dax-mmap")
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-05 11:26:28 +01:00
Mike Kravetz b4c8fce668 mm/cma: fix alloc_contig_range ret code/potential leak
commit 63cd448908 upstream.

If the call __alloc_contig_migrate_range() in alloc_contig_range returns
-EBUSY, processing continues so that test_pages_isolated() is called
where there is a tracepoint to identify the busy pages.  However, it is
possible for busy pages to become available between the calls to these
two routines.  In this case, the range of pages may be allocated.
Unfortunately, the original return code (ret == -EBUSY) is still set and
returned to the caller.  Therefore, the caller believes the pages were
not allocated and they are leaked.

Update the comment to indicate that allocation is still possible even if
__alloc_contig_migrate_range returns -EBUSY.  Also, clear return code in
this case so that it is not accidentally used or returned to caller.

Link: http://lkml.kernel.org/r/20171122185214.25285-1-mike.kravetz@oracle.com
Fixes: 8ef5849fa8 ("mm/cma: always check which page caused allocation failure")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-05 11:26:28 +01:00
Kirill A. Shutemov 01ca972745 mm, thp: Do not make page table dirty unconditionally in touch_p[mu]d()
commit a8f9736645 upstream.

Currently, we unconditionally make page table dirty in touch_pmd().
It may result in false-positive can_follow_write_pmd().

We may avoid the situation, if we would only make the page table entry
dirty if caller asks for write access -- FOLL_WRITE.

The patch also changes touch_pud() in the same way.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-05 11:26:28 +01:00
Wang Nan 786b924d39 mm, oom_reaper: gather each vma to prevent leaking TLB entry
commit 687cb0884a upstream.

tlb_gather_mmu(&tlb, mm, 0, -1) means gathering the whole virtual memory
space.  In this case, tlb->fullmm is true.  Some archs like arm64
doesn't flush TLB when tlb->fullmm is true:

  commit 5a7862e830 ("arm64: tlbflush: avoid flushing when fullmm == 1").

Which causes leaking of tlb entries.

Will clarifies his patch:
 "Basically, we tag each address space with an ASID (PCID on x86) which
  is resident in the TLB. This means we can elide TLB invalidation when
  pulling down a full mm because we won't ever assign that ASID to
  another mm without doing TLB invalidation elsewhere (which actually
  just nukes the whole TLB).

  I think that means that we could potentially not fault on a kernel
  uaccess, because we could hit in the TLB"

There could be a window between complete_signal() sending IPI to other
cores and all threads sharing this mm are really kicked off from cores.
In this window, the oom reaper may calls tlb_flush_mmu_tlbonly() to
flush TLB then frees pages.  However, due to the above problem, the TLB
entries are not really flushed on arm64.  Other threads are possible to
access these pages through TLB entries.  Moreover, a copy_to_user() can
also write to these pages without generating page fault, causes
use-after-free bugs.

This patch gathers each vma instead of gathering full vm space.  In this
case tlb->fullmm is not true.  The behavior of oom reaper become similar
to munmapping before do_exit, which should be safe for all archs.

Link: http://lkml.kernel.org/r/20171107095453.179940-1-wangnan0@huawei.com
Fixes: aac4536355 ("mm, oom: introduce oom reaper")
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Bob Liu <liubo95@huawei.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-05 11:26:28 +01:00
Michal Hocko b8d0c953d9 mm, memory_hotplug: do not back off draining pcp free pages from kworker context
commit 4b81cb2ff6 upstream.

drain_all_pages backs off when called from a kworker context since
commit 0ccce3b924 ("mm, page_alloc: drain per-cpu pages from workqueue
context") because the original IPI based pcp draining has been replaced
by a WQ based one and the check wanted to prevent from recursion and
inter workers dependencies.  This has made some sense at the time
because the system WQ has been used and one worker holding the lock
could be blocked while waiting for new workers to emerge which can be a
problem under OOM conditions.

Since then commit ce612879dd ("mm: move pcp and lru-pcp draining into
single wq") has moved draining to a dedicated (mm_percpu_wq) WQ with a
rescuer so we shouldn't depend on any other WQ activity to make a
forward progress so calling drain_all_pages from a worker context is
safe as long as this doesn't happen from mm_percpu_wq itself which is
not the case because all workers are required to _not_ depend on any MM
locks.

Why is this a problem in the first place? ACPI driven memory hot-remove
(acpi_device_hotplug) is executed from the worker context.  We end up
calling __offline_pages to free all the pages and that requires both
lru_add_drain_all_cpuslocked and drain_all_pages to do their job
otherwise we can have dangling pages on pcp lists and fail the offline
operation (__test_page_isolated_in_pageblock would see a page with 0 ref
count but without PageBuddy set).

Fix the issue by removing the worker check in drain_all_pages.
lru_add_drain_all_cpuslocked doesn't have this restriction so it works
as expected.

