Commit Graph

22666 Commits

Author SHA1 Message Date
Thomas Gleixner fc590c22f9 genirq: Robustify handle_percpu_devid_irq()
The percpu_devid handler is not robust against spurious interrupts. If a
spurious interrupt happens and no action is installed then the handler
crashes with a NULL pointer dereference.

Add a sanity check for this and log the wreckage once in dmesg.

Reported-by: Majun <majun258@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: guohanjun@huawei.com
Cc: dingtianhong@huawei.com
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1609021436160.5647@nanos
2016-09-02 18:06:49 +02:00
Vincent Stehle eb0dc47ab6 genirq: Fix missing irq allocation affinity hint
The new affinity hint argument of __irq_domain_alloc_irqs() is missing in
irq_reserve_ipi(). Add it.

This fixes the following compilation error:

  kernel/irq/ipi.c: In function ‘irq_reserve_ipi’:
  kernel/irq/ipi.c:85:9: error: too few arguments to function ‘__irq_domain_alloc_irqs’
    virq = __irq_domain_alloc_irqs(domain, virq, nr_irqs, NUMA_NO_NODE,
           ^
Fixes: 06ee6d571f ("genirq: Add affinity hint to irq allocation")
Signed-off-by: Vincent Stehlé <vincent.stehle@laposte.net>
Cc: linux-pci@vger.kernel.org
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-07-19 10:49:47 +02:00
Alexander Popov a1b7b1a57b irqdomain: Fix irq_domain_alloc_irqs_recursive() error handling
If an irq_domain is auto-recursive and irq_domain_alloc_irqs_recursive()
for its parent has returned an error, then do return and avoid calling
irq_domain_free_irqs_recursive() uselessly, because:
- if domain->ops->alloc() had failed for an auto-recursive irq_domain,
   then irq_domain_free_irqs_recursive() had already been called;
- if domain->ops->alloc() had failed for a not auto-recursive irq_domain,
   then there is nothing to free at all.

Signed-off-by: Alexander Popov <alex.popov@linux.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Link: http://lkml.kernel.org/r/1467505448-2850-1-git-send-email-alex.popov@linux.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-07-11 17:23:48 +02:00
Thomas Gleixner 4364e1a29b genirq/msi: Fix broken debug output
virq is not required to be the same for all msi descs. Use the base irq number
from the desc in the debug printk.

Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-07-04 15:32:25 +02:00
Thomas Gleixner 8658be133b Merge branch 'irq/for-block' into irq/core
Pull the irq affinity managing code which is in a seperate branch for block
developers to pull.
2016-07-04 12:26:05 +02:00
Christoph Hellwig 5e385a6ef3 genirq: Add a helper to spread an affinity mask for MSI/MSI-X vectors
This is lifted from the blk-mq code and adopted to use the affinity mask
concept just introduced in the irq handling code.  It tries to keep the
algorithm the same as the one current used by blk-mq, but improvements
like assining vectors on a per-node basis instead of just per sibling
are possible with this simple move and refactoring.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: linux-block@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Cc: linux-nvme@lists.infradead.org
Cc: axboe@fb.com
Cc: agordeev@redhat.com
Link: http://lkml.kernel.org/r/1467621574-8277-7-git-send-email-hch@lst.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-07-04 12:25:14 +02:00
Thomas Gleixner 0972fa57f5 genirq/msi: Make use of affinity aware allocations
Allow the MSI code to provide affinity hints per MSI descriptor.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: linux-block@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Cc: linux-nvme@lists.infradead.org
Cc: axboe@fb.com
Cc: agordeev@redhat.com
Link: http://lkml.kernel.org/r/1467621574-8277-6-git-send-email-hch@lst.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-07-04 12:25:14 +02:00
Thomas Gleixner 45ddcecbfa genirq: Use affinity hint in irqdesc allocation
Use the affinity hint in the irqdesc allocator. The hint is used to determine
the node for the allocation and to set the affinity of the interrupt.

If multiple interrupts are allocated (multi-MSI) then the allocator iterates
over the cpumask and for each set cpu it allocates on their node and sets the
initial affinity to that cpu.

If a single interrupt is allocated (MSI-X) then the allocator uses the first
cpu in the mask to compute the allocation node and uses the mask for the
initial affinity setting.

Interrupts set up this way are marked with the AFFINITY_MANAGED flag to
prevent userspace from messing with their affinity settings.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: linux-block@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Cc: linux-nvme@lists.infradead.org
Cc: axboe@fb.com
Cc: agordeev@redhat.com
Link: http://lkml.kernel.org/r/1467621574-8277-5-git-send-email-hch@lst.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-07-04 12:25:13 +02:00
Thomas Gleixner 06ee6d571f genirq: Add affinity hint to irq allocation
Add an extra argument to the irq(domain) allocation functions, so we can hand
down affinity hints to the allocator. Thats necessary to implement proper
support for multiqueue devices.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: linux-block@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Cc: linux-nvme@lists.infradead.org
Cc: axboe@fb.com
Cc: agordeev@redhat.com
Link: http://lkml.kernel.org/r/1467621574-8277-4-git-send-email-hch@lst.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-07-04 12:25:13 +02:00
Thomas Gleixner 9c2555835b genirq: Introduce IRQD_AFFINITY_MANAGED flag
Interupts marked with this flag are excluded from user space interrupt
affinity changes. Contrary to the IRQ_NO_BALANCING flag, the kernel internal
affinity mechanism is not blocked.

This flag will be used for multi-queue device interrupts.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: linux-block@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Cc: linux-nvme@lists.infradead.org
Cc: axboe@fb.com
Cc: agordeev@redhat.com
Link: http://lkml.kernel.org/r/1467621574-8277-3-git-send-email-hch@lst.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-07-04 12:25:13 +02:00
Thomas Gleixner b6140914fd genirq/msi: Remove unused MSI_FLAG_IDENTITY_MAP
No user and we definitely don't want to grow one.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: linux-block@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Cc: linux-nvme@lists.infradead.org
Cc: axboe@fb.com
Cc: agordeev@redhat.com
Link: http://lkml.kernel.org/r/1467621574-8277-2-git-send-email-hch@lst.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-07-04 12:25:12 +02:00
Linus Torvalds 89a82a9218 Merge branch 'stable-4.7' of git://git.infradead.org/users/pcmoore/audit
Pull audit fixes from Paul Moore:
 "Two small patches to fix audit problems in 4.7-rcX: the first fixes a
  potential kref leak, the second removes some header file noise.

