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22266 commits

Author SHA1 Message Date
Mateusz Guzik cd81a9170e mm: introduce get_task_exe_file
For more convenient access if one has a pointer to the task.

As a minor nit take advantage of the fact that only task lock + rcu are
needed to safely grab ->exe_file. This saves mm refcount dance.

Use the helper in proc_exe_link.

Signed-off-by: Mateusz Guzik <mguzik@redhat.com>
Acked-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Acked-by: Richard Guy Briggs <rgb@redhat.com>
Cc: <stable@vger.kernel.org> # 4.3.x
Signed-off-by: Paul Moore <paul@paul-moore.com>
2016-08-31 16:11:20 -04:00
Paul Moore 43761473c2 audit: fix a double fetch in audit_log_single_execve_arg()
There is a double fetch problem in audit_log_single_execve_arg()
where we first check the execve(2) argumnets for any "bad" characters
which would require hex encoding and then re-fetch the arguments for
logging in the audit record[1].  Of course this leaves a window of
opportunity for an unsavory application to munge with the data.

This patch reworks things by only fetching the argument data once[2]
into a buffer where it is scanned and logged into the audit
records(s).  In addition to fixing the double fetch, this patch
improves on the original code in a few other ways: better handling
of large arguments which require encoding, stricter record length
checking, and some performance improvements (completely unverified,
but we got rid of some strlen() calls, that's got to be a good
thing).

As part of the development of this patch, I've also created a basic
regression test for the audit-testsuite, the test can be tracked on
GitHub at the following link:

 * https://github.com/linux-audit/audit-testsuite/issues/25

[1] If you pay careful attention, there is actually a triple fetch
problem due to a strnlen_user() call at the top of the function.

[2] This is a tiny white lie, we do make a call to strnlen_user()
prior to fetching the argument data.  I don't like it, but due to the
way the audit record is structured we really have no choice unless we
copy the entire argument at once (which would require a rather
wasteful allocation).  The good news is that with this patch the
kernel no longer relies on this strnlen_user() value for anything
beyond recording it in the log, we also update it with a trustworthy
value whenever possible.

Reported-by: Pengfei Wang <wpengfeinudt@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2016-07-20 14:15:46 -04:00
Steve Grubb 0b7a0fdb29 audit: fix whitespace in CWD record
Fix the whitespace in the CWD record

Signed-off-by: Steve Grubb <sgrubb@redhat.com>
[PM: fixed subject line]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2016-07-14 17:47:43 -04:00
Richard Guy Briggs 86b2efbe3a audit: add fields to exclude filter by reusing user filter
RFE: add additional fields for use in audit filter exclude rules
https://github.com/linux-audit/audit-kernel/issues/5

Re-factor and combine audit_filter_type() with audit_filter_user() to
use audit_filter_user_rules() to enable the exclude filter to
additionally filter on PID, UID, GID, AUID, LOGINUID_SET, SUBJ_*.

The process of combining the similar audit_filter_user() and
audit_filter_type() functions, required inverting the meaning and
including the ALWAYS action of the latter.

Include audit_filter_user_rules() into audit_filter(), removing
unneeded logic in the process.

Keep the check to quit early if the list is empty.

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
[PM: checkpatch.pl fixes - whitespace damage, wrapped description]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2016-06-27 11:01:00 -04:00
Paul Moore 66b12abc84 audit: fix some horrible switch statement style crimes
Signed-off-by: Paul Moore <paul@paul-moore.com>
2016-06-16 17:08:19 -04:00
Richard Guy Briggs 2b4c7afe79 audit: fixup: log on errors from filter user rules
In commit 724e4fcc the intention was to pass any errors back from
audit_filter_user_rules() to audit_filter_user().  Add that code.

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2016-05-31 12:06:59 -04:00
Linus Torvalds 1410b74e40 Merge branch 'for-4.6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fixes from Tejun Heo:
 "During v4.6-rc1 cgroup namespace support was merged.  There is an
  issue where it's impossible to tell whether a given cgroup mount point
  is bind mounted or namespaced.  Serge has been working on the issue
  but it took longer than expected to resolve, so the late pull request.

  Given that it's a completely new feature and the patches don't touch
  anything else, the risk seems acceptable.  However, if this is too
  late, an alternative is plugging new cgroup ns creation for v4.6 and
  retrying for v4.7"

* 'for-4.6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: fix compile warning
  kernfs: kernfs_sop_show_path: don't return 0 after seq_dentry call
  cgroup, kernfs: make mountinfo show properly scoped path for cgroup namespaces
  kernfs_path_from_node_locked: don't overwrite nlen
2016-05-13 16:26:46 -07:00
Linus Torvalds da92223908 Merge branch 'for-4.6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull workqueue fix from Tejun Heo:
 "CPU hotplug callbacks can invoke DOWN_FAILED w/o preceding
  DOWN_PREPARE which can trigger a WARN_ON() in workqueue.

  The bug has been there for a very long time.  It only triggers if CPU
  down fails at a specific point and I don't think it has adverse
  effects other than the warning messages.  The fix is very low impact"

* 'for-4.6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: fix rebind bound workers warning
2016-05-13 16:16:51 -07:00
Linus Torvalds 65643e3abe Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fix from Ingo Molnar:
 "This is a revert to fix an interactivity problem.

  The proper fixes for the problems that the reverted commit exposed are
  now in sched/core (consisting of 3 patches), but were too risky for
  v4.6 and will arrive in the v4.7 merge window"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Revert "sched/fair: Fix fairness issue on migration"
2016-05-13 12:21:17 -07:00
Wanpeng Li f7c17d26f4 workqueue: fix rebind bound workers warning
------------[ cut here ]------------
WARNING: CPU: 0 PID: 16 at kernel/workqueue.c:4559 rebind_workers+0x1c0/0x1d0
Modules linked in:
CPU: 0 PID: 16 Comm: cpuhp/0 Not tainted 4.6.0-rc4+ #31
Hardware name: IBM IBM System x3550 M4 Server -[7914IUW]-/00Y8603, BIOS -[D7E128FUS-1.40]- 07/23/2013
 0000000000000000 ffff881037babb58 ffffffff8139d885 0000000000000010
 0000000000000000 0000000000000000 0000000000000000 ffff881037babba8
 ffffffff8108505d ffff881037ba0000 000011cf3e7d6e60 0000000000000046
Call Trace:
 dump_stack+0x89/0xd4
 __warn+0xfd/0x120
 warn_slowpath_null+0x1d/0x20
 rebind_workers+0x1c0/0x1d0
 workqueue_cpu_up_callback+0xf5/0x1d0
 notifier_call_chain+0x64/0x90
 ? trace_hardirqs_on_caller+0xf2/0x220
 ? notify_prepare+0x80/0x80
 __raw_notifier_call_chain+0xe/0x10
 __cpu_notify+0x35/0x50
 notify_down_prepare+0x5e/0x80
 ? notify_prepare+0x80/0x80
 cpuhp_invoke_callback+0x73/0x330
 ? __schedule+0x33e/0x8a0
 cpuhp_down_callbacks+0x51/0xc0
 cpuhp_thread_fun+0xc1/0xf0
 smpboot_thread_fn+0x159/0x2a0
 ? smpboot_create_threads+0x80/0x80
 kthread+0xef/0x110
 ? wait_for_completion+0xf0/0x120
 ? schedule_tail+0x35/0xf0
 ret_from_fork+0x22/0x50
 ? __init_kthread_worker+0x70/0x70
---[ end trace eb12ae47d2382d8f ]---
notify_down_prepare: attempt to take down CPU 0 failed

