linux-stable.git/include/linux, branch v4.4.164

mm: migration: fix migration of huge PMD shared pages

2018-11-21T08:27:44+00:00

commit 017b1660df89f5fb4bfe66c34e35f7d2031100c7 upstream.

The page migration code employs try_to_unmap() to try and unmap the source
page.  This is accomplished by using rmap_walk to find all vmas where the
page is mapped.  This search stops when page mapcount is zero.  For shared
PMD huge pages, the page map count is always 1 no matter the number of
mappings.  Shared mappings are tracked via the reference count of the PMD
page.  Therefore, try_to_unmap stops prematurely and does not completely
unmap all mappings of the source page.

This problem can result is data corruption as writes to the original
source page can happen after contents of the page are copied to the target
page.  Hence, data is lost.

This problem was originally seen as DB corruption of shared global areas
after a huge page was soft offlined due to ECC memory errors.  DB
developers noticed they could reproduce the issue by (hotplug) offlining
memory used to back huge pages.  A simple testcase can reproduce the
problem by creating a shared PMD mapping (note that this must be at least
PUD_SIZE in size and PUD_SIZE aligned (1GB on x86)), and using
migrate_pages() to migrate process pages between nodes while continually
writing to the huge pages being migrated.

To fix, have the try_to_unmap_one routine check for huge PMD sharing by
calling huge_pmd_unshare for hugetlbfs huge pages.  If it is a shared
mapping it will be 'unshared' which removes the page table entry and drops
the reference on the PMD page.  After this, flush caches and TLB.

mmu notifiers are called before locking page tables, but we can not be
sure of PMD sharing until page tables are locked.  Therefore, check for
the possibility of PMD sharing before locking so that notifiers can
prepare for the worst possible case.

Link: http://lkml.kernel.org/r/20180823205917.16297-2-mike.kravetz@oracle.com
[mike.kravetz@oracle.com: make _range_in_vma() a static inline]
  Link: http://lkml.kernel.org/r/6063f215-a5c8-2f0c-465a-2c515ddc952d@oracle.com
Fixes: 39dde65c9940 ("shared page table for hugetlb page")
Signed-off-by: Mike Kravetz 
Acked-by: Kirill A. Shutemov 
Reviewed-by: Naoya Horiguchi 
Acked-by: Michal Hocko 
Cc: Vlastimil Babka 
Cc: Davidlohr Bueso 
Cc: Jerome Glisse 
Cc: Mike Kravetz 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Mike Kravetz 
Acked-by: Michal Hocko 
Reviewed-by: Jérôme Glisse 
Signed-off-by: Greg Kroah-Hartman

clockevents/drivers/i8253: Add support for PIT shutdown quirk

2018-11-21T08:27:42+00:00

commit 35b69a420bfb56b7b74cb635ea903db05e357bec upstream.

Add support for platforms where pit_shutdown() doesn't work because of a
quirk in the PIT emulation. On these platforms setting the counter register
to zero causes the PIT to start running again, negating the shutdown.

Provide a global variable that controls whether the counter register is
zero'ed, which platform specific code can override.

Signed-off-by: Michael Kelley 
Signed-off-by: Thomas Gleixner 
Cc: "gregkh@linuxfoundation.org" 
Cc: "devel@linuxdriverproject.org" 
Cc: "daniel.lezcano@linaro.org" 
Cc: "virtualization@lists.linux-foundation.org" 
Cc: "jgross@suse.com" 
Cc: "akataria@vmware.com" 
Cc: "olaf@aepfle.de" 
Cc: "apw@canonical.com" 
Cc: vkuznets 
Cc: "jasowang@redhat.com" 
Cc: "marcelo.cerri@canonical.com" 
Cc: KY Srinivasan 
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/1541303219-11142-2-git-send-email-mikelley@microsoft.com
Signed-off-by: Greg Kroah-Hartman

libceph: bump CEPH_MSG_MAX_DATA_LEN

2018-11-21T08:27:42+00:00

commit 94e6992bb560be8bffb47f287194adf070b57695 upstream.

If the read is large enough, we end up spinning in the messenger:

  libceph: osd0 192.168.122.1:6801 io error
  libceph: osd0 192.168.122.1:6801 io error
  libceph: osd0 192.168.122.1:6801 io error

This is a receive side limit, so only reads were affected.

