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  1. 29 Aug, 2017 28 commits
  3. 28 Aug, 2017 10 commits
    • Linus Torvalds's avatar
      page waitqueue: always add new entries at the end · 9c3a815f
      Linus Torvalds authored 
      Commit 3510ca20 ("Minor page waitqueue cleanups") made the page
queue code always add new waiters to the back of the queue, which helps
upcoming patches to batch the wakeups for some horrid loads where the
wait queues grow to thousands of entries.

However, I forgot about the nasrt add_page_wait_queue() special case
code that is only used by the cachefiles code.  That one still continued
to add the new wait queue entries at the beginning of the list.

Fix it, because any sane batched wakeup will require that we don't
suddenly start getting new entries at the beginning of the list that we
already handled in a previous batch.

[ The current code always does the whole list while holding the lock, so
  wait queue ordering doesn't matter for correctness, but even then it's
  better to add later entries at the end from a fairness standpoint ]
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      9c3a815f
    • Tejun Heo's avatar
      cpumask: fix spurious cpumask_of_node() on non-NUMA multi-node configs · b339752d
      Tejun Heo authored 
      When !NUMA, cpumask_of_node(@node) equals cpu_online_mask regardless of
@node.  The assumption seems that if !NUMA, there shouldn't be more than
one node and thus reporting cpu_online_mask regardless of @node is
correct.  However, that assumption was broken years ago to support
DISCONTIGMEM and whether a system has multiple nodes or not is
separately controlled by NEED_MULTIPLE_NODES.

This means that, on a system with !NUMA && NEED_MULTIPLE_NODES,
cpumask_of_node() will report cpu_online_mask for all possible nodes,
indicating that the CPUs are associated with multiple nodes which is an
impossible configuration.

This bug has been around forever but doesn't look like it has caused any
noticeable symptoms.  However, it triggers a WARN recently added to
workqueue to verify NUMA affinity configuration.

Fix it by reporting empty cpumask on non-zero nodes if !NUMA.
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Reported-and-tested-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      b339752d
    • Alexey Brodkin's avatar
      ARCv2: SMP: Mask only private-per-core IRQ lines on boot at core intc · e8206d2b
      Alexey Brodkin authored 
      Recent commit a8ec3ee8 "arc: Mask individual IRQ lines during core
INTC init" breaks interrupt handling on ARCv2 SMP systems.

That commit masked all interrupts at onset, as some controllers on some
boards (customer as well as internal), would assert interrutps early
before any handlers were installed.  For SMP systems, the masking was
done at each cpu's core-intc.  Later, when the IRQ was actually
requested, it was unmasked, but only on the requesting cpu.

For "common" interrupts, which were wired up from the 2nd level IDU
intc, this was as issue as they needed to be enabled on ALL the cpus
(given that IDU IRQs are by default served Round Robin across cpus)

So fix that by NOT masking "common" interrupts at core-intc, but instead
at the 2nd level IDU intc (latter already being done in idu_of_init())

Fixes: a8ec3ee8 ("arc: Mask individual IRQ lines during core INTC init")
Signed-off-by: default avatarAlexey Brodkin <abrodkin@synopsys.com>
[vgupta: reworked changelog, removed the extraneous idu_irq_mask_raw()]
Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      e8206d2b
    • Helge Deller's avatar
      fs/select: Fix memory corruption in compat_get_fd_set() · 79de3cbe
      Helge Deller authored 
      Commit 464d6242 ("select: switch compat_{get,put}_fd_set() to
compat_{get,put}_bitmap()") changed the calculation on how many bytes
need to be zeroed when userspace handed over a NULL pointer for a fdset
array in the select syscall.

The calculation was changed in compat_get_fd_set() wrongly from
	memset(fdset, 0, ((nr + 1) & ~1)*sizeof(compat_ulong_t));
to
	memset(fdset, 0, ALIGN(nr, BITS_PER_LONG));

The ALIGN(nr, BITS_PER_LONG) calculates the number of _bits_ which need
to be zeroed in the target fdset array (rounded up to the next full bits
for an unsigned long).

