linux-stable.git/include/linux, branch v4.16.4

writeback: safer lock nesting

2018-04-24T07:43:11+00:00

commit 2e898e4c0a3897ccd434adac5abb8330194f527b upstream.

lock_page_memcg()/unlock_page_memcg() use spin_lock_irqsave/restore() if
the page's memcg is undergoing move accounting, which occurs when a
process leaves its memcg for a new one that has
memory.move_charge_at_immigrate set.

unlocked_inode_to_wb_begin,end() use spin_lock_irq/spin_unlock_irq() if
the given inode is switching writeback domains.  Switches occur when
enough writes are issued from a new domain.

This existing pattern is thus suspicious:
    lock_page_memcg(page);
    unlocked_inode_to_wb_begin(inode, &locked);
    ...
    unlocked_inode_to_wb_end(inode, locked);
    unlock_page_memcg(page);

If both inode switch and process memcg migration are both in-flight then
unlocked_inode_to_wb_end() will unconditionally enable interrupts while
still holding the lock_page_memcg() irq spinlock.  This suggests the
possibility of deadlock if an interrupt occurs before unlock_page_memcg().

    truncate
    __cancel_dirty_page
    lock_page_memcg
    unlocked_inode_to_wb_begin
    unlocked_inode_to_wb_end
    
                                    
                                    end_page_writeback
                                    test_clear_page_writeback
                                    lock_page_memcg
                                    
    unlock_page_memcg

Due to configuration limitations this deadlock is not currently possible
because we don't mix cgroup writeback (a cgroupv2 feature) and
memory.move_charge_at_immigrate (a cgroupv1 feature).

If the kernel is hacked to always claim inode switching and memcg
moving_account, then this script triggers lockup in less than a minute:

  cd /mnt/cgroup/memory
  mkdir a b
  echo 1 > a/memory.move_charge_at_immigrate
  echo 1 > b/memory.move_charge_at_immigrate
  (
    echo $BASHPID > a/cgroup.procs
    while true; do
      dd if=/dev/zero of=/mnt/big bs=1M count=256
    done
  ) &
  while true; do
    sync
  done &
  sleep 1h &
  SLEEP=$!
  while true; do
    echo $SLEEP > a/cgroup.procs
    echo $SLEEP > b/cgroup.procs
  done

The deadlock does not seem possible, so it's debatable if there's any
reason to modify the kernel.  I suggest we should to prevent future
surprises.  And Wang Long said "this deadlock occurs three times in our
environment", so there's more reason to apply this, even to stable.
Stable 4.4 has minor conflicts applying this patch.  For a clean 4.4 patch
see "[PATCH for-4.4] writeback: safer lock nesting"
https://lkml.org/lkml/2018/4/11/146

Wang Long said "this deadlock occurs three times in our environment"

[gthelen@google.com: v4]
  Link: http://lkml.kernel.org/r/20180411084653.254724-1-gthelen@google.com
[akpm@linux-foundation.org: comment tweaks, struct initialization simplification]
Change-Id: Ibb773e8045852978f6207074491d262f1b3fb613
Link: http://lkml.kernel.org/r/20180410005908.167976-1-gthelen@google.com
Fixes: 682aa8e1a6a1 ("writeback: implement unlocked_inode_to_wb transaction and use it for stat updates")
Signed-off-by: Greg Thelen 
Reported-by: Wang Long 
Acked-by: Wang Long 
Acked-by: Michal Hocko 
Reviewed-by: Andrew Morton 
Cc: Johannes Weiner 
Cc: Tejun Heo 
Cc: Nicholas Piggin 
Cc: 	[v4.2+]
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
[natechancellor: Adjust context due to lack of b93b016313b3b]
Signed-off-by: Nathan Chancellor 
Signed-off-by: Greg Kroah-Hartman

HID: input: fix battery level reporting on BT mice

2018-04-24T07:43:07+00:00

commit 2e210bbb7429cdcf1a1a3ad00c1bf98bd9bf2452 upstream.

The commit 581c4484769e ("HID: input: map digitizer battery usage")
assumed that devices having input (qas opposed to feature) report for
battery strength would report the data on their own, without the need to
be polled by the kernel; unfortunately it is not so. Many wireless mice
do not send unsolicited reports with battery strength data and have to
be polled explicitly. As a complication, stylus devices on digitizers
are not normally connected to the base and thus can not be polled - the
base can only determine battery strength in the stylus when it is in
proximity.

To solve this issue, we add a special flag that tells the kernel
to avoid polling the device (and expect unsolicited reports) and set it
when report field with physical usage of digitizer stylus (HID_DG_STYLUS).
Unless this flag is set, and we have not seen the unsolicited reports,
the kernel will attempt to poll the device when userspace attempts to
read "capacity" and "state" attributes of power_supply object
corresponding to the devices battery.

Fixes: 581c4484769e ("HID: input: map digitizer battery usage")
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=198095
Cc: stable@vger.kernel.org
Reported-and-tested-by: Martin van Es 
Signed-off-by: Dmitry Torokhov 
Signed-off-by: Jiri Kosina 
Signed-off-by: Greg Kroah-Hartman

block: use 32-bit blk_status_t on Alpha

2018-04-24T07:42:57+00:00

commit 6e2fb22103b99c26ae30a46512abe75526d8e4c9 upstream.

Early alpha processors cannot write a single byte or word; they read 8
bytes, modify the value in registers and write back 8 bytes.

The type blk_status_t is defined as one byte, it is often written
asynchronously by I/O completion routines, this asynchronous modification
can corrupt content of nearby bytes if these nearby bytes can be written
simultaneously by another CPU.

- one example of such corruption is the structure dm_io where
  "blk_status_t status" is written by an asynchronous completion routine
  and "atomic_t io_count" is modified synchronously
- another example is the structure dm_buffer where "unsigned hold_count"
  is modified synchronously from process context and "blk_status_t
  write_error" is modified asynchronously from bio completion routine

This patch fixes the bug by changing the type blk_status_t to 32 bits if
we are on Alpha and if we are compiling for a processor that doesn't have
the byte-word-extension.

Signed-off-by: Mikulas Patocka 
Cc: stable@vger.kernel.org	# 4.13+
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

HID: core: Fix size as type u32

2018-04-24T07:42:56+00:00

commit 6de0b13cc0b4ba10e98a9263d7a83b940720b77a upstream.

When size is negative, calling memset will make segment fault.
Declare the size as type u32 to keep memset safe.

size in struct hid_report is unsigned, fix return type of
hid_report_len to u32.

Cc: stable@vger.kernel.org
Signed-off-by: Aaron Ma 
Signed-off-by: Jiri Kosina 
Signed-off-by: Greg Kroah-Hartman

task_struct: only use anon struct under randstruct plugin

2018-04-24T07:42:49+00:00

commit 2cfe0d3009418a132b93d78642a8059a38fe5944 upstream.

The original intent for always adding the anonymous struct in
task_struct was to make sure we had compiler coverage.

However, this caused pathological padding of 40 bytes at the start of
task_struct.  Instead, move the anonymous struct to being only used when
struct layout randomization is enabled.

Link: http://lkml.kernel.org/r/20180327213609.GA2964@beast
Fixes: 29e48ce87f1e ("task_struct: Allow randomized")
Signed-off-by: Kees Cook 
Reported-by: Peter Zijlstra 
Cc: Peter Zijlstra 
Cc: Ingo Molnar 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

mm: hwpoison: disable memory error handling on 1GB hugepage

2018-04-24T07:42:49+00:00

commit 31286a8484a85e8b4e91ddb0f5415aee8a416827 upstream.

