linux-toradex.git/include, branch v4.2.4

sched/preempt: Fix cond_resched_lock() and cond_resched_softirq()

2015-10-22T21:49:35+00:00

commit fe32d3cd5e8eb0f82e459763374aa80797023403 upstream.

These functions check should_resched() before unlocking spinlock/bh-enable:
preempt_count always non-zero => should_resched() always returns false.
cond_resched_lock() worked iff spin_needbreak is set.

This patch adds argument "preempt_offset" to should_resched().

preempt_count offset constants for that:

  PREEMPT_DISABLE_OFFSET  - offset after preempt_disable()
  PREEMPT_LOCK_OFFSET     - offset after spin_lock()
  SOFTIRQ_DISABLE_OFFSET  - offset after local_bh_distable()
  SOFTIRQ_LOCK_OFFSET     - offset after spin_lock_bh()

Signed-off-by: Konstantin Khlebnikov 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Alexander Graf 
Cc: Boris Ostrovsky 
Cc: David Vrabel 
Cc: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Fixes: bdb438065890 ("sched: Extract the basic add/sub preempt_count modifiers")
Link: http://lkml.kernel.org/r/20150715095204.12246.98268.stgit@buzz
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

security: fix typo in security_task_prctl

2015-10-22T21:49:29+00:00

commit b7f76ea2ef6739ee484a165ffbac98deb855d3d3 upstream.

Signed-off-by: Jann Horn 
Reviewed-by: Andy Lutomirski 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

netfilter: conntrack: use nf_ct_tmpl_free in CT/synproxy error paths

2015-10-22T21:49:23+00:00

commit 9cf94eab8b309e8bcc78b41dd1561c75b537dd0b upstream.

Commit 0838aa7fcfcd ("netfilter: fix netns dependencies with conntrack
templates") migrated templates to the new allocator api, but forgot to
update error paths for them in CT and synproxy to use nf_ct_tmpl_free()
instead of nf_conntrack_free().

Due to that, memory is being freed into the wrong kmemcache, but also
we drop the per net reference count of ct objects causing an imbalance.

In Brad's case, this leads to a wrap-around of net->ct.count and thus
lets __nf_conntrack_alloc() refuse to create a new ct object:

  [   10.340913] xt_addrtype: ipv6 does not support BROADCAST matching
  [   10.810168] nf_conntrack: table full, dropping packet
  [   11.917416] r8169 0000:07:00.0 eth0: link up
  [   11.917438] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready
  [   12.815902] nf_conntrack: table full, dropping packet
  [   15.688561] nf_conntrack: table full, dropping packet
  [   15.689365] nf_conntrack: table full, dropping packet
  [   15.690169] nf_conntrack: table full, dropping packet
  [   15.690967] nf_conntrack: table full, dropping packet
  [...]

With slab debugging, it also reports the wrong kmemcache (kmalloc-512 vs.
nf_conntrack_ffffffff81ce75c0) and reports poison overwrites, etc. Thus,
to fix the problem, export and use nf_ct_tmpl_free() instead.

Fixes: 0838aa7fcfcd ("netfilter: fix netns dependencies with conntrack templates")
Reported-by: Brad Jackson 
Signed-off-by: Daniel Borkmann 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Greg Kroah-Hartman

netfilter: nf_tables: Use 32 bit addressing register from nft_type_to_reg()

2015-10-22T21:49:23+00:00

commit bf798657eb5ba57552096843c315f096fdf9b715 upstream.

nft_type_to_reg() needs to return the register in the new 32 bit addressing,
otherwise we hit EINVAL when using mappings.

Fixes: 49499c3 ("netfilter: nf_tables: switch registers to 32 bit addressing")
Reported-by: Andreas Schultz 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Greg Kroah-Hartman

netfilter: bridge: fix IPv6 packets not being bridged with CONFIG_IPV6=n

2015-10-22T21:49:23+00:00

commit 18e1db67e93ed75d9dc0d34c8d783ccf10547c2b upstream.

230ac490f7fba introduced a dependency to CONFIG_IPV6 which breaks bridging
of IPv6 packets on a bridge with CONFIG_IPV6=n.