This bug can be reproduced by below config w/ nohz_full= all cpus:

CONFIG_BOOTPARAM_HOTPLUG_CPU0=y
CONFIG_DEBUG_HOTPLUG_CPU0=y
CONFIG_NO_HZ_FULL=y

As Thomas pointed out:

| If a down prepare callback fails, then DOWN_FAILED is invoked for all
| callbacks which have successfully executed DOWN_PREPARE.
|
| But, workqueue has actually two notifiers. One which handles
| UP/DOWN_FAILED/ONLINE and one which handles DOWN_PREPARE.
|
| Now look at the priorities of those callbacks:
|
| CPU_PRI_WORKQUEUE_UP        = 5
| CPU_PRI_WORKQUEUE_DOWN      = -5
|
| So the call order on DOWN_PREPARE is:
|
| CB 1
| CB ...
| CB workqueue_up() -> Ignores DOWN_PREPARE
| CB ...
| CB X ---> Fails
|
| So we call up to CB X with DOWN_FAILED
|
| CB 1
| CB ...
| CB workqueue_up() -> Handles DOWN_FAILED
| CB ...
| CB X-1
|
| So the problem is that the workqueue stuff handles DOWN_FAILED in the up
| callback, while it should do it in the down callback. Which is not a good idea
| either because it wants to be called early on rollback...
|
| Brilliant stuff, isn't it? The hotplug rework will solve this problem because
| the callbacks become symetric, but for the existing mess, we need some
| workaround in the workqueue code.

The boot CPU handles housekeeping duty(unbound timers, workqueues,
timekeeping, ...) on behalf of full dynticks CPUs. It must remain
online when nohz full is enabled. There is a priority set to every
notifier_blocks:

workqueue_cpu_up > tick_nohz_cpu_down > workqueue_cpu_down

So tick_nohz_cpu_down callback failed when down prepare cpu 0, and
notifier_blocks behind tick_nohz_cpu_down will not be called any
more, which leads to workers are actually not unbound. Then hotplug
state machine will fallback to undo and online cpu 0 again. Workers
will be rebound unconditionally even if they are not unbound and
trigger the warning in this progress.

This patch fix it by catching !DISASSOCIATED to avoid rebind bound
workers.

Cc: Tejun Heo <tj@kernel.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: stable@vger.kernel.org
Suggested-by: Lai Jiangshan <jiangshanlai@gmail.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
2016-05-12 12:00:23 -04:00
Felipe Balbi 09be4c824e cgroup: fix compile warning
commit 4f41fc5962 ("cgroup, kernfs: make mountinfo
 show properly scoped path for cgroup namespaces")
 added the following compile warning:

kernel/cgroup.c: In function ‘cgroup_show_path’:
kernel/cgroup.c:1634:15: warning: unused variable ‘ret’ [-Wunused-variable]
  int len = 0, ret = 0;
               ^
fix it.

Fixes: 4f41fc5962 ("cgroup, kernfs: make mountinfo show properly scoped path for cgroup namespaces")
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2016-05-12 11:05:27 -04:00
Alexander Shishkin 9f448cd3cb perf/core: Disable the event on a truncated AUX record
When the PMU driver reports a truncated AUX record, it effectively means
that there is no more usable room in the event's AUX buffer (even though
there may still be some room, so that perf_aux_output_begin() doesn't take
action). At this point the consumer still has to be woken up and the event
has to be disabled, otherwise the event will just keep spinning between
perf_aux_output_begin() and perf_aux_output_end() until its context gets
unscheduled.

Again, for cpu-wide events this means never, so once in this condition,
they will be forever losing data.

Fix this by disabling the event and waking up the consumer in case of a
truncated AUX record.

Reported-by: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: vince@deater.net
Link: http://lkml.kernel.org/r/1462886313-13660-3-git-send-email-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-12 14:46:11 +02:00
Ingo Molnar 53d3bc773e Revert "sched/fair: Fix fairness issue on migration"
Mike reported that this recent commit:

  3a47d5124a ("sched/fair: Fix fairness issue on migration")

... broke interactivity and the signal starvation test.

We have a proper fix series in the works but ran out of time for
v4.6, so revert the commit.

Reported-by: Mike Galbraith <efault@gmx.de>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-11 08:25:53 +02:00
Linus Torvalds ac2440654d Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:
 "A UP kernel cpufreq fix and a rt/dl scheduler corner case fix"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/rt, sched/dl: Don't push if task's scheduling class was changed
  sched/fair: Fix !CONFIG_SMP kernel cpufreq governor breakage
2016-05-10 11:32:01 -07:00
Xunlei Pang 13b5ab02ae sched/rt, sched/dl: Don't push if task's scheduling class was changed
We got this warning:

    WARNING: CPU: 1 PID: 2468 at kernel/sched/core.c:1161 set_task_cpu+0x1af/0x1c0
    [...]
    Call Trace:

    dump_stack+0x63/0x87
    __warn+0xd1/0xf0
    warn_slowpath_null+0x1d/0x20
    set_task_cpu+0x1af/0x1c0
    push_dl_task.part.34+0xea/0x180
    push_dl_tasks+0x17/0x30
    __balance_callback+0x45/0x5c
    __sched_setscheduler+0x906/0xb90
    SyS_sched_setattr+0x150/0x190
    do_syscall_64+0x62/0x110
    entry_SYSCALL64_slow_path+0x25/0x25

This corresponds to:

    WARN_ON_ONCE(p->state == TASK_RUNNING &&
             p->sched_class == &fair_sched_class &&
             (p->on_rq && !task_on_rq_migrating(p)))

It happens because in find_lock_later_rq(), the task whose scheduling
class was changed to fair class is still pushed away as if it were
a deadline task ...

So, check in find_lock_later_rq() after double_lock_balance(), if the
scheduling class of the deadline task was changed, break and retry.

Apply the same logic to RT tasks.

