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  1. 13 Jan, 2013 1 commit
  3. 12 Jan, 2013 6 commits
  5. 11 Jan, 2013 7 commits
  7. 07 Jan, 2013 4 commits
    • Jan Beulich's avatar
      USB: ehci: make debug port in-use detection functional again · 75e1a2ae
      Jan Beulich authored 
      Debug port in-use determination must be done before the controller gets
reset the first time, i.e. before the call to ehci_setup() as of commit
1a49e2ac. That commit effectively
rendered commit 9fa5780b useless.

While moving that code around, also fix the BAR determination - the
respective capability field is a 3- rather than a 2-bit one -, and use
PCI_CAP_ID_DBG instead of the literal 0x0a.

It's unclear to me whether the debug port functionality is important
enough to warrant fixing this in stable kernels too.
Signed-off-by: default avatarJan Beulich <jbeulich@suse.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: stable <stable@vger.kernel.org>
Acked-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      75e1a2ae
    • Alan Stern's avatar
      USB: usbtest: fix test number in log message · 2cb50000
      Alan Stern authored 
      This patch (as1639) fixes a minor bug in the usbtest driver.  Due to
concurrent changes, a test originally written as number 17 got changed
to number 24, but the corresponding change was not made in the log
message.  This updates the log message.
Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      2cb50000
    • Greg Kroah-Hartman's avatar
      Merge tag 'for-usb-linus-2013-01-03' of... · 962426e0
      Greg Kroah-Hartman authored 
      Merge tag 'for-usb-linus-2013-01-03' of git://git.kernel.org/pub/scm/linux/kernel/git/sarah/xhci into usb-linus

Sarah says:
	usb-linus: USB core fixes for warm reset

	Hi Greg,

	Happy New Year!  Here's some bug fixes for 3.8.  I have usb-next
	patches that are based on this set, so please merge your usb-linus
	branch into usb-next after this set is applied.

	The bulk of the patchset (patches 2-7) improve the USB core's warm
	reset error handling.

	There's also one patch that fixes an arithmetic error in the xHCI
	driver, and another to avoid the "dead ports" issue caused by
	unhandled port status change events.

	These are all marked for stable.

	Sarah Sharp
      962426e0
    • Greg Kroah-Hartman's avatar
      Merge tag 'fixes-for-v3.8-rc2' of... · e4602391
      Greg Kroah-Hartman authored 
      Merge tag 'fixes-for-v3.8-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/balbi/usb into usb-linus

Felipe says:
	usb: fixes for v3.8-rc2

	Here is the first set of fixes for v3.8-rc cycle.

	There is a build fix for musb's dsps glue layer caused
	by some header cleanup on the OMAP tree.

	Marvel's USB drivers got a fix up for clk API usage
	switching over to clk_prepare() calls.

	u_serial has a bug fix for a missing wake_up() which
	would make gs_cleanup() wait forever for gs_close()
	to finish.

	A minor bug fix on dwc3's debugfs interface which
	would make us read wrong addresses when dumping
	all registers.

	dummy_hcd learned how to enumerate g_multi.

	s3c-hsotg now understands that we shouldn't kfree()
	memory allocated with devm_*.

	Other than that, there are a bunch of other minor fixes
	on renesas_usbhs, tcm_usb_gadget and amd5536udc.

	All patches have been pending on mailing for many weeks
	and shouldn't cause any problems.
      e4602391
  9. 03 Jan, 2013 18 commits
    • Sarah Sharp's avatar
      xhci: Avoid "dead ports", add roothub port polling. · c52804a4
      Sarah Sharp authored 
      The USB core hub thread (khubd) is designed with external USB hubs in
mind.  It expects that if a port status change bit is set, the hub will
continue to send a notification through the hub status data transfer.
Basically, it expects hub notifications to be level-triggered.

The xHCI host controller is designed to be edge-triggered on the logical
'OR' of all the port status change bits.  When all port status change
bits are clear, and a new change bit is set, the xHC will generate a
Port Status Change Event.  If another change bit is set in the same port
status register before the first bit is cleared, it will not send
another event.

This means that the hub code may lose port status changes because of
race conditions between clearing change bits.  The user sees this as a
"dead port" that doesn't react to device connects.

The fix is to turn on port polling whenever a new change bit is set.
Once the USB core issues a hub status request that shows that no change
bits are set in any USB ports, turn off port polling.