Sysctl entry /proc/sys/net/bridge/bridge-nf-call-ip6tables defaults to 1,
for this reason packets are handled by br_nf_pre_routing_ipv6(). When compiled
with CONFIG_IPV6=n this function returns NF_DROP but should return NF_ACCEPT
to let packets through.

Change CONFIG_IPV6=n br_nf_pre_routing_ipv6() return value to NF_ACCEPT.

Tested with a simple bridge with two interfaces and IPv6 packets trying
to pass from host on left side to host on right side of the bridge.

Fixes: 230ac490f7fba ("netfilter: bridge: split ipv6 code into separated file")
Signed-off-by: Bernhard Thaler 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Greg Kroah-Hartman

memcg: fix dirty page migration

2015-10-22T21:49:20+00:00

commit 0610c25daa3e76e38ad5a8fae683a89ff9f71798 upstream.

The problem starts with a file backed dirty page which is charged to a
memcg.  Then page migration is used to move oldpage to newpage.

Migration:
 - copies the oldpage's data to newpage
 - clears oldpage.PG_dirty
 - sets newpage.PG_dirty
 - uncharges oldpage from memcg
 - charges newpage to memcg

Clearing oldpage.PG_dirty decrements the charged memcg's dirty page
count.

However, because newpage is not yet charged, setting newpage.PG_dirty
does not increment the memcg's dirty page count.  After migration
completes newpage.PG_dirty is eventually cleared, often in
account_page_cleaned().  At this time newpage is charged to a memcg so
the memcg's dirty page count is decremented which causes underflow
because the count was not previously incremented by migration.  This
underflow causes balance_dirty_pages() to see a very large unsigned
number of dirty memcg pages which leads to aggressive throttling of
buffered writes by processes in non root memcg.

This issue:
 - can harm performance of non root memcg buffered writes.
 - can report too small (even negative) values in
   memory.stat[(total_)dirty] counters of all memcg, including the root.

To avoid polluting migrate.c with #ifdef CONFIG_MEMCG checks, introduce
page_memcg() and set_page_memcg() helpers.

Test:
    0) setup and enter limited memcg
    mkdir /sys/fs/cgroup/test
    echo 1G > /sys/fs/cgroup/test/memory.limit_in_bytes
    echo $$ > /sys/fs/cgroup/test/cgroup.procs

    1) buffered writes baseline
    dd if=/dev/zero of=/data/tmp/foo bs=1M count=1k
    sync
    grep ^dirty /sys/fs/cgroup/test/memory.stat

    2) buffered writes with compaction antagonist to induce migration
    yes 1 > /proc/sys/vm/compact_memory &
    rm -rf /data/tmp/foo
    dd if=/dev/zero of=/data/tmp/foo bs=1M count=1k
    kill %
    sync
    grep ^dirty /sys/fs/cgroup/test/memory.stat

    3) buffered writes without antagonist, should match baseline
    rm -rf /data/tmp/foo
    dd if=/dev/zero of=/data/tmp/foo bs=1M count=1k
    sync
    grep ^dirty /sys/fs/cgroup/test/memory.stat

                       (speed, dirty residue)
             unpatched                       patched
    1) 841 MB/s 0 dirty pages          886 MB/s 0 dirty pages
    2) 611 MB/s -33427456 dirty pages  793 MB/s 0 dirty pages
    3) 114 MB/s -33427456 dirty pages  891 MB/s 0 dirty pages

    Notice that unpatched baseline performance (1) fell after
    migration (3): 841 -> 114 MB/s.  In the patched kernel, post
    migration performance matches baseline.

Fixes: c4843a7593a9 ("memcg: add per cgroup dirty page accounting")
Signed-off-by: Greg Thelen 
Reported-by: Dave Hansen 
Acked-by: Michal Hocko 
Acked-by: Johannes Weiner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

Revert "sched, cgroup: replace signal_struct->group_rwsem with a global percpu_rwsem"

2015-10-22T21:49:19+00:00

commit 0c986253b939cc14c69d4adbe2b4121bdf4aa220 upstream.

This reverts commit d59cfc09c32a2ae31f1c3bc2983a0cd79afb3f14.

d59cfc09c32a ("sched, cgroup: replace signal_struct->group_rwsem with
a global percpu_rwsem") and b5ba75b5fc0e ("cgroup: simplify
threadgroup locking") changed how cgroup synchronizes against task
fork and exits so that it uses global percpu_rwsem instead of
per-process rwsem; unfortunately, the write [un]lock paths of
percpu_rwsem always involve synchronize_rcu_expedited() which turned
out to be too expensive.

Improvements for percpu_rwsem are scheduled to be merged in the coming
v4.4-rc1 merge window which alleviates this issue.  For now, revert
the two commits to restore per-process rwsem.  They will be re-applied
for the v4.4-rc1 merge window.

Signed-off-by: Tejun Heo 
Link: http://lkml.kernel.org/g/55F8097A.7000206@de.ibm.com
Reported-by: Christian Borntraeger 
Cc: Oleg Nesterov 
Cc: "Paul E. McKenney" 
Cc: Peter Zijlstra 
Cc: Paolo Bonzini 
Signed-off-by: Greg Kroah-Hartman

x86/xen: Support kexec/kdump in HVM guests by doing a soft reset

2015-10-22T21:49:19+00:00

commit 0b34a166f291d255755be46e43ed5497cdd194f2 upstream.

Currently there is a number of issues preventing PVHVM Xen guests from
doing successful kexec/kdump:

  - Bound event channels.
  - Registered vcpu_info.
  - PIRQ/emuirq mappings.
  - shared_info frame after XENMAPSPACE_shared_info operation.
  - Active grant mappings.

Basically, newly booted kernel stumbles upon already set up Xen
interfaces and there is no way to reestablish them. In Xen-4.7 a new
feature called 'soft reset' is coming. A guest performing kexec/kdump
operation is supposed to call SCHEDOP_shutdown hypercall with
SHUTDOWN_soft_reset reason before jumping to new kernel. Hypervisor
(with some help from toolstack) will do full domain cleanup (but
keeping its memory and vCPU contexts intact) returning the guest to
the state it had when it was first booted and thus allowing it to
start over.

Doing SHUTDOWN_soft_reset on Xen hypervisors which don't support it is
probably OK as by default all unknown shutdown reasons cause domain
destroy with a message in toolstack log: 'Unknown shutdown reason code
5. Destroying domain.'  which gives a clue to what the problem is and
eliminates false expectations.

Signed-off-by: Vitaly Kuznetsov 
Signed-off-by: David Vrabel 
Signed-off-by: Greg Kroah-Hartman

locking/qspinlock/x86: Fix performance regression under unaccelerated VMs

2015-10-22T21:49:15+00:00

commit 43b3f02899f74ae9914a39547cc5492156f0027a upstream.

Dave ran into horrible performance on a VM without PARAVIRT_SPINLOCKS
set and Linus noted that the test-and-set implementation was retarded.

One should spin on the variable with a load, not a RMW.

While there, remove 'queued' from the name, as the lock isn't queued
at all, but a simple test-and-set.

Suggested-by: Linus Torvalds 
Reported-by: Dave Chinner 
Tested-by: Dave Chinner 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Waiman Long 
Link: http://lkml.kernel.org/r/20150904152523.GR18673@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

target/iscsi: Fix np_ip bracket issue by removing np_ip

2015-10-22T21:49:14+00:00

commit 76c28f1fcfeb42b47f798fe498351ee1d60086ae upstream.

Revert commit 1997e6259, which causes double brackets on ipv6
inaddr_any addresses.

Since we have np_sockaddr, if we need a textual representation we can
use "%pISc".

Change iscsit_add_network_portal() and iscsit_add_np() signatures to remove
*ip_str parameter.

Fix and extend some comments earlier in the function.

Tested to work for :: and ::1 via iscsiadm, previously :: failed, see
https://bugzilla.redhat.com/show_bug.cgi?id=1249107 .

Signed-off-by: Andy Grover 
Signed-off-by: Nicholas Bellinger 
Signed-off-by: Greg Kroah-Hartman