Cc: stable@vger.kernel.org
Signed-off-by: Ilya Dryomov 
Signed-off-by: Greg Kroah-Hartman

TC: Set DMA masks for devices

2018-11-21T08:27:36+00:00

commit 3f2aa244ee1a0d17ed5b6c86564d2c1b24d1c96b upstream.

Fix a TURBOchannel support regression with commit 205e1b7f51e4
("dma-mapping: warn when there is no coherent_dma_mask") that caused
coherent DMA allocations to produce a warning such as:

defxx: v1.11 2014/07/01  Lawrence V. Stefani and others
tc1: DEFTA at MMIO addr = 0x1e900000, IRQ = 20, Hardware addr = 08-00-2b-a3-a3-29
------------[ cut here ]------------
WARNING: CPU: 0 PID: 1 at ./include/linux/dma-mapping.h:516 dfx_dev_register+0x670/0x678
Modules linked in:
CPU: 0 PID: 1 Comm: swapper Not tainted 4.19.0-rc6 #2
Stack : ffffffff8009ffc0 fffffffffffffec0 0000000000000000 ffffffff80647650
        0000000000000000 0000000000000000 ffffffff806f5f80 ffffffffffffffff
        0000000000000000 0000000000000000 0000000000000001 ffffffff8065d4e8
        98000000031b6300 ffffffff80563478 ffffffff805685b0 ffffffffffffffff
        0000000000000000 ffffffff805d6720 0000000000000204 ffffffff80388df8
        0000000000000000 0000000000000009 ffffffff8053efd0 ffffffff806657d0
        0000000000000000 ffffffff803177f8 0000000000000000 ffffffff806d0000
        9800000003078000 980000000307b9e0 000000001e900000 ffffffff80067940
        0000000000000000 ffffffff805d6720 0000000000000204 ffffffff80388df8
        ffffffff805176c0 ffffffff8004dc78 0000000000000000 ffffffff80067940
        ...
Call Trace:
[] show_stack+0xa0/0x130
[] __warn+0x128/0x170
---[ end trace b1d1e094f67f3bb2 ]---

This is because the TURBOchannel bus driver fails to set the coherent
DMA mask for devices enumerated.

Set the regular and coherent DMA masks for TURBOchannel devices then,
observing that the bus protocol supports a 34-bit (16GiB) DMA address
space, by interpreting the value presented in the address cycle across
the 32 `ad' lines as a 32-bit word rather than byte address[1].  The
architectural size of the TURBOchannel DMA address space exceeds the
maximum amount of RAM any actual TURBOchannel system in existence may
have, hence both masks are the same.

This removes the warning shown above.

References:

[1] "TURBOchannel Hardware Specification", EK-369AA-OD-007B, Digital
    Equipment Corporation, January 1993, Section "DMA", pp. 1-15 -- 1-17

Signed-off-by: Maciej W. Rozycki 
Signed-off-by: Paul Burton 
Patchwork: https://patchwork.linux-mips.org/patch/20835/
Fixes: 205e1b7f51e4 ("dma-mapping: warn when there is no coherent_dma_mask")
Cc: stable@vger.kernel.org # 4.16+
Cc: Ralf Baechle 
Signed-off-by: Greg Kroah-Hartman

cpuidle: Do not access cpuidle_devices when !CONFIG_CPU_IDLE

2018-11-10T15:41:43+00:00

commit 9bd616e3dbedfc103f158197c8ad93678849b1ed upstream.

The cpuidle_devices per-CPU variable is only defined when CPU_IDLE is
enabled. Commit c8cc7d4de7a4 ("sched/idle: Reorganize the idle loop")
removed the #ifdef CONFIG_CPU_IDLE around cpuidle_idle_call() with the
compiler optimising away __this_cpu_read(cpuidle_devices). However, with
CONFIG_UBSAN && !CONFIG_CPU_IDLE, this optimisation no longer happens
and the kernel fails to link since cpuidle_devices is not defined.

This patch introduces an accessor function for the current CPU cpuidle
device (returning NULL when !CONFIG_CPU_IDLE) and uses it in
cpuidle_idle_call().