Link: http://lkml.kernel.org/r/20170828093341.26341-1-mhocko@kernel.org
Fixes: 0ccce3b924 ("mm, page_alloc: drain per-cpu pages from workqueue context")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-05 11:26:27 +01:00
Vitaly Wool c1a14af38a mm/z3fold.c: use kref to prevent page free/compact race
commit 5d03a66139 upstream.

There is a race in the current z3fold implementation between
do_compact() called in a work queue context and the page release
procedure when page's kref goes to 0.

do_compact() may be waiting for page lock, which is released by
release_z3fold_page_locked right before putting the page onto the
"stale" list, and then the page may be freed as do_compact() modifies
its contents.

The mechanism currently implemented to handle that (checking the
PAGE_STALE flag) is not reliable enough.  Instead, we'll use page's kref
counter to guarantee that the page is not released if its compaction is
scheduled.  It then becomes compaction function's responsibility to
decrease the counter and quit immediately if the page was actually
freed.

Link: http://lkml.kernel.org/r/20171117092032.00ea56f42affbed19f4fcc6c@gmail.com
Signed-off-by: Vitaly Wool <vitaly.wool@sonymobile.com>
Cc: <Oleksiy.Avramchenko@sony.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-30 08:40:44 +00:00
Jaewon Kim cb58b8f8a8 mm/page_ext.c: check if page_ext is not prepared
commit e492080e64 upstream.

online_page_ext() and page_ext_init() allocate page_ext for each
section, but they do not allocate if the first PFN is !pfn_present(pfn)
or !pfn_valid(pfn).  Then section->page_ext remains as NULL.
lookup_page_ext checks NULL only if CONFIG_DEBUG_VM is enabled.  For a
valid PFN, __set_page_owner will try to get page_ext through
lookup_page_ext.  Without CONFIG_DEBUG_VM lookup_page_ext will misuse
NULL pointer as value 0.  This incurrs invalid address access.

This is the panic example when PFN 0x100000 is not valid but PFN
0x13FC00 is being used for page_ext.  section->page_ext is NULL,
get_entry returned invalid page_ext address as 0x1DFA000 for a PFN
0x13FC00.

To avoid this panic, CONFIG_DEBUG_VM should be removed so that page_ext
will be checked at all times.

  Unable to handle kernel paging request at virtual address 01dfa014
  ------------[ cut here ]------------
  Kernel BUG at ffffff80082371e0 [verbose debug info unavailable]
  Internal error: Oops: 96000045 [#1] PREEMPT SMP
  Modules linked in:
  PC is at __set_page_owner+0x48/0x78
  LR is at __set_page_owner+0x44/0x78
    __set_page_owner+0x48/0x78
    get_page_from_freelist+0x880/0x8e8
    __alloc_pages_nodemask+0x14c/0xc48
    __do_page_cache_readahead+0xdc/0x264
    filemap_fault+0x2ac/0x550
    ext4_filemap_fault+0x3c/0x58
    __do_fault+0x80/0x120
    handle_mm_fault+0x704/0xbb0
    do_page_fault+0x2e8/0x394
    do_mem_abort+0x88/0x124

Pre-4.7 kernels also need commit f86e427197 ("mm: check the return
value of lookup_page_ext for all call sites").

Link: http://lkml.kernel.org/r/20171107094131.14621-1-jaewon31.kim@samsung.com
Fixes: eefa864b70 ("mm/page_ext: resurrect struct page extending code for debugging")
Signed-off-by: Jaewon Kim <jaewon31.kim@samsung.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-24 08:37:05 +01:00
Pavel Tatashin 5a77c92fa1 mm/page_alloc.c: broken deferred calculation
commit d135e57502 upstream.

In reset_deferred_meminit() we determine number of pages that must not
be deferred.  We initialize pages for at least 2G of memory, but also
pages for reserved memory in this node.

The reserved memory is determined in this function:
memblock_reserved_memory_within(), which operates over physical
addresses, and returns size in bytes.  However, reset_deferred_meminit()
assumes that that this function operates with pfns, and returns page
count.

The result is that in the best case machine boots slower than expected
due to initializing more pages than needed in single thread, and in the
worst case panics because fewer than needed pages are initialized early.

Link: http://lkml.kernel.org/r/20171021011707.15191-1-pasha.tatashin@oracle.com
Fixes: 864b9a393d ("mm: consider memblock reservations for deferred memory initialization sizing")
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-24 08:37:05 +01:00
Jann Horn bbce81fc96 mm/pagewalk.c: report holes in hugetlb ranges
commit 373c4557d2 upstream.

This matters at least for the mincore syscall, which will otherwise copy
uninitialized memory from the page allocator to userspace.  It is
probably also a correctness error for /proc/$pid/pagemap, but I haven't
tested that.

Removing the `walk->hugetlb_entry` condition in walk_hugetlb_range() has
no effect because the caller already checks for that.

This only reports holes in hugetlb ranges to callers who have specified
a hugetlb_entry callback.

This issue was found using an AFL-based fuzzer.

v2:
 - don't crash on ->pte_hole==NULL (Andrew Morton)
 - add Cc stable (Andrew Morton)

Fixes: 1e25a271c8 ("mincore: apply page table walker on do_mincore()")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-24 08:37:04 +01:00
Huang Ying 2628bd6fc0 mm, swap: fix race between swap count continuation operations
One page may store a set of entries of the sis->swap_map
(swap_info_struct->swap_map) in multiple swap clusters.