Signed-off-by: Xunlei Pang <xlpang@redhat.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Juri Lelli <juri.lelli@arm.com>
Link: http://lkml.kernel.org/r/1462767091-1215-1-git-send-email-xlpang@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-10 10:02:46 +02:00
Andy Lutomirski 0161028b7c perf/core: Change the default paranoia level to 2
Allowing unprivileged kernel profiling lets any user dump follow kernel
control flow and dump kernel registers.  This most likely allows trivial
kASLR bypassing, and it may allow other mischief as well.  (Off the top
of my head, the PERF_SAMPLE_REGS_INTR output during /dev/urandom reads
could be quite interesting.)

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-09 17:57:12 -07:00
Serge E. Hallyn 4f41fc5962 cgroup, kernfs: make mountinfo show properly scoped path for cgroup namespaces
Patch summary:

When showing a cgroupfs entry in mountinfo, show the path of the mount
root dentry relative to the reader's cgroup namespace root.

Short explanation (courtesy of mkerrisk):

If we create a new cgroup namespace, then we want both /proc/self/cgroup
and /proc/self/mountinfo to show cgroup paths that are correctly
virtualized with respect to the cgroup mount point.  Previous to this
patch, /proc/self/cgroup shows the right info, but /proc/self/mountinfo
does not.

Long version:

When a uid 0 task which is in freezer cgroup /a/b, unshares a new cgroup
namespace, and then mounts a new instance of the freezer cgroup, the new
mount will be rooted at /a/b.  The root dentry field of the mountinfo
entry will show '/a/b'.

 cat > /tmp/do1 << EOF
 mount -t cgroup -o freezer freezer /mnt
 grep freezer /proc/self/mountinfo
 EOF

 unshare -Gm  bash /tmp/do1
 > 330 160 0:34 / /sys/fs/cgroup/freezer rw,nosuid,nodev,noexec,relatime - cgroup cgroup rw,freezer
 > 355 133 0:34 /a/b /mnt rw,relatime - cgroup freezer rw,freezer

The task's freezer cgroup entry in /proc/self/cgroup will simply show
'/':

 grep freezer /proc/self/cgroup
 9:freezer:/

If instead the same task simply bind mounts the /a/b cgroup directory,
the resulting mountinfo entry will again show /a/b for the dentry root.
However in this case the task will find its own cgroup at /mnt/a/b,
not at /mnt:

 mount --bind /sys/fs/cgroup/freezer/a/b /mnt
 130 25 0:34 /a/b /mnt rw,nosuid,nodev,noexec,relatime shared:21 - cgroup cgroup rw,freezer

In other words, there is no way for the task to know, based on what is
in mountinfo, which cgroup directory is its own.

Example (by mkerrisk):

First, a little script to save some typing and verbiage:

echo -e "\t/proc/self/cgroup:\t$(cat /proc/self/cgroup | grep freezer)"
cat /proc/self/mountinfo | grep freezer |
        awk '{print "\tmountinfo:\t\t" $4 "\t" $5}'

Create cgroup, place this shell into the cgroup, and look at the state
of the /proc files:

2653
2653                         # Our shell
14254                        # cat(1)
        /proc/self/cgroup:      10:freezer:/a/b
        mountinfo:              /       /sys/fs/cgroup/freezer

Create a shell in new cgroup and mount namespaces. The act of creating
a new cgroup namespace causes the process's current cgroups directories
to become its cgroup root directories. (Here, I'm using my own version
of the "unshare" utility, which takes the same options as the util-linux
version):

Look at the state of the /proc files:

        /proc/self/cgroup:      10:freezer:/
        mountinfo:              /       /sys/fs/cgroup/freezer

The third entry in /proc/self/cgroup (the pathname of the cgroup inside
the hierarchy) is correctly virtualized w.r.t. the cgroup namespace, which
is rooted at /a/b in the outer namespace.

However, the info in /proc/self/mountinfo is not for this cgroup
namespace, since we are seeing a duplicate of the mount from the
old mount namespace, and the info there does not correspond to the
new cgroup namespace. However, trying to create a new mount still
doesn't show us the right information in mountinfo:

                                      # propagating to other mountns
        /proc/self/cgroup:      7:freezer:/
        mountinfo:              /a/b    /mnt/freezer

The act of creating a new cgroup namespace caused the process's
current freezer directory, "/a/b", to become its cgroup freezer root
directory. In other words, the pathname directory of the directory
within the newly mounted cgroup filesystem should be "/",
but mountinfo wrongly shows us "/a/b". The consequence of this is
that the process in the cgroup namespace cannot correctly construct
the pathname of its cgroup root directory from the information in
/proc/PID/mountinfo.

With this patch, the dentry root field in mountinfo is shown relative
to the reader's cgroup namespace.  So the same steps as above:

        /proc/self/cgroup:      10:freezer:/a/b
        mountinfo:              /       /sys/fs/cgroup/freezer
        /proc/self/cgroup:      10:freezer:/
        mountinfo:              /../..  /sys/fs/cgroup/freezer
        /proc/self/cgroup:      10:freezer:/
        mountinfo:              /       /mnt/freezer

cgroup.clone_children  freezer.parent_freezing  freezer.state      tasks
cgroup.procs           freezer.self_freezing    notify_on_release
3164
2653                   # First shell that placed in this cgroup
3164                   # Shell started by 'unshare'
14197                  # cat(1)

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Tested-by: Michael Kerrisk <mtk.manpages@gmail.com>
Acked-by: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2016-05-09 12:15:03 -04:00
Rafael J. Wysocki 536bd00cdb sched/fair: Fix !CONFIG_SMP kernel cpufreq governor breakage
The following commit:

  34e2c555f3 ("cpufreq: Add mechanism for registering utilization update callbacks")

overlooked the fact that update_load_avg(), where CFS invokes cpufreq
utilization update callbacks, becomes an empty stub on UP kernels.

In consequence, if !CONFIG_SMP, cpufreq governors are never invoked
from CFS and they do not have a chance to evaluate CPU performace
levels and update them often enough.

Needless to say, things don't work as expected then.

Fix the problem by making the !CONFIG_SMP stub of update_load_avg()
invoke cpufreq update callbacks too.

Reported-by: Steve Muckle <steve.muckle@linaro.org>
Tested-by: Steve Muckle <steve.muckle@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Steve Muckle <steve.muckle@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linux PM list <linux-pm@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Fixes: 34e2c555f3 (cpufreq: Add mechanism for registering utilization update callbacks)
Link: http://lkml.kernel.org/r/6282396.VVEdgVYxO3@vostro.rjw.lan
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-07 07:45:34 +02:00
Linus Torvalds 17d25a337b Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fix from Ingo Molnar:
 "This contains a single fix that fixes a nohz tick stopping bug when
  mixed-poliocy SCHED_FIFO and SCHED_RR tasks are present on a runqueue"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  nohz/full, sched/rt: Fix missed tick-reenabling bug in sched_can_stop_tick()
2016-05-06 11:53:27 -07:00
Linus Torvalds 83858a701c Chunyu Hu noticed that if one writes into the trigger files within the
ftrace subsystem of events that it can cause an oops. This file is only
 writable by root, but still is a bug that needs to be fixed.
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Merge tag 'trace-fixes-v4.6-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fix from Steven Rostedt:
 "Chunyu Hu noticed that if one writes into the trigger files within the
  ftrace subsystem of events that it can cause an oops.  This file is
  only writable by root, but still is a bug that needs to be fixed"

* tag 'trace-fixes-v4.6-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Don't display trigger file for events that can't be enabled
2016-05-03 18:02:38 -07:00
Chunyu Hu 854145e0a8 tracing: Don't display trigger file for events that can't be enabled
Currently register functions for events will be called
through the 'reg' field of event class directly without
any check when seting up triggers.

