sched: Fix select_fallback_rq() vs cpu_active/cpu_online

Commit 5fbd036b55 ("sched: Cleanup cpu_active madness"), which was
supposed to finally sort the cpu_active mess, instead uncovered more.

Since CPU_STARTING is ran before setting the cpu online, there's a
(small) window where the cpu has active,!online.

If during this time there's a wakeup of a task that used to reside on
that cpu select_task_rq() will use select_fallback_rq() to compute an
alternative cpu to run on since we find !online.

select_fallback_rq() however will compute the new cpu against
cpu_active, this means that it can return the same cpu it started out
with, the !online one, since that cpu is in fact marked active.

This results in us trying to scheduling a task on an offline cpu and
triggering a WARN in the IPI code.

The solution proposed by Chuansheng Liu of setting cpu_active in
set_cpu_online() is buggy, firstly not all archs actually use
set_cpu_online(), secondly, not all archs call set_cpu_online() with
IRQs disabled, this means we would introduce either the same race or
the race from fd8a7de17 ("x86: cpu-hotplug: Prevent softirq wakeup on
wrong CPU") -- albeit much narrower.

[ By setting online first and active later we have a window of
  online,!active, fresh and bound kthreads have task_cpu() of 0 and
  since cpu0 isn't in tsk_cpus_allowed() we end up in
  select_fallback_rq() which excludes !active, resulting in a reset
  of ->cpus_allowed and the thread running all over the place. ]

The solution is to re-work select_fallback_rq() to require active
_and_ online. This makes the active,!online case work as expected,
OTOH archs running CPU_STARTING after setting online are now
vulnerable to the issue from fd8a7de17 -- these are alpha and
blackfin.

Change-Id: I34bedb461f77bfe4af78ef5ddd3fb3a230ca3551
Reported-by: Chuansheng Liu <chuansheng.liu@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: linux-alpha@vger.kernel.org
Link: http://lkml.kernel.org/n/tip-hubqk1i10o4dpvlm06gq7v6j@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Taras Kondratiuk <taras@ti.com>
smsc95xx: mark link down on startup and let PHY interrupt deal with carrier changes

commit 07d69d4238418746a7b85c5d05ec17c658a2a390 upstream.

Without this patch sysfs reports the cable as present

flag@flag-desktop:~$ cat /sys/class/net/eth0/carrier
1

while it's not:

flag@flag-desktop:~$ sudo mii-tool eth0
eth0: no link

Tested on my Beagle XM.

v2: added mantainer to the list of recipient

Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>
Acked-by: Steve Glendinning <steve.glendinning@shawell.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
xen/pte: Fix crashes when trying to see non-existent PGD/PMD/PUD/PTEs

commit b7e5ffe5d83fa40d702976d77452004abbe35791 upstream.

If I try to do "cat /sys/kernel/debug/kernel_page_tables"
I end up with:

BUG: unable to handle kernel paging request at ffffc7fffffff000
IP: [<ffffffff8106aa51>] ptdump_show+0x221/0x480
PGD 0
Oops: 0000 [#1] SMP
CPU 0
.. snip..
RAX: 0000000000000000 RBX: ffffc00000000fff RCX: 0000000000000000
RDX: 0000800000000000 RSI: 0000000000000000 RDI: ffffc7fffffff000

which is due to the fact we are trying to access a PFN that is not
accessible to us. The reason (at least in this case) was that
PGD[256] is set to __HYPERVISOR_VIRT_START which was setup (by the
hypervisor) to point to a read-only linear map of the MFN->PFN array.
During our parsing we would get the MFN (a valid one), try to look
it up in the MFN->PFN tree and find it invalid and return ~0 as PFN.
Then pte_mfn_to_pfn would happilly feed that in, attach the flags
and return it back to the caller. 'ptdump_show' bitshifts it and
gets and invalid value that it tries to dereference.

Instead of doing all of that, we detect the ~0 case and just
return !_PAGE_PRESENT.

This bug has been in existence .. at least until 2.6.37 (yikes!)

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
xen/pci: don't use PCI BIOS service for configuration space accesses

commit 76a8df7b49168509df02461f83fab117a4a86e08 upstream.

The accessing PCI configuration space with the PCI BIOS32 service does
not work in PV guests.

