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  1. 25 Oct, 2012 10 commits
    • Thadeu Lima de Souza Cascardo's avatar
      genalloc: stop crashing the system when destroying a pool · eedce141
      Thadeu Lima de Souza Cascardo authored 
      The genalloc code uses the bitmap API from include/linux/bitmap.h and
lib/bitmap.c, which is based on long values.  Both bitmap_set from
lib/bitmap.c and bitmap_set_ll, which is the lockless version from
genalloc.c, use BITMAP_LAST_WORD_MASK to set the first bits in a long in
the bitmap.

That one uses (1 << bits) - 1, 0b111, if you are setting the first three
bits.  This means that the API counts from the least significant bits
(LSB from now on) to the MSB.  The LSB in the first long is bit 0, then.
The same works for the lookup functions.

The genalloc code uses longs for the bitmap, as it should.  In
include/linux/genalloc.h, struct gen_pool_chunk has unsigned long
bits[0] as its last member.  When allocating the struct, genalloc should
reserve enough space for the bitmap.  This should be a proper number of
longs that can fit the amount of bits in the bitmap.

However, genalloc allocates an integer number of bytes that fit the
amount of bits, but may not be an integer amount of longs.  9 bytes, for
example, could be allocated for 70 bits.

This is a problem in itself if the Least Significat Bit in a long is in
the byte with the largest address, which happens in Big Endian machines.
This means genalloc is not allocating the byte in which it will try to
set or check for a bit.

This may end up in memory corruption, where genalloc will try to set the
bits it has not allocated.  In fact, genalloc may not set these bits
because it may find them already set, because they were not zeroed since
they were not allocated.  And that's what causes a BUG when
gen_pool_destroy is called and check for any set bits.

What really happens is that genalloc uses kmalloc_node with __GFP_ZERO
on gen_pool_add_virt.  With SLAB and SLUB, this means the whole slab
will be cleared, not only the requested bytes.  Since struct
gen_pool_chunk has a size that is a multiple of 8, and slab sizes are
multiples of 8, we get lucky and allocate and clear the right amount of
bytes.

Hower, this is not the case with SLOB or with older code that did memset
after allocating instead of using __GFP_ZERO.

So, a simple module as this (running 3.6.0), will cause a crash when
rmmod'ed.

  [root@phantom-lp2 foo]# cat foo.c
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/genalloc.h>

  MODULE_LICENSE("GPL");
  MODULE_VERSION("0.1");

  static struct gen_pool *foo_pool;

  static __init int foo_init(void)
  {
          int ret;
          foo_pool = gen_pool_create(10, -1);
          if (!foo_pool)
                  return -ENOMEM;
          ret = gen_pool_add(foo_pool, 0xa0000000, 32 << 10, -1);
          if (ret) {
                  gen_pool_destroy(foo_pool);
                  return ret;
          }
          return 0;
  }

  static __exit void foo_exit(void)
  {
          gen_pool_destroy(foo_pool);
  }

  module_init(foo_init);
  module_exit(foo_exit);
  [root@phantom-lp2 foo]# zcat /proc/config.gz | grep SLOB
  CONFIG_SLOB=y
  [root@phantom-lp2 foo]# insmod ./foo.ko
  [root@phantom-lp2 foo]# rmmod foo
  ------------[ cut here ]------------
  kernel BUG at lib/genalloc.c:243!
  cpu 0x4: Vector: 700 (Program Check) at [c0000000bb0e7960]
      pc: c0000000003cb50c: .gen_pool_destroy+0xac/0x110
      lr: c0000000003cb4fc: .gen_pool_destroy+0x9c/0x110
      sp: c0000000bb0e7be0
     msr: 8000000000029032
    current = 0xc0000000bb0e0000
    paca    = 0xc000000006d30e00   softe: 0        irq_happened: 0x01
      pid   = 13044, comm = rmmod
  kernel BUG at lib/genalloc.c:243!
  [c0000000bb0e7ca0] d000000004b00020 .foo_exit+0x20/0x38 [foo]
  [c0000000bb0e7d20] c0000000000dff98 .SyS_delete_module+0x1a8/0x290
  [c0000000bb0e7e30] c0000000000097d4 syscall_exit+0x0/0x94
  --- Exception: c00 (System Call) at 000000800753d1a0
  SP (fffd0b0e640) is in userspace
Signed-off-by: default avatarThadeu Lima de Souza Cascardo <cascardo@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Benjamin Gaignard <benjamin.gaignard@stericsson.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      eedce141
    • Jingoo Han's avatar
      backlight: ili9320: add missing SPI dependency · fd6de530
      Jingoo Han authored 
      Add this missing SPI dependency and prevent the driver from building
without SPI, because functions of the spi driver are used in this
driver.

