linux-stable.git/include/linux, branch v3.0.38

timekeeping: Provide hrtimer update function

2012-07-19T15:58:46+00:00

This is a backport of f6c06abfb3972ad4914cef57d8348fcb2932bc3b

To finally fix the infamous leap second issue and other race windows
caused by functions which change the offsets between the various time
bases (CLOCK_MONOTONIC, CLOCK_REALTIME and CLOCK_BOOTTIME) we need a
function which atomically gets the current monotonic time and updates
the offsets of CLOCK_REALTIME and CLOCK_BOOTTIME with minimalistic
overhead. The previous patch which provides ktime_t offsets allows us
to make this function almost as cheap as ktime_get() which is going to
be replaced in hrtimer_interrupt().

Signed-off-by: Thomas Gleixner 
Reviewed-by: Ingo Molnar 
Acked-by: Peter Zijlstra 
Acked-by: Prarit Bhargava 
Signed-off-by: John Stultz 
Link: http://lkml.kernel.org/r/1341960205-56738-7-git-send-email-johnstul@us.ibm.com
Signed-off-by: Thomas Gleixner 
Cc: Prarit Bhargava 
Cc: Thomas Gleixner 
Signed-off-by: John Stultz 
Signed-off-by: Greg Kroah-Hartman

hrtimer: Provide clock_was_set_delayed()

2012-07-19T15:58:37+00:00

This is a backport of f55a6faa384304c89cfef162768e88374d3312cb

clock_was_set() cannot be called from hard interrupt context because
it calls on_each_cpu().

For fixing the widely reported leap seconds issue it is necessary to
call it from hard interrupt context, i.e. the timer tick code, which
does the timekeeping updates.

Provide a new function which denotes it in the hrtimer cpu base
structure of the cpu on which it is called and raise the hrtimer
softirq. We then execute the clock_was_set() notificiation from
softirq context in run_hrtimer_softirq(). The hrtimer softirq is
rarely used, so polling the flag there is not a performance issue.

[ tglx: Made it depend on CONFIG_HIGH_RES_TIMERS. We really should get
  rid of all this ifdeffery ASAP ]

Signed-off-by: John Stultz 
Reported-by: Jan Engelhardt 
Reviewed-by: Ingo Molnar 
Acked-by: Peter Zijlstra 
Acked-by: Prarit Bhargava 
Link: http://lkml.kernel.org/r/1341960205-56738-2-git-send-email-johnstul@us.ibm.com
Signed-off-by: Thomas Gleixner 
Cc: Prarit Bhargava 
Cc: Thomas Gleixner 
Signed-off-by: John Stultz 
Signed-off-by: Greg Kroah-Hartman

ntp: Fix leap-second hrtimer livelock

2012-07-19T15:58:22+00:00

This is a backport of 6b43ae8a619d17c4935c3320d2ef9e92bdeed05d

This should have been backported when it was commited, but I
mistook the problem as requiring the ntp_lock changes
that landed in 3.4 in order for it to occur.

Unfortunately the same issue can happen (with only one cpu)
as follows:
do_adjtimex()
 write_seqlock_irq(&xtime_lock);
  process_adjtimex_modes()
   process_adj_status()
    ntp_start_leap_timer()
     hrtimer_start()
      hrtimer_reprogram()
       tick_program_event()
        clockevents_program_event()
         ktime_get()
          seq = req_seqbegin(xtime_lock); [DEADLOCK]

This deadlock will no always occur, as it requires the
leap_timer to force a hrtimer_reprogram which only happens
if its set and there's no sooner timer to expire.

NOTE: This patch, being faithful to the original commit,
introduces a bug (we don't update wall_to_monotonic),
which will be resovled by backporting a following fix.

Original commit message below:

Since commit 7dffa3c673fbcf835cd7be80bb4aec8ad3f51168 the ntp
subsystem has used an hrtimer for triggering the leapsecond
adjustment. However, this can cause a potential livelock.

