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  1. Oct 29, 2013
  3. Oct 28, 2013
  5. Oct 27, 2013
    • Helge Deller's avatar
      parisc: Do not crash 64bit SMP kernels on machines with >= 4GB RAM · 54e181e0
      Helge Deller authored 
      

Since the beginning of the parisc-linux port, sometimes 64bit SMP kernels were
not able to bring up other CPUs than the monarch CPU and instead crashed the
kernel.  The reason was unclear, esp. since it involved various machines (e.g.
J5600, J6750 and SuperDome). Testing showed, that those crashes didn't happened
when less than 4GB were installed, or if a 32bit Linux kernel was booted.

In the end, the fix for those SMP problems is trivial:
During the early phase of the initialization of the CPUs, including the monarch
CPU, the PDC_PSW firmware function to enable WIDE (=64bit) mode is called.
It's documented that this firmware function may clobber various registers, and
one one of those possibly clobbered registers is %cr30 which holds the task
thread info pointer.

Now, if %cr30 would always have been clobbered, then this bug would have been
detected much earlier. But lots of testing finally showed, that - at least for
%cr30 - on some machines only the upper 32bits of the 64bit register suddenly
turned zero after the firmware call.

So, after finding the root cause, the explanation for the various crashes
became clear:
- On 32bit SMP Linux kernels all upper 32bit were zero, so we didn't faced this
  problem.
- Monarch CPUs in 64bit mode always booted sucessfully, because the inital task
  thread info pointer was below 4GB.
- Secondary CPUs booted sucessfully on machines with less than 4GB RAM because
  the upper 32bit were zero anyay.
- Secondary CPus failed to boot if we had more than 4GB RAM and the task thread
  info pointer was located above the 4GB boundary.

Finally, the patch to fix this problem is trivial by saving the %cr30 register
before the firmware call and restoring it afterwards.

Signed-off-by: default avatarHelge Deller <deller@gmx.de>
Signed-off-by: default avatarJohn David Anglin <dave.anglin@bell.net>
Cc: <stable@vger.kernel.org> # 2.6.12+
Signed-off-by: default avatarHelge Deller <deller@gmx.de>
      54e181e0
  7. Oct 26, 2013
    • Linus Torvalds's avatar
      Merge tag 'pm+acpi-3.12-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm · 20582e34
      Linus Torvalds authored 
      Pull ACPI and power management fixes from
 "These fix two bugs in the intel_pstate driver, a hibernate bug leading
  to nasty resume failures sometimes and acpi-cpufreq initialization bug
  that causes problems to happen during module unload when intel_pstate
  is in use.

  Specifics:

   - Fix for rounding errors in intel_pstate causing CPU utilization to
     be underestimated from Brennan Shacklett.

   - intel_pstate fix to always use the correct max pstate value when
     computing the min pstate from Dirk Brandewie.

   - Hibernation fix for deadlocking resume in cases when the probing of
     the device containing the image is deferred from Russ Dill.

   - acpi-cpufreq fix to prevent the module from staying in memory when
     the driver cannot be registered and then attempting to unregister
     things that have never been registered on exit"

* tag 'pm+acpi-3.12-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  acpi-cpufreq: Fail initialization if driver cannot be registered
  PM / hibernate: Move software_resume to late_initcall_sync
  intel_pstate: Correct calculation of min pstate value
  intel_pstate: Improve accuracy by not truncating until final result
      20582e34
    • Linus Torvalds's avatar
      Merge tag 'for-linus-20131025' of git://git.infradead.org/linux-mtd · d255c59a
      Linus Torvalds authored 
      Pull final mtd fixes from Brian Norris:
 "A few more last-minute regression fixes, prepared jointly by me and
  David Woodhouse:

   - Revert pxa3xx to its old name to avoid breaking existing
     'mtdparts=' boot strings.

   - Return GPMI NAND to its legacy ECC layout for backwards
     compatibility.  We will revisit this in 3.13.

  A note from David on the latter fix: 'This leaves a harmless cosmetic
  warning about an unused function.  At this point in the cycle I really
  don't care.'"

* tag 'for-linus-20131025' of git://git.infradead.org/linux-mtd:
  mtd: gpmi: fix ECC regression
  mtd: nand: pxa3xx: Fix registered MTD name
      d255c59a
    • Nicholas Bellinger's avatar
      vhost/scsi: Fix incorrect usage of get_user_pages_fast write parameter · 60a01f55
      Nicholas Bellinger authored 
      

This patch addresses a long-standing bug where the get_user_pages_fast()
write parameter used for setting the underlying page table entry permission
bits was incorrectly set to write=1 for data_direction=DMA_TO_DEVICE, and
passed into get_user_pages_fast() via vhost_scsi_map_iov_to_sgl().