  The first is an important bug fix that really should go in before 4.7
  is released, the second is not critical, but falls into the very-nice-
  to-have category so I'm including in the pull request.

  Both patches are straightforward, self-contained, and pass our
  testsuite without problem"

* 'stable-4.7' of git://git.infradead.org/users/pcmoore/audit:
  audit: move audit_get_tty to reduce scope and kabi changes
  audit: move calcs after alloc and check when logging set loginuid
2016-06-29 15:18:47 -07:00
Linus Torvalds 32826ac41f Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Pull networking fixes from David Miller:
 "I've been traveling so this accumulates more than week or so of bug
  fixing.  It perhaps looks a little worse than it really is.

   1) Fix deadlock in ath10k driver, from Ben Greear.

   2) Increase scan timeout in iwlwifi, from Luca Coelho.

   3) Unbreak STP by properly reinjecting STP packets back into the
      stack.  Regression fix from Ido Schimmel.

   4) Mediatek driver fixes (missing malloc failure checks, leaking of
      scratch memory, wrong indexing when mapping TX buffers, etc.) from
      John Crispin.

   5) Fix endianness bug in icmpv6_err() handler, from Hannes Frederic
      Sowa.

   6) Fix hashing of flows in UDP in the ruseport case, from Xuemin Su.

   7) Fix netlink notifications in ovs for tunnels, delete link messages
      are never emitted because of how the device registry state is
      handled.  From Nicolas Dichtel.

   8) Conntrack module leaks kmemcache on unload, from Florian Westphal.

   9) Prevent endless jump loops in nft rules, from Liping Zhang and
      Pablo Neira Ayuso.

  10) Not early enough spinlock initialization in mlx4, from Eric
      Dumazet.

  11) Bind refcount leak in act_ipt, from Cong WANG.

  12) Missing RCU locking in HTB scheduler, from Florian Westphal.

  13) Several small MACSEC bug fixes from Sabrina Dubroca (missing RCU
      barrier, using heap for SG and IV, and erroneous use of async flag
      when allocating AEAD conext.)

  14) RCU handling fix in TIPC, from Ying Xue.

  15) Pass correct protocol down into ipv4_{update_pmtu,redirect}() in
      SIT driver, from Simon Horman.

  16) Socket timer deadlock fix in TIPC from Jon Paul Maloy.

  17) Fix potential deadlock in team enslave, from Ido Schimmel.

  18) Memory leak in KCM procfs handling, from Jiri Slaby.

  19) ESN generation fix in ipv4 ESP, from Herbert Xu.

  20) Fix GFP_KERNEL allocations with locks held in act_ife, from Cong
      WANG.

  21) Use after free in netem, from Eric Dumazet.

  22) Uninitialized last assert time in multicast router code, from Tom
      Goff.

  23) Skip raw sockets in sock_diag destruction broadcast, from Willem
      de Bruijn.

  24) Fix link status reporting in thunderx, from Sunil Goutham.

  25) Limit resegmentation of retransmit queue so that we do not
      retransmit too large GSO frames.  From Eric Dumazet.

  26) Delay bpf program release after grace period, from Daniel
      Borkmann"

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (141 commits)
  openvswitch: fix conntrack netlink event delivery
  qed: Protect the doorbell BAR with the write barriers.
  neigh: Explicitly declare RCU-bh read side critical section in neigh_xmit()
  e1000e: keep VLAN interfaces functional after rxvlan off
  cfg80211: fix proto in ieee80211_data_to_8023 for frames without LLC header
  qlcnic: use the correct ring in qlcnic_83xx_process_rcv_ring_diag()
  bpf, perf: delay release of BPF prog after grace period
  net: bridge: fix vlan stats continue counter
  tcp: do not send too big packets at retransmit time
  ibmvnic: fix to use list_for_each_safe() when delete items
  net: thunderx: Fix TL4 configuration for secondary Qsets
  net: thunderx: Fix link status reporting
  net/mlx5e: Reorganize ethtool statistics
  net/mlx5e: Fix number of PFC counters reported to ethtool
  net/mlx5e: Prevent adding the same vxlan port
  net/mlx5e: Check for BlueFlame capability before allocating SQ uar
  net/mlx5e: Change enum to better reflect usage
  net/mlx5: Add ConnectX-5 PCIe 4.0 to list of supported devices
  net/mlx5: Update command strings
  net: marvell: Add separate config ANEG function for Marvell 88E1111
  ...
2016-06-29 11:50:42 -07:00
Linus Torvalds 52827f389b Merge branch 'for-4.7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fixes from Tejun Heo:
 "Three fix patches.  Two are for cgroup / css init failure path.  The
  last one makes css_set_lock irq-safe as the deadline scheduler ends up
  calling put_css_set() from irq context"

* 'for-4.7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: Disable IRQs while holding css_set_lock
  cgroup: set css->id to -1 during init
  cgroup: remove redundant cleanup in css_create
2016-06-29 10:04:42 -07:00
Daniel Borkmann ceb5607035 bpf, perf: delay release of BPF prog after grace period
Commit dead9f29dd ("perf: Fix race in BPF program unregister") moved
destruction of BPF program from free_event_rcu() callback to __free_event(),
which is problematic if used with tail calls: if prog A is attached as
trace event directly, but at the same time present in a tail call map used
by another trace event program elsewhere, then we need to delay destruction
via RCU grace period since it can still be in use by the program doing the
tail call (the prog first needs to be dropped from the tail call map, then
trace event with prog A attached destroyed, so we get immediate destruction).

Fixes: dead9f29dd ("perf: Fix race in BPF program unregister")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Cc: Jann Horn <jann@thejh.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-29 05:42:55 -04:00
Richard Guy Briggs 3f5be2da85 audit: move audit_get_tty to reduce scope and kabi changes
The only users of audit_get_tty and audit_put_tty are internal to
audit, so move it out of include/linux/audit.h to kernel.h and create
a proper function rather than inlining it.  This also reduces kABI
changes.

Suggested-by: Paul Moore <pmoore@redhat.com>
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
[PM: line wrapped description]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2016-06-28 15:48:48 -04:00
Richard Guy Briggs 76a658c20e audit: move calcs after alloc and check when logging set loginuid
Move the calculations of values after the allocation in case the
allocation fails.  This avoids wasting effort in the rare case that it
fails, but more importantly saves us extra logic to release the tty
ref.

