linux-stable.git, branch v4.4.217

Linux 4.4.217

2020-03-20T08:06:35+00:00

ipv4: ensure rcu_read_lock() in cipso_v4_error()

2020-03-20T08:06:34+00:00

commit 3e72dfdf8227b052393f71d820ec7599909dddc2 upstream.

Similarly to commit c543cb4a5f07 ("ipv4: ensure rcu_read_lock() in
ipv4_link_failure()"), __ip_options_compile() must be called under rcu
protection.

Fixes: 3da1ed7ac398 ("net: avoid use IPCB in cipso_v4_error")
Suggested-by: Guillaume Nault 
Signed-off-by: Matteo Croce 
Acked-by: Paul Moore 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

mm: slub: add missing TID bump in kmem_cache_alloc_bulk()

2020-03-20T08:06:34+00:00

commit fd4d9c7d0c71866ec0c2825189ebd2ce35bd95b8 upstream.

When kmem_cache_alloc_bulk() attempts to allocate N objects from a percpu
freelist of length M, and N > M > 0, it will first remove the M elements
from the percpu freelist, then call ___slab_alloc() to allocate the next
element and repopulate the percpu freelist. ___slab_alloc() can re-enable
IRQs via allocate_slab(), so the TID must be bumped before ___slab_alloc()
to properly commit the freelist head change.

Fix it by unconditionally bumping c->tid when entering the slowpath.

Cc: stable@vger.kernel.org
Fixes: ebe909e0fdb3 ("slub: improve bulk alloc strategy")
Signed-off-by: Jann Horn 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

ARM: 8958/1: rename missed uaccess .fixup section

2020-03-20T08:06:34+00:00

commit f87b1c49bc675da30d8e1e8f4b60b800312c7b90 upstream.

When the uaccess .fixup section was renamed to .text.fixup, one case was
missed. Under ld.bfd, the orphaned section was moved close to .text
(since they share the "ax" bits), so things would work normally on
uaccess faults. Under ld.lld, the orphaned section was placed outside
the .text section, making it unreachable.

Link: https://github.com/ClangBuiltLinux/linux/issues/282
Link: https://bugs.chromium.org/p/chromium/issues/detail?id=1020633#c44
Link: https://lore.kernel.org/r/nycvar.YSQ.7.76.1912032147340.17114@knanqh.ubzr
Link: https://lore.kernel.org/lkml/202002071754.F5F073F1D@keescook/

Fixes: c4a84ae39b4a5 ("ARM: 8322/1: keep .text and .fixup regions closer together")
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook 
Reviewed-by: Ard Biesheuvel 
Reviewed-by: Nick Desaulniers 
Signed-off-by: Russell King 
Signed-off-by: Greg Kroah-Hartman

ARM: 8957/1: VDSO: Match ARMv8 timer in cntvct_functional()

2020-03-20T08:06:34+00:00

commit 45939ce292b4b11159719faaf60aba7d58d5fe33 upstream.

It is possible for a system with an ARMv8 timer to run a 32-bit kernel.
When this happens we will unconditionally have the vDSO code remove the
__vdso_gettimeofday and __vdso_clock_gettime symbols because
cntvct_functional() returns false since it does not match that
compatibility string.

Fixes: ecf99a439105 ("ARM: 8331/1: VDSO initialization, mapping, and synchronization")
Signed-off-by: Florian Fainelli 
Signed-off-by: Russell King 
Signed-off-by: Greg Kroah-Hartman

jbd2: fix data races at struct journal_head

2020-03-20T08:06:34+00:00

[ Upstream commit 6c5d911249290f41f7b50b43344a7520605b1acb ]

journal_head::b_transaction and journal_head::b_next_transaction could
be accessed concurrently as noticed by KCSAN,

 LTP: starting fsync04
 /dev/zero: Can't open blockdev
 EXT4-fs (loop0): mounting ext3 file system using the ext4 subsystem
 EXT4-fs (loop0): mounted filesystem with ordered data mode. Opts: (null)
 ==================================================================
 BUG: KCSAN: data-race in __jbd2_journal_refile_buffer [jbd2] / jbd2_write_access_granted [jbd2]

 write to 0xffff99f9b1bd0e30 of 8 bytes by task 25721 on cpu 70:
  __jbd2_journal_refile_buffer+0xdd/0x210 [jbd2]
  __jbd2_journal_refile_buffer at fs/jbd2/transaction.c:2569
  jbd2_journal_commit_transaction+0x2d15/0x3f20 [jbd2]
  (inlined by) jbd2_journal_commit_transaction at fs/jbd2/commit.c:1034
  kjournald2+0x13b/0x450 [jbd2]
  kthread+0x1cd/0x1f0
  ret_from_fork+0x27/0x50