If some of the entries has sis->swap_map[offset] > SWAP_MAP_MAX,
multiple pages will be used to store the set of entries of the
sis->swap_map.  And the pages are linked with page->lru.  This is called
swap count continuation.  To access the pages which store the set of
entries of the sis->swap_map simultaneously, previously, sis->lock is
used.  But to improve the scalability of __swap_duplicate(), swap
cluster lock may be used in swap_count_continued() now.  This may race
with add_swap_count_continuation() which operates on a nearby swap
cluster, in which the sis->swap_map entries are stored in the same page.

The race can cause wrong swap count in practice, thus cause unfreeable
swap entries or software lockup, etc.

To fix the race, a new spin lock called cont_lock is added to struct
swap_info_struct to protect the swap count continuation page list.  This
is a lock at the swap device level, so the scalability isn't very well.
But it is still much better than the original sis->lock, because it is
only acquired/released when swap count continuation is used.  Which is
considered rare in practice.  If it turns out that the scalability
becomes an issue for some workloads, we can split the lock into some
more fine grained locks.

Link: http://lkml.kernel.org/r/20171017081320.28133-1-ying.huang@intel.com
Fixes: 235b621767 ("mm/swap: add cluster lock")
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Shaohua Li <shli@kernel.org>
Cc: Tim Chen <tim.c.chen@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Aaron Lu <aaron.lu@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>	[4.11+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-03 07:39:19 -07:00
Zi Yan dd8a67f9a3 mm/huge_memory.c: deposit page table when copying a PMD migration entry
We need to deposit pre-allocated PTE page table when a PMD migration
entry is copied in copy_huge_pmd().  Otherwise, we will leak the
pre-allocated page and cause a NULL pointer dereference later in
zap_huge_pmd().

The missing counters during PMD migration entry copy process are added
as well.

The bug report is here: https://lkml.org/lkml/2017/10/29/214

Link: http://lkml.kernel.org/r/20171030144636.4836-1-zi.yan@sent.com
Fixes: 84c3fc4e9c ("mm: thp: check pmd migration entry in common path")
Signed-off-by: Zi Yan <zi.yan@cs.rutgers.edu>
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-03 07:39:19 -07:00
Andrea Arcangeli 1e39214713 userfaultfd: hugetlbfs: prevent UFFDIO_COPY to fill beyond the end of i_size
This oops:

  kernel BUG at fs/hugetlbfs/inode.c:484!
  RIP: remove_inode_hugepages+0x3d0/0x410
  Call Trace:
    hugetlbfs_setattr+0xd9/0x130
    notify_change+0x292/0x410
    do_truncate+0x65/0xa0
    do_sys_ftruncate.constprop.3+0x11a/0x180
    SyS_ftruncate+0xe/0x10
    tracesys+0xd9/0xde

was caused by the lack of i_size check in hugetlb_mcopy_atomic_pte.

mmap() can still succeed beyond the end of the i_size after vmtruncate
zapped vmas in those ranges, but the faults must not succeed, and that
includes UFFDIO_COPY.

We could differentiate the retval to userland to represent a SIGBUS like
a page fault would do (vs SIGSEGV), but it doesn't seem very useful and
we'd need to pick a random retval as there's no meaningful syscall
retval that would differentiate from SIGSEGV and SIGBUS, there's just
-EFAULT.

Link: http://lkml.kernel.org/r/20171016223914.2421-2-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-03 07:39:19 -07:00
Greg Kroah-Hartman b24413180f License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-02 11:10:55 +01:00
Linus Torvalds b5ac3beb5a Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Pull networking fixes from David Miller:
 "A little more than usual this time around. Been travelling, so that is
  part of it.

  Anyways, here are the highlights:

   1) Deal with memcontrol races wrt. listener dismantle, from Eric
      Dumazet.

   2) Handle page allocation failures properly in nfp driver, from Jaku
      Kicinski.

   3) Fix memory leaks in macsec, from Sabrina Dubroca.

   4) Fix crashes in pppol2tp_session_ioctl(), from Guillaume Nault.

   5) Several fixes in bnxt_en driver, including preventing potential
      NVRAM parameter corruption from Michael Chan.

   6) Fix for KRACK attacks in wireless, from Johannes Berg.

   7) rtnetlink event generation fixes from Xin Long.

   8) Deadlock in mlxsw driver, from Ido Schimmel.

   9) Disallow arithmetic operations on context pointers in bpf, from
      Jakub Kicinski.

  10) Missing sock_owned_by_user() check in sctp_icmp_redirect(), from
      Xin Long.

  11) Only TCP is supported for sockmap, make that explicit with a
      check, from John Fastabend.

  12) Fix IP options state races in DCCP and TCP, from Eric Dumazet.

  13) Fix panic in packet_getsockopt(), also from Eric Dumazet.