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2016-06-28 15:40:17 -04:00
Linus Torvalds 57801c1b81 Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Thomas Gleixner:
 "A couple of scheduler fixes:

   - force watchdog reset while processing sysrq-w

   - fix a deadlock when enabling trace events in the scheduler

   - fixes to the throttled next buddy logic

   - fixes for the average accounting (missing serialization and
     underflow handling)

   - allow kernel threads for fallback to online but not active cpus"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/core: Allow kthreads to fall back to online && !active cpus
  sched/fair: Do not announce throttled next buddy in dequeue_task_fair()
  sched/fair: Initialize throttle_count for new task-groups lazily
  sched/fair: Fix cfs_rq avg tracking underflow
  kernel/sysrq, watchdog, sched/core: Reset watchdog on all CPUs while processing sysrq-w
  sched/debug: Fix deadlock when enabling sched events
  sched/fair: Fix post_init_entity_util_avg() serialization
2016-06-25 06:38:42 -07:00
Linus Torvalds e3b22bc3d7 Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fix from Thomas Gleixner:
 "A single fix to address a race in the static key logic"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/static_key: Fix concurrent static_key_slow_inc()
2016-06-25 06:14:44 -07:00
Michael Ellerman 9521d39976 Fix build break in fork.c when THREAD_SIZE < PAGE_SIZE
Commit b235beea9e ("Clarify naming of thread info/stack allocators")
breaks the build on some powerpc configs, where THREAD_SIZE < PAGE_SIZE:

  kernel/fork.c:235:2: error: implicit declaration of function 'free_thread_stack'
  kernel/fork.c:355:8: error: assignment from incompatible pointer type
    stack = alloc_thread_stack_node(tsk, node);
    ^

Fix it by renaming free_stack() to free_thread_stack(), and updating the
return type of alloc_thread_stack_node().

Fixes: b235beea9e ("Clarify naming of thread info/stack allocators")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-06-25 06:01:28 -07:00
Linus Torvalds 086e3eb65e Merge branch 'akpm' (patches from Andrew)
Merge misc fixes from Andrew Morton:
 "Two weeks worth of fixes here"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (41 commits)
  init/main.c: fix initcall_blacklisted on ia64, ppc64 and parisc64
  autofs: don't get stuck in a loop if vfs_write() returns an error
  mm/page_owner: avoid null pointer dereference
  tools/vm/slabinfo: fix spelling mistake: "Ocurrences" -> "Occurrences"
  fs/nilfs2: fix potential underflow in call to crc32_le
  oom, suspend: fix oom_reaper vs. oom_killer_disable race
  ocfs2: disable BUG assertions in reading blocks
  mm, compaction: abort free scanner if split fails
  mm: prevent KASAN false positives in kmemleak
  mm/hugetlb: clear compound_mapcount when freeing gigantic pages
  mm/swap.c: flush lru pvecs on compound page arrival
  memcg: css_alloc should return an ERR_PTR value on error
  memcg: mem_cgroup_migrate() may be called with irq disabled
  hugetlb: fix nr_pmds accounting with shared page tables
  Revert "mm: disable fault around on emulated access bit architecture"
  Revert "mm: make faultaround produce old ptes"
  mailmap: add Boris Brezillon's email
  mailmap: add Antoine Tenart's email
  mm, sl[au]b: add __GFP_ATOMIC to the GFP reclaim mask
  mm: mempool: kasan: don't poot mempool objects in quarantine
  ...
2016-06-24 19:08:33 -07:00
Michal Hocko 7407054209 oom, suspend: fix oom_reaper vs. oom_killer_disable race
Tetsuo has reported the following potential oom_killer_disable vs.
oom_reaper race:

 (1) freeze_processes() starts freezing user space threads.
 (2) Somebody (maybe a kenrel thread) calls out_of_memory().
 (3) The OOM killer calls mark_oom_victim() on a user space thread
     P1 which is already in __refrigerator().
 (4) oom_killer_disable() sets oom_killer_disabled = true.
 (5) P1 leaves __refrigerator() and enters do_exit().
 (6) The OOM reaper calls exit_oom_victim(P1) before P1 can call
     exit_oom_victim(P1).
 (7) oom_killer_disable() returns while P1 not yet finished
 (8) P1 perform IO/interfere with the freezer.

This situation is unfortunate.  We cannot move oom_killer_disable after
all the freezable kernel threads are frozen because the oom victim might
depend on some of those kthreads to make a forward progress to exit so
we could deadlock.  It is also far from trivial to teach the oom_reaper
to not call exit_oom_victim() because then we would lose a guarantee of
the OOM killer and oom_killer_disable forward progress because
exit_mm->mmput might block and never call exit_oom_victim.

It seems the easiest way forward is to workaround this race by calling
try_to_freeze_tasks again after oom_killer_disable.  This will make sure
that all the tasks are frozen or it bails out.

Fixes: 449d777d7a ("mm, oom_reaper: clear TIF_MEMDIE for all tasks queued for oom_reaper")
Link: http://lkml.kernel.org/r/1466597634-16199-1-git-send-email-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-06-24 17:23:52 -07:00
Linus Torvalds b235beea9e Clarify naming of thread info/stack allocators
We've had the thread info allocated together with the thread stack for
most architectures for a long time (since the thread_info was split off
from the task struct), but that is about to change.

But the patches that move the thread info to be off-stack (and a part of
the task struct instead) made it clear how confused the allocator and
freeing functions are.

Because the common case was that we share an allocation with the thread
stack and the thread_info, the two pointers were identical.  That
identity then meant that we would have things like

	ti = alloc_thread_info_node(tsk, node);
	...
	tsk->stack = ti;

which certainly _worked_ (since stack and thread_info have the same
value), but is rather confusing: why are we assigning a thread_info to
the stack? And if we move the thread_info away, the "confusing" code
just gets to be entirely bogus.

So remove all this confusion, and make it clear that we are doing the
stack allocation by renaming and clarifying the function names to be
about the stack.  The fact that the thread_info then shares the
allocation is an implementation detail, and not really about the
allocation itself.

This is a pure renaming and type fix: we pass in the same pointer, it's
just that we clarify what the pointer means.

The ia64 code that actually only has one single allocation (for all of
task_struct, thread_info and kernel thread stack) now looks a bit odd,
but since "tsk->stack" is actually not even used there, that oddity
doesn't matter.  It would be a separate thing to clean that up, I
intentionally left the ia64 changes as a pure brute-force renaming and
type change.