We can't allow the USB core to poll the roothub for port events during
host suspend because if the PCI host is in D3cold, the port registers
will be all f's.  Instead, stop the port polling timer, and
unconditionally restart it when the host resumes.  If there are no port
change bits set after the resume, the first call to hub_status_data will
disable polling.

This patch should be backported to stable kernels with the first xHCI
support, 2.6.31 and newer, that include the commit
0f2a7930 "USB: xhci: Root hub support."
There will be merge conflicts because the check for HC_STATE_SUSPENDED
was moved into xhci_suspend in 3.8.
Signed-off-by: default avatarSarah Sharp <sarah.a.sharp@linux.intel.com>
Acked-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Cc: stable@vger.kernel.org
      c52804a4
    • Sarah Sharp's avatar
      USB: Handle warm reset failure on empty port. · 65bdac5e
      Sarah Sharp authored 
      An empty port can transition to either Inactive or Compliance Mode if a
newly connected USB 3.0 device fails to link train.  In that case, we
issue a warm reset.  Some devices, such as John's Roseweil eusb3
enclosure, slip back into Compliance Mode after the warm reset.

The current warm reset code does not check for device connect status on
warm reset completion, and it incorrectly reports the warm reset
succeeded.  This causes the USB core to attempt to send a Set Address
control transfer to a port in Compliance Mode, which will always fail.

Make hub_port_wait_reset check the current connect status and link state
after the warm reset completes.  Return a failure status if the device
is disconnected or the link state is Compliance Mode or SS.Inactive.

Make hub_events disable the port if warm reset fails.  This will disable
the port, and then bring it back into the RxDetect state.  Make the USB
core ignore the connect change until the device reconnects.

Note that this patch does NOT handle connected devices slipping into the
Inactive state very well.  This is a concern, because devices can go
into the Inactive state on U1/U2 exit failure.  However, the fix for
that case is too large for stable, so it will be submitted in a separate
patch.

This patch should be backported to kernels as old as 3.2, contain the
commit ID 75d7cf72 "usbcore: refine warm
reset logic"
Signed-off-by: default avatarSarah Sharp <sarah.a.sharp@linux.intel.com>
Acked-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Reported-by: default avatarJohn Covici <covici@ccs.covici.com>
Cc: stable@vger.kernel.org
      65bdac5e
    • Sarah Sharp's avatar
      USB: Ignore port state until reset completes. · 4f43447e
      Sarah Sharp authored 
      The port reset code bails out early if the current connect status is
cleared (device disconnected).  If we're issuing a hot reset, it may
also look at the link state before the reset is finished.

Section 10.14.2.6 of the USB 3.0 spec says that when a port enters the
Error state or Resetting state, the port connection bit retains the
value from the previous state.  Therefore we can't trust it until the
reset finishes.  Also, the xHCI spec section 4.19.1.2.5 says software
shall ignore the link state while the port is resetting, as it can be in
an unknown state.

The port state during reset is also unknown for USB 2.0 hubs.  The hub
sends a reset signal by driving the bus into an SE0 state.  This
overwhelms the "connect" signal from the device, so the port can't tell
whether anything is connected or not.

Fix the port reset code to ignore the port link state and current
connect bit until the reset finishes, and USB_PORT_STAT_RESET is
cleared.

Remove the check for USB_PORT_STAT_C_BH_RESET in the warm reset case,
because it's redundant.  When the warm reset finishes, the port reset
bit will be cleared at the same time USB_PORT_STAT_C_BH_RESET is set.
Remove the now-redundant check for a cleared USB_PORT_STAT_RESET bit
in the code to deal with the finished reset.

This patch should be backported to all stable kernels.
Signed-off-by: default avatarSarah Sharp <sarah.a.sharp@linux.intel.com>
Acked-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Cc: stable@vger.kernel.org
      4f43447e
    • Sarah Sharp's avatar
      USB: Increase reset timeout. · 77c7f072
      Sarah Sharp authored 
      John's NEC 0.96 xHCI host controller needs a longer timeout for a warm
reset to complete.  The logs show it takes 650ms to complete the warm
reset, so extend the hub reset timeout to 800ms to be on the safe side.