But the memset() call expects the number of _bytes_ to be zeroed.

This leads to clearing more memory than wanted (on the stack area or
even at kmalloc()ed memory areas) and to random kernel crashes as we
have seen them on the parisc platform.

The correct change should have been

	memset(fdset, 0, (ALIGN(nr, BITS_PER_LONG) / BITS_PER_LONG) * BYTES_PER_LONG);

which is the same as can be archieved with a call to

	zero_fd_set(nr, fdset).

Fixes: 464d6242 ("select: switch compat_{get,put}_fd_set() to compat_{get,put}_bitmap()"
Acked-by: default avatar: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarHelge Deller <deller@gmx.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      79de3cbe
    • Linus Torvalds's avatar
      Merge tag 'for-linus' of git://linux-c6x.org/git/projects/linux-c6x-upstreaming · 702e9762
      Linus Torvalds authored 
      Pull c6x tweaks from Mark Salter.

* tag 'for-linus' of git://linux-c6x.org/git/projects/linux-c6x-upstreaming:
  c6x: Convert to using %pOF instead of full_name
  c6x: defconfig: Cleanup from old Kconfig options
      702e9762
    • Linus Torvalds's avatar
      Linux 4.13-rc7 · cc4a41fe
      Linus Torvalds authored
      cc4a41fe
    • Linus Torvalds's avatar
      Merge tag 'iommu-fixes-v4.13-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu · 2c25833c
      Linus Torvalds authored 
      Pull IOMMU fix from Joerg Roedel:
 "Another fix, this time in common IOMMU sysfs code.

  In the conversion from the old iommu sysfs-code to the
  iommu_device_register interface, I missed to update the release path
  for the struct device associated with an IOMMU. It freed the 'struct
  device', which was a pointer before, but is now embedded in another
  struct.

  Freeing from the middle of allocated memory had all kinds of nasty
  side effects when an IOMMU was unplugged. Unfortunatly nobody
  unplugged and IOMMU until now, so this was not discovered earlier. The
  fix is to make the 'struct device' a pointer again"

* tag 'iommu-fixes-v4.13-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
  iommu: Fix wrong freeing of iommu_device->dev
      2c25833c
    • Linus Torvalds's avatar
      Merge tag 'char-misc-4.13-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc · 80f73b2d
      Linus Torvalds authored 
      Pull char/misc fix from Greg KH:
 "Here is a single misc driver fix for 4.13-rc7. It resolves a reported
  problem in the Android binder driver due to previous patches in
  4.13-rc.

  It's been in linux-next with no reported issues"

* tag 'char-misc-4.13-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  ANDROID: binder: fix proc->tsk check.
      80f73b2d
    • Linus Torvalds's avatar
      Merge tag 'staging-4.13-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging · c3c16263
      Linus Torvalds authored 
      Pull staging/iio fixes from Greg KH:
 "Here are few small staging driver fixes, and some more IIO driver
  fixes for 4.13-rc7. Nothing major, just resolutions for some reported
  problems.

  All of these have been in linux-next with no reported problems"

* tag 'staging-4.13-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  iio: magnetometer: st_magn: remove ihl property for LSM303AGR
  iio: magnetometer: st_magn: fix status register address for LSM303AGR
  iio: hid-sensor-trigger: Fix the race with user space powering up sensors
  iio: trigger: stm32-timer: fix get trigger mode
  iio: imu: adis16480: Fix acceleration scale factor for adis16480
  PATCH] iio: Fix some documentation warnings
  staging: rtl8188eu: add RNX-N150NUB support
  Revert "staging: fsl-mc: be consistent when checking strcmp() return"
  iio: adc: stm32: fix common clock rate
  iio: adc: ina219: Avoid underflow for sleeping time
  iio: trigger: stm32-timer: add enable attribute
  iio: trigger: stm32-timer: fix get/set down count direction
  iio: trigger: stm32-timer: fix write_raw return value
  iio: trigger: stm32-timer: fix quadrature mode get routine
  iio: bmp280: properly initialize device for humidity reading
      c3c16263
    • Linus Torvalds's avatar
      Merge tag 'ntb-4.13-bugfixes' of git://github.com/jonmason/ntb · fff4e7a0
      Linus Torvalds authored 
      Pull NTB fixes from Jon Mason:
 "NTB bug fixes to address an incorrect ntb_mw_count reference in the
  NTB transport, improperly bringing down the link if SPADs are
  corrupted, and an out-of-order issue regarding link negotiation and
  data passing"

* tag 'ntb-4.13-bugfixes' of git://github.com/jonmason/ntb:
  ntb: ntb_test: ensure the link is up before trying to configure the mws
  ntb: transport shouldn't disable link due to bogus values in SPADs
  ntb: use correct mw_count function in ntb_tool and ntb_transport
      fff4e7a0
  5. 27 Aug, 2017 2 commits
    • Linus Torvalds's avatar
      Avoid page waitqueue race leaving possible page locker waiting · a8b169af
      Linus Torvalds authored 
      The "lock_page_killable()" function waits for exclusive access to the
page lock bit using the WQ_FLAG_EXCLUSIVE bit in the waitqueue entry
set.

That means that if it gets woken up, other waiters may have been
skipped.

That, in turn, means that if it sees the page being unlocked, it *must*
take that lock and return success, even if a lethal signal is also
pending.

So instead of checking for lethal signals first, we need to check for
them after we've checked the actual bit that we were waiting for.  Even
if that might then delay the killing of the process.

This matches the order of the old "wait_on_bit_lock()" infrastructure
that the page locking used to use (and is still used in a few other
areas).

Note that if we still return an error after having unsuccessfully tried
to acquire the page lock, that is ok: that means that some other thread
was able to get ahead of us and lock the page, and when that other
thread then unlocks the page, the wakeup event will be repeated.  So any
other pending waiters will now get properly woken up.

Fixes: 62906027 ("mm: add PageWaiters indicating tasks are waiting for a page bit")
Cc: Nick Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Jan Kara <jack@suse.cz>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Andi Kleen <ak@linux.intel.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      a8b169af
    • Linus Torvalds's avatar
      Minor page waitqueue cleanups · 3510ca20
      Linus Torvalds authored 
      Tim Chen and Kan Liang have been battling a customer load that shows
extremely long page wakeup lists.  The cause seems to be constant NUMA
migration of a hot page that is shared across a lot of threads, but the
actual root cause for the exact behavior has not been found.

Tim has a patch that batches the wait list traversal at wakeup time, so
that we at least don't get long uninterruptible cases where we traverse
and wake up thousands of processes and get nasty latency spikes.  That
is likely 4.14 material, but we're still discussing the page waitqueue
specific parts of it.

In the meantime, I've tried to look at making the page wait queues less
expensive, and failing miserably.  If you have thousands of threads
waiting for the same page, it will be painful.  We'll need to try to
figure out the NUMA balancing issue some day, in addition to avoiding
the excessive spinlock hold times.

That said, having tried to rewrite the page wait queues, I can at least
fix up some of the braindamage in the current situation. In particular:

 (a) we don't want to continue walking the page wait list if the bit
     we're waiting for already got set again (which seems to be one of
     the patterns of the bad load).  That makes no progress and just
     causes pointless cache pollution chasing the pointers.

 (b) we don't want to put the non-locking waiters always on the front of
     the queue, and the locking waiters always on the back.  Not only is
     that unfair, it means that we wake up thousands of reading threads
     that will just end up being blocked by the writer later anyway.

Also add a comment about the layout of 'struct wait_page_key' - there is
an external user of it in the cachefiles code that means that it has to
match the layout of 'struct wait_bit_key' in the two first members.  It
so happens to match, because 'struct page *' and 'unsigned long *' end
up having the same values simply because the page flags are the first
member in struct page.

Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Christopher Lameter <cl@linux.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3510ca20
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