Acked-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-06-24 15:09:37 -07:00
Tejun Heo feb245e304 sched/core: Allow kthreads to fall back to online && !active cpus
During CPU hotplug, CPU_ONLINE callbacks are run while the CPU is
online but not active.  A CPU_ONLINE callback may create or bind a
kthread so that its cpus_allowed mask only allows the CPU which is
being brought online.  The kthread may start executing before the CPU
is made active and can end up in select_fallback_rq().

In such cases, the expected behavior is selecting the CPU which is
coming online; however, because select_fallback_rq() only chooses from
active CPUs, it determines that the task doesn't have any viable CPU
in its allowed mask and ends up overriding it to cpu_possible_mask.

CPU_ONLINE callbacks should be able to put kthreads on the CPU which
is coming online.  Update select_fallback_rq() so that it follows
cpu_online() rather than cpu_active() for kthreads.

Reported-by: Gautham R Shenoy <ego@linux.vnet.ibm.com>
Tested-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kernel-team@fb.com
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/20160616193504.GB3262@mtj.duckdns.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-24 08:26:53 +02:00
Konstantin Khlebnikov 754bd598be sched/fair: Do not announce throttled next buddy in dequeue_task_fair()
Hierarchy could be already throttled at this point. Throttled next
buddy could trigger a NULL pointer dereference in pick_next_task_fair().

Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ben Segall <bsegall@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/146608183552.21905.15924473394414832071.stgit@buzz
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-24 08:26:45 +02:00
Konstantin Khlebnikov 094f469172 sched/fair: Initialize throttle_count for new task-groups lazily
Cgroup created inside throttled group must inherit current throttle_count.
Broken throttle_count allows to nominate throttled entries as a next buddy,
later this leads to null pointer dereference in pick_next_task_fair().

This patch initialize cfs_rq->throttle_count at first enqueue: laziness
allows to skip locking all rq at group creation. Lazy approach also allows
to skip full sub-tree scan at throttling hierarchy (not in this patch).

Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: bsegall@google.com
Link: http://lkml.kernel.org/r/146608182119.21870.8439834428248129633.stgit@buzz
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-24 08:26:44 +02:00
Paolo Bonzini 4c5ea0a9cd locking/static_key: Fix concurrent static_key_slow_inc()
The following scenario is possible:

    CPU 1                                   CPU 2
    static_key_slow_inc()
     atomic_inc_not_zero()
      -> key.enabled == 0, no increment
     jump_label_lock()
     atomic_inc_return()
      -> key.enabled == 1 now
                                            static_key_slow_inc()
                                             atomic_inc_not_zero()
                                              -> key.enabled == 1, inc to 2
                                             return
                                            ** static key is wrong!
     jump_label_update()
     jump_label_unlock()

Testing the static key at the point marked by (**) will follow the
wrong path for jumps that have not been patched yet.  This can
actually happen when creating many KVM virtual machines with userspace
LAPIC emulation; just run several copies of the following program:

    #include <fcntl.h>
    #include <unistd.h>
    #include <sys/ioctl.h>
    #include <linux/kvm.h>

    int main(void)
    {
        for (;;) {
            int kvmfd = open("/dev/kvm", O_RDONLY);
            int vmfd = ioctl(kvmfd, KVM_CREATE_VM, 0);
            close(ioctl(vmfd, KVM_CREATE_VCPU, 1));
            close(vmfd);
            close(kvmfd);
        }
        return 0;
    }

Every KVM_CREATE_VCPU ioctl will attempt a static_key_slow_inc() call.
The static key's purpose is to skip NULL pointer checks and indeed one
of the processes eventually dereferences NULL.

As explained in the commit that introduced the bug:

  706249c222 ("locking/static_keys: Rework update logic")

jump_label_update() needs key.enabled to be true.  The solution adopted
here is to temporarily make key.enabled == -1, and use go down the
slow path when key.enabled <= 0.

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@vger.kernel.org> # v4.3+
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 706249c222 ("locking/static_keys: Rework update logic")
Link: http://lkml.kernel.org/r/1466527937-69798-1-git-send-email-pbonzini@redhat.com
[ Small stylistic edits to the changelog and the code. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-24 08:23:16 +02:00
Daniel Bristot de Oliveira 82d6489d0f cgroup: Disable IRQs while holding css_set_lock
While testing the deadline scheduler + cgroup setup I hit this
warning.

[  132.612935] ------------[ cut here ]------------
[  132.612951] WARNING: CPU: 5 PID: 0 at kernel/softirq.c:150 __local_bh_enable_ip+0x6b/0x80
[  132.612952] Modules linked in: (a ton of modules...)
[  132.612981] CPU: 5 PID: 0 Comm: swapper/5 Not tainted 4.7.0-rc2 #2
[  132.612981] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.8.2-20150714_191134- 04/01/2014
[  132.612982]  0000000000000086 45c8bb5effdd088b ffff88013fd43da0 ffffffff813d229e
[  132.612984]  0000000000000000 0000000000000000 ffff88013fd43de0 ffffffff810a652b
[  132.612985]  00000096811387b5 0000000000000200 ffff8800bab29d80 ffff880034c54c00
[  132.612986] Call Trace:
[  132.612987]  <IRQ>  [<ffffffff813d229e>] dump_stack+0x63/0x85
[  132.612994]  [<ffffffff810a652b>] __warn+0xcb/0xf0
[  132.612997]  [<ffffffff810e76a0>] ? push_dl_task.part.32+0x170/0x170
[  132.612999]  [<ffffffff810a665d>] warn_slowpath_null+0x1d/0x20
[  132.613000]  [<ffffffff810aba5b>] __local_bh_enable_ip+0x6b/0x80
[  132.613008]  [<ffffffff817d6c8a>] _raw_write_unlock_bh+0x1a/0x20
[  132.613010]  [<ffffffff817d6c9e>] _raw_spin_unlock_bh+0xe/0x10
[  132.613015]  [<ffffffff811388ac>] put_css_set+0x5c/0x60
[  132.613016]  [<ffffffff8113dc7f>] cgroup_free+0x7f/0xa0
[  132.613017]  [<ffffffff810a3912>] __put_task_struct+0x42/0x140
[  132.613018]  [<ffffffff810e776a>] dl_task_timer+0xca/0x250
[  132.613027]  [<ffffffff810e76a0>] ? push_dl_task.part.32+0x170/0x170
[  132.613030]  [<ffffffff8111371e>] __hrtimer_run_queues+0xee/0x270
[  132.613031]  [<ffffffff81113ec8>] hrtimer_interrupt+0xa8/0x190
[  132.613034]  [<ffffffff81051a58>] local_apic_timer_interrupt+0x38/0x60
[  132.613035]  [<ffffffff817d9b0d>] smp_apic_timer_interrupt+0x3d/0x50
[  132.613037]  [<ffffffff817d7c5c>] apic_timer_interrupt+0x8c/0xa0
[  132.613038]  <EOI>  [<ffffffff81063466>] ? native_safe_halt+0x6/0x10
[  132.613043]  [<ffffffff81037a4e>] default_idle+0x1e/0xd0
[  132.613044]  [<ffffffff810381cf>] arch_cpu_idle+0xf/0x20
[  132.613046]  [<ffffffff810e8fda>] default_idle_call+0x2a/0x40
[  132.613047]  [<ffffffff810e92d7>] cpu_startup_entry+0x2e7/0x340
[  132.613048]  [<ffffffff81050235>] start_secondary+0x155/0x190
[  132.613049] ---[ end trace f91934d162ce9977 ]---