On systems without MMCONFIG or where the BIOS hasn't marked the
MMCONFIG region as reserved in the e820 map, the BIOS service is
probed (even though direct access is preferred) and this hangs.

Acked-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
[v1: Fixed compile error when CONFIG_PCI is not set]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
percpu, x86: don't use PMD_SIZE as embedded atom_size on 32bit

commit d5e28005a1d2e67833852f4c9ea8ec206ea3ff85 upstream.

With the embed percpu first chunk allocator, x86 uses either PAGE_SIZE
or PMD_SIZE for atom_size.  PMD_SIZE is used when CPU supports PSE so
that percpu areas are aligned to PMD mappings and possibly allow using
PMD mappings in vmalloc areas in the future.  Using larger atom_size
doesn't waste actual memory; however, it does require larger vmalloc
space allocation later on for !first chunks.

With reasonably sized vmalloc area, PMD_SIZE shouldn't be a problem
but x86_32 at this point is anything but reasonable in terms of
address space and using larger atom_size reportedly leads to frequent
percpu allocation failures on certain setups.

As there is no reason to not use PMD_SIZE on x86_64 as vmalloc space
is aplenty and most x86_64 configurations support PSE, fix the issue
by always using PMD_SIZE on x86_64 and PAGE_SIZE on x86_32.

v2: drop cpu_has_pse test and make x86_64 always use PMD_SIZE and
    x86_32 PAGE_SIZE as suggested by hpa.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Yanmin Zhang <yanmin.zhang@intel.com>
Reported-by: ShuoX Liu <shuox.liu@intel.com>
Acked-by: H. Peter Anvin <hpa@zytor.com>
LKML-Reference: <4F97BA98.6010001@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
asm-generic: Use __BITS_PER_LONG in statfs.h

commit f5c2347ee20a8d6964d6a6b1ad04f200f8d4dfa7 upstream.

<asm-generic/statfs.h> is exported to userspace, so using
BITS_PER_LONG is invalid.  We need to use __BITS_PER_LONG instead.

This is kernel bugzilla 43165.

Reported-by: H.J. Lu <hjl.tools@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/1335465916-16965-1-git-send-email-hpa@linux.intel.com
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fix __read_seqcount_begin() to use ACCESS_ONCE for sequence value read

commit 2f624278626677bfaf73fef97f86b37981621f5c upstream.

We really need to use a ACCESS_ONCE() on the sequence value read in
__read_seqcount_begin(), because otherwise the compiler might end up
reloading the value in between the test and the return of it.  As a
result, it might end up returning an odd value (which means that a write
is in progress).

If the reader is then fast enough that that odd value is still the
current one when the read_seqcount_retry() is done, we might end up with
a "successful" read sequence, even despite the concurrent write being
active.

In practice this probably never really happens - there just isn't
anything else going on around the read of the sequence count, and the
common case is that we end up having a read barrier immediately
afterwards.

So the code sequence in which gcc might decide to reaload from memory is
small, and there's no reason to believe it would ever actually do the
reload.  But if the compiler ever were to decide to do so, it would be
incredibly annoying to debug.  Let's just make sure.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ARM: 7410/1: Add extra clobber registers for assembly in kernel_execve

commit e787ec1376e862fcea1bfd523feb7c5fb43ecdb9 upstream.

The inline assembly in kernel_execve() uses r8 and r9.  Since this
code sequence does not return, it usually doesn't matter if the
register clobber list is accurate.  However, I saw a case where a
particular version of gcc used r8 as an intermediate for the value
eventually passed to r9.  Because r8 is used in the inline
assembly, and not mentioned in the clobber list, r9 was set
to an incorrect value.

This resulted in a kernel panic on execution of the first user-space
program in the system.  r9 is used in ret_to_user as the thread_info
pointer, and if it's wrong, bad things happen.

Signed-off-by: Tim Bird <tim.bird@am.sony.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ARM: 7414/1: SMP: prevent use of the console when using idmap_pgd

commit fde165b2a29673aabf18ceff14dea1f1cfb0daad upstream.

Commit 4e8ee7de227e3ab9a72040b448ad728c5428a042 (ARM: SMP: use
idmap_pgd for mapping MMU enable during secondary booting)
switched secondary boot to use idmap_pgd, which is initialized
during early_initcall, instead of a page table initialized during
__cpu_up.  This causes idmap_pgd to contain the static mappings
but be missing all dynamic mappings.

