Tejun reported that his resume was failing due to order-3 allocations
from sched_domain building.

Replace the NR_CPUS arrays in there with a dynamically allocated
array.
Reported-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-7cysnkw1gik45r864t1nkudh@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Tejun reported that his resume was failing due to order-3 allocations
from sched_domain building.

Replace the NR_CPUS arrays in there with a dynamically allocated
array.
Reported-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NJuri Lelli <juri.lelli@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-kat4gl1m5a6dwy6nzuqox45e@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Michael Kerrisk noticed that creating SCHED_DEADLINE reservations
with certain parameters (e.g, a runtime of something near 2^64 ns)
can cause a system freeze for some amount of time.

The problem is that in the interface we have

 u64 sched_runtime;

while internally we need to have a signed runtime (to cope with
budget overruns)

 s64 runtime;

At the time we setup a new dl_entity we copy the first value in
the second. The cast turns out with negative values when
sched_runtime is too big, and this causes the scheduler to go crazy
right from the start.

Moreover, considering how we deal with deadlines wraparound

 (s64)(a - b) < 0

we also have to restrict acceptable values for sched_{deadline,period}.

This patch fixes the thing checking that user parameters are always
below 2^63 ns (still large enough for everyone).

It also rewrites other conditions that we check, since in
__checkparam_dl we don't have to deal with deadline wraparounds
and what we have now erroneously fails when the difference between
values is too big.
Reported-by: NMichael Kerrisk <mtk.manpages@gmail.com>
Suggested-by: NPeter Zijlstra <peterz@infradead.org>
Signed-off-by: NJuri Lelli <juri.lelli@gmail.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Cc: Dario Faggioli<raistlin@linux.it>
Cc: Dave Jones <davej@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140513141131.20d944f81633ee937f256385@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

The way we read POSIX one should only call sched_getparam() when
sched_getscheduler() returns either SCHED_FIFO or SCHED_RR.

Given that we currently return sched_param::sched_priority=0 for all
others, extend the same behaviour to SCHED_DEADLINE.
Requested-by: NMichael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NMichael Kerrisk <mtk.manpages@gmail.com>
Cc: Dario Faggioli <raistlin@linux.it>
Cc: linux-man <linux-man@vger.kernel.org>
Cc: "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>
Cc: Juri Lelli <juri.lelli@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20140512205034.GH13467@laptop.programming.kicks-ass.netSigned-off-by: NIngo Molnar <mingo@kernel.org>

The scheduler uses policy=-1 to preserve the current policy state to
implement sys_sched_setparam(), this got exposed to userspace by
accident through sys_sched_setattr(), cure this.
Reported-by: NMichael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NMichael Kerrisk <mtk.manpages@gmail.com>
Cc: <stable@vger.kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140509085311.GJ30445@twins.programming.kicks-ass.netSigned-off-by: NIngo Molnar <mingo@kernel.org>

The documented[1] behavior of sched_attr() in the proposed man page text is:

    sched_attr::size must be set to the size of the structure, as in
    sizeof(struct sched_attr), if the provided structure is smaller
    than the kernel structure, any additional fields are assumed
    '0'. If the provided structure is larger than the kernel structure,
    the kernel verifies all additional fields are '0' if not the
    syscall will fail with -E2BIG.

As currently implemented, sched_copy_attr() returns -EFBIG for
for this case, but the logic in sys_sched_setattr() converts that
error to -EFAULT. This patch fixes the behavior.

[1] http://thread.gmane.org/gmane.linux.kernel/1615615/focus=1697760Signed-off-by: NMichael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/536CEC17.9070903@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Also initialize the per-sd variables for newidle load balancing
in sd_numa_init().
Signed-off-by: NJason Low <jason.low2@hp.com>
Acked-by: morten.rasmussen@arm.com
Cc: daniel.lezcano@linaro.org
Cc: alex.shi@linaro.org
Cc: preeti@linux.vnet.ibm.com
Cc: efault@gmx.de
Cc: vincent.guittot@linaro.org
Cc: aswin@hp.com
Cc: chegu_vinod@hp.com
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1398303035-18255-3-git-send-email-jason.low2@hp.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

The following commit:

  e5fc6611 ("sched: Fix race in idle_balance()")

can potentially cause rq->max_idle_balance_cost to not be updated,
even when load_balance(NEWLY_IDLE) is attempted and the per-sd
max cost value is updated.