 read to 0xffff99f9b1bd0e30 of 8 bytes by task 25724 on cpu 68:
  jbd2_write_access_granted+0x1b2/0x250 [jbd2]
  jbd2_write_access_granted at fs/jbd2/transaction.c:1155
  jbd2_journal_get_write_access+0x2c/0x60 [jbd2]
  __ext4_journal_get_write_access+0x50/0x90 [ext4]
  ext4_mb_mark_diskspace_used+0x158/0x620 [ext4]
  ext4_mb_new_blocks+0x54f/0xca0 [ext4]
  ext4_ind_map_blocks+0xc79/0x1b40 [ext4]
  ext4_map_blocks+0x3b4/0x950 [ext4]
  _ext4_get_block+0xfc/0x270 [ext4]
  ext4_get_block+0x3b/0x50 [ext4]
  __block_write_begin_int+0x22e/0xae0
  __block_write_begin+0x39/0x50
  ext4_write_begin+0x388/0xb50 [ext4]
  generic_perform_write+0x15d/0x290
  ext4_buffered_write_iter+0x11f/0x210 [ext4]
  ext4_file_write_iter+0xce/0x9e0 [ext4]
  new_sync_write+0x29c/0x3b0
  __vfs_write+0x92/0xa0
  vfs_write+0x103/0x260
  ksys_write+0x9d/0x130
  __x64_sys_write+0x4c/0x60
  do_syscall_64+0x91/0xb05
  entry_SYSCALL_64_after_hwframe+0x49/0xbe

 5 locks held by fsync04/25724:
  #0: ffff99f9911093f8 (sb_writers#13){.+.+}, at: vfs_write+0x21c/0x260
  #1: ffff99f9db4c0348 (&sb->s_type->i_mutex_key#15){+.+.}, at: ext4_buffered_write_iter+0x65/0x210 [ext4]
  #2: ffff99f5e7dfcf58 (jbd2_handle){++++}, at: start_this_handle+0x1c1/0x9d0 [jbd2]
  #3: ffff99f9db4c0168 (&ei->i_data_sem){++++}, at: ext4_map_blocks+0x176/0x950 [ext4]
  #4: ffffffff99086b40 (rcu_read_lock){....}, at: jbd2_write_access_granted+0x4e/0x250 [jbd2]
 irq event stamp: 1407125
 hardirqs last  enabled at (1407125): [] __find_get_block+0x107/0x790
 hardirqs last disabled at (1407124): [] __find_get_block+0x49/0x790
 softirqs last  enabled at (1405528): [] __do_softirq+0x34c/0x57c
 softirqs last disabled at (1405521): [] irq_exit+0xa2/0xc0

 Reported by Kernel Concurrency Sanitizer on:
 CPU: 68 PID: 25724 Comm: fsync04 Tainted: G L 5.6.0-rc2-next-20200221+ #7
 Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019

The plain reads are outside of jh->b_state_lock critical section which result
in data races. Fix them by adding pairs of READ|WRITE_ONCE().

Reviewed-by: Jan Kara 
Signed-off-by: Qian Cai 
Link: https://lore.kernel.org/r/20200222043111.2227-1-cai@lca.pw
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin

signal: avoid double atomic counter increments for user accounting

2020-03-20T08:06:34+00:00

[ Upstream commit fda31c50292a5062332fa0343c084bd9f46604d9 ]

When queueing a signal, we increment both the users count of pending
signals (for RLIMIT_SIGPENDING tracking) and we increment the refcount
of the user struct itself (because we keep a reference to the user in
the signal structure in order to correctly account for it when freeing).

That turns out to be fairly expensive, because both of them are atomic
updates, and particularly under extreme signal handling pressure on big
machines, you can get a lot of cache contention on the user struct.
That can then cause horrid cacheline ping-pong when you do these
multiple accesses.

So change the reference counting to only pin the user for the _first_
pending signal, and to unpin it when the last pending signal is
dequeued.  That means that when a user sees a lot of concurrent signal
queuing - which is the only situation when this matters - the only
atomic access needed is generally the 'sigpending' count update.

This was noticed because of a particularly odd timing artifact on a
dual-socket 96C/192T Cascade Lake platform: when you get into bad
contention, on that machine for some reason seems to be much worse when
the contention happens in the upper 32-byte half of the cacheline.

