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  1. 31 10月, 2013 3 次提交
    • G
      memcg: use __this_cpu_sub() to dec stats to avoid incorrect subtrahend casting · 5e8cfc3c
      由 Greg Thelen 提交于 
      As of commit 3ea67d06 ("memcg: add per cgroup writeback pages
accounting") memcg counter errors are possible when moving charged
memory to a different memcg.  Charge movement occurs when processing
writes to memory.force_empty, moving tasks to a memcg with
memcg.move_charge_at_immigrate=1, or memcg deletion.

An example showing error after memory.force_empty:

  $ cd /sys/fs/cgroup/memory
  $ mkdir x
  $ rm /data/tmp/file
  $ (echo $BASHPID >> x/tasks && exec mmap_writer /data/tmp/file 1M) &
  [1] 13600
  $ grep ^mapped x/memory.stat
  mapped_file 1048576
  $ echo 13600 > tasks
  $ echo 1 > x/memory.force_empty
  $ grep ^mapped x/memory.stat
  mapped_file 4503599627370496

mapped_file should end with 0.
  4503599627370496 == 0x10,0000,0000,0000 == 0x100,0000,0000 pages
  1048576          == 0x10,0000           == 0x100 pages

This issue only affects the source memcg on 64 bit machines; the
destination memcg counters are correct.  So the rmdir case is not too
important because such counters are soon disappearing with the entire
memcg.  But the memcg.force_empty and memory.move_charge_at_immigrate=1
cases are larger problems as the bogus counters are visible for the
(possibly long) remaining life of the source memcg.

The problem is due to memcg use of __this_cpu_from(.., -nr_pages), which
is subtly wrong because it subtracts the unsigned int nr_pages (either
-1 or -512 for THP) from a signed long percpu counter.  When
nr_pages=-1, -nr_pages=0xffffffff.  On 64 bit machines stat->count[idx]
is signed 64 bit.  So memcg's attempt to simply decrement a count (e.g.
from 1 to 0) boils down to:

  long count = 1
  unsigned int nr_pages = 1
  count += -nr_pages  /* -nr_pages == 0xffff,ffff */
  count is now 0x1,0000,0000 instead of 0

The fix is to subtract the unsigned page count rather than adding its
negation.  This only works once "percpu: fix this_cpu_sub() subtrahend
casting for unsigneds" is applied to fix this_cpu_sub().
Signed-off-by: NGreg Thelen <gthelen@google.com>
Acked-by: NTejun Heo <tj@kernel.org>
Acked-by: NJohannes Weiner <hannes@cmpxchg.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      5e8cfc3c
    • G
      percpu: fix this_cpu_sub() subtrahend casting for unsigneds · bd09d9a3
      由 Greg Thelen 提交于 
      this_cpu_sub() is implemented as negation and addition.

This patch casts the adjustment to the counter type before negation to
sign extend the adjustment.  This helps in cases where the counter type
is wider than an unsigned adjustment.  An alternative to this patch is
to declare such operations unsupported, but it seemed useful to avoid
surprises.

This patch specifically helps the following example:
  unsigned int delta = 1
  preempt_disable()
  this_cpu_write(long_counter, 0)
  this_cpu_sub(long_counter, delta)
  preempt_enable()

Before this change long_counter on a 64 bit machine ends with value
0xffffffff, rather than 0xffffffffffffffff.  This is because
this_cpu_sub(pcp, delta) boils down to this_cpu_add(pcp, -delta),
which is basically:
  long_counter = 0 + 0xffffffff

Also apply the same cast to:
  __this_cpu_sub()
  __this_cpu_sub_return()
  this_cpu_sub_return()

All percpu_test.ko passes, especially the following cases which
previously failed:

  l -= ui_one;
  __this_cpu_sub(long_counter, ui_one);
  CHECK(l, long_counter, -1);

  l -= ui_one;
  this_cpu_sub(long_counter, ui_one);
  CHECK(l, long_counter, -1);
  CHECK(l, long_counter, 0xffffffffffffffff);

  ul -= ui_one;
  __this_cpu_sub(ulong_counter, ui_one);
  CHECK(ul, ulong_counter, -1);
  CHECK(ul, ulong_counter, 0xffffffffffffffff);

  ul = this_cpu_sub_return(ulong_counter, ui_one);
  CHECK(ul, ulong_counter, 2);