  drivers/video/backlight/ili9320.c:51: undefined reference to `spi_sync'

Also, a prompt string for CONFIG_LCD_ILI9320 is added for explicit
selection.
Signed-off-by: default avatarJingoo Han <jg1.han@samsung.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      fd6de530
    • Aristeu Rozanski's avatar
      device_cgroup: add proper checking when changing default behavior · 4cef7299
      Aristeu Rozanski authored 
      Before changing a group's default behavior to ALLOW, we must check if
its parent's behavior is also ALLOW.
Signed-off-by: default avatarAristeu Rozanski <aris@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: James Morris <jmorris@namei.org>
Cc: Pavel Emelyanov <xemul@openvz.org>
Acked-by: default avatarSerge Hallyn <serge.hallyn@canonical.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      4cef7299
    • Aristeu Rozanski's avatar
      device_cgroup: stop using simple_strtoul() · 26fd8405
      Aristeu Rozanski authored 
      Convert the code to use kstrtou32() instead of simple_strtoul() which is
deprecated.  The real size of the variables are u32, so use kstrtou32
instead of kstrtoul
Signed-off-by: default avatarAristeu Rozanski <aris@redhat.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: James Morris <jmorris@namei.org>
Cc: Pavel Emelyanov <xemul@openvz.org>
Acked-by: default avatarSerge Hallyn <serge.hallyn@canonical.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      26fd8405
    • Aristeu Rozanski's avatar
      device_cgroup: rename deny_all to behavior · 5b7aa7d5
      Aristeu Rozanski authored 
      This was done in a v2 patch but v1 ended up being committed.  The
variable name is less confusing and stores the default behavior when no
matching exception exists.
Signed-off-by: default avatarAristeu Rozanski <aris@redhat.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: James Morris <jmorris@namei.org>
Cc: Pavel Emelyanov <xemul@openvz.org>
Acked-by: default avatarSerge Hallyn <serge.hallyn@canonical.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      5b7aa7d5
    • Jiri Slaby's avatar
      cgroup: fix invalid rcu dereference · 8c9506d1
      Jiri Slaby authored 
      Commit ad676077 ("device_cgroup: convert device_cgroup internally to
policy + exceptions") removed rcu locks which are needed in
task_devcgroup called in this chain:

  devcgroup_inode_mknod OR __devcgroup_inode_permission ->
    __devcgroup_inode_permission ->
      task_devcgroup ->
        task_subsys_state ->
          task_subsys_state_check.

Change the code so that task_devcgroup is safely called with rcu read
lock held.

  ===============================
  [ INFO: suspicious RCU usage. ]
  3.6.0-rc5-next-20120913+ #42 Not tainted
  -------------------------------
  include/linux/cgroup.h:553 suspicious rcu_dereference_check() usage!

  other info that might help us debug this:

  rcu_scheduler_active = 1, debug_locks = 0
  2 locks held by kdevtmpfs/23:
   #0:  (sb_writers){.+.+.+}, at: [<ffffffff8116873f>]
  mnt_want_write+0x1f/0x50
   #1:  (&sb->s_type->i_mutex_key#3/1){+.+.+.}, at: [<ffffffff811558af>]
  kern_path_create+0x7f/0x170

  stack backtrace:
  Pid: 23, comm: kdevtmpfs Not tainted 3.6.0-rc5-next-20120913+ #42
  Call Trace:
    lockdep_rcu_suspicious+0xfd/0x130
    devcgroup_inode_mknod+0x19d/0x240
    vfs_mknod+0x71/0xf0
    handle_create.isra.2+0x72/0x200
    devtmpfsd+0x114/0x140
    ? handle_create.isra.2+0x200/0x200
    kthread+0xd6/0xe0
    kernel_thread_helper+0x4/0x10
Signed-off-by: default avatarJiri Slaby <jslaby@suse.cz>
Cc: Dave Jones <davej@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: James Morris <jmorris@namei.org>
Cc: Pavel Emelyanov <xemul@openvz.org>
Acked-by: default avatarSerge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8c9506d1
    • Jan Kara's avatar
      mm: fix XFS oops due to dirty pages without buffers on s390 · ef5d437f
      Jan Kara authored 
      On s390 any write to a page (even from kernel itself) sets architecture
specific page dirty bit.  Thus when a page is written to via buffered
write, HW dirty bit gets set and when we later map and unmap the page,
page_remove_rmap() finds the dirty bit and calls set_page_dirty().