  14) Add missing locked in hv_sock layer, from Dexuan Cui.

  15) Various aquantia bug fixes, including several statistics handling
      cures. From Igor Russkikh et al.

  16) Fix arithmetic overflow in devmap code, from John Fastabend.

  17) Fix busted socket memory accounting when we get a fault in the tcp
      zero copy paths. From Willem de Bruijn.

  18) Don't leave opt->tot_len uninitialized in ipv6, from Eric Dumazet"

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (106 commits)
  stmmac: Don't access tx_q->dirty_tx before netif_tx_lock
  ipv6: flowlabel: do not leave opt->tot_len with garbage
  of_mdio: Fix broken PHY IRQ in case of probe deferral
  textsearch: fix typos in library helpers
  rxrpc: Don't release call mutex on error pointer
  net: stmmac: Prevent infinite loop in get_rx_timestamp_status()
  net: stmmac: Fix stmmac_get_rx_hwtstamp()
  net: stmmac: Add missing call to dev_kfree_skb()
  mlxsw: spectrum_router: Configure TIGCR on init
  mlxsw: reg: Add Tunneling IPinIP General Configuration Register
  net: ethtool: remove error check for legacy setting transceiver type
  soreuseport: fix initialization race
  net: bridge: fix returning of vlan range op errors
  sock: correct sk_wmem_queued accounting on efault in tcp zerocopy
  bpf: add test cases to bpf selftests to cover all access tests
  bpf: fix pattern matches for direct packet access
  bpf: fix off by one for range markings with L{T, E} patterns
  bpf: devmap fix arithmetic overflow in bitmap_size calculation
  net: aquantia: Bad udp rate on default interrupt coalescing
  net: aquantia: Enable coalescing management via ethtool interface
  ...
2017-10-21 22:44:48 -04:00
Daniel Borkmann 0ea7eeec24 mm, percpu: add support for __GFP_NOWARN flag
Add an option for pcpu_alloc() to support __GFP_NOWARN flag.
Currently, we always throw a warning when size or alignment
is unsupported (and also dump stack on failed allocation
requests). The warning itself is harmless since we return
NULL anyway for any failed request, which callers are
required to handle anyway. However, it becomes harmful when
panic_on_warn is set.

The rationale for the WARN() in pcpu_alloc() is that it can
be tracked when larger than supported allocation requests are
made such that allocations limits can be tweaked if warranted.
This makes sense for in-kernel users, however, there are users
of pcpu allocator where allocation size is derived from user
space requests, e.g. when creating BPF maps. In these cases,
the requests should fail gracefully without throwing a splat.

The current work-around was to check allocation size against
the upper limit of PCPU_MIN_UNIT_SIZE from call-sites for
bailing out prior to a call to pcpu_alloc() in order to
avoid throwing the WARN(). This is bad in multiple ways since
PCPU_MIN_UNIT_SIZE is an implementation detail, and having
the checks on call-sites only complicates the code for no
good reason. Thus, lets fix it generically by supporting the
__GFP_NOWARN flag that users can then use with calling the
__alloc_percpu_gfp() helper instead.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Tejun Heo <tj@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-19 13:13:49 +01:00
Huang Ying 61b639723b mm, swap: use page-cluster as max window of VMA based swap readahead
When the VMA based swap readahead was introduced, a new knob

  /sys/kernel/mm/swap/vma_ra_max_order

was added as the max window of VMA swap readahead.  This is to make it
possible to use different max window for VMA based readahead and
original physical readahead.  But Minchan Kim pointed out that this will
cause a regression because setting page-cluster sysctl to zero cannot
disable swap readahead with the change.

To fix the regression, the page-cluster sysctl is used as the max window
of both the VMA based swap readahead and original physical swap
readahead.  If more fine grained control is needed in the future, more
knobs can be added as the subordinate knobs of the page-cluster sysctl.

The vma_ra_max_order knob is deleted.  Because the knob was introduced
in v4.14-rc1, and this patch is targeting being merged before v4.14
releasing, there should be no existing users of this newly added ABI.

Link: http://lkml.kernel.org/r/20171011070847.16003-1-ying.huang@intel.com
Fixes: ec560175c0 ("mm, swap: VMA based swap readahead")
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Reported-by: Minchan Kim <minchan@kernel.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Tim Chen <tim.c.chen@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-13 16:18:33 -07:00
Will Deacon a7b100953a mm: page_vma_mapped: ensure pmd is loaded with READ_ONCE outside of lock
Loading the pmd without holding the pmd_lock exposes us to races with
concurrent updaters of the page tables but, worse still, it also allows
the compiler to cache the pmd value in a register and reuse it later on,
even if we've performed a READ_ONCE in between and seen a more recent
value.