Preeti noticed a similar issue with updating rq->next_balance.

In this patch, we fix this by making sure we still check/update those values
even if a task gets enqueued while browsing the domains.
Signed-off-by: NJason Low <jason.low2@hp.com>
Reviewed-by: NPreeti U Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Cc: morten.rasmussen@arm.com
Cc: aswin@hp.com
Cc: daniel.lezcano@linaro.org
Cc: alex.shi@linaro.org
Cc: efault@gmx.de
Cc: vincent.guittot@linaro.org
Link: http://lkml.kernel.org/r/1398725155-7591-2-git-send-email-jason.low2@hp.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Tim wrote:

 "The current code will call pick_next_task_fair a second time in the
  slow path if we did not pull any task in our first try.  This is
  really unnecessary as we already know no task can be pulled and it
  doubles the delay for the cpu to enter idle.

  We instrumented some network workloads and that saw that
  pick_next_task_fair is frequently called twice before a cpu enters
  idle.  The call to pick_next_task_fair can add non trivial latency as
  it calls load_balance which runs find_busiest_group on an hierarchy of
  sched domains spanning the cpus for a large system.  For some 4 socket
  systems, we saw almost 0.25 msec spent per call of pick_next_task_fair
  before a cpu can be idled."

Optimize the second call away for the common case and document the
dependency.
Reported-by: NTim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Len Brown <len.brown@intel.com>
Link: http://lkml.kernel.org/r/20140424100047.GP11096@twins.programming.kicks-ass.netSigned-off-by: NIngo Molnar <mingo@kernel.org>

The check at the beginning of cpupri_find() makes sure that the task_pri
variable does not exceed the cp->pri_to_cpu array length. But that length
is CPUPRI_NR_PRIORITIES not MAX_RT_PRIO, where it will miss the last two
priorities in that array.

As task_pri is computed from convert_prio() which should never be bigger
than CPUPRI_NR_PRIORITIES, if the check should cause a panic if it is
hit.
Reported-by: NMike Galbraith <umgwanakikbuti@gmail.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1397015410.5212.13.camel@marge.simpson.netSigned-off-by: NIngo Molnar <mingo@kernel.org>

Free cpudl->free_cpus allocated in cpudl_init().
Signed-off-by: NLi Zefan <lizefan@huawei.com>
Acked-by: NJuri Lelli <juri.lelli@gmail.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Cc: <stable@vger.kernel.org> # 3.14+
Link: http://lkml.kernel.org/r/534F36CE.2000409@huawei.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

yield_task_dl() is broken:

 o it forces current to be throttled setting its runtime to zero;
 o it sets current's dl_se->dl_new to one, expecting that dl_task_timer()
   will queue it back with proper parameters at replenish time.

Unfortunately, dl_task_timer() has this check at the very beginning:

	if (!dl_task(p) || dl_se->dl_new)
		goto unlock;

So, it just bails out and the task is never replenished. It actually
yielded forever.

To fix this, introduce a new flag indicating that the task properly yielded
the CPU before its current runtime expired. While this is a little overdoing
at the moment, the flag would be useful in the future to discriminate between
"good" jobs (of which remaining runtime could be reclaimed, i.e. recycled)
and "bad" jobs (for which dl_throttled task has been set) that needed to be
stopped.
Reported-by: Nyjay.kim <yjay.kim@lge.com>
Signed-off-by: NJuri Lelli <juri.lelli@gmail.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140429103953.e68eba1b2ac3309214e3dc5a@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Russell reported, that irqtime_account_idle_ticks() takes ages due to:

       for (i = 0; i < ticks; i++)
               irqtime_account_process_tick(current, 0, rq);

It's sad, that this code was written way _AFTER_ the NOHZ idle
functionality was available. I charge myself guitly for not paying
attention when that crap got merged with commit abb74cef ("sched:
Export ns irqtimes through /proc/stat")

So instead of looping nr_ticks times just apply the whole thing at
once.