However, this parameter is intended to signal WRITEs to pinned userspace
PTEs for the virtio-scsi DMA_FROM_DEVICE -> READ payload case, and *not*
for the virtio-scsi DMA_TO_DEVICE -> WRITE payload case.

This bug would manifest itself as random process segmentation faults on
KVM host after repeated vhost starts + stops and/or with lots of vhost
endpoints + LUNs.

Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Asias He <asias@redhat.com>
Cc: <stable@vger.kernel.org> # 3.6+
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
      60a01f55
    • Wei Yongjun's avatar
      target/pscsi: fix return value check · 58932e96
      Wei Yongjun authored 
      

In case of error, the function scsi_host_lookup() returns NULL
pointer not ERR_PTR(). The IS_ERR() test in the return value check
should be replaced with NULL test.

Signed-off-by: default avatarWei Yongjun <yongjun_wei@trendmicro.com.cn>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
      58932e96
    • Linus Torvalds's avatar
      Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs · f55ac56d
      Linus Torvalds authored 
      Pull vfs fixes (try two) from Al Viro:
 "nfsd performance regression fix + seq_file lseek(2) fix"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  seq_file: always update file->f_pos in seq_lseek()
  nfsd regression since delayed fput()
      f55ac56d
    • David Woodhouse's avatar
      mtd: gpmi: fix ECC regression · 031e2777
      David Woodhouse authored 
      The "legacy" ECC layout used until 3.12-rc1 uses all the OOB area by
computing the ECC strength and ECC step size ourselves.

Commit 2febcdf8

 ("mtd: gpmi: set the BCHs geometry with the ecc info")
makes the driver use the ECC info (ECC strength and ECC step size)
provided by the MTD code, and creates a different NAND ECC layout
for the BCH, and use the new ECC layout. This causes a regression:

   We can not mount the ubifs which was created by the old NAND ECC layout.

This patch fixes this issue by reverting to the legacy ECC layout.

We will probably introduce a new device-tree property to indicate that
the new ECC layout can be used. For now though, for the imminent 3.12
release, we just unconditionally revert to the 3.11 behaviour.

This leaves a harmless cosmetic warning about an unused function. At
this point in the cycle I really don't care.

Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: default avatarBrian Norris <computersforpeace@gmail.com>
Acked-by: default avatarHuang Shijie <b32955@freescale.com>
Acked-by: default avatarMarek Vasut <marex@denx.de>
Tested-by: default avatarMarek Vasut <marex@denx.de>
      031e2777
  9. Oct 25, 2013
  11. Oct 24, 2013
    • Joseph Schuchart's avatar
      perf script python: Fix mem leak due to missing Py_DECREFs on dict entries · c0268e8d
      Joseph Schuchart authored 
      We are using the Python scripting interface in perf to extract kernel
events relevant for performance analysis of HPC codes. We noticed that
the "perf script" call allocates a significant amount of memory (in the
order of several 100 MiB) during it's run, e.g. 125 MiB for a 25 MiB
input file:

  $> perf record -o perf.data -a -R -g fp \
       -e power:cpu_frequency -e sched:sched_switch \
       -e sched:sched_migrate_task -e sched:sched_process_exit \
       -e sched:sched_process_fork -e sched:sched_process_exec \
       -e cycles  -m 4096 --freq 4000
  $> /usr/bin/time perf script -i perf.data -s dummy_script.py
  0.84user 0.13system 0:01.92elapsed 51%CPU (0avgtext+0avgdata
  125532maxresident)k
  73072inputs+0outputs (57major+33086minor)pagefaults 0swaps

Upon further investigation using the valgrind massif tool, we noticed
that Python objects that are created in trace-event-python.c via
PyString_FromString*() (and their Integer and Long counterparts) are
never free'd.

The reason for this seem to be missing Py_DECREF calls on the objects
that are returned by these functions and stored in the Python
dictionaries. The Python dictionaries do not steal references (as
opposed to Python tuples and lists) but instead add their own reference.

Hence, the reference that is returned by these object creation functions
is never released and the memory is leaked. (see [1,2])

The attached patch fixes this by wrapping all relevant calls to
PyDict_SetItemString() and decrementing the reference counter
immediately after the Python function call.

This reduces the allocated memory to a reasonable amount:

  $> /usr/bin/time perf script -i perf.data -s dummy_script.py
  0.73user 0.05system 0:00.79elapsed 99%CPU (0avgtext+0avgdata
  49132maxresident)k
  0inputs+0outputs (0major+14045minor)pagefaults 0swaps

For comparison, with a 120 MiB input file the memory consumption
reported by time drops from almost 600 MiB to 146 MiB.

The patch has been tested using Linux 3.8.2 with Python 2.7.4 and Linux
3.11.6 with Python 2.7.5.

Please let me know if you need any further information.

[1] http://docs.python.org/2/c-api/tuple.html#PyTuple_SetItem
[2] http://docs.python.org/2/c-api/dict.html#PyDict_SetItemString



Signed-off-by: default avatarJoseph Schuchart <joseph.schuchart@tu-dresden.de>
Reviewed-by: default avatarTom Zanussi <tom.zanussi@linux.intel.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Link: http://lkml.kernel.org/r/1381468543-25334-4-git-send-email-namhyung@kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      c0268e8d
    • Nicholas Bellinger's avatar
      target: Fail XCOPY for non matching source + destination block_size · 48502ddb
      Nicholas Bellinger authored 
      

This patch adds an explicit check + failure for XCOPY I/O to source +
destination devices with a non-matching block_size.

This limitiation is currently due to the fact that the scatterlist
memory allocated for the XCOPY READ operation is passed zero-copy
to the XCOPY WRITE operation.

Reported-by: default avatarThomas Glanzmann <thomas@glanzmann.de>
Reported-by: default avatarDouglas Gilbert <dgilbert@interlog.com>
Cc: Thomas Glanzmann <thomas@glanzmann.de>
Cc: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
      48502ddb
    • Nicholas Bellinger's avatar
      target: Generate failure for XCOPY I/O with non-zero scsi_status · 8a955d6d
      Nicholas Bellinger authored 
      

This patch adds the missing non-zero se_cmd->scsi_status check required
for local XCOPY I/O within target_xcopy_issue_pt_cmd() to signal an
exception case failure.

This will trigger the generation of SAM_STAT_CHECK_CONDITION status
from within target_xcopy_do_work() process context code.

Reported-by: default avatarThomas Glanzmann <thomas@glanzmann.de>
Reported-by: default avatarDouglas Gilbert <dgilbert@interlog.com>
Cc: Thomas Glanzmann <thomas@glanzmann.de>
Cc: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
      8a955d6d
    • Nicholas Bellinger's avatar
      target: Add missing XCOPY I/O operation sense_buffer · 366bda19
      Nicholas Bellinger authored 
      

This patch adds the missing xcopy_pt_cmd->sense_buffer[] required for
correctly handling CHECK_CONDITION exceptions within the locally
generated XCOPY I/O path.

Also update target_xcopy_read_source() + target_xcopy_setup_pt_cmd()
to pass this buffer into transport_init_se_cmd() to correctly setup
se_cmd->sense_buffer.

Reported-by: default avatarThomas Glanzmann <thomas@glanzmann.de>
Reported-by: default avatarDouglas Gilbert <dgilbert@interlog.com>
Cc: Thomas Glanzmann <thomas@glanzmann.de>
Cc: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
      366bda19
    • Ingo Molnar's avatar
      Merge tag 'perf-core-for-mingo' of... · 2f5e9880
      Ingo Molnar authored 
      Merge tag 'perf-core-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux

 into perf/core

Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:

  * Show progress on histogram collapsing, that can take a long time, from
    Namhyung Kim.

  * Support "$vars" meta argument syntax for local variables, allowing
    asking for all possible variables at a given probe point to be
    collected when it hits, from Masami Hiramatsu.

  * Address the root cause of that 'perf sched' stack initialization build
    slowdown, by programmatically setting a big array after moving the
    global variable back to the stack. Fix from Adrian Hunter.

  * Do not repipe attributes to a perf.data file in 'perf inject',
    fix from Adrian Hunter

  * Change the procps visible command-name of invididual benchmark tests
    plus cleanups, from Ingo Molnar.

  * Do not accept parse_tag_value() overflow, fix from Adrian Hunter.

  * Validate that mmap_pages is not too big. From Adrian Hunter.

  * Fix non-debug build, from Adrian Hunter.

  * Clarify the "sample parsing" test entry, from Arnaldo Carvalho de Melo.

  * Consider PERF_SAMPLE_TRANSACTION in the "sample parsing" test,
    from Arnaldo Carvalho de Melo.

Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      2f5e9880