In the case of page_vma_mapped_walk, this leads to the following crash
when the pmd loaded for the initial pmd_trans_huge check is all zeroes
and a subsequent valid table entry is loaded by check_pmd.  We then
proceed into map_pte, but the compiler re-uses the zero entry inside
pte_offset_map, resulting in a junk pointer being installed in
pvmw->pte:

  PC is at check_pte+0x20/0x170
  LR is at page_vma_mapped_walk+0x2e0/0x540
  [...]
  Process doio (pid: 2463, stack limit = 0xffff00000f2e8000)
  Call trace:
    check_pte+0x20/0x170
    page_vma_mapped_walk+0x2e0/0x540
    page_mkclean_one+0xac/0x278
    rmap_walk_file+0xf0/0x238
    rmap_walk+0x64/0xa0
    page_mkclean+0x90/0xa8
    clear_page_dirty_for_io+0x84/0x2a8
    mpage_submit_page+0x34/0x98
    mpage_process_page_bufs+0x164/0x170
    mpage_prepare_extent_to_map+0x134/0x2b8
    ext4_writepages+0x484/0xe30
    do_writepages+0x44/0xe8
    __filemap_fdatawrite_range+0xbc/0x110
    file_write_and_wait_range+0x48/0xd8
    ext4_sync_file+0x80/0x4b8
    vfs_fsync_range+0x64/0xc0
    SyS_msync+0x194/0x1e8

This patch fixes the problem by ensuring that READ_ONCE is used before
the initial checks on the pmd, and this value is subsequently used when
checking whether or not the pmd is present.  pmd_check is removed and
the pmd_present check is inlined directly.

Link: http://lkml.kernel.org/r/1507222630-5839-1-git-send-email-will.deacon@arm.com
Fixes: f27176cfc3 ("mm: convert page_mkclean_one() to use page_vma_mapped_walk()")
Signed-off-by: Will Deacon <will.deacon@arm.com>
Tested-by: Yury Norov <ynorov@caviumnetworks.com>
Tested-by: Richard Ruigrok <rruigrok@codeaurora.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-13 16:18:33 -07:00
Johannes Weiner b8c8a338f7 Revert "vmalloc: back off when the current task is killed"
This reverts commits 5d17a73a2e ("vmalloc: back off when the current
task is killed") and 171012f561 ("mm: don't warn when vmalloc() fails
due to a fatal signal").

Commit 5d17a73a2e ("vmalloc: back off when the current task is
killed") made all vmalloc allocations from a signal-killed task fail.
We have seen crashes in the tty driver from this, where a killed task
exiting tries to switch back to N_TTY, fails n_tty_open because of the
vmalloc failing, and later crashes when dereferencing tty->disc_data.

Arguably, relying on a vmalloc() call to succeed in order to properly
exit a task is not the most robust way of doing things.  There will be a
follow-up patch to the tty code to fall back to the N_NULL ldisc.

But the justification to make that vmalloc() call fail like this isn't
convincing, either.  The patch mentions an OOM victim exhausting the
memory reserves and thus deadlocking the machine.  But the OOM killer is
only one, improbable source of fatal signals.  It doesn't make sense to
fail allocations preemptively with plenty of memory in most cases.

The patch doesn't mention real-life instances where vmalloc sites would
exhaust memory, which makes it sound more like a theoretical issue to
begin with.  But just in case, the OOM access to memory reserves has
been restricted on the allocator side in cd04ae1e2d ("mm, oom: do not
rely on TIF_MEMDIE for memory reserves access"), which should take care
of any theoretical concerns on that front.

Revert this patch, and the follow-up that suppresses the allocation
warnings when we fail the allocations due to a signal.

Link: http://lkml.kernel.org/r/20171004185906.GB2136@cmpxchg.org
Fixes:  171012f561 ("mm: don't warn when vmalloc() fails due to a fatal signal")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Alan Cox <alan@llwyncelyn.cymru>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-13 16:18:32 -07:00
Boris Brezillon ef4650144e mm/cma.c: take __GFP_NOWARN into account in cma_alloc()
cma_alloc() unconditionally prints an INFO message when the CMA
allocation fails.  Make this message conditional on the non-presence of
__GFP_NOWARN in gfp_mask.

This patch aims at removing INFO messages that are displayed when the
VC4 driver tries to allocate buffer objects.  From the driver
perspective an allocation failure is acceptable, and the driver can
possibly do something to make following allocation succeed (like
flushing the VC4 internal cache).

Link: http://lkml.kernel.org/r/20171004125447.15195-1-boris.brezillon@free-electrons.com
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: Laura Abbott <labbott@redhat.com>
Cc: Jaewon Kim <jaewon31.kim@samsung.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Eric Anholt <eric@anholt.net>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-13 16:18:32 -07:00
Zi Yan af0db981f3 mm: remove unnecessary WARN_ONCE in page_vma_mapped_walk().
A non present pmd entry can appear after pmd_lock is taken in
page_vma_mapped_walk(), even if THP migration is not enabled.  The
WARN_ONCE is unnecessary.