The warn is the spin_(lock|unlock)_bh(&css_set_lock) in the interrupt
context. Converting the spin_lock_bh to spin_lock_irq(save) to avoid
this problem - and other problems of sharing a spinlock with an
interrupt.

Cc: Tejun Heo <tj@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: cgroups@vger.kernel.org
Cc: stable@vger.kernel.org # 4.5+
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Acked-by: Zefan Li <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2016-06-23 17:23:12 -04:00
Linus Torvalds 6720a305df locking: avoid passing around 'thread_info' in mutex debugging code
None of the code actually wants a thread_info, it all wants a
task_struct, and it's just converting back and forth between the two
("ti->task" to get the task_struct from the thread_info, and
"task_thread_info(task)" to go the other way).

No semantic change.

Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-06-23 12:11:17 -07:00
Jon Hunter d16dcd3d18 irqdomain: Fix disposal of mappings for interrupt hierarchies
The function irq_create_of_mapping() is used to create an interrupt
mapping. However, depending on whether the irqdomain, to which the
interrupt belongs, is part of a hierarchy, determines whether the
mapping is created via calling irq_domain_alloc_irqs() or
irq_create_mapping().

To dispose of the interrupt mapping, drivers call irq_dispose_mapping().
However, this function does not check to see if the irqdomain is part
of a hierarchy or not and simply assumes that it was mapped via calling
irq_create_mapping() so calls irq_domain_disassociate() to unmap the
interrupt.

Fix this by checking to see if the irqdomain is part of a hierarchy and
if so call irq_domain_free_irqs() to free/unmap the interrupt.

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Link: http://lkml.kernel.org/r/1466501002-16368-1-git-send-email-jonathanh@nvidia.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-06-23 10:21:06 +02:00
Linus Torvalds f780f00d72 Two fixes for the tracing system.
o When trace_printk() is used with a non constant format descriptor,
    it adds a NULL pointer into the trace format section, and the code
    isn't prepared to deal with it. This bug appeared by a change that
    was added in v3.5.
 
  o The ftracetest (selftests section) can't handle testing histograms
    when histograms are not configured. Currently it shows that they
    fail the test, when they should state that they are unsupported.
    This bug was added in the 4.7 merge window with the addition of
    the historgram code.
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Merge tag 'trace-v4.7-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fixes from Steven Rostedt:
 "Two fixes for the tracing system:

   - When trace_printk() is used with a non constant format descriptor,
     it adds a NULL pointer into the trace format section, and the code
     isn't prepared to deal with it.  This bug appeared by a change that
     was added in v3.5.

   - The ftracetest (selftests section) can't handle testing histograms
     when histograms are not configured.  Currently it shows that they
     fail the test, when they should state that they are unsupported.
     This bug was added in the 4.7 merge window with the addition of the
     historgram code"

* tag 'trace-v4.7-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  ftracetest: Fix hist unsupported result in hist selftests
  tracing: Handle NULL formats in hold_module_trace_bprintk_format()
2016-06-20 10:35:48 -07:00
Steven Rostedt (Red Hat) 70c8217acd tracing: Handle NULL formats in hold_module_trace_bprintk_format()
If a task uses a non constant string for the format parameter in
trace_printk(), then the trace_printk_fmt variable is set to NULL. This
variable is then saved in the __trace_printk_fmt section.

The function hold_module_trace_bprintk_format() checks to see if duplicate
formats are used by modules, and reuses them if so (saves them to the list
if it is new). But this function calls lookup_format() that does a strcmp()
to the value (which is now NULL) and can cause a kernel oops.

This wasn't an issue till 3debb0a9dd ("tracing: Fix trace_printk() to print
when not using bprintk()") which added "__used" to the trace_printk_fmt
variable, and before that, the kernel simply optimized it out (no NULL value
was saved).

The fix is simply to handle the NULL pointer in lookup_format() and have the
caller ignore the value if it was NULL.

Link: http://lkml.kernel.org/r/1464769870-18344-1-git-send-email-zhengjun.xing@intel.com

Reported-by: xingzhen <zhengjun.xing@intel.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Fixes: 3debb0a9dd ("tracing: Fix trace_printk() to print when not using bprintk()")
Cc: stable@vger.kernel.org # v3.5+
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-06-20 09:46:12 -04:00
Peter Zijlstra 8974189222 sched/fair: Fix cfs_rq avg tracking underflow
As per commit:

  b7fa30c9cc ("sched/fair: Fix post_init_entity_util_avg() serialization")

> the code generated from update_cfs_rq_load_avg():
>
> 	if (atomic_long_read(&cfs_rq->removed_load_avg)) {
> 		s64 r = atomic_long_xchg(&cfs_rq->removed_load_avg, 0);
> 		sa->load_avg = max_t(long, sa->load_avg - r, 0);
> 		sa->load_sum = max_t(s64, sa->load_sum - r * LOAD_AVG_MAX, 0);
> 		removed_load = 1;
> 	}
>
> turns into:
>
> ffffffff81087064:       49 8b 85 98 00 00 00    mov    0x98(%r13),%rax
> ffffffff8108706b:       48 85 c0                test   %rax,%rax
> ffffffff8108706e:       74 40                   je     ffffffff810870b0 <update_blocked_averages+0xc0>
> ffffffff81087070:       4c 89 f8                mov    %r15,%rax
> ffffffff81087073:       49 87 85 98 00 00 00    xchg   %rax,0x98(%r13)
> ffffffff8108707a:       49 29 45 70             sub    %rax,0x70(%r13)
> ffffffff8108707e:       4c 89 f9                mov    %r15,%rcx
> ffffffff81087081:       bb 01 00 00 00          mov    $0x1,%ebx
> ffffffff81087086:       49 83 7d 70 00          cmpq   $0x0,0x70(%r13)
> ffffffff8108708b:       49 0f 49 4d 70          cmovns 0x70(%r13),%rcx
>
> Which you'll note ends up with sa->load_avg -= r in memory at
> ffffffff8108707a.