Triggers for events that don't support register through
debug fs (events under events/ftrace are for trace-cmd to
read event format, and most of them don't have a register
function except events/ftrace/functionx) can't be enabled
at all, and an oops will be hit when setting up trigger
for those events, so just not creating them is an easy way
to avoid the oops.

Link: http://lkml.kernel.org/r/1462275274-3911-1-git-send-email-chuhu@redhat.com

Cc: stable@vger.kernel.org # 3.14+
Fixes: 85f2b08268 ("tracing: Add basic event trigger framework")
Signed-off-by: Chunyu Hu <chuhu@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-05-03 12:59:30 -04:00
Linus Torvalds 9c5d1bc2b7 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Pull networking fixes from David Miller:

 1) MODULE_FIRMWARE firmware string not correct for iwlwifi 8000 chips,
    from Sara Sharon.

 2) Fix SKB size checks in batman-adv stack on receive, from Sven
    Eckelmann.

 3) Leak fix on mac80211 interface add error paths, from Johannes Berg.

 4) Cannot invoke napi_disable() with BH disabled in myri10ge driver,
    fix from Stanislaw Gruszka.

 5) Fix sign extension problem when computing feature masks in
    net_gso_ok(), from Marcelo Ricardo Leitner.

 6) lan78xx driver doesn't count packets and packet lengths in its
    statistics properly, fix from Woojung Huh.

 7) Fix the buffer allocation sizes in pegasus USB driver, from Petko
    Manolov.

 8) Fix refcount overflows in bpf, from Alexei Starovoitov.

 9) Unified dst cache handling introduced a preempt warning in
    ip_tunnel, fix by resetting rather then setting the cached route.
    From Paolo Abeni.

10) Listener hash collision test fix in soreuseport, from Craig Gallak

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (47 commits)
  gre: do not pull header in ICMP error processing
  net: Implement net_dbg_ratelimited() for CONFIG_DYNAMIC_DEBUG case
  tipc: only process unicast on intended node
  cxgb3: fix out of bounds read
  net/smscx5xx: use the device tree for mac address
  soreuseport: Fix TCP listener hash collision
  net: l2tp: fix reversed udp6 checksum flags
  ip_tunnel: fix preempt warning in ip tunnel creation/updating
  samples/bpf: fix trace_output example
  bpf: fix check_map_func_compatibility logic
  bpf: fix refcnt overflow
  drivers: net: cpsw: use of_phy_connect() in fixed-link case
  dt: cpsw: phy-handle, phy_id, and fixed-link are mutually exclusive
  drivers: net: cpsw: don't ignore phy-mode if phy-handle is used
  drivers: net: cpsw: fix segfault in case of bad phy-handle
  drivers: net: cpsw: fix parsing of phy-handle DT property in dual_emac config
  MAINTAINERS: net: Change maintainer for GRETH 10/100/1G Ethernet MAC device driver
  gre: reject GUE and FOU in collect metadata mode
  pegasus: fixes reported packet length
  pegasus: fixes URB buffer allocation size;
  ...
2016-05-02 09:40:42 -07:00
Linus Torvalds 1d003af2ef Merge branch 'akpm' (patches from Andrew)
Merge fixes from Andrew Morton:
 "20 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  Documentation/sysctl/vm.txt: update numa_zonelist_order description
  lib/stackdepot.c: allow the stack trace hash to be zero
  rapidio: fix potential NULL pointer dereference
  mm/memory-failure: fix race with compound page split/merge
  ocfs2/dlm: return zero if deref_done message is successfully handled
  Ananth has moved
  kcov: don't profile branches in kcov
  kcov: don't trace the code coverage code
  mm: wake kcompactd before kswapd's short sleep
  .mailmap: add Frank Rowand
  mm/hwpoison: fix wrong num_poisoned_pages accounting
  mm: call swap_slot_free_notify() with page lock held
  mm: vmscan: reclaim highmem zone if buffer_heads is over limit
  numa: fix /proc/<pid>/numa_maps for THP
  mm/huge_memory: replace VM_NO_THP VM_BUG_ON with actual VMA check
  mailmap: fix Krzysztof Kozlowski's misspelled name
  thp: keep huge zero page pinned until tlb flush
  mm: exclude HugeTLB pages from THP page_mapped() logic
  kexec: export OFFSET(page.compound_head) to find out compound tail page
  kexec: update VMCOREINFO for compound_order/dtor
2016-04-29 11:21:22 -07:00
Linus Torvalds 814dd9481d Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Ingo Molnar:
 "x86 PMU driver fixes plus a core code race fix"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/intel: Fix incorrect lbr_sel_mask value
  perf/x86/intel/pt: Don't die on VMXON
  perf/core: Fix perf_event_open() vs. execve() race
  perf/x86/amd: Set the size of event map array to PERF_COUNT_HW_MAX
  perf/core: Make sysctl_perf_cpu_time_max_percent conform to documentation
  perf/x86/intel/rapl: Add missing Haswell model
  perf/x86/intel: Add model number for Skylake Server to perf
2016-04-28 20:19:04 -07:00
Linus Torvalds 2113caed87 Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fixes from Ingo Molnar:
 "Two lockdep fixes"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  lockdep: Fix lock_chain::base size
  locking/lockdep: Fix ->irq_context calculation
2016-04-28 19:59:17 -07:00
Andrey Ryabinin 36f05ae8bc kcov: don't profile branches in kcov
Profiling 'if' statements in __sanitizer_cov_trace_pc() leads to
unbound recursion and crash:

	__sanitizer_cov_trace_pc() ->
		ftrace_likely_update ->
			__sanitizer_cov_trace_pc() ...

Define DISABLE_BRANCH_PROFILING to disable this tracer.

Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-28 19:34:04 -07:00
James Morse bdab42dfc9 kcov: don't trace the code coverage code
Kcov causes the compiler to add a call to __sanitizer_cov_trace_pc() in
every basic block.  Ftrace patches in a call to _mcount() to each
function it has annotated.

