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  1. 18 3月, 2011 9 次提交
    • M
      smp_call_function_many: handle concurrent clearing of mask · 723aae25
      由 Milton Miller 提交于 
      Mike Galbraith reported finding a lockup ("perma-spin bug") where the
cpumask passed to smp_call_function_many was cleared by other cpu(s)
while a cpu was preparing its call_data block, resulting in no cpu to
clear the last ref and unlock the block.

Having cpus clear their bit asynchronously could be useful on a mask of
cpus that might have a translation context, or cpus that need a push to
complete an rcu window.

Instead of adding a BUG_ON and requiring yet another cpumask copy, just
detect the race and handle it.

Note: arch_send_call_function_ipi_mask must still handle an empty
cpumask because the data block is globally visible before the that arch
callback is made.  And (obviously) there are no guarantees to which cpus
are notified if the mask is changed during the call; only cpus that were
online and had their mask bit set during the whole call are guaranteed
to be called.
Reported-by: NMike Galbraith <efault@gmx.de>
Reported-by: NJan Beulich <JBeulich@novell.com>
Acked-by: NJan Beulich <jbeulich@novell.com>
Cc: stable@kernel.org
Signed-off-by: NMilton Miller <miltonm@bga.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      723aae25
    • M
      call_function_many: add missing ordering · 45a57919
      由 Milton Miller 提交于 
      Paul McKenney's review pointed out two problems with the barriers in the
2.6.38 update to the smp call function many code.

First, a barrier that would force the func and info members of data to
be visible before their consumption in the interrupt handler was
missing.  This can be solved by adding a smp_wmb between setting the
func and info members and setting setting the cpumask; this will pair
with the existing and required smp_rmb ordering the cpumask read before
the read of refs.  This placement avoids the need a second smp_rmb in
the interrupt handler which would be executed on each of the N cpus
executing the call request.  (I was thinking this barrier was present
but was not).

Second, the previous write to refs (establishing the zero that we the
interrupt handler was testing from all cpus) was performed by a third
party cpu.  This would invoke transitivity which, as a recient or
concurrent addition to memory-barriers.txt now explicitly states, would
require a full smp_mb().

However, we know the cpumask will only be set by one cpu (the data
owner) and any preivous iteration of the mask would have cleared by the
reading cpu.  By redundantly writing refs to 0 on the owning cpu before
the smp_wmb, the write to refs will follow the same path as the writes
that set the cpumask, which in turn allows us to keep the barrier in the
interrupt handler a smp_rmb instead of promoting it to a smp_mb (which
will be be executed by N cpus for each of the possible M elements on the
list).

I moved and expanded the comment about our (ab)use of the rcu list
primitives for the concurrent walk earlier into this function.  I
considered moving the first two paragraphs to the queue list head and
lock, but felt it would have been too disconected from the code.

Cc: Paul McKinney <paulmck@linux.vnet.ibm.com>
Cc: stable@kernel.org (2.6.32 and later)
Signed-off-by: NMilton Miller <miltonm@bga.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      45a57919
    • M
      call_function_many: fix list delete vs add race · e6cd1e07
      由 Milton Miller 提交于 
      Peter pointed out there was nothing preventing the list_del_rcu in
smp_call_function_interrupt from running before the list_add_rcu in
smp_call_function_many.

Fix this by not setting refs until we have gotten the lock for the list.
Take advantage of the wmb in list_add_rcu to save an explicit additional
one.

I tried to force this race with a udelay before the lock & list_add and
by mixing all 64 online cpus with just 3 random cpus in the mask, but
was unsuccessful.  Still, inspection shows a valid race, and the fix is
a extension of the existing protection window in the current code.

Cc: stable@kernel.org (v2.6.32 and later)
Reported-by: NPeter Zijlstra <peterz@infradead.org>
Signed-off-by: NMilton Miller <miltonm@bga.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      e6cd1e07
    • A
      mm: PageBuddy and mapcount robustness · ef2b4b95
      由 Andrea Arcangeli 提交于 
      Change the _mapcount value indicating PageBuddy from -2 to -128 for
more robusteness against page_mapcount() undeflows.