Link: http://lkml.kernel.org/r/20171003142606.12324-1-zi.yan@sent.com
Fixes: 616b837153 ("mm: thp: enable thp migration in generic path")
Signed-off-by: Zi Yan <zi.yan@cs.rutgers.edu>
Reported-by: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Tested-by: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-13 16:18:32 -07:00
Andrey Ryabinin de55c8b251 mm/mempolicy: fix NUMA_INTERLEAVE_HIT counter
Commit 3a321d2a3d ("mm: change the call sites of numa statistics
items") separated NUMA counters from zone counters, but the
NUMA_INTERLEAVE_HIT call site wasn't updated to use the new interface.
So alloc_page_interleave() actually increments NR_ZONE_INACTIVE_FILE
instead of NUMA_INTERLEAVE_HIT.

Fix this by using __inc_numa_state() interface to increment
NUMA_INTERLEAVE_HIT.

Link: http://lkml.kernel.org/r/20171003191003.8573-1-aryabinin@virtuozzo.com
Fixes: 3a321d2a3d ("mm: change the call sites of numa statistics items")
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Kemi Wang <kemi.wang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-13 16:18:32 -07:00
Yang Shi c02c300932 mm/madvise.c: add description for MADV_WIPEONFORK and MADV_KEEPONFORK
mm/madvise.c has a brief description about all MADV_ flags.  Add a
description for the newly added MADV_WIPEONFORK and MADV_KEEPONFORK.

Although man page has the similar information, but it'd better to keep
the consistent with other flags.

Link: http://lkml.kernel.org/r/1506117328-88228-1-git-send-email-yang.s@alibaba-inc.com
Signed-off-by: Yang Shi <yang.s@alibaba-inc.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-13 16:18:32 -07:00
Mark Hairgrove e20d103b6c mm/migrate: fix indexing bug (off by one) and avoid out of bound access
Index was incremented before last use and thus the second array could
dereference to an invalid address (not mentioning the fact that it did
not properly clear the entry we intended to clear).

Link: http://lkml.kernel.org/r/1506973525-16491-1-git-send-email-jglisse@redhat.com
Fixes: 8315ada7f0 ("mm/migrate: allow migrate_vma() to alloc new page on empty entry")
Signed-off-by: Mark Hairgrove <mhairgrove@nvidia.com>
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-13 16:18:32 -07:00
Eric Dumazet 9f1c2674b3 net: memcontrol: defer call to mem_cgroup_sk_alloc()
Instead of calling mem_cgroup_sk_alloc() from BH context,
it is better to call it from inet_csk_accept() in process context.

Not only this removes code in mem_cgroup_sk_alloc(), but it also
fixes a bug since listener might have been dismantled and css_get()
might cause a use-after-free.

Fixes: e994b2f0fb ("tcp: do not lock listener to process SYN packets")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-09 20:55:01 -07:00
YASUAKI ISHIMATSU d09b0137d2 mm/memory_hotplug: define find_{smallest|biggest}_section_pfn as unsigned long
find_{smallest|biggest}_section_pfn()s find the smallest/biggest section
and return the pfn of the section.  But the functions are defined as int.
So the functions always return 0x00000000 - 0xffffffff.  It means if
memory address is over 16TB, the functions does not work correctly.

To handle 64 bit value, the patch defines
find_{smallest|biggest}_section_pfn() as unsigned long.

Fixes: 815121d2b5 ("memory_hotplug: clear zone when removing the memory")
Link: http://lkml.kernel.org/r/d9d5593a-d0a4-c4be-ab08-493df59a85c6@gmail.com
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-03 17:54:26 -07:00
YASUAKI ISHIMATSU 1dd2bfc868 mm/memory_hotplug: change pfn_to_section_nr/section_nr_to_pfn macro to inline function
pfn_to_section_nr() and section_nr_to_pfn() are defined as macro.
pfn_to_section_nr() has no issue even if it is defined as macro.  But
section_nr_to_pfn() has overflow issue if sec is defined as int.

section_nr_to_pfn() just shifts sec by PFN_SECTION_SHIFT.  If sec is
defined as unsigned long, section_nr_to_pfn() returns pfn as 64 bit value.
But if sec is defined as int, section_nr_to_pfn() returns pfn as 32 bit
value.

__remove_section() calculates start_pfn using section_nr_to_pfn() and
scn_nr defined as int.  So if hot-removed memory address is over 16TB,
overflow issue occurs and section_nr_to_pfn() does not calculate correct
pfn.

To make callers use proper arg, the patch changes the macros to inline
functions.

Fixes: 815121d2b5 ("memory_hotplug: clear zone when removing the memory")
Link: http://lkml.kernel.org/r/e643a387-e573-6bbf-d418-c60c8ee3d15e@gmail.com
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-03 17:54:25 -07:00
Michal Hocko 9b6e63cbf8 mm, page_alloc: add scheduling point to memmap_init_zone
memmap_init_zone gets a pfn range to initialize and it can be really
large resulting in a soft lockup on non-preemptible kernels