So I _should_ have looked at other unserialized users of ->load_avg,
but alas. Luckily nikbor reported a similar /0 from task_h_load() which
instantly triggered recollection of this here problem.

Aside from the intermediate value hitting memory and causing problems,
there's another problem: the underflow detection relies on the signed
bit. This reduces the effective width of the variables, IOW its
effectively the same as having these variables be of signed type.

This patch changes to a different means of unsigned underflow
detection to not rely on the signed bit. This allows the variables to
use the 'full' unsigned range. And it does so with explicit LOAD -
STORE to ensure any intermediate value will never be visible in
memory, allowing these unserialized loads.

Note: GCC generates crap code for this, might warrant a look later.

Note2: I say 'full' above, if we end up at U*_MAX we'll still explode;
       maybe we should do clamping on add too.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yuyang Du <yuyang.du@intel.com>
Cc: bsegall@google.com
Cc: kernel@kyup.com
Cc: morten.rasmussen@arm.com
Cc: pjt@google.com
Cc: steve.muckle@linaro.org
Fixes: 9d89c257df ("sched/fair: Rewrite runnable load and utilization average tracking")
Link: http://lkml.kernel.org/r/20160617091948.GJ30927@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-20 11:29:09 +02:00
Keith Busch edd14cfebc genirq: Add untracked irq handler
This adds a software irq handler for controllers that multiplex
interrupts from multiple devices, but don't know which device generated
the interrupt. For these devices, the irq handler that demuxes must
check every action for every software irq using the same h/w irq in order
to find out which device generated the interrupt. This will inevitably
trigger spurious interrupt detection if we are noting the irq.

The new irq handler does not track the handling for spurious interrupt
detection. An irq that uses this also won't get stats tracked since it
didn't generate the interrupt, nor added to randomness since they are
not random.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-pci@vger.kernel.org
Cc: Jon Derrick <jonathan.derrick@intel.com>
Link: http://lkml.kernel.org/r/1466200821-29159-1-git-send-email-keith.busch@intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-06-18 10:00:55 +02:00
Tejun Heo 8fa3b8d689 cgroup: set css->id to -1 during init
If percpu_ref initialization fails during css_create(), the free path
can end up trying to free css->id of zero.  As ID 0 is unused, it
doesn't cause a critical breakage but it does trigger a warning
message.  Fix it by setting css->id to -1 from init_and_link_css().

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Wenwei Tao <ww.tao0320@gmail.com>
Fixes: 01e586598b ("cgroup: release css->id after css_free")
Cc: stable@vger.kernel.org # v4.0+
Signed-off-by: Tejun Heo <tj@kernel.org>
2016-06-16 17:59:35 -04:00
Alexei Starovoitov ad572d1747 bpf, trace: check event type in bpf_perf_event_read
similar to bpf_perf_event_output() the bpf_perf_event_read() helper
needs to check the type of the perf_event before reading the counter.

Fixes: a43eec3042 ("bpf: introduce bpf_perf_event_output() helper")
Reported-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-15 23:37:54 -07:00
Alexei Starovoitov 19de99f70b bpf: fix matching of data/data_end in verifier
The ctx structure passed into bpf programs is different depending on bpf
program type. The verifier incorrectly marked ctx->data and ctx->data_end
access based on ctx offset only. That caused loads in tracing programs
int bpf_prog(struct pt_regs *ctx) { .. ctx->ax .. }
to be incorrectly marked as PTR_TO_PACKET which later caused verifier
to reject the program that was actually valid in tracing context.
Fix this by doing program type specific matching of ctx offsets.

Fixes: 969bf05eb3 ("bpf: direct packet access")
Reported-by: Sasha Goldshtein <goldshtn@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-15 23:37:54 -07:00
Nicolai Stange df4565f9eb kernel/kcov: unproxify debugfs file's fops
Since commit 49d200deaa ("debugfs: prevent access to removed files'
private data"), a debugfs file's file_operations methods get proxied
through lifetime aware wrappers.

However, only a certain subset of the file_operations members is supported
by debugfs and ->mmap isn't among them -- it appears to be NULL from the
VFS layer's perspective.

This behaviour breaks the /sys/kernel/debug/kcov file introduced
concurrently with commit 5c9a8750a6 ("kernel: add kcov code coverage").

Since that file never gets removed, there is no file removal race and thus,
a lifetime checking proxy isn't needed.

Avoid the proxying for /sys/kernel/debug/kcov by creating it via
debugfs_create_file_unsafe() rather than debugfs_create_file().

Fixes: 49d200deaa ("debugfs: prevent access to removed files' private data")
Fixes: 5c9a8750a6 ("kernel: add kcov code coverage")
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Nicolai Stange <nicstange@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-06-15 04:56:35 -07:00
Andrey Ryabinin 57675cb976 kernel/sysrq, watchdog, sched/core: Reset watchdog on all CPUs while processing sysrq-w
Lengthy output of sysrq-w may take a lot of time on slow serial console.

Currently we reset NMI-watchdog on the current CPU to avoid spurious
lockup messages. Sometimes this doesn't work since softlockup watchdog
might trigger on another CPU which is waiting for an IPI to proceed.
We reset softlockup watchdogs on all CPUs, but we do this only after
listing all tasks, and this may be too late on a busy system.

So, reset watchdogs CPUs earlier, in for_each_process_thread() loop.

Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/1465474805-14641-1-git-send-email-aryabinin@virtuozzo.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-14 12:48:38 +02:00
Josh Poimboeuf eda8dca519 sched/debug: Fix deadlock when enabling sched events
I see a hang when enabling sched events:

  echo 1 > /sys/kernel/debug/tracing/events/sched/enable

The printk buffer shows:

  BUG: spinlock recursion on CPU#1, swapper/1/0
   lock: 0xffff88007d5d8c00, .magic: dead4ead, .owner: swapper/1/0, .owner_cpu: 1
  CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.7.0-rc2+ #1
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.8.1-20150318_183358- 04/01/2014
  ...
  Call Trace:
   <IRQ>  [<ffffffff8143d663>] dump_stack+0x85/0xc2
   [<ffffffff81115948>] spin_dump+0x78/0xc0
   [<ffffffff81115aea>] do_raw_spin_lock+0x11a/0x150
   [<ffffffff81891471>] _raw_spin_lock+0x61/0x80
   [<ffffffff810e5466>] ? try_to_wake_up+0x256/0x4e0
   [<ffffffff810e5466>] try_to_wake_up+0x256/0x4e0
   [<ffffffff81891a0a>] ? _raw_spin_unlock_irqrestore+0x4a/0x80
   [<ffffffff810e5705>] wake_up_process+0x15/0x20
   [<ffffffff810cebb4>] insert_work+0x84/0xc0
   [<ffffffff810ced7f>] __queue_work+0x18f/0x660
   [<ffffffff810cf9a6>] queue_work_on+0x46/0x90
   [<ffffffffa00cd95b>] drm_fb_helper_dirty.isra.11+0xcb/0xe0 [drm_kms_helper]
   [<ffffffffa00cdac0>] drm_fb_helper_sys_imageblit+0x30/0x40 [drm_kms_helper]
   [<ffffffff814babcd>] soft_cursor+0x1ad/0x230
   [<ffffffff814ba379>] bit_cursor+0x649/0x680
   [<ffffffff814b9d30>] ? update_attr.isra.2+0x90/0x90
   [<ffffffff814b5e6a>] fbcon_cursor+0x14a/0x1c0
   [<ffffffff81555ef8>] hide_cursor+0x28/0x90
   [<ffffffff81558b6f>] vt_console_print+0x3bf/0x3f0
   [<ffffffff81122c63>] call_console_drivers.constprop.24+0x183/0x200
   [<ffffffff811241f4>] console_unlock+0x3d4/0x610
   [<ffffffff811247f5>] vprintk_emit+0x3c5/0x610
   [<ffffffff81124bc9>] vprintk_default+0x29/0x40
   [<ffffffff811e965b>] printk+0x57/0x73
   [<ffffffff810f7a9e>] enqueue_entity+0xc2e/0xc70
   [<ffffffff810f7b39>] enqueue_task_fair+0x59/0xab0
   [<ffffffff8106dcd9>] ? kvm_sched_clock_read+0x9/0x20
   [<ffffffff8103fb39>] ? sched_clock+0x9/0x10
   [<ffffffff810e3fcc>] activate_task+0x5c/0xa0
   [<ffffffff810e4514>] ttwu_do_activate+0x54/0xb0
   [<ffffffff810e5cea>] sched_ttwu_pending+0x7a/0xb0
   [<ffffffff810e5e51>] scheduler_ipi+0x61/0x170
   [<ffffffff81059e7f>] smp_trace_reschedule_interrupt+0x4f/0x2a0
   [<ffffffff81893ba6>] trace_reschedule_interrupt+0x96/0xa0
   <EOI>  [<ffffffff8106e0d6>] ? native_safe_halt+0x6/0x10
   [<ffffffff8110fb1d>] ? trace_hardirqs_on+0xd/0x10
   [<ffffffff81040ac0>] default_idle+0x20/0x1a0
   [<ffffffff8104147f>] arch_cpu_idle+0xf/0x20
   [<ffffffff81102f8f>] default_idle_call+0x2f/0x50
   [<ffffffff8110332e>] cpu_startup_entry+0x37e/0x450
   [<ffffffff8105af70>] start_secondary+0x160/0x1a0

Note the hang only occurs when echoing the above from a physical serial
console, not from an ssh session.

The bug is caused by a deadlock where the task is trying to grab the rq
lock twice because printk()'s aren't safe in sched code.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Fixes: cb2517653f ("sched/debug: Make schedstats a runtime tunable that is disabled by default")
Link: http://lkml.kernel.org/r/20160613073209.gdvdybiruljbkn3p@treble
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-14 12:47:21 +02:00
Peter Zijlstra b7fa30c9cc sched/fair: Fix post_init_entity_util_avg() serialization
Chris Wilson reported a divide by 0 at:

 post_init_entity_util_avg():

 >    725	if (cfs_rq->avg.util_avg != 0) {
 >    726		sa->util_avg  = cfs_rq->avg.util_avg * se->load.weight;
 > -> 727		sa->util_avg /= (cfs_rq->avg.load_avg + 1);
 >    728
 >    729		if (sa->util_avg > cap)
 >    730			sa->util_avg = cap;
 >    731	} else {

Which given the lack of serialization, and the code generated from
update_cfs_rq_load_avg() is entirely possible:

	if (atomic_long_read(&cfs_rq->removed_load_avg)) {
		s64 r = atomic_long_xchg(&cfs_rq->removed_load_avg, 0);
		sa->load_avg = max_t(long, sa->load_avg - r, 0);
		sa->load_sum = max_t(s64, sa->load_sum - r * LOAD_AVG_MAX, 0);
		removed_load = 1;
	}

turns into:

  ffffffff81087064:       49 8b 85 98 00 00 00    mov    0x98(%r13),%rax
  ffffffff8108706b:       48 85 c0                test   %rax,%rax
  ffffffff8108706e:       74 40                   je     ffffffff810870b0
  ffffffff81087070:       4c 89 f8                mov    %r15,%rax
  ffffffff81087073:       49 87 85 98 00 00 00    xchg   %rax,0x98(%r13)
  ffffffff8108707a:       49 29 45 70             sub    %rax,0x70(%r13)
  ffffffff8108707e:       4c 89 f9                mov    %r15,%rcx
  ffffffff81087081:       bb 01 00 00 00          mov    $0x1,%ebx
  ffffffff81087086:       49 83 7d 70 00          cmpq   $0x0,0x70(%r13)
  ffffffff8108708b:       49 0f 49 4d 70          cmovns 0x70(%r13),%rcx

Which you'll note ends up with 'sa->load_avg - r' in memory at
ffffffff8108707a.

By calling post_init_entity_util_avg() under rq->lock we're sure to be
fully serialized against PELT updates and cannot observe intermediate
state like this.