Use reset_page_mapcount instead of __ClearPageBuddy in bad_page to
ignore the previous retval of PageBuddy().
Signed-off-by: NAndrea Arcangeli <aarcange@redhat.com>
Reported-by: NHugh Dickins <hughd@google.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      ef2b4b95
    • L
      Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/epip/linux-2.6-unicore32 · 7b7adc4a
      由 Linus Torvalds 提交于 
      * 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/epip/linux-2.6-unicore32: (40 commits)
  unicore32: rewrite arch-specific tlb.h to use asm-generic version
  unicore32: modify io_p2v and io_v2p macros, and adjust PKUNITY_mmio_BASEs
  unicore32: replace unicore32-specific iomap functions with generic lib implementation
  unicore32 machine related: add frame buffer driver for pkunity-v3 soc
  unicore32 machine related files: add i2c bus drivers for pkunity-v3 soc
  unicore32 io: redefine __REG(x) and re-use readl/writel funcs
  unicore32 i8042 upgrade and bugfix: adjust resource request region type
  unicore32 upgrade to v2.6.38-rc5: add one more paramter for pte_alloc_map call
  unicore32 i8042: adjust io funcs of i8042-unicore32io.h
  unicore32: rename PKUNITY_IOSPACE_BASE to PKUNITY_MMIO_BASE
  unicore32: modify function names and parameters for irq_chips
  unicore32: remove unused lines in arch/unicore32/include/asm/irq.h
  unicore32 time.c: change calculate method for clock_event_device
  unicore32: ADD MAINTAINER for unicore32 architecture
  unicore32 machine related files: ps2 driver
  unicore32 machine related files: pci bus handling
  unicore32 machine related files: hardware registers
  unicore32 machine related files: core files
  unicore32 additional architecture files: boot process
  unicore32 additional architecture files: low-level lib: misc
  ...
Acked-by: NArnd Bergmann <arnd@arndb.de>
      7b7adc4a
    • L
      Merge branch 'for-linus' of git://git390.marist.edu/pub/scm/linux-2.6 · 31598e87
      由 Linus Torvalds 提交于 
      * 'for-linus' of git://git390.marist.edu/pub/scm/linux-2.6:
  [S390] kexec: Disable ftrace during kexec
  [S390] support XZ compressed kernel
  [S390] css_bus_type: make it static
  [S390] css_driver: remove duplicate members
  [S390] css: remove subchannel private
  [S390] css: move chsc_private to drv_data
  [S390] css: move io_private to drv_data
  [S390] cio: move cdev pointer to io_subchannel_private
  [S390] cio: move options to io_sch_private
  [S390] cio: move asms to generic header
  [S390] cio: move orb definitions to separate header
  [S390] Write protect module text and RO data
  [S390] dasd: get rid of compile warning
  [S390] remove superfluous check from do_IRQ
  [S390] remove redundant stack check option
      31598e87
    • L
      Merge branch 'sh-latest' of git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6 · 241eb956
      由 Linus Torvalds 提交于 
      * 'sh-latest' of git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6: (34 commits)
  sh: Convert to generic show_interrupts.
  sh: Wire up new fhandle and clock_adjtime syscalls.
  sh: modify platform_device for sh_eth driver
  sh: add GETHER's platform_device in board-sh7757lcr
  sh: update sh7757lcr_defconfig
  sh: add platform_device of tmio_mmc and sh_mmcif to sh7757lcr
  sh: dmaengine support for SH7757
  sh: add mmc clock in clock-sh7757
  sh: add spi_board_info in sh7757lcr
  sh: add platform_device for SPI
  sh: add USB_ARCH_HAS_EHCI and OHCI for SH7757
  sh: Rename cpuidle states to fit general conventions
  serial: sh-sci: fix deadlock when resuming from S3 sleep
  sh: Enable CONFIG_GCOV_PROFILE_ALL for sh
  sh: Fix up async PCIe probing on SMP.
  serial: sh-sci: Kill off the special earlyprintk device.
  serial: sh-sci: Use dev_name() for region reservations.
  serial: sh-sci: Fix up earlyprintk port mapping.
  serial: sh-sci: Limit early console to one device.
  serial: sh-sci: Fix up break timer scheduling race.
  ...
      241eb956
    • L
      Merge git://git.kernel.org/pub/scm/linux/kernel/git/lethal/fbdev-2.6 · fd34b0de
      由 Linus Torvalds 提交于 
      * git://git.kernel.org/pub/scm/linux/kernel/git/lethal/fbdev-2.6:
  fbdev: sh_mobile_lcdc: Add YUV framebuffer support
  viafb: split pll configs up
  viafb: remove duplicated clock storage
  viafb: always return the best possible clock
  viafb: remove duplicated clock information
  fbdev: sh_mobile_lcdcfb: add backlight support
  viafb: factor lcd scaling parameters out
  viafb: strip some structures
  viafb: remove unused data_mode and device_type
  viafb: kill lcd_panel_id
  video via: make local variables static
  video via: fix iomem access
  video/via: drop deprecated (and unused) i2c_adapter.id
      fd34b0de
    • L
      Merge branch 'drm-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6 · 40c7f211
      由 Linus Torvalds 提交于 
      * 'drm-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6: (177 commits)
  drm/radeon: fixup refcounts in radeon dumb create ioctl.
  drm: radeon: *_cs_packet_parse_vline() cleanup
  radeon: merge list_del()/list_add_tail() to list_move_tail()
  drm: Retry i2c transfer of EDID block after failure
  drm/radeon/kms: fix typo in atom overscan setup
  drm: Hold the mode mutex whilst probing for sysfs status
  drm/nouveau: fix __nouveau_fence_wait performance
  drm/nv40: attempt to reserve just enough vram for all 32 channels
  drm/nv50: check for vm traps on every gr irq
  drm/nv50: decode vm faults some more
  drm/nouveau: add nouveau_enum_find() util function
  drm/nouveau: properly handle pushbuffer check failures
  drm/nvc0: remove vm hack forcing large/small pages to not share a PDE
  drm/i915: disable opregion lid detection for now.
  drm/i915: Only wait on a pending flip if we intend to write to the buffer
  drm/i915/dp: Sanity check eDP existence
  drm: add cap bit to denote if dumb ioctl is available or not.
  drm/core: add ioctl to query device/driver capabilities
  drm/radeon/kms: allow max clock of 340 Mhz on hdmi 1.3+
  drm/radeon/kms: add cayman pci ids
  ...
      40c7f211
  3. 17 3月, 2011 31 次提交