As a side note: The whole cputime_t vs. u64 business in that context
wants to be cleaned up as well. There is no point in having all these
back and forth conversions. Lets standardise on u64 nsec for all
kernel internal accounting and be done with it. Everything else does
not make sense at all for fine grained accounting. Frederic, can you
please take care of that?
Reported-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Reviewed-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Cc: Venkatesh Pallipadi <venki@google.com>
Cc: Shaun Ruffell <sruffell@digium.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1405022307000.6261@ionos.tec.linutronix.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

When 'flags' argument to sched_{set,get}attr() syscalls were
added in:

  6d35ab48 ("sched: Add 'flags' argument to sched_{set,get}attr() syscalls")

no description for 'flags' was added. It causes the following warnings on "make htmldocs":

  Warning(/kernel/sched/core.c:3645): No description found for parameter 'flags'
  Warning(/kernel/sched/core.c:3789): No description found for parameter 'flags'
Signed-off-by: NMasanari Iida <standby24x7@gmail.com>
Cc: peterz@infradead.org
Link: http://lkml.kernel.org/r/1397753955-2914-1-git-send-email-standby24x7@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Pull gpio fixes from Linus Walleij:
 "A small batch of GPIO fixes for the v3.15 series.  I expect more to
  come in but I'm a bit behind on mail, might as well get these to you
  right now:

   - Change a crucial semantic ordering in the GPIO irqchip helpers

   - Fix two nasty regressions in the ACPI gpiolib extensions"

* tag 'gpio-v3.15-2' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio:
  gpio / ACPI: Prevent potential wrap of GPIO value on OpRegion read
  gpio / ACPI: Don't crash on NULL chip->dev
  gpio: set data first, then chip and handler

Pull x86 vdso fix from Peter Anvin:
 "This is a single build fix for building with gold as opposed to GNU
  ld.  It got queued up separately and was expected to be pushed during
  the merge window, but it got left behind"

* 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, vdso: Make the vdso linker script compatible with Gold

Pull UML fixes from Richard Weinberger:
 "Assorted fixes for UML"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
  um: Memory corruption on startup
  um: Missing pipe handling
  uml: Simplify tempdir logic.

Pull ext4 fixes from Ted Ts'o:
 "These are regression and bug fixes for ext4.

  We had a number of new features in ext4 during this merge window
  (ZERO_RANGE and COLLAPSE_RANGE fallocate modes, renameat, etc.) so
  there were many more regression and bug fixes this time around.  It
  didn't help that xfstests hadn't been fully updated to fully stress
  test COLLAPSE_RANGE until after -rc1"

* tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (31 commits)
  ext4: disable COLLAPSE_RANGE for bigalloc
  ext4: fix COLLAPSE_RANGE failure with 1KB block size
  ext4: use EINVAL if not a regular file in ext4_collapse_range()
  ext4: enforce we are operating on a regular file in ext4_zero_range()
  ext4: fix extent merging in ext4_ext_shift_path_extents()
  ext4: discard preallocations after removing space
  ext4: no need to truncate pagecache twice in collapse range
  ext4: fix removing status extents in ext4_collapse_range()
  ext4: use filemap_write_and_wait_range() correctly in collapse range
  ext4: use truncate_pagecache() in collapse range
  ext4: remove temporary shim used to merge COLLAPSE_RANGE and ZERO_RANGE
  ext4: fix ext4_count_free_clusters() with EXT4FS_DEBUG and bigalloc enabled
  ext4: always check ext4_ext_find_extent result
  ext4: fix error handling in ext4_ext_shift_extents
  ext4: silence sparse check warning for function ext4_trim_extent
  ext4: COLLAPSE_RANGE only works on extent-based files
  ext4: fix byte order problems introduced by the COLLAPSE_RANGE patches
  ext4: use i_size_read in ext4_unaligned_aio()
  fs: disallow all fallocate operation on active swapfile
  fs: move falloc collapse range check into the filesystem methods
  ...