This commit should be backported to kernels as old as 3.2, that contain
the commit 75d7cf72 "usbcore: refine
warm reset logic".
Signed-off-by: default avatarSarah Sharp <sarah.a.sharp@linux.intel.com>
Acked-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Reported-by: default avatarJohn Covici <covici@ccs.covici.com>
Cc: stable@vger.kernel.org
      77c7f072
    • Sarah Sharp's avatar
      USB: Allow USB 3.0 ports to be disabled. · 41e7e056
      Sarah Sharp authored 
      If hot and warm reset fails, or a port remains in the Compliance Mode,
the USB core needs to be able to disable a USB 3.0 port.  Unlike USB 2.0
ports, once the port is placed into the Disabled link state, it will not
report any new device connects.  To get device connect notifications, we
need to put the link into the Disabled state, and then the RxDetect
state.

The xHCI driver needs to atomically clear all change bits on USB 3.0
port disable, so that we get Port Status Change Events for future port
changes.  We could technically do this in the USB core instead of in the
xHCI roothub code, since the port state machine can't advance out of the
disabled state until we set the link state to RxDetect.  However,
external USB 3.0 hubs don't need this code.  They are level-triggered,
not edge-triggered like xHCI, so they will continue to send interrupt
events when any change bit is set.  Therefore it doesn't make sense to
put this code in the USB core.

This patch is part of a series to fix several reports of infinite loops
on device enumeration failure.  This includes John, when he boots with
a USB 3.0 device (Roseweil eusb3 enclosure) attached to his NEC 0.96
host controller.  The fix requires warm reset support, so it does not
make sense to backport this patch to stable kernels without warm reset
support.

This patch should be backported to kernels as old as 3.2, contain the
commit ID 75d7cf72 "usbcore: refine warm
reset logic"
Signed-off-by: default avatarSarah Sharp <sarah.a.sharp@linux.intel.com>
Acked-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Reported-by: default avatarJohn Covici <covici@ccs.covici.com>
Cc: stable@vger.kernel.org
      41e7e056
    • Sarah Sharp's avatar
      USB: Ignore xHCI Reset Device status. · 8b8132bc
      Sarah Sharp authored 
      When the USB core finishes reseting a USB device, the xHCI driver sends
a Reset Device command to the host.  The xHC then updates its internal
representation of the USB device to the 'Default' device state.  If the
device was already in the Default state, the xHC will complete the
command with an error status.

If a device needs to be reset several times during enumeration, the
second reset will always fail because of the xHCI Reset Device command.
This can cause issues during enumeration.

For example, usb_reset_and_verify_device calls into hub_port_init in a
loop.  Say that on the first call into hub_port_init, the device is
successfully reset, but doesn't respond to several set address control
transfers.  Then the port will be disabled, but the udev will remain in
tact.  usb_reset_and_verify_device will call into hub_port_init again.

On the second call into hub_port_init, the device will be reset, and the
xHCI driver will issue a Reset Device command.  This command will fail
(because the device is already in the Default state), and
usb_reset_and_verify_device will fail.  The port will be disabled, and
the device won't be able to enumerate.

Fix this by ignoring the return value of the HCD reset_device callback.

This commit should be backported to kernels as old as 3.2, that contain
the commit 75d7cf72 "usbcore: refine
warm reset logic".
Signed-off-by: default avatarSarah Sharp <sarah.a.sharp@linux.intel.com>
Acked-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Cc: stable@vger.kernel.org
      8b8132bc
    • Sarah Sharp's avatar
      USB: Handle auto-transition from hot to warm reset. · 1c7439c6
      Sarah Sharp authored 
      USB 3.0 hubs and roothubs will automatically transition a failed hot
reset to a warm (BH) reset.  In that case, the warm reset change bit
will be set, and the link state change bit may also be set.  Change
hub_port_finish_reset to unconditionally clear those change bits for USB
3.0 hubs.  If these bits are not cleared, we may lose port change events
from the roothub.

This commit should be backported to kernels as old as 3.2, that contain
the commit 75d7cf72 "usbcore: refine
warm reset logic".
Signed-off-by: default avatarSarah Sharp <sarah.a.sharp@linux.intel.com>
Acked-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Cc: stable@vger.kernel.org
      1c7439c6
    • Sarah Sharp's avatar
      xhci: Handle HS bulk/ctrl endpoints that don't NAK. · 55c1945e
      Sarah Sharp authored 
      A high speed control or bulk endpoint may have bInterval set to zero,
which means it does not NAK.  If bInterval is non-zero, it means the
endpoint NAKs at a rate of 2^(bInterval - 1).