Recently the following BUG was reported:

    Injecting memory failure for pfn 0x3c0000 at process virtual address 0x7fe300000000
    Memory failure: 0x3c0000: recovery action for huge page: Recovered
    BUG: unable to handle kernel paging request at ffff8dfcc0003000
    IP: gup_pgd_range+0x1f0/0xc20
    PGD 17ae72067 P4D 17ae72067 PUD 0
    Oops: 0000 [#1] SMP PTI
    ...
    CPU: 3 PID: 5467 Comm: hugetlb_1gb Not tainted 4.15.0-rc8-mm1-abc+ #3
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.3-1.fc25 04/01/2014

You can easily reproduce this by calling madvise(MADV_HWPOISON) twice on
a 1GB hugepage.  This happens because get_user_pages_fast() is not aware
of a migration entry on pud that was created in the 1st madvise() event.

I think that conversion to pud-aligned migration entry is working, but
other MM code walking over page table isn't prepared for it.  We need
some time and effort to make all this work properly, so this patch
avoids the reported bug by just disabling error handling for 1GB
hugepage.

[n-horiguchi@ah.jp.nec.com: v2]
  Link: http://lkml.kernel.org/r/1517284444-18149-1-git-send-email-n-horiguchi@ah.jp.nec.com
Link: http://lkml.kernel.org/r/1517207283-15769-1-git-send-email-n-horiguchi@ah.jp.nec.com
Signed-off-by: Naoya Horiguchi 
Acked-by: Michal Hocko 
Reviewed-by: Andrew Morton 
Reviewed-by: Mike Kravetz 
Acked-by: Punit Agrawal 
Tested-by: Michael Ellerman 
Cc: Anshuman Khandual 
Cc: "Aneesh Kumar K.V" 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

mm/hmm: fix header file if/else/endif maze

2018-04-24T07:42:49+00:00

commit b28b08de436a638c82d0cf3dcdbdbad055baf1fc upstream.

The #if/#else/#endif for IS_ENABLED(CONFIG_HMM) were wrong.  Because of
this after multiple include there was multiple definition of both
hmm_mm_init() and hmm_mm_destroy() leading to build failure if HMM was
enabled (CONFIG_HMM set).

Link: http://lkml.kernel.org/r/20180323005527.758-3-jglisse@redhat.com
Signed-off-by: Jérôme Glisse 
Acked-by: Balbir Singh 
Cc: Andrew Morton 
Cc: Ralph Campbell 
Cc: John Hubbard 
Cc: Evgeny Baskakov 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

signal: Correct the offset of si_pkey and si_lower in struct siginfo on m68k

2018-04-08T12:29:52+00:00

commit 8420f71943ae96dcd78da5bd4a5c2827419d340c upstream.

The change moving addr_lsb into the _sigfault union failed to take
into account that _sigfault._addr_bnd._lower being a pointer forced
the entire union to have pointer alignment.  The fix for
_sigfault._addr_bnd._lower having pointer alignment failed to take
into account that m68k has a pointer alignment less than the size
of a pointer.  So simply making the padding members pointers changed
the location of later members in the structure.

Fix this by directly computing the needed size of the padding members,
and making the padding members char arrays of the needed size.  AKA
if __alignof__(void *) is 1 sizeof(short) otherwise __alignof__(void *).
Which should be exactly the same rules the compiler whould have
used when computing the padding.

I have tested this change by adding BUILD_BUG_ONs to m68k to verify
the offset of every member of struct siginfo, and with those testing
that the offsets of the fields in struct siginfo is the same before
I changed the generic _sigfault member and after the correction
to the _sigfault member.

I have also verified that the x86 with it's own BUILD_BUG_ONs to verify
the offsets of the siginfo members also compiles cleanly.

Cc: stable@vger.kernel.org
Reported-by: Eugene Syromiatnikov 
Fixes: 859d880cf544 ("signal: Correct the offset of si_pkey in struct siginfo")
Fixes: b68a68d3dcc1 ("signal: Move addr_lsb into the _sigfault union for clarity")
Signed-off-by: "Eric W. Biederman" 
Signed-off-by: Greg Kroah-Hartman

bitmap: fix memset optimization on big-endian systems

2018-04-08T12:29:49+00:00

commit 21035965f60b0502fc6537b232839389bb4ce664 upstream.