The reverse case of this race (you must msync before read) is
well known. This is the not so common one.

It can be triggered only on systems which do a lot of task
switching and only at UML startup. If you are starting 200+ UMLs
~ 0.5% will always die without this fix.
Signed-off-by: NAnton Ivanov <antivano@cisco.com>
[rw: minor whitespace fixes]
Signed-off-by: NRichard Weinberger <richard@nod.at>

UML does not handle sigpipe. As a result when running it under
expect or redirecting the IO from the console to an external program
it will crash if the program stops or exits.
Signed-off-by: NAnton Ivanov <antivano@cisco.com>
Signed-off-by: NRichard Weinberger <richard@nod.at>

Inferring the mount hierarchy correctly from /proc/mounts is hard when MS_MOVE
may have been used, and the previous code did it wrongly. This change simplifies
the logic to only require that /dev/shm be _on_ tmpfs (which can be checked
trivially with statfs) rather than that it be a _mountpoint_ of tmpfs, since
there isn't a compelling reason to be that strict. We also now check for tmpfs
on whatever directory we ultimately use so that the user is better informed.

This change also moves the more standard TMPDIR environment variable check ahead
of the others.

Applies to 3.12.
Signed-off-by: NTristan Schmelcher <tschmelcher@google.com>
Signed-off-by: NRichard Weinberger <richard@nod.at>

Pull slave-dmaengine fixes from Vinod Koul:
 "Back from long weekend here in India and now the time to send fixes
  for slave dmaengine.
   - Dan's fix of sirf xlate code
   - Jean's fix for timberland
   - edma fixes by Sekhar for SG handling and Yuan for changing init
     call"

* 'fixes' of git://git.infradead.org/users/vkoul/slave-dma:
  dma: fix eDMA driver as a subsys_initcall
  dmaengine: sirf: off by one in of_dma_sirfsoc_xlate()
  platform: Fix timberdale dependencies
  dma: edma: fix incorrect SG list handling

Pull iommu fixes from Joerg Roedel:
 "Fixes for regressions:

   - fix wrong IOMMU enumeration causing some SCSI device drivers
     initialization failures
   - ARM-SMMU fixes for a panic condition and a wrong return value"

* tag 'iommu-fixes-v3.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
  iommu/arm-smmu: fix panic in arm_smmu_alloc_init_pte
  iommu/arm-smmu: Return 0 on unmap failure
  iommu/vt-d: fix bug in matching PCI devices with DRHD/RMRR descriptors
  iommu/vt-d: Fix get_domain_for_dev() handling of upstream PCIe bridges
  iommu/vt-d: fix memory leakage caused by commit ea8ea460

Pull perf tooling fixes from Ingo Molnar:
 "Three small tooling fixes"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf tools: Improve error reporting
  perf tools: Adjust symbols in VDSO
  perf kvm: Fix 'Min time' counting in report command

Merge tag 'perf-urgent-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf into perf/urgent

Pull perf/urgent fixes from Jiri Olsa:

User visible changes:

  * Adjust symbols in VDSO to properly resolve its function names (Vladimir Nikulichev)

  * Improve error reporting for record session failure (Adrien BAK)

  * Fix 'Min time' counting in report command (Alexander Yarygin)
Signed-off-by: NJiri Olsa <jolsa@redhat.com>
Signed-off-by: NIngo Molnar <mingo@kernel.org>

In the current version, when using perf record, if something goes
wrong in tools/perf/builtin-record.c:375
  session = perf_session__new(file, false, NULL);

The error message:
"Not enough memory for reading per file header"

is issued. This error message seems to be outdated and is not very
helpful. This patch proposes to replace this error message by
"Perf session creation failed"

I believe this issue has been brought to lkml:
https://lkml.org/lkml/2014/2/24/458
although this patch only tackles a (small) part of the issue.

Additionnaly, this patch improves error reporting in
tools/perf/util/data.c open_file_write.