Signed-off-by: Catalin Marinas 
Cc: 4.5+  # 4.5+
Signed-off-by: Rafael J. Wysocki 
Cc: Guenter Roeck 
Signed-off-by: Greg Kroah-Hartman

bpf: generally move prog destruction to RCU deferral

2018-11-10T15:41:37+00:00

[ Upstream commit 1aacde3d22c42281236155c1ef6d7a5aa32a826b ]

Jann Horn reported following analysis that could potentially result
in a very hard to trigger (if not impossible) UAF race, to quote his
event timeline:

 - Set up a process with threads T1, T2 and T3
 - Let T1 set up a socket filter F1 that invokes another filter F2
   through a BPF map [tail call]
 - Let T1 trigger the socket filter via a unix domain socket write,
   don't wait for completion
 - Let T2 call PERF_EVENT_IOC_SET_BPF with F2, don't wait for completion
 - Now T2 should be behind bpf_prog_get(), but before bpf_prog_put()
 - Let T3 close the file descriptor for F2, dropping the reference
   count of F2 to 2
 - At this point, T1 should have looked up F2 from the map, but not
   finished executing it
 - Let T3 remove F2 from the BPF map, dropping the reference count of
   F2 to 1
 - Now T2 should call bpf_prog_put() (wrong BPF program type), dropping
   the reference count of F2 to 0 and scheduling bpf_prog_free_deferred()
   via schedule_work()
 - At this point, the BPF program could be freed
 - BPF execution is still running in a freed BPF program

While at PERF_EVENT_IOC_SET_BPF time it's only guaranteed that the perf
event fd we're doing the syscall on doesn't disappear from underneath us
for whole syscall time, it may not be the case for the bpf fd used as
an argument only after we did the put. It needs to be a valid fd pointing
to a BPF program at the time of the call to make the bpf_prog_get() and
while T2 gets preempted, F2 must have dropped reference to 1 on the other
CPU. The fput() from the close() in T3 should also add additionally delay
to the reference drop via exit_task_work() when bpf_prog_release() gets
called as well as scheduling bpf_prog_free_deferred().

That said, it makes nevertheless sense to move the BPF prog destruction
generally after RCU grace period to guarantee that such scenario above,
but also others as recently fixed in ceb56070359b ("bpf, perf: delay release
of BPF prog after grace period") with regards to tail calls won't happen.
Integrating bpf_prog_free_deferred() directly into the RCU callback is
not allowed since the invocation might happen from either softirq or
process context, so we're not permitted to block. Reviewing all bpf_prog_put()
invocations from eBPF side (note, cBPF -> eBPF progs don't use this for
their destruction) with call_rcu() look good to me.

Since we don't know whether at the time of attaching the program, we're
already part of a tail call map, we need to use RCU variant. However, due
to this, there won't be severely more stress on the RCU callback queue:
situations with above bpf_prog_get() and bpf_prog_put() combo in practice
normally won't lead to releases, but even if they would, enough effort/
cycles have to be put into loading a BPF program into the kernel already.

Reported-by: Jann Horn 
Signed-off-by: Daniel Borkmann 
Acked-by: Alexei Starovoitov 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

radix-tree: fix radix_tree_iter_retry() for tagged iterators.

2018-11-10T15:41:35+00:00

[ Upstream commit 3cb9185c67304b2a7ea9be73e7d13df6fb2793a1 ]

radix_tree_iter_retry() resets slot to NULL, but it doesn't reset tags.
Then NULL slot and non-zero iter.tags passed to radix_tree_next_slot()
leading to crash:

  RIP: radix_tree_next_slot include/linux/radix-tree.h:473
    find_get_pages_tag+0x334/0x930 mm/filemap.c:1452
  ....
  Call Trace:
    pagevec_lookup_tag+0x3a/0x80 mm/swap.c:960
    mpage_prepare_extent_to_map+0x321/0xa90 fs/ext4/inode.c:2516
    ext4_writepages+0x10be/0x2b20 fs/ext4/inode.c:2736
    do_writepages+0x97/0x100 mm/page-writeback.c:2364
    __filemap_fdatawrite_range+0x248/0x2e0 mm/filemap.c:300
    filemap_write_and_wait_range+0x121/0x1b0 mm/filemap.c:490
    ext4_sync_file+0x34d/0xdb0 fs/ext4/fsync.c:115
    vfs_fsync_range+0x10a/0x250 fs/sync.c:195
    vfs_fsync fs/sync.c:209
    do_fsync+0x42/0x70 fs/sync.c:219
    SYSC_fdatasync fs/sync.c:232
    SyS_fdatasync+0x19/0x20 fs/sync.c:230
    entry_SYSCALL_64_fastpath+0x23/0xc1 arch/x86/entry/entry_64.S:207

We must reset iterator's tags to bail out from radix_tree_next_slot()
and go to the slow-path in radix_tree_next_chunk().