Thomas diagnosed this as the following pattern:
CPU 0                                                    CPU 1
do_adjtimex()
  spin_lock_irq(&ntp_lock);
    process_adjtimex_modes();				 timer_interrupt()
      process_adj_status();                                do_timer()
        ntp_start_leap_timer();                             write_lock(&xtime_lock);
          hrtimer_start();                                  update_wall_time();
             hrtimer_reprogram();                            ntp_tick_length()
               tick_program_event()                            spin_lock(&ntp_lock);
                 clockevents_program_event()
		   ktime_get()
                     seq = req_seqbegin(xtime_lock);

This patch tries to avoid the problem by reverting back to not using
an hrtimer to inject leapseconds, and instead we handle the leapsecond
processing in the second_overflow() function.

The downside to this change is that on systems that support highres
timers, the leap second processing will occur on a HZ tick boundary,
(ie: ~1-10ms, depending on HZ)  after the leap second instead of
possibly sooner (~34us in my tests w/ x86_64 lapic).

This patch applies on top of tip/timers/core.

CC: Sasha Levin 
CC: Thomas Gleixner 
Reported-by: Sasha Levin 
Diagnoised-by: Thomas Gleixner 
Tested-by: Sasha Levin 
Cc: Prarit Bhargava 
Cc: Thomas Gleixner 
Signed-off-by: John Stultz 
Signed-off-by: Greg Kroah-Hartman

memory hotplug: fix invalid memory access caused by stale kswapd pointer

2012-07-16T15:47:52+00:00

commit d8adde17e5f858427504725218c56aef90e90fc7 upstream.

kswapd_stop() is called to destroy the kswapd work thread when all memory
of a NUMA node has been offlined.  But kswapd_stop() only terminates the
work thread without resetting NODE_DATA(nid)->kswapd to NULL.  The stale
pointer will prevent kswapd_run() from creating a new work thread when
adding memory to the memory-less NUMA node again.  Eventually the stale
pointer may cause invalid memory access.

An example stack dump as below. It's reproduced with 2.6.32, but latest
kernel has the same issue.

  BUG: unable to handle kernel NULL pointer dereference at (null)
  IP: [] exit_creds+0x12/0x78
  PGD 0
  Oops: 0000 [#1] SMP
  last sysfs file: /sys/devices/system/memory/memory391/state
  CPU 11
  Modules linked in: cpufreq_conservative cpufreq_userspace cpufreq_powersave acpi_cpufreq microcode fuse loop dm_mod tpm_tis rtc_cmos i2c_i801 rtc_core tpm serio_raw pcspkr sg tpm_bios igb i2c_core iTCO_wdt rtc_lib mptctl iTCO_vendor_support button dca bnx2 usbhid hid uhci_hcd ehci_hcd usbcore sd_mod crc_t10dif edd ext3 mbcache jbd fan ide_pci_generic ide_core ata_generic ata_piix libata thermal processor thermal_sys hwmon mptsas mptscsih mptbase scsi_transport_sas scsi_mod
  Pid: 7949, comm: sh Not tainted 2.6.32.12-qiuxishi-5-default #92 Tecal RH2285
  RIP: 0010:exit_creds+0x12/0x78
  RSP: 0018:ffff8806044f1d78  EFLAGS: 00010202
  RAX: 0000000000000000 RBX: ffff880604f22140 RCX: 0000000000019502
  RDX: 0000000000000000 RSI: 0000000000000202 RDI: 0000000000000000
  RBP: ffff880604f22150 R08: 0000000000000000 R09: ffffffff81a4dc10
  R10: 00000000000032a0 R11: ffff880006202500 R12: 0000000000000000
  R13: 0000000000c40000 R14: 0000000000008000 R15: 0000000000000001
  FS:  00007fbc03d066f0(0000) GS:ffff8800282e0000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
  CR2: 0000000000000000 CR3: 000000060f029000 CR4: 00000000000006e0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
  Process sh (pid: 7949, threadinfo ffff8806044f0000, task ffff880603d7c600)
  Stack:
   ffff880604f22140 ffffffff8103aac5 ffff880604f22140 ffffffff8104d21e
   ffff880006202500 0000000000008000 0000000000c38000 ffffffff810bd5b1
   0000000000000000 ffff880603d7c600 00000000ffffdd29 0000000000000003
  Call Trace:
    __put_task_struct+0x5d/0x97
    kthread_stop+0x50/0x58
    offline_pages+0x324/0x3da
    memory_block_change_state+0x179/0x1db
    store_mem_state+0x9e/0xbb
    sysfs_write_file+0xd0/0x107
    vfs_write+0xad/0x169
    sys_write+0x45/0x6e
    system_call_fastpath+0x16/0x1b
  Code: ff 4d 00 0f 94 c0 84 c0 74 08 48 89 ef e8 1f fd ff ff 5b 5d 31 c0 41 5c c3 53 48 8b 87 20 06 00 00 48 89 fb 48 8b bf 18 06 00 00 <8b> 00 48 c7 83 18 06 00 00 00 00 00 00 f0 ff 0f 0f 94 c0 84 c0
  RIP  exit_creds+0x12/0x78
   RSP 
  CR2: 0000000000000000