Currently, if the call to open fails, the user is unaware of it.
This patch logs the error, before returning the error code to
the caller.
Reported-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NAdrien BAK <adrien.bak@metascale.org>
Link: http://lkml.kernel.org/r/1397786443.3093.4.camel@beast
[ Reorganize the changelog into paragraphs ]
[ Added empty line after fd declaration in open_file_write ]
Signed-off-by: NJiri Olsa <jolsa@redhat.com>

pert-report doesn't resolve function names in VDSO:

$ perf report --stdio -g flat,0.0,15,callee --sort pid
...
            8.76%
               0x7fff6b1fe861
               __gettimeofday
               ACE_OS::gettimeofday()
...

In this case symbol values should be adjusted the same way as for executables,
relocatable objects and prelinked libraries.

After fix:

$ perf report --stdio -g flat,0.0,15,callee --sort pid
...
            8.76%
               __vdso_gettimeofday
               __gettimeofday
               ACE_OS::gettimeofday()
Signed-off-by: NVladimir Nikulichev <nvs@tbricks.com>
Tested-by: NNamhyung Kim <namhyung@kernel.org>
Reviewed-by: NAdrian Hunter <adrian.hunter@intel.com>
Link: http://lkml.kernel.org/r/969812.163009436-sendEmail@nvsSigned-off-by: NJiri Olsa <jolsa@redhat.com>

Every event in the perf-kvm has a 'stats' structure, which contains
max/min/average/etc times of handling this event.
The problem is that the 'perf-kvm stat report' command always shows
that 'min time' is 0us for every event. Example:

 # perf kvm stat report

 Analyze events for all VCPUs:

    VM-EXIT    Samples  Samples%     Time%   Min Time   Max Time Avg time
  [..]
  0xB2 MSCH         12     0.07%     0.00%        0us        8us 7.31us ( +-   2.11% )
  0xB2 CHSC         12     0.07%     0.00%        0us       18us 9.39us ( +-   9.49% )
  0xB2 STPX          8     0.05%     0.00%        0us        2us 1.88us ( +-   7.18% )
  0xB2 STSI          7     0.04%     0.00%        0us       44us 16.49us ( +-  38.20% )
  [..]

This happens because the 'stats' structure is not initialized and
stats->min equals to 0. Lets initialize the structure for every
event after its allocation using init_stats() function. This initializes
stats->min to -1 and makes 'Min time' statistics counting work:

 # perf kvm stat report

 Analyze events for all VCPUs:

    VM-EXIT    Samples  Samples%     Time%   Min Time   Max Time Avg time
  [..]
  0xB2 MSCH         12     0.07%     0.00%        6us        8us 7.31us ( +-   2.11% )
  0xB2 CHSC         12     0.07%     0.00%        7us       18us 9.39us ( +-   9.49% )
  0xB2 STPX          8     0.05%     0.00%        1us        2us 1.88us ( +-   7.18% )
  0xB2 STSI          7     0.04%     0.00%        1us       44us 16.49us ( +-  38.20% )
  [..]
Signed-off-by: NAlexander Yarygin <yarygin@linux.vnet.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Link: http://lkml.kernel.org/r/1397053319-2130-3-git-send-email-borntraeger@de.ibm.com
[ Fixing the perf examples changelog output ]
Signed-off-by: NJiri Olsa <jolsa@redhat.com>

Once COLLAPSE RANGE is be disable for ext4 with bigalloc feature till finding
root-cause of problem. It will be enable with fixing that regression of
xfstest(generic 075 and 091) again.
Signed-off-by: NNamjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: NAshish Sangwan <a.sangwan@samsung.com>
Reviewed-by: NLukas Czerner <lczerner@redhat.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

When formatting with 1KB or 2KB(not aligned with PAGE SIZE) block
size, xfstests generic/075 and 091 are failing. The offset supplied to
function truncate_pagecache_range is block size aligned. In this
function start offset is re-aligned to PAGE_SIZE by rounding_up to the
next page boundary.  Due to this rounding up, old data remains in the
page cache when blocksize is less than page size and start offset is
not aligned with page size.  In case of collapse range, we need to
align start offset to page size boundary by doing a round down
operation instead of round up.
Signed-off-by: NNamjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: NAshish Sangwan <a.sangwan@samsung.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

A va_list needs to be copied in case it needs to be used twice.