The xHCI code to compute the NAK interval does not handle the special
case of zero properly.  The current code unconditionally subtracts one
from bInterval and uses it as an exponent.  This causes a very large
bInterval to be used, and warning messages like these will be printed:

usb 1-1: ep 0x1 - rounding interval to 32768 microframes, ep desc says 0 microframes

This may cause the xHCI host hardware to reject the Configure Endpoint
command, which means the HS device will be unusable under xHCI ports.

This patch should be backported to kernels as old as 2.6.31, that contain
commit dfa49c4a "USB: xhci - fix math in
xhci_get_endpoint_interval()".
Reported-by: default avatarVincent Pelletier <plr.vincent@gmail.com>
Suggested-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarSarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@vger.kernel.org
      55c1945e
    • Linus Torvalds's avatar
      Linux 3.8-rc2 · d1c3ed66
      Linus Torvalds authored
      d1c3ed66
    • Linus Torvalds's avatar
      Merge branch 'fixes-for-3.8' of git://git.kernel.org/pub/scm/linux/kernel/git/cooloney/linux-leds · d50403dc
      Linus Torvalds authored 
      Pull LED fix from Bryan Wu.

* 'fixes-for-3.8' of git://git.kernel.org/pub/scm/linux/kernel/git/cooloney/linux-leds:
  leds: leds-gpio: set devm_gpio_request_one() flags param correctly
      d50403dc
    • Javier Martinez Canillas's avatar
      leds: leds-gpio: set devm_gpio_request_one() flags param correctly · 2d7c22f6
      Javier Martinez Canillas authored 
      commit a99d76f9 leds: leds-gpio: use gpio_request_one

changed the leds-gpio driver to use gpio_request_one() instead
of gpio_request() + gpio_direction_output()

Unfortunately, it also made a semantic change that breaks the
leds-gpio driver.

The gpio_request_one() flags parameter was set to:

GPIOF_DIR_OUT | (led_dat->active_low ^ state)

Since GPIOF_DIR_OUT is 0, the final flags value will just be the
XOR'ed value of led_dat->active_low and state.

This value were used to distinguish between HIGH/LOW output initial
level and call gpio_direction_output() accordingly.

With this new semantic gpio_request_one() will take the flags value
of 1 as a configuration of input direction (GPIOF_DIR_IN) and will
call gpio_direction_input() instead of gpio_direction_output().

int gpio_request_one(unsigned gpio, unsigned long flags, const char *label)
{
..
	if (flags & GPIOF_DIR_IN)
		err = gpio_direction_input(gpio);
	else
		err = gpio_direction_output(gpio,
				(flags & GPIOF_INIT_HIGH) ? 1 : 0);
..
}

The right semantic is to evaluate led_dat->active_low ^ state and
set the output initial level explicitly.
Signed-off-by: default avatarJavier Martinez Canillas <javier.martinez@collabora.co.uk>
Reported-by: default avatarArnaud Patard <arnaud.patard@rtp-net.org>
Tested-by: default avatarEzequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: default avatarBryan Wu <cooloney@gmail.com>
      2d7c22f6
    • Linus Torvalds's avatar
      Merge git://www.linux-watchdog.org/linux-watchdog · ef05e9b9
      Linus Torvalds authored 
      Pull watchdog fixes from Wim Van Sebroeck:
 "This fixes some small errors in the new da9055 driver, eliminates a
  compiler warning and adds DT support for the twl4030_wdt driver (so
  that we can have multiple watchdogs with DT on the omap platforms)."

* git://www.linux-watchdog.org/linux-watchdog:
  watchdog: twl4030_wdt: add DT support
  watchdog: omap_wdt: eliminate unused variable and a compiler warning
  watchdog: da9055: Don't update wdt_dev->timeout in da9055_wdt_set_timeout error path
  watchdog: da9055: Fix invalid free of devm_ allocated data
      ef05e9b9
    • Linus Torvalds's avatar
      Merge tag '3.8-pci-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci · 080a62e2
      Linus Torvalds authored 
      Pull PCI updates from Bjorn Helgaas:
 "Some fixes for v3.8.  They include a fix for the new SR-IOV sysfs
  management support, an expanded quirk for Ricoh SD card readers, a
  Stratus DMI quirk fix, and a PME polling fix."

* tag '3.8-pci-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
  PCI: Reduce Ricoh 0xe822 SD card reader base clock frequency to 50MHz
  PCI/PM: Do not suspend port if any subordinate device needs PME polling
  PCI: Add PCIe Link Capability link speed and width names
  PCI: Work around Stratus ftServer broken PCIe hierarchy (fix DMI check)
  PCI: Remove spurious error for sriov_numvfs store and simplify flow
      080a62e2
    • David Howells's avatar
      UAPI: Strip _UAPI prefix on header install no matter the whitespace · 8a7eab2b
      David Howells authored 
      Commit 56c176c9 ("UAPI: strip the _UAPI prefix from header guards
during header installation") strips the _UAPI prefix from header guards,
but only if there's a single space between the cpp directive and the
label.