[akpm@linux-foundation.org: add pglist_data.kswapd locking comments]
Signed-off-by: Xishi Qiu 
Signed-off-by: Jiang Liu 
Acked-by: KAMEZAWA Hiroyuki 
Acked-by: KOSAKI Motohiro 
Acked-by: Mel Gorman 
Acked-by: David Rientjes 
Reviewed-by: Minchan Kim 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

PCI: EHCI: fix crash during suspend on ASUS computers

2012-07-16T15:47:50+00:00

commit dbf0e4c7257f8d684ec1a3c919853464293de66e upstream.

Quite a few ASUS computers experience a nasty problem, related to the
EHCI controllers, when going into system suspend.  It was observed
that the problem didn't occur if the controllers were not put into the
D3 power state before starting the suspend, and commit
151b61284776be2d6f02d48c23c3625678960b97 (USB: EHCI: fix crash during
suspend on ASUS computers) was created to do this.

It turned out this approach messed up other computers that didn't have
the problem -- it prevented USB wakeup from working.  Consequently
commit c2fb8a3fa25513de8fedb38509b1f15a5bbee47b (USB: add
NO_D3_DURING_SLEEP flag and revert 151b61284776be2) was merged; it
reverted the earlier commit and added a whitelist of known good board
names.

Now we know the actual cause of the problem.  Thanks to AceLan Kao for
tracking it down.

According to him, an engineer at ASUS explained that some of their
BIOSes contain a bug that was added in an attempt to work around a
problem in early versions of Windows.  When the computer goes into S3
suspend, the BIOS tries to verify that the EHCI controllers were first
quiesced by the OS.  Nothing's wrong with this, but the BIOS does it
by checking that the PCI COMMAND registers contain 0 without checking
the controllers' power state.  If the register isn't 0, the BIOS
assumes the controller needs to be quiesced and tries to do so.  This
involves making various MMIO accesses to the controller, which don't
work very well if the controller is already in D3.  The end result is
a system hang or memory corruption.

Since the value in the PCI COMMAND register doesn't matter once the
controller has been suspended, and since the value will be restored
anyway when the controller is resumed, we can work around the BIOS bug
simply by setting the register to 0 during system suspend.  This patch
(as1590) does so and also reverts the second commit mentioned above,
which is now unnecessary.

In theory we could do this for every PCI device.  However to avoid
introducing new problems, the patch restricts itself to EHCI host
controllers.

Finally the affected systems can suspend with USB wakeup working
properly.