Letting these mechanisms annotate each other is a bad thing.  Break the
loop by adding 'notrace' to __sanitizer_cov_trace_pc() so that ftrace
won't try to patch this code.

This patch lets arm64 with KCOV and STACK_TRACER boot.

Signed-off-by: James Morse <james.morse@arm.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-28 19:34:04 -07:00
Atsushi Kumagai d7f53518f7 kexec: export OFFSET(page.compound_head) to find out compound tail page
PageAnon() always look at head page to check PAGE_MAPPING_ANON and tail
page's page->mapping has just a poisoned data since commit 1c290f6421
("mm: sanitize page->mapping for tail pages").

If makedumpfile checks page->mapping of a compound tail page to
distinguish anonymous page as usual, it must fail in newer kernel.  So
it's necessary to export OFFSET(page.compound_head) to avoid checking
compound tail pages.

The problem is that unnecessary hugepages won't be removed from a dump
file in kernels 4.5.x and later.  This means that extra disk space would
be consumed.  It's a problem, but not critical.

Signed-off-by: Atsushi Kumagai <ats-kumagai@wm.jp.nec.com>
Acked-by: Dave Young <dyoung@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-28 19:34:04 -07:00
Atsushi Kumagai 8639a847b0 kexec: update VMCOREINFO for compound_order/dtor
makedumpfile refers page.lru.next to get the order of compound pages for
page filtering.

However, now the order is stored in page.compound_order, hence
VMCOREINFO should be updated to export the offset of
page.compound_order.

The fact is, page.compound_order was introduced already in kernel 4.0,
but the offset of it was the same as page.lru.next until kernel 4.3, so
this was not actual problem.

The above can be said also for page.lru.prev and page.compound_dtor,
it's necessary to detect hugetlbfs pages.  Further, the content was
changed from direct address to the ID which means dtor.

The problem is that unnecessary hugepages won't be removed from a dump
file in kernels 4.4.x and later.  This means that extra disk space would
be consumed.  It's a problem, but not critical.

Signed-off-by: Atsushi Kumagai <ats-kumagai@wm.jp.nec.com>
Acked-by: Dave Young <dyoung@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-28 19:34:04 -07:00
Alexei Starovoitov 6aff67c85c bpf: fix check_map_func_compatibility logic
The commit 35578d7984 ("bpf: Implement function bpf_perf_event_read() that get the selected hardware PMU conuter")
introduced clever way to check bpf_helper<->map_type compatibility.
Later on commit a43eec3042 ("bpf: introduce bpf_perf_event_output() helper") adjusted
the logic and inadvertently broke it.
Get rid of the clever bool compare and go back to two-way check
from map and from helper perspective.

Fixes: a43eec3042 ("bpf: introduce bpf_perf_event_output() helper")
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-28 17:29:45 -04:00
Alexei Starovoitov 92117d8443 bpf: fix refcnt overflow
On a system with >32Gbyte of phyiscal memory and infinite RLIMIT_MEMLOCK,
the malicious application may overflow 32-bit bpf program refcnt.
It's also possible to overflow map refcnt on 1Tb system.
Impose 32k hard limit which means that the same bpf program or
map cannot be shared by more than 32k processes.

Fixes: 1be7f75d16 ("bpf: enable non-root eBPF programs")
Reported-by: Jann Horn <jannh@google.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>
2016-04-28 17:29:45 -04:00
Peter Zijlstra 79c9ce57eb perf/core: Fix perf_event_open() vs. execve() race
Jann reported that the ptrace_may_access() check in
find_lively_task_by_vpid() is racy against exec().

Specifically:

  perf_event_open()		execve()

  ptrace_may_access()
				commit_creds()
  ...				if (get_dumpable() != SUID_DUMP_USER)
				  perf_event_exit_task();
  perf_install_in_context()

would result in installing a counter across the creds boundary.

Fix this by wrapping lots of perf_event_open() in cred_guard_mutex.
This should be fine as perf_event_exit_task() is already called with
cred_guard_mutex held, so all perf locks already nest inside it.

Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-28 10:32:41 +02:00
Peter Zijlstra 2548d546d4 nohz/full, sched/rt: Fix missed tick-reenabling bug in sched_can_stop_tick()
Chris Metcalf reported a that sched_can_stop_tick() sometimes fails to
re-enable the tick.

His observed problem is that rq->cfs.nr_running can be 1 even though
there are multiple runnable CFS tasks. This happens in the cgroup
case, in which case cfs.nr_running is the number of runnable entities
for that level.

If there is a single runnable cgroup (which can have an arbitrary
number of runnable child entries itself) rq->cfs.nr_running will be 1.

However, looking at that function I think there's more problems with it.

It seems to assume that if there's FIFO tasks, those will run. This is
incorrect. The FIFO task can have a lower prio than an RR task, in which
case the RR task will run.

So the whole fifo_nr_running test seems misplaced, it should go after
the rr_nr_running tests. That is, only if !rr_nr_running, can we use
fifo_nr_running like this.

Reported-by: Chris Metcalf <cmetcalf@mellanox.com>
Tested-by: Chris Metcalf <cmetcalf@mellanox.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Wanpeng Li <kernellwp@gmail.com>
Fixes: 76d92ac305 ("sched: Migrate sched to use new tick dependency mask model")
Link: http://lkml.kernel.org/r/20160421160315.GK24771@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-28 10:28:55 +02:00
Linus Torvalds b75a2bf899 Merge branch 'for-4.6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull workqueue fix from Tejun Heo:
 "So, it turns out we had a silly bug in the most fundamental part of
  workqueue for a very long time.  AFAICS, this dates back to pre-git
  era and has quite likely been there from the time workqueue was first
  introduced.

  A work item uses its PENDING bit to synchronize multiple queuers.
  Anyone who wins the PENDING bit owns the pending state of the work
  item.  Whether a queuer wins or loses the race, one thing should be
  guaranteed - there will soon be at least one execution of the work
  item - where "after" means that the execution instance would be able
  to see all the changes that the queuer has made prior to the queueing
  attempt.

  Unfortunately, we were missing a smp_mb() after clearing PENDING for
  execution, so nothing guaranteed visibility of the changes that a
  queueing loser has made, which manifested as a reproducible blk-mq
  stall.

  Lots of kudos to Roman for debugging the problem.  The patch for
  -stable is the minimal one.  For v3.7, Peter is working on a patch to
  make the code path slightly more efficient and less fragile"

* 'for-4.6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: fix ghost PENDING flag while doing MQ IO
2016-04-27 12:03:59 -07:00
Linus Torvalds 763cfc86ee Merge branch 'for-4.6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fixes from Tejun Heo:
 "Two patches to fix a deadlock which can be easily triggered if memcg
  charge moving is used.

  This bug was introduced while converting threadgroup locking to a
  global percpu_rwsem and is caused by cgroup controller task migration
  path depending on the ability to create new kthreads.  cpuset had a
  similar issue which was fixed by performing heavy-lifting operations
  asynchronous to task migration.  The two patches fix the same issue in
  memcg in a similar way.  The first patch makes the mechanism generic
  and the second relocates memcg charge moving outside the migration
  path.

  Given that we don't want to perform heavy operations while
  writelocking threadgroup lock anyway, moving them out of the way is a
  desirable solution.  One thing to note is that the problem was
  difficult to debug because lockdep couldn't figure out the deadlock
  condition.  Looking into how to improve that"

* 'for-4.6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  memcg: relocate charge moving from ->attach to ->post_attach
  cgroup, cpuset: replace cpuset_post_attach_flush() with cgroup_subsys->post_attach callback
2016-04-27 11:41:14 -07:00
Linus Torvalds f28f20da70 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Pull networking fixes from David Miller:

 1) Handle v4/v6 mixed sockets properly in soreuseport, from Craig
    Gallak.

 2) Bug fixes for the new macsec facility (missing kmalloc NULL checks,
    missing locking around netdev list traversal, etc.) from Sabrina
    Dubroca.

 3) Fix handling of host routes on ifdown in ipv6, from David Ahern.

 4) Fix double-fdput in bpf verifier.  From Jann Horn.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (31 commits)
  bpf: fix double-fdput in replace_map_fd_with_map_ptr()
  net: ipv6: Delete host routes on an ifdown
  Revert "ipv6: Revert optional address flusing on ifdown."
  net/mlx4_en: fix spurious timestamping callbacks
  net: dummy: remove note about being Y by default
  cxgbi: fix uninitialized flowi6
  ipv6: Revert optional address flusing on ifdown.
  ipv4/fib: don't warn when primary address is missing if in_dev is dead
  net/mlx5: Add pci shutdown callback
  net/mlx5_core: Remove static from local variable
  net/mlx5e: Use vport MTU rather than physical port MTU
  net/mlx5e: Fix minimum MTU
  net/mlx5e: Device's mtu field is u16 and not int
  net/mlx5_core: Add ConnectX-5 to list of supported devices
  net/mlx5e: Fix MLX5E_100BASE_T define
  net/mlx5_core: Fix soft lockup in steering error flow
  qlcnic: Update version to 5.3.64
  net: stmmac: socfpga: Remove re-registration of reset controller
  macsec: fix netlink attribute validation
  macsec: add missing macsec prefix in uapi
  ...
2016-04-26 16:25:51 -07:00
Jann Horn 8358b02bf6 bpf: fix double-fdput in replace_map_fd_with_map_ptr()
When bpf(BPF_PROG_LOAD, ...) was invoked with a BPF program whose bytecode
references a non-map file descriptor as a map file descriptor, the error
handling code called fdput() twice instead of once (in __bpf_map_get() and
in replace_map_fd_with_map_ptr()). If the file descriptor table of the
current task is shared, this causes f_count to be decremented too much,
allowing the struct file to be freed while it is still in use
(use-after-free). This can be exploited to gain root privileges by an
unprivileged user.

This bug was introduced in
commit 0246e64d9a ("bpf: handle pseudo BPF_LD_IMM64 insn"), but is only
exploitable since
commit 1be7f75d16 ("bpf: enable non-root eBPF programs") because
previously, CAP_SYS_ADMIN was required to reach the vulnerable code.

(posted publicly according to request by maintainer)

Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-26 17:37:21 -04:00
Roman Pen 346c09f804 workqueue: fix ghost PENDING flag while doing MQ IO
The bug in a workqueue leads to a stalled IO request in MQ ctx->rq_list
with the following backtrace:

[  601.347452] INFO: task kworker/u129:5:1636 blocked for more than 120 seconds.
[  601.347574]       Tainted: G           O    4.4.5-1-storage+ #6
[  601.347651] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[  601.348142] kworker/u129:5  D ffff880803077988     0  1636      2 0x00000000
[  601.348519] Workqueue: ibnbd_server_fileio_wq ibnbd_dev_file_submit_io_worker [ibnbd_server]
[  601.348999]  ffff880803077988 ffff88080466b900 ffff8808033f9c80 ffff880803078000
[  601.349662]  ffff880807c95000 7fffffffffffffff ffffffff815b0920 ffff880803077ad0
[  601.350333]  ffff8808030779a0 ffffffff815b01d5 0000000000000000 ffff880803077a38
[  601.350965] Call Trace:
[  601.351203]  [<ffffffff815b0920>] ? bit_wait+0x60/0x60
[  601.351444]  [<ffffffff815b01d5>] schedule+0x35/0x80
[  601.351709]  [<ffffffff815b2dd2>] schedule_timeout+0x192/0x230
[  601.351958]  [<ffffffff812d43f7>] ? blk_flush_plug_list+0xc7/0x220
[  601.352208]  [<ffffffff810bd737>] ? ktime_get+0x37/0xa0
[  601.352446]  [<ffffffff815b0920>] ? bit_wait+0x60/0x60
[  601.352688]  [<ffffffff815af784>] io_schedule_timeout+0xa4/0x110
[  601.352951]  [<ffffffff815b3a4e>] ? _raw_spin_unlock_irqrestore+0xe/0x10
[  601.353196]  [<ffffffff815b093b>] bit_wait_io+0x1b/0x70
[  601.353440]  [<ffffffff815b056d>] __wait_on_bit+0x5d/0x90
[  601.353689]  [<ffffffff81127bd0>] wait_on_page_bit+0xc0/0xd0
[  601.353958]  [<ffffffff81096db0>] ? autoremove_wake_function+0x40/0x40
[  601.354200]  [<ffffffff81127cc4>] __filemap_fdatawait_range+0xe4/0x140
[  601.354441]  [<ffffffff81127d34>] filemap_fdatawait_range+0x14/0x30
[  601.354688]  [<ffffffff81129a9f>] filemap_write_and_wait_range+0x3f/0x70
[  601.354932]  [<ffffffff811ced3b>] blkdev_fsync+0x1b/0x50
[  601.355193]  [<ffffffff811c82d9>] vfs_fsync_range+0x49/0xa0
[  601.355432]  [<ffffffff811cf45a>] blkdev_write_iter+0xca/0x100
[  601.355679]  [<ffffffff81197b1a>] __vfs_write+0xaa/0xe0
[  601.355925]  [<ffffffff81198379>] vfs_write+0xa9/0x1a0
[  601.356164]  [<ffffffff811c59d8>] kernel_write+0x38/0x50

The underlying device is a null_blk, with default parameters:

  queue_mode    = MQ
  submit_queues = 1

Verification that nullb0 has something inflight:

root@pserver8:~# cat /sys/block/nullb0/inflight
       0        1
root@pserver8:~# find /sys/block/nullb0/mq/0/cpu* -name rq_list -print -exec cat {} \;
...
/sys/block/nullb0/mq/0/cpu2/rq_list
CTX pending:
        ffff8838038e2400
...

During debug it became clear that stalled request is always inserted in
the rq_list from the following path:

   save_stack_trace_tsk + 34
   blk_mq_insert_requests + 231
   blk_mq_flush_plug_list + 281
   blk_flush_plug_list + 199
   wait_on_page_bit + 192
   __filemap_fdatawait_range + 228
   filemap_fdatawait_range + 20
   filemap_write_and_wait_range + 63
   blkdev_fsync + 27
   vfs_fsync_range + 73
   blkdev_write_iter + 202
   __vfs_write + 170
   vfs_write + 169
   kernel_write + 56

So blk_flush_plug_list() was called with from_schedule == true.

If from_schedule is true, that means that finally blk_mq_insert_requests()
offloads execution of __blk_mq_run_hw_queue() and uses kblockd workqueue,
i.e. it calls kblockd_schedule_delayed_work_on().

That means, that we race with another CPU, which is about to execute
__blk_mq_run_hw_queue() work.

Further debugging shows the following traces from different CPUs:

  CPU#0                                  CPU#1
  ----------------------------------     -------------------------------
  reqeust A inserted
  STORE hctx->ctx_map[0] bit marked
  kblockd_schedule...() returns 1
  <schedule to kblockd workqueue>
                                         request B inserted
                                         STORE hctx->ctx_map[1] bit marked
                                         kblockd_schedule...() returns 0
  *** WORK PENDING bit is cleared ***
  flush_busy_ctxs() is executed, but
  bit 1, set by CPU#1, is not observed

As a result request B pended forever.

This behaviour can be explained by speculative LOAD of hctx->ctx_map on
CPU#0, which is reordered with clear of PENDING bit and executed _before_
actual STORE of bit 1 on CPU#1.

The proper fix is an explicit full barrier <mfence>, which guarantees
that clear of PENDING bit is to be executed before all possible
speculative LOADS or STORES inside actual work function.

Signed-off-by: Roman Pen <roman.penyaev@profitbricks.com>
Cc: Gioh Kim <gi-oh.kim@profitbricks.com>
Cc: Michael Wang <yun.wang@profitbricks.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Tejun Heo <tj@kernel.org>
2016-04-26 11:23:22 -04:00
Tejun Heo 5cf1cacb49 cgroup, cpuset: replace cpuset_post_attach_flush() with cgroup_subsys->post_attach callback
Since e93ad19d05 ("cpuset: make mm migration asynchronous"), cpuset
kicks off asynchronous NUMA node migration if necessary during task
migration and flushes it from cpuset_post_attach_flush() which is
called at the end of __cgroup_procs_write().  This is to avoid
performing migration with cgroup_threadgroup_rwsem write-locked which
can lead to deadlock through dependency on kworker creation.

memcg has a similar issue with charge moving, so let's convert it to
an official callback rather than the current one-off cpuset specific
function.  This patch adds cgroup_subsys->post_attach callback and
makes cpuset register cpuset_post_attach_flush() as its ->post_attach.

The conversion is mostly one-to-one except that the new callback is
called under cgroup_mutex.  This is to guarantee that no other
migration operations are started before ->post_attach callbacks are
finished.  cgroup_mutex is one of the outermost mutex in the system
and has never been and shouldn't be a problem.  We can add specialized
synchronization around __cgroup_procs_write() but I don't think
there's any noticeable benefit.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: <stable@vger.kernel.org> # 4.4+ prerequisite for the next patch
2016-04-25 15:45:14 -04:00
Linus Torvalds 82b23cb94b Merge branches 'perf-urgent-for-linus', 'smp-urgent-for-linus' and 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf, cpu hotplug and timer fixes from Ingo Molnar:
 "perf:
   - A single tooling fix for a user-triggerable segfault.

  CPU hotplug:
   - Fix a CPU hotplug corner case regression, introduced by the recent
     hotplug rework

  timers:
   - Fix a boot hang in the ARM based Tango SoC clocksource driver"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf intel-pt: Fix segfault tracing transactions

* 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  cpu/hotplug: Fix rollback during error-out in __cpu_disable()

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  clocksource/drivers/tango-xtal: Fix boot hang due to incorrect test
2016-04-23 11:45:52 -07:00
Linus Torvalds 0e11d25651 Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fixes from Ingo Molnar:
 "Misc fixes:

  pvqspinlocks:
   - an instrumentation fix

  futexes:
   - preempt-count vs pagefault_disable decouple corner case fix
   - futex requeue plist race window fix
   - futex UNLOCK_PI transaction fix for a corner case"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  asm-generic/futex: Re-enable preemption in futex_atomic_cmpxchg_inatomic()
  futex: Acknowledge a new waiter in counter before plist
  futex: Handle unlock_pi race gracefully
  locking/pvqspinlock: Fix division by zero in qstat_read()
2016-04-23 11:39:48 -07:00
Linus Torvalds 16ecb41410 Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull irq fixes from Ingo Molnar:
 "A core irq affinity masks related fix and a MIPS irqchip driver fix"

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/mips-gic: Don't overrun pcpu_masks array
  genirq: Dont allow affinity mask to be updated on IPIs
2016-04-23 11:34:39 -07:00
Peter Zijlstra 75dd602a51 lockdep: Fix lock_chain::base size
lock_chain::base is used to store an index into the chain_hlocks[]
array, however that array contains more elements than can be indexed
using the u16.

Change the lock_chain structure to use a bitfield to encode the data
it needs and add BUILD_BUG_ON() assertions to check the fields are
wide enough.

Also, for DEBUG_LOCKDEP, assert that we don't run out of elements of
that array; as that would wreck the collision detectoring.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alfredo Alvarez Fernandez <alfredoalvarezfernandez@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20160330093659.GS3408@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-23 13:53:03 +02:00
Boqun Feng c246975662 locking/lockdep: Fix ->irq_context calculation
task_irq_context() returns the encoded irq_context of the task, the
return value is encoded in the same as ->irq_context of held_lock.

Always return 0 if !(CONFIG_TRACE_IRQFLAGS && CONFIG_PROVE_LOCKING)

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: sasha.levin@oracle.com
Link: http://lkml.kernel.org/r/1455602265-16490-2-git-send-email-boqun.feng@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-23 13:53:03 +02:00
Peter Zijlstra b303e7c15d perf/core: Make sysctl_perf_cpu_time_max_percent conform to documentation
Markus reported that 0 should also disable the throttling we per
Documentation/sysctl/kernel.txt.

Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Fixes: 91a612eea9 ("perf/core: Fix dynamic interrupt throttle")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-23 13:47:50 +02:00
Sebastian Andrzej Siewior 3b9d6da67e cpu/hotplug: Fix rollback during error-out in __cpu_disable()
The recent introduction of the hotplug thread which invokes the callbacks on
the plugged cpu, cased the following regression:

If takedown_cpu() fails, then we run into several issues:

 1) The rollback of the target cpu states is not invoked. That leaves the smp
    threads and the hotplug thread in disabled state.