As a result, the kernel test robot will-it-scale 'signal1' benchmark had
an odd performance regression simply due to random alignment of the
'struct user_struct' (and pointed to a completely unrelated and
apparently nonsensical commit for the regression).

Avoiding the double increments (and decrements on the dequeueing side,
of course) makes for much less contention and hugely improved
performance on that will-it-scale microbenchmark.

Quoting Feng Tang:

 "It makes a big difference, that the performance score is tripled! bump
  from original 17000 to 54000. Also the gap between 5.0-rc6 and
  5.0-rc6+Jiri's patch is reduced to around 2%"

[ The "2% gap" is the odd cacheline placement difference on that
  platform: under the extreme contention case, the effect of which half
  of the cacheline was hot was 5%, so with the reduced contention the
  odd timing artifact is reduced too ]

It does help in the non-contended case too, but is not nearly as
noticeable.

Reported-and-tested-by: Feng Tang 
Cc: Eric W. Biederman 
Cc: Huang, Ying 
Cc: Philip Li 
Cc: Andi Kleen 
Cc: Jiri Olsa 
Cc: Peter Zijlstra 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

net: ks8851-ml: Fix IRQ handling and locking

2020-03-20T08:06:33+00:00

[ Upstream commit 44343418d0f2f623cb9da6f5000df793131cbe3b ]

The KS8851 requires that packet RX and TX are mutually exclusive.
Currently, the driver hopes to achieve this by disabling interrupt
from the card by writing the card registers and by disabling the
interrupt on the interrupt controller. This however is racy on SMP.

Replace this approach by expanding the spinlock used around the
ks_start_xmit() TX path to ks_irq() RX path to assure true mutual
exclusion and remove the interrupt enabling/disabling, which is
now not needed anymore. Furthermore, disable interrupts also in
ks_net_stop(), which was missing before.

Note that a massive improvement here would be to re-use the KS8851
driver approach, which is to move the TX path into a worker thread,
interrupt handling to threaded interrupt, and synchronize everything
with mutexes, but that would be a much bigger rework, for a separate
patch.

Signed-off-by: Marek Vasut 
Cc: David S. Miller 
Cc: Lukas Wunner 
Cc: Petr Stetiar 
Cc: YueHaibing 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

perf/amd/uncore: Replace manual sampling check with CAP_NO_INTERRUPT flag

2020-03-20T08:06:33+00:00

[ Upstream commit f967140dfb7442e2db0868b03b961f9c59418a1b ]

Enable the sampling check in kernel/events/core.c::perf_event_open(),
which returns the more appropriate -EOPNOTSUPP.

BEFORE:

  $ sudo perf record -a -e instructions,l3_request_g1.caching_l3_cache_accesses true
  Error:
  The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (l3_request_g1.caching_l3_cache_accesses).
  /bin/dmesg | grep -i perf may provide additional information.

With nothing relevant in dmesg.

AFTER:

  $ sudo perf record -a -e instructions,l3_request_g1.caching_l3_cache_accesses true
  Error:
  l3_request_g1.caching_l3_cache_accesses: PMU Hardware doesn't support sampling/overflow-interrupts. Try 'perf stat'

Fixes: c43ca5091a37 ("perf/x86/amd: Add support for AMD NB and L2I "uncore" counters")
Signed-off-by: Kim Phillips 
Signed-off-by: Borislav Petkov 
Acked-by: Peter Zijlstra 
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20200311191323.13124-1-kim.phillips@amd.com
Signed-off-by: Sasha Levin

batman-adv: Don't schedule OGM for disabled interface

2020-03-20T08:06:33+00:00

A transmission scheduling for an interface which is currently dropped by
batadv_iv_ogm_iface_disable could still be in progress. The B.A.T.M.A.N. V
is simply cancelling the workqueue item in an synchronous way but this is
not possible with B.A.T.M.A.N. IV because the OGM submissions are
intertwined.

Instead it has to stop submitting the OGM when it detect that the buffer
pointer is set to NULL.

Reported-by: syzbot+a98f2016f40b9cd3818a@syzkaller.appspotmail.com
Reported-by: syzbot+ac36b6a33c28a491e929@syzkaller.appspotmail.com
Fixes: c6c8fea29769 ("net: Add batman-adv meshing protocol")
Signed-off-by: Sven Eckelmann 
Cc: Hillf Danton 
Signed-off-by: Simon Wunderlich 
Signed-off-by: Sven Eckelmann 
Signed-off-by: Greg Kroah-Hartman