  ul = __this_cpu_sub_return(ulong_counter, ui_one);
  CHECK(ul, ulong_counter, 1);
Signed-off-by: NGreg Thelen <gthelen@google.com>
Acked-by: NTejun Heo <tj@kernel.org>
Acked-by: NJohannes Weiner <hannes@cmpxchg.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      bd09d9a3
    • C
      mm/pagewalk.c: fix walk_page_range() access of wrong PTEs · 3017f079
      由 Chen LinX 提交于 
      When walk_page_range walk a memory map's page tables, it'll skip
VM_PFNMAP area, then variable 'next' will to assign to vma->vm_end, it
maybe larger than 'end'.  In next loop, 'addr' will be larger than
'next'.  Then in /proc/XXXX/pagemap file reading procedure, the 'addr'
will growing forever in pagemap_pte_range, pte_to_pagemap_entry will
access the wrong pte.

  BUG: Bad page map in process procrank  pte:8437526f pmd:785de067
  addr:9108d000 vm_flags:00200073 anon_vma:f0d99020 mapping:  (null) index:9108d
  CPU: 1 PID: 4974 Comm: procrank Tainted: G    B   W  O 3.10.1+ #1
  Call Trace:
    dump_stack+0x16/0x18
    print_bad_pte+0x114/0x1b0
    vm_normal_page+0x56/0x60
    pagemap_pte_range+0x17a/0x1d0
    walk_page_range+0x19e/0x2c0
    pagemap_read+0x16e/0x200
    vfs_read+0x84/0x150
    SyS_read+0x4a/0x80
    syscall_call+0x7/0xb
Signed-off-by: NLiu ShuoX <shuox.liu@intel.com>
Signed-off-by: NChen LinX <linx.z.chen@intel.com>
Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: <stable@vger.kernel.org>	[3.10.x+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      3017f079
  3. 30 10月, 2013 1 次提交
    • L
      Fix a few incorrectly checked [io_]remap_pfn_range() calls · 7314e613
      由 Linus Torvalds 提交于 
      Nico Golde reports a few straggling uses of [io_]remap_pfn_range() that
really should use the vm_iomap_memory() helper.  This trivially converts
two of them to the helper, and comments about why the third one really
needs to continue to use remap_pfn_range(), and adds the missing size
check.
Reported-by: NNico Golde <nico@ngolde.de>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org.
      7314e613
  5. 29 10月, 2013 9 次提交
  7. 28 10月, 2013 9 次提交
  9. 27 10月, 2013 1 次提交
    • H
      parisc: Do not crash 64bit SMP kernels on machines with >= 4GB RAM · 54e181e0
      由 Helge Deller 提交于 
      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: NHelge Deller <deller@gmx.de>
Signed-off-by: NJohn David Anglin <dave.anglin@bell.net>
Cc: <stable@vger.kernel.org> # 2.6.12+
Signed-off-by: NHelge Deller <deller@gmx.de>
      54e181e0
  11. 26 10月, 2013 6 次提交
    • L
      Merge tag 'pm+acpi-3.12-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm · 20582e34
      由 Linus Torvalds 提交于 
      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
    • L
      Merge tag 'for-linus-20131025' of git://git.infradead.org/linux-mtd · d255c59a
      由 Linus Torvalds 提交于 
      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
    • N
      vhost/scsi: Fix incorrect usage of get_user_pages_fast write parameter · 60a01f55
      由 Nicholas Bellinger 提交于 
      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: NNicholas Bellinger <nab@linux-iscsi.org>
      60a01f55
    • W
      target/pscsi: fix return value check · 58932e96
      由 Wei Yongjun 提交于 
      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: NWei Yongjun <yongjun_wei@trendmicro.com.cn>
Cc: <stable@vger.kernel.org>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>
      58932e96
    • L
      Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs · f55ac56d
      由 Linus Torvalds 提交于 
      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
    • D
      mtd: gpmi: fix ECC regression · 031e2777
      由 David Woodhouse 提交于 
      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: NDavid Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>
Acked-by: NHuang Shijie <b32955@freescale.com>
Acked-by: NMarek Vasut <marex@denx.de>
Tested-by: NMarek Vasut <marex@denx.de>
      031e2777
  13. 25 10月, 2013 11 次提交