Reference: https://bugzilla.kernel.org/show_bug.cgi?id=37632
Reference: https://bugzilla.kernel.org/show_bug.cgi?id=42728
Based-on-patch-by: AceLan Kao 
Signed-off-by: Alan Stern 
Tested-by: Dâniel Fraga 
Tested-by: Javier Marcet 
Tested-by: Andrey Rahmatullin 
Tested-by: Oleksij Rempel 
Tested-by: Pavel Pisa 
Acked-by: Bjorn Helgaas 
Acked-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

USB: add NO_D3_DURING_SLEEP flag and revert 151b61284776be2

2012-06-22T18:34:15+00:00

commit c2fb8a3fa25513de8fedb38509b1f15a5bbee47b upstream.

This patch (as1558) fixes a problem affecting several ASUS computers:
The machine crashes or corrupts memory when going into suspend if the
ehci-hcd driver is bound to any controllers.  Users have been forced
to unbind or unload ehci-hcd before putting their systems to sleep.

After extensive testing, it was determined that the machines don't
like going into suspend when any EHCI controllers are in the PCI D3
power state.  Presumably this is a firmware bug, but there's nothing
we can do about it except to avoid putting the controllers in D3
during system sleep.

The patch adds a new flag to indicate whether the problem is present,
and avoids changing the controller's power state if the flag is set.
Runtime suspend is unaffected; this matters only for system suspend.
However as a side effect, the controller will not respond to remote
wakeup requests while the system is asleep.  Hence USB wakeup is not
functional -- but of course, this is already true in the current state
of affairs.

A similar patch has already been applied as commit
151b61284776be2d6f02d48c23c3625678960b97 (USB: EHCI: fix crash during
suspend on ASUS computers).  The patch supersedes that one and reverts
it.  There are two differences:

	The old patch added the flag at the USB level; this patch
	adds it at the PCI level.

	The old patch applied to all chipsets with the same vendor,
	subsystem vendor, and product IDs; this patch makes an
	exception for a known-good system (based on DMI information).

Signed-off-by: Alan Stern 
Tested-by: Dâniel Fraga 
Tested-by: Andrey Rahmatullin 
Tested-by: Steven Rostedt 
Reviewed-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

skb: avoid unnecessary reallocations in __skb_cow

2012-06-09T15:33:03+00:00

[ Upstream commit 617c8c11236716dcbda877e764b7bf37c6fd8063 ]

At the beginning of __skb_cow, headroom gets set to a minimum of
NET_SKB_PAD. This causes unnecessary reallocations if the buffer was not
cloned and the headroom is just below NET_SKB_PAD, but still more than the
amount requested by the caller.
This was showing up frequently in my tests on VLAN tx, where
vlan_insert_tag calls skb_cow_head(skb, VLAN_HLEN).

Locally generated packets should have enough headroom, and for forward
paths, we already have NET_SKB_PAD bytes of headroom, so we don't need to
add any extra space here.

Signed-off-by: Felix Fietkau 
Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

Revert "net: maintain namespace isolation between vlan and real device"

2012-06-09T15:33:03+00:00

[ Upstream commit 59b9997baba5242997ddc7bd96b1391f5275a5a4 ]

This reverts commit 8a83a00b0735190384a348156837918271034144.

It causes regressions for S390 devices, because it does an
unconditional DST drop on SKBs for vlans and the QETH device
needs the neighbour entry hung off the DST for certain things
on transmit.

Arnd can't remember exactly why he even needed this change.

Conflicts:

	drivers/net/macvlan.c
	net/8021q/vlan_dev.c
	net/core/dev.c

Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

mmc: sdio: avoid spurious calls to interrupt handlers

2012-06-01T07:13:00+00:00

commit bbbc4c4d8c5face097d695f9bf3a39647ba6b7e7 upstream.

Commit 06e8935feb ("optimized SDIO IRQ handling for single irq")
introduced some spurious calls to SDIO function interrupt handlers,
such as when the SDIO IRQ thread is started, or the safety check
performed upon a system resume.  Let's add a flag to perform the
optimization only when a real interrupt is signaled by the host
driver and we know there is no point confirming it.