Fixes: 46437f9a554f ("radix-tree: fix race in gang lookup")
Link: http://lkml.kernel.org/r/1468495196-10604-1-git-send-email-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin 
Reported-by: Dmitry Vyukov 
Acked-by: Konstantin Khlebnikov 
Cc: Matthew Wilcox 
Cc: Hugh Dickins 
Cc: Ross Zwisler 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

Drivers: hv: util: Pass the channel information during the init call

2018-10-20T07:52:38+00:00

commit b9830d120cbe155863399f25eaef6aa8353e767f upstream.

Pass the channel information to the util drivers that need to defer
reading the channel while they are processing a request. This would address
the following issue reported by Vitaly:

Commit 3cace4a61610 ("Drivers: hv: utils: run polling callback always in
interrupt context") removed direct *_transaction.state = HVUTIL_READY
assignments from *_handle_handshake() functions introducing the following
race: if a userspace daemon connects before we get first non-negotiation
request from the server hv_poll_channel() won't set transaction state to
HVUTIL_READY as (!channel) condition will fail, we set it to non-NULL on
the first real request from the server.

Signed-off-by: K. Y. Srinivasan 
Reported-by: Vitaly Kuznetsov 
Signed-off-by: Dexuan Cui 
Signed-off-by: Greg Kroah-Hartman

net: ipv4: update fnhe_pmtu when first hop's MTU changes

2018-10-20T07:52:36+00:00

[ Upstream commit af7d6cce53694a88d6a1bb60c9a239a6a5144459 ]

Since commit 5aad1de5ea2c ("ipv4: use separate genid for next hop
exceptions"), exceptions get deprecated separately from cached
routes. In particular, administrative changes don't clear PMTU anymore.

As Stefano described in commit e9fa1495d738 ("ipv6: Reflect MTU changes
on PMTU of exceptions for MTU-less routes"), the PMTU discovered before
the local MTU change can become stale:
 - if the local MTU is now lower than the PMTU, that PMTU is now
   incorrect
 - if the local MTU was the lowest value in the path, and is increased,
   we might discover a higher PMTU

Similarly to what commit e9fa1495d738 did for IPv6, update PMTU in those
cases.

If the exception was locked, the discovered PMTU was smaller than the
minimal accepted PMTU. In that case, if the new local MTU is smaller
than the current PMTU, let PMTU discovery figure out if locking of the
exception is still needed.

To do this, we need to know the old link MTU in the NETDEV_CHANGEMTU
notifier. By the time the notifier is called, dev->mtu has been
changed. This patch adds the old MTU as additional information in the
notifier structure, and a new call_netdevice_notifiers_u32() function.

Fixes: 5aad1de5ea2c ("ipv4: use separate genid for next hop exceptions")
Signed-off-by: Sabrina Dubroca 
Reviewed-by: Stefano Brivio 
Reviewed-by: David Ahern 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

ebtables: arpreply: Add the standard target sanity check

2018-10-13T07:11:35+00:00

commit c953d63548207a085abcb12a15fefc8a11ffdf0a upstream.

The info->target comes from userspace and it would be used directly.
So we need to add the sanity check to make sure it is a valid standard
target, although the ebtables tool has already checked it. Kernel needs
to validate anything coming from userspace.

If the target is set as an evil value, it would break the ebtables
and cause a panic. Because the non-standard target is treated as one
offset.

Now add one helper function ebt_invalid_target, and we would replace
the macro INVALID_TARGET later.

Signed-off-by: Gao Feng 
Signed-off-by: Pablo Neira Ayuso 
Cc: Loic 
Signed-off-by: Greg Kroah-Hartman