Commit 2a98dc028f91 ("include/linux/bitmap.h: turn bitmap_set and
bitmap_clear into memset when possible") introduced an optimization to
bitmap_{set,clear}() which uses memset() when the start and length are
constants aligned to a byte.

This is wrong on big-endian systems; our bitmaps are arrays of unsigned
long, so bit n is not at byte n / 8 in memory.  This was caught by the
Btrfs selftests, but the bitmap selftests also fail when run on a
big-endian machine.

We can still use memset if the start and length are aligned to an
unsigned long, so do that on big-endian.  The same problem applies to
the memcmp in bitmap_equal(), so fix it there, too.

Fixes: 2a98dc028f91 ("include/linux/bitmap.h: turn bitmap_set and bitmap_clear into memset when possible")
Fixes: 2c6deb01525a ("bitmap: use memcmp optimisation in more situations")
Cc: stable@kernel.org
Reported-by: "Erhard F." 
Cc: Matthew Wilcox 
Cc: Rasmus Villemoes 
Cc: Andrew Morton 
Cc: Arnd Bergmann 
Signed-off-by: Omar Sandoval 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2018-03-31T04:47:28+00:00

Pull networking fixes from David Miller:

 1) Fix RCU locking in xfrm_local_error(), from Taehee Yoo.

 2) Fix return value assignments and thus error checking in
    iwl_mvm_start_ap_ibss(), from Johannes Berg.

 3) Don't count header length twice in vti4, from Stefano Brivio.

 4) Fix deadlock in rt6_age_examine_exception, from Eric Dumazet.

 5) Fix out-of-bounds access in nf_sk_lookup_slow{v4,v6}() from Subash
    Abhinov.

 6) Check nladdr size in netlink_connect(), from Alexander Potapenko.

 7) VF representor SQ numbers are 32 not 16 bits, in mlx5 driver, from
    Or Gerlitz.

 8) Out of bounds read in skb_network_protocol(), from Eric Dumazet.

 9) r8169 driver sets driver data pointer after register_netdev() which
    is too late. Fix from Heiner Kallweit.

10) Fix memory leak in mlx4 driver, from Moshe Shemesh.

11) The multi-VLAN decap fix added a regression when dealing with device
    that lack a MAC header, such as tun. Fix from Toshiaki Makita.

12) Fix integer overflow in dynamic interrupt coalescing code. From Tal
    Gilboa.

13) Use after free in vrf code, from David Ahern.

14) IPV6 route leak between VRFs fix, also from David Ahern.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (81 commits)
  net: mvneta: fix enable of all initialized RXQs
  net/ipv6: Fix route leaking between VRFs
  vrf: Fix use after free and double free in vrf_finish_output
  ipv6: sr: fix seg6 encap performances with TSO enabled
  net/dim: Fix int overflow
  vlan: Fix vlan insertion for packets without ethernet header
  net: Fix untag for vlan packets without ethernet header
  atm: iphase: fix spelling mistake: "Receiverd" -> "Received"
  vhost: validate log when IOTLB is enabled
  qede: Do not drop rx-checksum invalidated packets.
  hv_netvsc: enable multicast if necessary
  ip_tunnel: Resolve ipsec merge conflict properly.
  lan78xx: Crash in lan78xx_writ_reg (Workqueue: events lan78xx_deferred_multicast_write)
  qede: Fix barrier usage after tx doorbell write.
  vhost: correctly remove wait queue during poll failure
  net/mlx4_core: Fix memory leak while delete slave's resources
  net/mlx4_en: Fix mixed PFC and Global pause user control requests
  net/smc: use announced length in sock_recvmsg()
  llc: properly handle dev_queue_xmit() return value
  strparser: Fix sign of err codes
  ...