 2) notify_online() is executed due to a missing skip_onerr flag. That causes
    that both CPU_DOWN_FAILED and CPU_ONLINE notifications are invoked which
    confuses quite some notifiers.

 3) The CPU_DOWN_FAILED notification is not invoked on the target CPU. That's
    not an issue per se, but it is inconsistent and in consequence blocks the
    patches which rely on these states being invoked on the target CPU and not
    on the controlling cpu. It also does not preserve the strict call order on
    rollback which is problematic for the ongoing state machine conversion as
    well.

To fix this we add a rollback flag to the remote callback machinery and invoke
the rollback including the CPU_DOWN_FAILED notification on the remote
cpu. Further mark the notify online state with 'skip_onerr' so we don't get a
double invokation.

This workaround will go away once we moved the unplug invocation to the target
cpu itself.

[ tglx: Massaged changelog and moved the CPU_DOWN_FAILED notifiaction to the
  	target cpu ]

Fixes: 4cb28ced23 ("cpu/hotplug: Create hotplug threads")
Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: linux-s390@vger.kernel.org
Cc: rt@linutronix.de
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Anna-Maria Gleixner <anna-maria@linutronix.de>
Link: http://lkml.kernel.org/r/20160408124015.GA21960@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-04-22 09:49:49 +02:00
Linus Torvalds c5edde3a81 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Pull networking fixes from David Miller:

 1) Fix memory leak in iwlwifi, from Matti Gottlieb.

 2) Add missing registration of netfilter arp_tables into initial
    namespace, from Florian Westphal.

 3) Fix potential NULL deref in DecNET routing code.

 4) Restrict NETLINK_URELEASE to truly bound sockets only, from Dmitry
    Ivanov.

 5) Fix dst ref counting in VRF, from David Ahern.

 6) Fix TSO segmenting limits in i40e driver, from Alexander Duyck.

 7) Fix heap leak in PACKET_DIAG_MCLIST, from Mathias Krause.

 8) Ravalidate IPV6 datagram socket cached routes properly, particularly
    with UDP, from Martin KaFai Lau.

 9) Fix endian bug in RDS dp_ack_seq handling, from Qing Huang.

10) Fix stats typing in bcmgenet driver, from Eric Dumazet.

11) Openvswitch needs to orphan SKBs before ipv6 fragmentation handing,
    from Joe Stringer.

12) SPI device reference leak in spi_ks8895 PHY driver, from Mark Brown.

13) atl2 doesn't actually support scatter-gather, so don't advertise the
    feature.  From Ben Hucthings.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (72 commits)
  openvswitch: use flow protocol when recalculating ipv6 checksums
  Driver: Vmxnet3: set CHECKSUM_UNNECESSARY for IPv6 packets
  atl2: Disable unimplemented scatter/gather feature
  net/mlx4_en: Split SW RX dropped counter per RX ring
  net/mlx4_core: Don't allow to VF change global pause settings
  net/mlx4_core: Avoid repeated calls to pci enable/disable
  net/mlx4_core: Implement pci_resume callback
  net: phy: spi_ks8895: Don't leak references to SPI devices
  net: ethernet: davinci_emac: Fix platform_data overwrite
  net: ethernet: davinci_emac: Fix Unbalanced pm_runtime_enable
  qede: Fix single MTU sized packet from firmware GRO flow
  qede: Fix setting Skb network header
  qede: Fix various memory allocation error flows for fastpath
  tcp: Merge tx_flags and tskey in tcp_shifted_skb
  tcp: Merge tx_flags and tskey in tcp_collapse_retrans
  drivers: net: cpsw: fix wrong regs access in cpsw_ndo_open
  tcp: Fix SOF_TIMESTAMPING_TX_ACK when handling dup acks
  openvswitch: Orphan skbs before IPv6 defrag
  Revert "Prevent NUll pointer dereference with two PHYs on cpsw"
  VSOCK: Only check error on skb_recv_datagram when skb is NULL
  ...
2016-04-21 12:57:34 -07:00
Matt Redfearn 4589f450fb genirq: Dont allow affinity mask to be updated on IPIs
The IPI domain re-purposes the IRQ affinity to signify the mask of CPUs
that this IPI will deliver to. This must not be modified before the IPI
is destroyed again, so set the IRQ_NO_BALANCING flag to prevent the
affinity being overwritten by setup_affinity().

Without this, if an IPI is reserved for a single target CPU, then
allocated using __setup_irq(), the affinity is overwritten with
cpu_online_mask. When ipi_destroy() is subsequently called on a
multi-cpu system, it will attempt to free cpumask_weight() IRQs
that were never allocated, and crash.

Fixes: d17bf24e69 ("genirq: Add a new generic IPI reservation code to irq core")
Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: jason@lakedaemon.net
Cc: marc.zyngier@arm.com
Cc: ralf@linux-mips.org
Cc: Qais Yousef <qsyousef@gmail.com>
Cc: lisa.parratt@imgtec.com
Link: http://lkml.kernel.org/r/1461229712-13057-1-git-send-email-matt.redfearn@imgtec.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-04-21 12:05:15 +02:00
Davidlohr Bueso fe1bce9e21 futex: Acknowledge a new waiter in counter before plist
Otherwise an incoming waker on the dest hash bucket can miss
the waiter adding itself to the plist during the lockless
check optimization (small window but still the correct way
of doing this); similarly to the decrement counterpart.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: bigeasy@linutronix.de
Cc: dvhart@infradead.org
Cc: stable@kernel.org
Link: http://lkml.kernel.org/r/1461208164-29150-1-git-send-email-dave@stgolabs.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-04-21 11:06:09 +02:00
Sebastian Andrzej Siewior 89e9e66ba1 futex: Handle unlock_pi race gracefully
If userspace calls UNLOCK_PI unconditionally without trying the TID -> 0
transition in user space first then the user space value might not have the
waiters bit set. This opens the following race:

CPU0	    	      	    CPU1
uval = get_user(futex)
			    lock(hb)
lock(hb)
			    futex |= FUTEX_WAITERS
			    ....
			    unlock(hb)

cmpxchg(futex, uval, newval)

So the cmpxchg fails and returns -EINVAL to user space, which is wrong because
the futex value is valid.

To handle this (yes, yet another) corner case gracefully, check for a flag
change and retry.

[ tglx: Massaged changelog and slightly reworked implementation ]

Fixes: ccf9e6a80d ("futex: Make unlock_pi more robust")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: stable@vger.kernel.org
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Darren Hart <dvhart@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1460723739-5195-1-git-send-email-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-04-20 12:33:13 +02:00