Reported-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yuyang Du <yuyang.du@intel.com>
Cc: bsegall@google.com
Cc: morten.rasmussen@arm.com
Cc: pjt@google.com
Cc: steve.muckle@linaro.org
Fixes: 2b8c41daba ("sched/fair: Initiate a new task's util avg to a bounded value")
Link: http://lkml.kernel.org/r/20160609130750.GQ30909@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-14 10:58:34 +02:00
Thomas Gleixner a5c8a01968 First drop of irqchip updates for 4.8:
- Fix a few bugs in configuring the default trigger from the irqdomain layer
 - Make the genirq layer PM aware
 - Add PM capability to the ARM GIC driver
 - Add support for 2-level translation tables to the GICv3 ITS driver
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Merge tag 'irqchip-for-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms into irq/core

First drop of irqchip updates for 4.8 from Marc Zyngier:

 - Fix a few bugs in configuring the default trigger from the irqdomain layer
 - Make the genirq layer PM aware
 - Add PM capability to the ARM GIC driver
 - Add support for 2-level translation tables to the GICv3 ITS driver
2016-06-13 16:34:16 +02:00
Jon Hunter be45beb2df genirq: Add runtime power management support for IRQ chips
Some IRQ chips may be located in a power domain outside of the CPU
subsystem and hence will require device specific runtime power
management. In order to support such IRQ chips, add a pointer for a
device structure to the irq_chip structure, and if this pointer is
populated by the IRQ chip driver and CONFIG_PM is selected in the kernel
configuration, then the pm_runtime_get/put APIs for this chip will be
called when an IRQ is requested/freed, respectively.

Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-06-13 11:53:51 +01:00
Jon Hunter 1e2a7d7849 irqdomain: Don't set type when mapping an IRQ
Some IRQ chips, such as GPIO controllers or secondary level interrupt
controllers, may require require additional runtime power management
control to ensure they are accessible. For such IRQ chips, it makes sense
to enable the IRQ chip when interrupts are requested and disabled them
again once all interrupts have been freed.

When mapping an IRQ, the IRQ type settings are read and then programmed.
The mapping of the IRQ happens before the IRQ is requested and so the
programming of the type settings occurs before the IRQ is requested. This
is a problem for IRQ chips that require additional power management
control because they may not be accessible yet. Therefore, when mapping
the IRQ, don't program the type settings, just save them and then program
these saved settings when the IRQ is requested (so long as if they are not
overridden via the call to request the IRQ).

Add a stub function for irq_domain_free_irqs() to avoid any compilation
errors when CONFIG_IRQ_DOMAIN_HIERARCHY is not selected.

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-06-13 11:53:51 +01:00
Marc Zyngier f35ad08378 genirq: Look-up percpu trigger type if not specified by caller
As we now do for non-percpu interrupt, perform a lookup of the
interrupt trigger if the user doesn't supply one. The difference
here is that we can only do it at enable time (trigger configuration
can be per-cpu as well).

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-06-13 11:53:51 +01:00
Jon Hunter 4b357daed6 genirq: Look-up trigger type if not specified by caller
For some devices the IRQ trigger type for a device is read from
firmware, such as device-tree. The IRQ trigger type is typically read
when the mapping for IRQ is created, which is before the IRQ is
requested. Hence, the IRQ trigger type is programmed when mapping the
IRQ and not when requesting the IRQ.

Although this works for most cases, in order to support IRQ chips which
require runtime power management, which may not be accessible prior
to requesting the IRQ, it is desirable to look-up the IRQ trigger type
when it is requested. Therefore, if the IRQ trigger type is not
specified when __setup_irq() is called, look-up the saved IRQ trigger
type. This will allow us to defer the programming of the trigger type
from when the IRQ is mapped to when it is actually requested.

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-06-13 11:53:51 +01:00
Jon Hunter b62b2cf575 irqdomain: Fix handling of type settings for existing mappings
When mapping an IRQ, it is possible that a mapping for the IRQ already
exists. If mapping does exist then there are the following issues with
regard to the handling of the IRQ type settings ...
1. If the domain is part of a hierarchy, then:
   a. We do not check that the type settings for the existing mapping
      match those of the new mapping.
   b. We do not check to see if the type settings have been programmed
      yet (and they might not have been) and so we may never set the
      type.
2. If the domain is NOT part of a hierarchy, we will overwrite the
   current type settings programmed if they are different from the
   previous mapping. Please note that irq_create_mapping()
   calls irq_find_mapping() to check if a mapping already exists.

Although, it may be unlikely that the type settings for a shared
interrupt would not match, nonetheless we should check for this.
Therefore, to fix this check if a mapping exists (regardless of whether
the domain is part of a hierarchy or not) and if it does then:
1. Return the IRQ number if the type settings match or are not
   specified.
2. Program the type settings and return the IRQ number if the type
   settings have not been programmed yet.
3. Otherwise if the type setting do not match, then print a warning
   and don't return the IRQ number.

Furthermore, add a warning if the type return by irq_domain_translate()
has bits outside the sense mask set and then clear these bits. If these
bits are not cleared then this will cause the comparision of the type
settings for an existing mapping to fail with that of the new mapping
even if the sense bit themselves match. The reason being is that the
existing type settings are read by calling irq_get_trigger_type() which
will clear any bits outside the sense mask. This will allow us to detect
irqchips that are not correctly clearing these bits and fix them.

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-06-13 11:53:50 +01:00
Linus Torvalds f5364c150a Merge branch 'stacking-fixes' (vfs stacking fixes from Jann)
Merge filesystem stacking fixes from Jann Horn.

* emailed patches from Jann Horn <jannh@google.com>:
  sched: panic on corrupted stack end
  ecryptfs: forbid opening files without mmap handler
  proc: prevent stacking filesystems on top
2016-06-10 12:10:02 -07:00
Jann Horn 29d6455178 sched: panic on corrupted stack end
Until now, hitting this BUG_ON caused a recursive oops (because oops
handling involves do_exit(), which calls into the scheduler, which in
turn raises an oops), which caused stuff below the stack to be
overwritten until a panic happened (e.g.  via an oops in interrupt
context, caused by the overwritten CPU index in the thread_info).

Just panic directly.

Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-06-10 12:09:43 -07:00
Linus Torvalds 60e383037b Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:
 "Two scheduler debugging fixes"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/debug: Fix 'schedstats=enable' cmdline option
  sched/debug: Fix /proc/sched_debug regression
2016-06-10 11:24:39 -07:00