Make it more flexible and able to handle tabs and multiple white space
characters.
Signed-off-by: default avatarDavid Howells <dhowell@redhat.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8a7eab2b
    • David Howells's avatar
      UAPI: Remove empty Kbuild files · 3d33fcc1
      David Howells authored 
      Empty files can get deleted by the patch program, so remove empty Kbuild
files and their links from the parent Kbuilds.
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3d33fcc1
    • Linus Torvalds's avatar
      Merge tag 'ecryptfs-3.8-rc2-fixes' of... · 007f6c3a
      Linus Torvalds authored 
      Merge tag 'ecryptfs-3.8-rc2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tyhicks/ecryptfs

Pull ecryptfs fixes from Tyler Hicks:
 "Two self-explanatory fixes and a third patch which improves
  performance: when overwriting a full page in the eCryptfs page cache,
  skip reading in and decrypting the corresponding lower page."

* tag 'ecryptfs-3.8-rc2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tyhicks/ecryptfs:
  fs/ecryptfs/crypto.c: make ecryptfs_encode_for_filename() static
  eCryptfs: fix to use list_for_each_entry_safe() when delete items
  eCryptfs: Avoid unnecessary disk read and data decryption during writing
      007f6c3a
    • Linus Torvalds's avatar
      Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client · 58890c06
      Linus Torvalds authored 
      Pull Ceph fixes from Sage Weil:
 "Two of Alex's patches deal with a race when reseting server
  connections for open RBD images, one demotes some non-fatal BUGs to
  WARNs, and my patch fixes a protocol feature bit failure path."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
  libceph: fix protocol feature mismatch failure path
  libceph: WARN, don't BUG on unexpected connection states
  libceph: always reset osds when kicking
  libceph: move linger requests sooner in kick_requests()
      58890c06
    • Mel Gorman's avatar
      mm: mempolicy: Convert shared_policy mutex to spinlock · 42288fe3
      Mel Gorman authored 
      Sasha was fuzzing with trinity and reported the following problem:

  BUG: sleeping function called from invalid context at kernel/mutex.c:269
  in_atomic(): 1, irqs_disabled(): 0, pid: 6361, name: trinity-main
  2 locks held by trinity-main/6361:
   #0:  (&mm->mmap_sem){++++++}, at: [<ffffffff810aa314>] __do_page_fault+0x1e4/0x4f0
   #1:  (&(&mm->page_table_lock)->rlock){+.+...}, at: [<ffffffff8122f017>] handle_pte_fault+0x3f7/0x6a0
  Pid: 6361, comm: trinity-main Tainted: G        W
  3.7.0-rc2-next-20121024-sasha-00001-gd95ef01-dirty #74
  Call Trace:
    __might_sleep+0x1c3/0x1e0
    mutex_lock_nested+0x29/0x50
    mpol_shared_policy_lookup+0x2e/0x90
    shmem_get_policy+0x2e/0x30
    get_vma_policy+0x5a/0xa0
    mpol_misplaced+0x41/0x1d0
    handle_pte_fault+0x465/0x6a0

This was triggered by a different version of automatic NUMA balancing
but in theory the current version is vunerable to the same problem.

do_numa_page
  -> numa_migrate_prep
    -> mpol_misplaced
      -> get_vma_policy
        -> shmem_get_policy

It's very unlikely this will happen as shared pages are not marked
pte_numa -- see the page_mapcount() check in change_pte_range() -- but
it is possible.

To address this, this patch restores sp->lock as originally implemented
by Kosaki Motohiro.  In the path where get_vma_policy() is called, it
should not be calling sp_alloc() so it is not necessary to treat the PTL
specially.
Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Tested-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: default avatarMel Gorman <mgorman@suse.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      42288fe3
  11. 02 Jan, 2013 4 commits
    • Linus Torvalds's avatar
      Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 · 5439ca6b
      Linus Torvalds authored 
      Pull ext4 bug fixes from Ted Ts'o:
 "Various bug fixes for ext4.  Perhaps the most serious bug fixed is one
  which could cause file system corruptions when performing file punch
  operations."

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: avoid hang when mounting non-journal filesystems with orphan list
  ext4: lock i_mutex when truncating orphan inodes
  ext4: do not try to write superblock on ro remount w/o journal
  ext4: include journal blocks in df overhead calcs
  ext4: remove unaligned AIO warning printk
  ext4: fix an incorrect comment about i_mutex
  ext4: fix deadlock in journal_unmap_buffer()
  ext4: split off ext4_journalled_invalidatepage()
  jbd2: fix assertion failure in jbd2_journal_flush()
  ext4: check dioread_nolock on remount
  ext4: fix extent tree corruption caused by hole punch
      5439ca6b
    • Hugh Dickins's avatar
      mempolicy: remove arg from mpol_parse_str, mpol_to_str · a7a88b23
      Hugh Dickins authored 
      Remove the unused argument (formerly no_context) from mpol_parse_str()
and from mpol_to_str().
Signed-off-by: default avatarHugh Dickins <hughd@google.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      a7a88b23
    • Hugh Dickins's avatar
      tmpfs mempolicy: fix /proc/mounts corrupting memory · f2a07f40
      Hugh Dickins authored 
      Recently I suggested using "mount -o remount,mpol=local /tmp" in NUMA
mempolicy testing.  Very nasty.  Reading /proc/mounts, /proc/pid/mounts
or /proc/pid/mountinfo may then corrupt one bit of kernel memory, often
in a page table (causing "Bad swap" or "Bad page map" warning or "Bad
pagetable" oops), sometimes in a vm_area_struct or rbnode or somewhere
worse.  "mpol=prefer" and "mpol=prefer:Node" are equally toxic.

Recent NUMA enhancements are not to blame: this dates back to 2.6.35,
when commit e17f74af "mempolicy: don't call mpol_set_nodemask() when
no_context" skipped mpol_parse_str()'s call to mpol_set_nodemask(),
which used to initialize v.preferred_node, or set MPOL_F_LOCAL in flags.
With slab poisoning, you can then rely on mpol_to_str() to set the bit
for node 0x6b6b, probably in the next page above the caller's stack.

mpol_parse_str() is only called from shmem_parse_options(): no_context
is always true, so call it unused for now, and remove !no_context code.
Set v.nodes or v.preferred_node or MPOL_F_LOCAL as mpol_to_str() might
expect.  Then mpol_to_str() can ignore its no_context argument also,
the mpol being appropriately initialized whether contextualized or not.
Rename its no_context unused too, and let subsequent patch remove them
(that's not needed for stable backporting, which would involve rejects).

I don't understand why MPOL_LOCAL is described as a pseudo-policy:
it's a reasonable policy which suffers from a confusing implementation
in terms of MPOL_PREFERRED with MPOL_F_LOCAL.  I believe this would be
much more robust if MPOL_LOCAL were recognized in switch statements
throughout, MPOL_F_LOCAL deleted, and MPOL_PREFERRED use the (possibly
empty) nodes mask like everyone else, instead of its preferred_node
variant (I presume an optimization from the days before MPOL_LOCAL).
But that would take me too long to get right and fully tested.
Signed-off-by: default avatarHugh Dickins <hughd@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      f2a07f40
    • Eric Wong's avatar
      epoll: prevent missed events on EPOLL_CTL_MOD · 128dd175
      Eric Wong authored 
      EPOLL_CTL_MOD sets the interest mask before calling f_op->poll() to
ensure events are not missed.  Since the modifications to the interest
mask are not protected by the same lock as ep_poll_callback, we need to
ensure the change is visible to other CPUs calling ep_poll_callback.

We also need to ensure f_op->poll() has an up-to-date view of past
events which occured before we modified the interest mask.  So this
barrier also pairs with the barrier in wq_has_sleeper().

This should guarantee either ep_poll_callback or f_op->poll() (or both)
will notice the readiness of a recently-ready/modified item.

This issue was encountered by Andreas Voellmy and Junchang(Jason) Wang in:
http://thread.gmane.org/gmane.linux.kernel/1408782/Signed-off-by: default avatarEric Wong <normalperson@yhbt.net>
Cc: Hans Verkuil <hans.verkuil@cisco.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Davide Libenzi <davidel@xmailserver.org>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: David Miller <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andreas Voellmy <andreas.voellmy@yale.edu>
Tested-by: default avatar"Junchang(Jason) Wang" <junchang.wang@yale.edu>
Cc: netdev@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      128dd175
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