  NMI watchdog: BUG: soft lockup - CPU#31 stuck for 23s! [kworker/u642:5:1720]
  [...]
  task: ffff88ecd7e902c0 ti: ffff88eca4e50000 task.ti: ffff88eca4e50000
  RIP: move_pfn_range_to_zone+0x185/0x1d0
  [...]
  Call Trace:
    devm_memremap_pages+0x2c7/0x430
    pmem_attach_disk+0x2fd/0x3f0 [nd_pmem]
    nvdimm_bus_probe+0x64/0x110 [libnvdimm]
    driver_probe_device+0x1f7/0x420
    bus_for_each_drv+0x52/0x80
    __device_attach+0xb0/0x130
    bus_probe_device+0x87/0xa0
    device_add+0x3fc/0x5f0
    nd_async_device_register+0xe/0x40 [libnvdimm]
    async_run_entry_fn+0x43/0x150
    process_one_work+0x14e/0x410
    worker_thread+0x116/0x490
    kthread+0xc7/0xe0
    ret_from_fork+0x3f/0x70

Fix this by adding a scheduling point once per page block.

Link: http://lkml.kernel.org/r/20170918121410.24466-3-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Johannes Thumshirn <jthumshirn@suse.de>
Tested-by: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Dan Williams <dan.j.williams@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-03 17:54:25 -07:00
Michal Hocko f64ac5e6e3 mm, memory_hotplug: add scheduling point to __add_pages
Patch series "mm, memory_hotplug: fix few soft lockups in memory
hotadd".

Johannes has noticed few soft lockups when adding a large nvdimm device.
All of them were caused by a long loop without any explicit cond_resched
which is a problem for !PREEMPT kernels.

The fix is quite straightforward.  Just make sure that cond_resched gets
called from time to time.

This patch (of 3):

__add_pages gets a pfn range to add and there is no upper bound for a
single call.  This is usually a memory block aligned size for the
regular memory hotplug - smaller sizes are usual for memory balloning
drivers, or the whole NUMA node for physical memory online.  There is no
explicit scheduling point in that code path though.

This can lead to long latencies while __add_pages is executed and we
have even seen a soft lockup report during nvdimm initialization with
!PREEMPT kernel

  NMI watchdog: BUG: soft lockup - CPU#11 stuck for 23s! [kworker/u641:3:832]
  [...]
  Workqueue: events_unbound async_run_entry_fn
  task: ffff881809270f40 ti: ffff881809274000 task.ti: ffff881809274000
  RIP: _raw_spin_unlock_irqrestore+0x11/0x20
  RSP: 0018:ffff881809277b10  EFLAGS: 00000286
  [...]
  Call Trace:
    sparse_add_one_section+0x13d/0x18e
    __add_pages+0x10a/0x1d0
    arch_add_memory+0x4a/0xc0
    devm_memremap_pages+0x29d/0x430
    pmem_attach_disk+0x2fd/0x3f0 [nd_pmem]
    nvdimm_bus_probe+0x64/0x110 [libnvdimm]
    driver_probe_device+0x1f7/0x420
    bus_for_each_drv+0x52/0x80
    __device_attach+0xb0/0x130
    bus_probe_device+0x87/0xa0
    device_add+0x3fc/0x5f0
    nd_async_device_register+0xe/0x40 [libnvdimm]
    async_run_entry_fn+0x43/0x150
    process_one_work+0x14e/0x410
    worker_thread+0x116/0x490
    kthread+0xc7/0xe0
    ret_from_fork+0x3f/0x70
  DWARF2 unwinder stuck at ret_from_fork+0x3f/0x70

Fix this by adding cond_resched once per each memory section in the
given pfn range.  Each section is constant amount of work which itself
is not too expensive but many of them will just add up.

Link: http://lkml.kernel.org/r/20170918121410.24466-2-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Johannes Thumshirn <jthumshirn@suse.de>
Tested-by: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Dan Williams <dan.j.williams@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-03 17:54:25 -07:00
Johannes Weiner f80c7dab95 mm: memcontrol: use vmalloc fallback for large kmem memcg arrays
For quick per-memcg indexing, slab caches and list_lru structures
maintain linear arrays of descriptors.  As the number of concurrent
memory cgroups in the system goes up, this requires large contiguous
allocations (8k cgroups = order-5, 16k cgroups = order-6 etc.) for every
existing slab cache and list_lru, which can easily fail on loaded
systems.  E.g.:

  mkdir: page allocation failure: order:5, mode:0x14040c0(GFP_KERNEL|__GFP_COMP), nodemask=(null)
  CPU: 1 PID: 6399 Comm: mkdir Not tainted 4.13.0-mm1-00065-g720bbe532b7c-dirty #481
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-20170228_101828-anatol 04/01/2014
  Call Trace:
   ? __alloc_pages_direct_compact+0x4c/0x110
   __alloc_pages_nodemask+0xf50/0x1430
   alloc_pages_current+0x60/0xc0
   kmalloc_order_trace+0x29/0x1b0
   __kmalloc+0x1f4/0x320
   memcg_update_all_list_lrus+0xca/0x2e0
   mem_cgroup_css_alloc+0x612/0x670
   cgroup_apply_control_enable+0x19e/0x360
   cgroup_mkdir+0x322/0x490
   kernfs_iop_mkdir+0x55/0x80
   vfs_mkdir+0xd0/0x120
   SyS_mkdirat+0x6c/0xe0
   SyS_mkdir+0x14/0x20
   entry_SYSCALL_64_fastpath+0x18/0xad
  Mem-Info:
  active_anon:2965 inactive_anon:19 isolated_anon:0
   active_file:100270 inactive_file:98846 isolated_file:0
   unevictable:0 dirty:0 writeback:0 unstable:0
   slab_reclaimable:7328 slab_unreclaimable:16402
   mapped:771 shmem:52 pagetables:278 bounce:0
   free:13718 free_pcp:0 free_cma:0