Reported-by: Sujit Reddy Thumma 
Signed-off-by: Nicolas Pitre 
Signed-off-by: Chris Ball 
Signed-off-by: Greg Kroah-Hartman

block: don't mark buffers beyond end of disk as mapped

2012-06-01T07:12:52+00:00

commit 080399aaaf3531f5b8761ec0ac30ff98891e8686 upstream.

Hi,

We have a bug report open where a squashfs image mounted on ppc64 would
exhibit errors due to trying to read beyond the end of the disk.  It can
easily be reproduced by doing the following:

[root@ibm-p750e-02-lp3 ~]# ls -l install.img
-rw-r--r-- 1 root root 142032896 Apr 30 16:46 install.img
[root@ibm-p750e-02-lp3 ~]# mount -o loop ./install.img /mnt/test
[root@ibm-p750e-02-lp3 ~]# dd if=/dev/loop0 of=/dev/null
dd: reading `/dev/loop0': Input/output error
277376+0 records in
277376+0 records out
142016512 bytes (142 MB) copied, 0.9465 s, 150 MB/s

In dmesg, you'll find the following:

squashfs: version 4.0 (2009/01/31) Phillip Lougher
[   43.106012] attempt to access beyond end of device
[   43.106029] loop0: rw=0, want=277410, limit=277408
[   43.106039] Buffer I/O error on device loop0, logical block 138704
[   43.106053] attempt to access beyond end of device
[   43.106057] loop0: rw=0, want=277412, limit=277408
[   43.106061] Buffer I/O error on device loop0, logical block 138705
[   43.106066] attempt to access beyond end of device
[   43.106070] loop0: rw=0, want=277414, limit=277408
[   43.106073] Buffer I/O error on device loop0, logical block 138706
[   43.106078] attempt to access beyond end of device
[   43.106081] loop0: rw=0, want=277416, limit=277408
[   43.106085] Buffer I/O error on device loop0, logical block 138707
[   43.106089] attempt to access beyond end of device
[   43.106093] loop0: rw=0, want=277418, limit=277408
[   43.106096] Buffer I/O error on device loop0, logical block 138708
[   43.106101] attempt to access beyond end of device
[   43.106104] loop0: rw=0, want=277420, limit=277408
[   43.106108] Buffer I/O error on device loop0, logical block 138709
[   43.106112] attempt to access beyond end of device
[   43.106116] loop0: rw=0, want=277422, limit=277408
[   43.106120] Buffer I/O error on device loop0, logical block 138710
[   43.106124] attempt to access beyond end of device
[   43.106128] loop0: rw=0, want=277424, limit=277408
[   43.106131] Buffer I/O error on device loop0, logical block 138711
[   43.106135] attempt to access beyond end of device
[   43.106139] loop0: rw=0, want=277426, limit=277408
[   43.106143] Buffer I/O error on device loop0, logical block 138712
[   43.106147] attempt to access beyond end of device
[   43.106151] loop0: rw=0, want=277428, limit=277408
[   43.106154] Buffer I/O error on device loop0, logical block 138713
[   43.106158] attempt to access beyond end of device
[   43.106162] loop0: rw=0, want=277430, limit=277408
[   43.106166] attempt to access beyond end of device
[   43.106169] loop0: rw=0, want=277432, limit=277408
...
[   43.106307] attempt to access beyond end of device
[   43.106311] loop0: rw=0, want=277470, limit=2774

Squashfs manages to read in the end block(s) of the disk during the
mount operation.  Then, when dd reads the block device, it leads to
block_read_full_page being called with buffers that are beyond end of
disk, but are marked as mapped.  Thus, it would end up submitting read
I/O against them, resulting in the errors mentioned above.  I fixed the
problem by modifying init_page_buffers to only set the buffer mapped if
it fell inside of i_size.

Cheers,
Jeff

Signed-off-by: Jeff Moyer 
Acked-by: Nick Piggin 

--

Changes from v1->v2: re-used max_block, as suggested by Nick Piggin.
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman