linux.git, branch v3.10.27

Linux 3.10.27

2014-01-15T23:29:14+00:00

sched: Guarantee new group-entities always have weight

2014-01-15T23:28:54+00:00

commit 0ac9b1c21874d2490331233b3242085f8151e166 upstream.

Currently, group entity load-weights are initialized to zero. This
admits some races with respect to the first time they are re-weighted in
earlty use. ( Let g[x] denote the se for "g" on cpu "x". )

Suppose that we have root->a and that a enters a throttled state,
immediately followed by a[0]->t1 (the only task running on cpu[0])
blocking:

  put_prev_task(group_cfs_rq(a[0]), t1)
  put_prev_entity(..., t1)
  check_cfs_rq_runtime(group_cfs_rq(a[0]))
  throttle_cfs_rq(group_cfs_rq(a[0]))

Then, before unthrottling occurs, let a[0]->b[0]->t2 wake for the first
time:

  enqueue_task_fair(rq[0], t2)
  enqueue_entity(group_cfs_rq(b[0]), t2)
  enqueue_entity_load_avg(group_cfs_rq(b[0]), t2)
  account_entity_enqueue(group_cfs_ra(b[0]), t2)
  update_cfs_shares(group_cfs_rq(b[0]))
  < skipped because b is part of a throttled hierarchy >
  enqueue_entity(group_cfs_rq(a[0]), b[0])
  ...

We now have b[0] enqueued, yet group_cfs_rq(a[0])->load.weight == 0
which violates invariants in several code-paths. Eliminate the
possibility of this by initializing group entity weight.

Signed-off-by: Paul Turner 
Signed-off-by: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20131016181627.22647.47543.stgit@sword-of-the-dawn.mtv.corp.google.com
Signed-off-by: Ingo Molnar 
Cc: Chris J Arges 
Signed-off-by: Greg Kroah-Hartman

sched: Fix hrtimer_cancel()/rq->lock deadlock

2014-01-15T23:28:54+00:00

commit 927b54fccbf04207ec92f669dce6806848cbec7d upstream.

__start_cfs_bandwidth calls hrtimer_cancel while holding rq->lock,
waiting for the hrtimer to finish. However, if sched_cfs_period_timer
runs for another loop iteration, the hrtimer can attempt to take
rq->lock, resulting in deadlock.

Fix this by ensuring that cfs_b->timer_active is cleared only if the
_latest_ call to do_sched_cfs_period_timer is returning as idle. Then
__start_cfs_bandwidth can just call hrtimer_try_to_cancel and wait for
that to succeed or timer_active == 1.

Signed-off-by: Ben Segall 
Signed-off-by: Peter Zijlstra 
Cc: pjt@google.com
Link: http://lkml.kernel.org/r/20131016181622.22647.16643.stgit@sword-of-the-dawn.mtv.corp.google.com
Signed-off-by: Ingo Molnar 
Cc: Chris J Arges 
Signed-off-by: Greg Kroah-Hartman

sched: Fix cfs_bandwidth misuse of hrtimer_expires_remaining

2014-01-15T23:28:54+00:00

commit db06e78cc13d70f10877e0557becc88ab3ad2be8 upstream.

hrtimer_expires_remaining does not take internal hrtimer locks and thus
must be guarded against concurrent __hrtimer_start_range_ns (but
returning HRTIMER_RESTART is safe). Use cfs_b->lock to make it safe.

Signed-off-by: Ben Segall 
Signed-off-by: Peter Zijlstra 
Cc: pjt@google.com
Link: http://lkml.kernel.org/r/20131016181617.22647.73829.stgit@sword-of-the-dawn.mtv.corp.google.com
Signed-off-by: Ingo Molnar 
Cc: Chris J Arges 
Signed-off-by: Greg Kroah-Hartman

sched: Fix race on toggling cfs_bandwidth_used

2014-01-15T23:28:54+00:00

commit 1ee14e6c8cddeeb8a490d7b54cd9016e4bb900b4 upstream.

When we transition cfs_bandwidth_used to false, any currently
throttled groups will incorrectly return false from cfs_rq_throttled.
While tg_set_cfs_bandwidth will unthrottle them eventually, currently
running code (including at least dequeue_task_fair and
distribute_cfs_runtime) will cause errors.

Fix this by turning off cfs_bandwidth_used only after unthrottling all
cfs_rqs.

Tested: toggle bandwidth back and forth on a loaded cgroup. Caused
crashes in minutes without the patch, hasn't crashed with it.

Signed-off-by: Ben Segall 
Signed-off-by: Peter Zijlstra 
Cc: pjt@google.com
Link: http://lkml.kernel.org/r/20131016181611.22647.80365.stgit@sword-of-the-dawn.mtv.corp.google.com
Signed-off-by: Ingo Molnar 
Cc: Chris J Arges 
Signed-off-by: Greg Kroah-Hartman

x86, fpu, amd: Clear exceptions in AMD FXSAVE workaround

2014-01-15T23:28:53+00:00

commit 26bef1318adc1b3a530ecc807ef99346db2aa8b0 upstream.

Before we do an EMMS in the AMD FXSAVE information leak workaround we
need to clear any pending exceptions, otherwise we trap with a
floating-point exception inside this code.

Reported-by: halfdog 
Tested-by: Borislav Petkov 
Link: http://lkml.kernel.org/r/CA%2B55aFxQnY_PCG_n4=0w-VG=YLXL-yr7oMxyy0WU2gCBAf3ydg@mail.gmail.com
Signed-off-by: H. Peter Anvin 
Signed-off-by: Greg Kroah-Hartman

netfilter: nf_nat: fix access to uninitialized buffer in IRC NAT helper

2014-01-15T23:28:53+00:00

commit 2690d97ade05c5325cbf7c72b94b90d265659886 upstream.

Commit 5901b6be885e attempted to introduce IPv6 support into
IRC NAT helper. By doing so, the following code seemed to be removed
by accident:

  ip = ntohl(exp->master->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3.ip);
  sprintf(buffer, "%u %u", ip, port);
  pr_debug("nf_nat_irc: inserting '%s' == %pI4, port %u\n", buffer, &ip, port);

This leads to the fact that buffer[] was left uninitialized and
contained some stack value. When we call nf_nat_mangle_tcp_packet(),
we call strlen(buffer) on excatly this uninitialized buffer. If we
are unlucky and the skb has enough tailroom, we overwrite resp. leak
contents with values that sit on our stack into the packet and send
that out to the receiver.

Since the rather informal DCC spec [1] does not seem to specify
IPv6 support right now, we log such occurences so that admins can
act accordingly, and drop the packet. I've looked into XChat source,
and IPv6 is not supported there: addresses are in u32 and print
via %u format string.

Therefore, restore old behaviour as in IPv4, use snprintf(). The
IRC helper does not support IPv6 by now. By this, we can safely use
strlen(buffer) in nf_nat_mangle_tcp_packet() and prevent a buffer
overflow. Also simplify some code as we now have ct variable anyway.

  [1] http://www.irchelp.org/irchelp/rfc/ctcpspec.html

Fixes: 5901b6be885e ("netfilter: nf_nat: support IPv6 in IRC NAT helper")
Signed-off-by: Daniel Borkmann 
Cc: Harald Welte 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Greg Kroah-Hartman

SCSI: sd: Reduce buffer size for vpd request

2014-01-15T23:28:53+00:00

commit af73623f5f10eb3832c87a169b28f7df040a875b upstream.

Somehow older areca firmware versions have issues with
scsi_get_vpd_page() and a large buffer, the firmware
seems to crash and the scsi error-handler will start endless
recovery retries.
Limiting the buf-size to 64-bytes fixes this issue with older
firmware versions (<1.49 for my controller).

Fixes a regression with areca controllers and older firmware versions
introduced by commit: 66c28f97120e8a621afd5aa7a31c4b85c547d33d

Reported-by: Nix 
Tested-by: Nix 
Signed-off-by: Bernd Schubert 
Acked-by: Martin K. Petersen 
Signed-off-by: James Bottomley 
Signed-off-by: Greg Kroah-Hartman

intel_pstate: Add X86_FEATURE_APERFMPERF to cpu match parameters.

2014-01-15T23:28:53+00:00

commit 6cbd7ee10e2842a3d1f9b60abede1c8f3d1f1130 upstream.

KVM environments do not support APERF/MPERF MSRs. intel_pstate cannot
operate without these registers.

The previous validity checks in intel_pstate_msrs_not_valid() are
insufficent in nested KVMs.

References: https://bugzilla.redhat.com/show_bug.cgi?id=1046317
Signed-off-by: Dirk Brandewie 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

mac80211: move "bufferable MMPDU" check to fix AP mode scan

2014-01-15T23:28:53+00:00

commit 277d916fc2e959c3f106904116bb4f7b1148d47a upstream.

The check needs to apply to both multicast and unicast packets,
otherwise probe requests on AP mode scans are sent through the multicast
buffer queue, which adds long delays (often longer than the scanning
interval).

Signed-off-by: Felix Fietkau 
Signed-off-by: Johannes Berg 
Signed-off-by: Greg Kroah-Hartman