Dirtying of a page which shouldn't be dirty can cause all sorts of
problems to filesystems.  The bug we observed in practice is that
buffers from the page get freed, so when the page gets later marked as
dirty and writeback writes it, XFS crashes due to an assertion
BUG_ON(!PagePrivate(page)) in page_buffers() called from
xfs_count_page_state().

Similar problem can also happen when zero_user_segment() call from
xfs_vm_writepage() (or block_write_full_page() for that matter) set the
hardware dirty bit during writeback, later buffers get freed, and then
page unmapped.

Fix the issue by ignoring s390 HW dirty bit for page cache pages of
mappings with mapping_cap_account_dirty().  This is safe because for
such mappings when a page gets marked as writeable in PTE it is also
marked dirty in do_wp_page() or do_page_fault().  When the dirty bit is
cleared by clear_page_dirty_for_io(), the page gets writeprotected in
page_mkclean().  So pagecache page is writeable if and only if it is
dirty.

Thanks to Hugh Dickins for pointing out mapping has to have
mapping_cap_account_dirty() for things to work and proposing a cleaned
up variant of the patch.

The patch has survived about two hours of running fsx-linux on tmpfs
while heavily swapping and several days of running on out build machines
where the original problem was triggered.
Signed-off-by: default avatarJan Kara <jack@suse.cz>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: <stable@vger.kernel.org>		[3.0+]
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ef5d437f
    • Linus Torvalds's avatar
      Merge tag 'spi-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/misc · 4864ccbb
      Linus Torvalds authored 
      Pull spi fixes from Mark Brown:
 "A bunch of fixes here, mostly minor except for the pl022 which has
  just been a bit of a shambles all round, the recent runtime PM changes
  have as far as I can tell never worked so they're just getting thrown
  out."

* tag 'spi-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/misc:
  spi/pl022: Revert recent runtime PM changes
  spi: tsc2005: delete soon-obsolete e-mail address
  spi: spi-rspi: fix build error for the latest shdma driver
      4864ccbb
    • Linus Torvalds's avatar
      Merge tag 'iommu-fixes-v3.7-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu · 735f0a98
      Linus Torvalds authored 
      Pull IOMMU fixes from Joerg Roedel:
 "Two fixes this time:

   1. Another fix for a broken BIOS to detect when AMD IOMMU interrupt
      remapping can not work reliably
   2. Typo fix for NVidia IOMMU driver"

* tag 'iommu-fixes-v3.7-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
  iommu/tegra: smmu: Fix deadly typo
  iommu/amd: Work around wrong IOAPIC device-id in IVRS table
      735f0a98
    • Linus Torvalds's avatar
      Merge tag 'pinctrl-v3.7-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl · 99103f77
      Linus Torvalds authored 
      Pull pinctrl fixes from Linus Walleij:
 "This fixes a few pinctrl problems seen since v3.7-rc1:
   - Section tagging for init code
   - Use proper pointers to lookup struct device * in the bcm2835
     (a.k.a.  Raspberry Pi)
   - Remove duplicate #includes
   - Fix bad return values in errorpath
   - Remove extraneous pull function from the sirf driver causing build
     errors
   - Provide compilation stubs for the Nomadik pinctrl driver when used
     with legacy systems without PRCMU units
   - Various irqdomain fixes in the Nomadik driver as predicted
   - Various smallish bugs in the Tegra driver, most also targeted for
     stable
   - Removed a deadlocking mutex in the groups debugfs show function"

* tag 'pinctrl-v3.7-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl:
  pinctrl/nomadik: pass DT node to the irqdomain
  pinctrl/nomadik: use zero as default irq_start
  pinctrl: fix missing unlock on error in pinctrl_groups_show()
  pinctrl/nomadik: use irq_create_mapping()
  pinctrl: remove mutex lock in groups show
  pinctrl: tegra: correct bank for pingroup and drv pingroup
  pinctrl: tegra: set low power mode bank width to 2
  dt: Document: correct tegra20/30 pinctrl slew-rate name
      99103f77
  3. 24 Oct, 2012 16 commits
  5. 23 Oct, 2012 14 commits
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