This output is from an artificial reproducer, but we have repeatedly
observed order-7 failures in production in the Facebook fleet.  These
systems become useless as they cannot run more jobs, even though there
is plenty of memory to allocate 128 individual pages.

Use kvmalloc and kvzalloc to fall back to vmalloc space if these arrays
prove too large for allocating them physically contiguous.

Link: http://lkml.kernel.org/r/20170918184919.20644-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-03 17:54:25 -07:00
Reza Arbab 7d790d2da3 mm/device-public-memory: fix edge case in _vm_normal_page()
With device public pages at the end of my memory space, I'm getting
output from _vm_normal_page():

  BUG: Bad page map in process migrate_pages  pte:c0800001ffff0d06 pmd:f95d3000
  addr:00007fff89330000 vm_flags:00100073 anon_vma:c0000000fa899320 mapping:          (null) index:7fff8933
  file:          (null) fault:          (null) mmap:          (null) readpage:          (null)
  CPU: 0 PID: 13963 Comm: migrate_pages Tainted: P    B      OE 4.14.0-rc1-wip #155
  Call Trace:
     dump_stack+0xb0/0xf4 (unreliable)
     print_bad_pte+0x28c/0x340
     _vm_normal_page+0xc0/0x140
     zap_pte_range+0x664/0xc10
     unmap_page_range+0x318/0x670
     unmap_vmas+0x74/0xe0
     exit_mmap+0xe8/0x1f0
     mmput+0xac/0x1f0
     do_exit+0x348/0xcd0
     do_group_exit+0x5c/0xf0
     SyS_exit_group+0x1c/0x20
     system_call+0x58/0x6c

The pfn causing this is the very last one.  Correct the bounds check
accordingly.

Fixes: df6ad69838 ("mm/device-public-memory: device memory cache coherent with CPU")
Link: http://lkml.kernel.org/r/1506092178-20351-1-git-send-email-arbab@linux.vnet.ibm.com
Signed-off-by: Reza Arbab <arbab@linux.vnet.ibm.com>
Reviewed-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-03 17:54:25 -07:00
Shaohua Li 9625456cc7 mm: fix data corruption caused by lazyfree page
MADV_FREE clears pte dirty bit and then marks the page lazyfree (clear
SwapBacked).  There is no lock to prevent the page is added to swap
cache between these two steps by page reclaim.  If page reclaim finds
such page, it will simply add the page to swap cache without pageout the
page to swap because the page is marked as clean.  Next time, page fault
will read data from the swap slot which doesn't have the original data,
so we have a data corruption.  To fix issue, we mark the page dirty and
pageout the page.

However, we shouldn't dirty all pages which is clean and in swap cache.
swapin page is swap cache and clean too.  So we only dirty page which is
added into swap cache in page reclaim, which shouldn't be swapin page.
As Minchan suggested, simply dirty the page in add_to_swap can do the
job.

Fixes: 802a3a92ad ("mm: reclaim MADV_FREE pages")
Link: http://lkml.kernel.org/r/08c84256b007bf3f63c91d94383bd9eb6fee2daa.1506446061.git.shli@fb.com
Signed-off-by: Shaohua Li <shli@fb.com>
Reported-by: Artem Savkov <asavkov@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org>	[4.12+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-03 17:54:25 -07:00
Shaohua Li 24c92eb7dc mm: avoid marking swap cached page as lazyfree
MADV_FREE clears pte dirty bit and then marks the page lazyfree (clear
SwapBacked).  There is no lock to prevent the page is added to swap
cache between these two steps by page reclaim.  Page reclaim could add
the page to swap cache and unmap the page.  After page reclaim, the page
is added back to lru.  At that time, we probably start draining per-cpu
pagevec and mark the page lazyfree.  So the page could be in a state
with SwapBacked cleared and PG_swapcache set.  Next time there is a
refault in the virtual address, do_swap_page can find the page from swap
cache but the page has PageSwapCache false because SwapBacked isn't set,
so do_swap_page will bail out and do nothing.  The task will keep
running into fault handler.

Fixes: 802a3a92ad ("mm: reclaim MADV_FREE pages")
Link: http://lkml.kernel.org/r/6537ef3814398c0073630b03f176263bc81f0902.1506446061.git.shli@fb.com
Signed-off-by: Shaohua Li <shli@fb.com>
Reported-by: Artem Savkov <asavkov@redhat.com>
Tested-by: Artem Savkov <asavkov@redhat.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org>	[4.12+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-03 17:54:24 -07:00