Thanks to Hugh for debugging this issue, leading to various panics.

Tested:

  lpq84:~# echo "|/foobar12345 %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h" >/proc/sys/kernel/core_pattern

'produce_core' is simply : main() { *(int *)0 = 1;}

  lpq84:~# ./produce_core
  Segmentation fault (core dumped)
  lpq84:~# dmesg | tail -1
  [  614.352947] Core dump to |/foobar12345 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 (null) pipe failed

Notice the last argument was replaced by a NULL (we were lucky enough to
not crash, but do not try this on your production machine !)

After fix :

  lpq83:~# echo "|/foobar12345 %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h" >/proc/sys/kernel/core_pattern
  lpq83:~# ./produce_core
  Segmentation fault
  lpq83:~# dmesg | tail -1
  [  740.800441] Core dump to |/foobar12345 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 pipe failed

Fixes: 5fe9d8ca ("coredump: cn_vprintf() has no reason to call vsnprintf() twice")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Diagnosed-by: NHugh Dickins <hughd@google.com>
Acked-by: NOleg Nesterov <oleg@redhat.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@vger.kernel.org # 3.11+
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pull x86 fix from Ingo Molnar:
 "This fixes the preemption-count imbalance crash reported by Owen
  Kibel"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mce: Fix CMCI preemption bugs

Pull scheduler fixes from Ingo Molnar:
 "Two fixes:

   - a SCHED_DEADLINE task selection fix
   - a sched/numa related lockdep splat fix"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched: Check for stop task appearance when balancing happens
  sched/numa: Fix task_numa_free() lockdep splat

Pull perf fixes from Ingo Molnar:
 "Two kernel side fixes:

   - an Intel uncore PMU driver potential crash fix
   - a kprobes/perf-call-graph interaction fix"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/intel: Use rdmsrl_safe() when initializing RAPL PMU
  kprobes/x86: Fix page-fault handling logic

Pull drm fixes from Dave Airlie:
 "Unfortunately this contains no easter eggs, its a bit larger than I'd
  like, but I included a patch that just moves code from one file to
  another and I'd like to avoid merge conflicts with that later, so it
  makes it seem worse than it is,

  Otherwise:
   - radeon: fixes to use new microcode to stabilise some cards, use
     some common displayport code, some runtime pm fixes, pll regression
     fixes
   - i915: fix for some context oopses, a warn in a used path, backlight
     fixes
   - nouveau: regression fix
   - omap: a bunch of fixes"

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux: (51 commits)
  drm: bochs: drop unused struct fields
  drm: bochs: add power management support
  drm: cirrus: add power management support
  drm: Split out drm_probe_helper.c from drm_crtc_helper.c
  drm/plane-helper: Don't fake-implement primary plane disabling
  drm/ast: fix value check in cbr_scan2
  drm/nouveau/bios: fix a bit shift error introduced by 457e77b2
  drm/radeon/ci: make sure mc ucode is loaded before checking the size
  drm/radeon/si: make sure mc ucode is loaded before checking the size
  drm/radeon: improve PLL params if we don't match exactly v2
  drm/radeon: memory leak on bo reservation failure. v2
  drm/radeon: fix VCE fence command
  drm/radeon: re-enable mclk dpm on R7 260X asics
  drm/radeon: add support for newer mc ucode on CI (v2)
  drm/radeon: add support for newer mc ucode on SI (v2)
  drm/radeon: apply more strict limits for PLL params v2
  drm/radeon: update CI DPM powertune settings
  drm/radeon: fix runpm handling on APUs (v4)
  drm/radeon: disable mclk dpm on R7 260X
  drm/tegra: Remove gratuitous pad field
  ...

Some i2c fixes over DisplayPort.

* 'drm-next-3.15-wip' of git://people.freedesktop.org/~deathsimple/linux:
  drm/radeon: Improve vramlimit module param documentation
  drm/radeon: fix audio pin counts for DCE6+ (v2)
  drm/radeon/dp: switch to the common i2c over aux code
  drm/dp/i2c: Update comments about common i2c over dp assumptions (v3)
  drm/dp/i2c: send bare addresses to properly reset i2c connections (v4)
  drm/radeon/dp: handle zero sized i2c over aux transactions (v2)
  drm/i915: support address only i2c-over-aux transactions
  drm/tegra: dp: Support address-only I2C-over-AUX transactions

Pull more networking fixes from David Miller:

 1) Fix mlx4_en_netpoll implementation, it needs to schedule a NAPI
    context, not synchronize it.  From Chris Mason.

 2) Ipv4 flow input interface should never be zero, it should be
    LOOPBACK_IFINDEX instead.  From Cong Wang and Julian Anastasov.

 3) Properly configure MAC to PHY connection in mvneta devices, from
    Thomas Petazzoni.

 4) sys_recv should use SYSCALL_DEFINE.  From Jan Glauber.

 5) Tunnel driver ioctls do not use the correct namespace, fix from
    Nicolas Dichtel.

 6) Fix memory leak on seccomp filter attach, from Kees Cook.

 7) Fix lockdep warning for nested vlans, from Ding Tianhong.

 8) Crashes can happen in SCTP due to how the auth_enable value is
    managed, fix from Vlad Yasevich.

 9) Wireless fixes from John W Linville and co.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (45 commits)
  net: sctp: cache auth_enable per endpoint
  tg3: update rx_jumbo_pending ring param only when jumbo frames are enabled
  vlan: Fix lockdep warning when vlan dev handle notification
  seccomp: fix memory leak on filter attach
  isdn: icn: buffer overflow in icn_command()
  ip6_tunnel: use the right netns in ioctl handler
  sit: use the right netns in ioctl handler
  ip_tunnel: use the right netns in ioctl handler
  net: use SYSCALL_DEFINEx for sys_recv
  net: mdio-gpio: Add support for separate MDI and MDO gpio pins
  net: mdio-gpio: Add support for active low gpio pins
  net: mdio-gpio: Use devm_ functions where possible
  ipv4, route: pass 0 instead of LOOPBACK_IFINDEX to fib_validate_source()
  ipv4, fib: pass LOOPBACK_IFINDEX instead of 0 to flowi4_iif
  mlx4_en: don't use napi_synchronize inside mlx4_en_netpoll
  net: mvneta: properly configure the MAC <-> PHY connection in all situations
  net: phy: add minimal support for QSGMII PHY
  sfc:On MCDI timeout, issue an FLR (and mark MCDI to fail-fast)
  mwifiex: fix hung task on command timeout
  mwifiex: process event before command response
  ...

Pull cifs fixes from Steve French:
 "A set of 5 small cifs fixes"

* 'for-next' of git://git.samba.org/sfrench/cifs-2.6:
  cif: fix dead code
  cifs: fix error handling cifs_user_readv
  fs: cifs: remove unused variable.
  Return correct error on query of xattr on file with empty xattrs
  cifs: Wait for writebacks to complete before attempting write.

Pull char/misc driver fixes from Greg KH:
 "Here are a few driver fixes for char/misc drivers that resolve
  reported issues.

  All have been in linux-next successfully for a few days"

* tag 'char-misc-3.15-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  Drivers: hv: vmbus: Negotiate version 3.0 when running on ws2012r2 hosts
  Tools: hv: Handle the case when the target file exists correctly
  vme_tsi148: Utilize to_pci_dev() macro
  vme_tsi148: Fix PCI address mapping assumption
  vme_tsi148: Fix typo in tsi148_slave_get()
  w1: avoid recursive device_add
  w1: fix netlink refcnt leak on error path
  misc: Grammar s/addition/additional/
  drivers: mcb: fix memory leak in chameleon_parse_cells() error path
  mei: ignore client writing state during cb completion
  mei: me: do not load the driver if the FW doesn't support MEI interface
  GenWQE: Increase driver version number
  GenWQE: Fix multithreading problems
  GenWQE: Ensure rc is not returning an uninitialized value
  GenWQE: Add wmb before DDCB is started
  GenWQE: Enable access to VPD flash area