If a console is registered that creates a dynamic mapping, the
printk in secondary_start_kernel will trigger a data abort on
the missing mapping before the exception handlers have been
initialized, leading to a hang.  Initial boot is not affected
because no consoles have been registered, and resume is usually
not affected because the offending console is suspended.
Onlining a cpu with hotplug triggers the problem.

A workaround is to the printk in secondary_start_kernel until
after the page tables have been switched back to init_mm.

Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
regulator: Fix the logic to ensure new voltage setting in valid range

commit f55205f4d4a8823a11bb8b37ef2ecbd78fb09463 upstream.

I think this is a typo.
To ensure new voltage setting won't greater than desc->max,
the equation should be desc->min + desc->step * new_val <= desc->max.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ARM: orion5x: Fix GPIO enable bits for MPP9

commit 48d99f47a81a66bdd61a348c7fe8df5a7afdf5f3 upstream.

Commit 554cdaefd1cf7bb54b209c4e68c7cec87ce442a9 ('ARM: orion5x: Refactor
mpp code to use common orion platform mpp.') seems to have accidentally
inverted the GPIO valid bits for MPP9 (only).  For the mv2120 platform
which uses MPP9 as a GPIO LED device, this results in the error:

[   12.711476] leds-gpio: probe of leds-gpio failed with error -22

Reported-by: Henry von Tresckow <hvontres@gmail.com>
References: http://bugs.debian.org/667446
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Tested-by: Hans Henry von Tresckow <hvontres@gmail.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
asix: Fix tx transfer padding for full-speed USB

[ Upstream commit 2a5809499e35b53a6044fd34e72b242688b7a862 ]

The asix.c USB Ethernet driver avoids ending a tx transfer with a zero-
length packet by appending a four-byte padding to transfers whose length
is a multiple of maxpacket. However, the hard-coded 512 byte maxpacket
length is valid for high-speed USB only; full-speed USB uses 64 byte
packets.

Signed-off-by: Ingo van Lil <inguin@gmx.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
netem: fix possible skb leak

[ Upstream commit 116a0fc31c6c9b8fc821be5a96e5bf0b43260131 ]

skb_checksum_help(skb) can return an error, we must free skb in this
case. qdisc_drop(skb, sch) can also be feeded with a NULL skb (if
skb_unshare() failed), so lets use this generic helper.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net: In unregister_netdevice_notifier unregister the netdevices.

[ Upstream commit 7d3d43dab4e978d8d9ad1acf8af15c9b1c4b0f0f ]

We already synthesize events in register_netdevice_notifier and synthesizing
events in unregister_netdevice_notifier allows to us remove the need for
special case cleanup code.

This change should be safe as it adds no new cases for existing callers
of unregiser_netdevice_notifier to handle.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net: l2tp: unlock socket lock before returning from l2tp_ip_sendmsg

[ Upstream commit 84768edbb2721637620b2d84501bb0d5aed603f1 ]

l2tp_ip_sendmsg could return without releasing socket lock, making it all the
way to userspace, and generating the following warning:

[  130.891594] ================================================
[  130.894569] [ BUG: lock held when returning to user space! ]
[  130.897257] 3.4.0-rc5-next-20120501-sasha #104 Tainted: G        W
[  130.900336] ------------------------------------------------
[  130.902996] trinity/8384 is leaving the kernel with locks still held!
[  130.906106] 1 lock held by trinity/8384:
[  130.907924]  #0:  (sk_lock-AF_INET){+.+.+.}, at: [<ffffffff82b9503f>] l2tp_ip_sendmsg+0x2f/0x550

Introduced by commit 2f16270 ("l2tp: Fix locking in l2tp_ip.c").

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sky2: propogate rx hash when packet is copied

[ Upstream commit 3f42941b5d1d13542b1a755a9e4f633aa72e4d3e ]

When a small packet is received, the driver copies it to a new skb to allow
reusing the full size Rx buffer. The copy was propogating the checksum offload
but not the receive hash information. The bug is impact was mostly harmless
and therefore not observed until reviewing this area of code.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sky2: fix receive length error in mixed non-VLAN/VLAN traffic

[ Upstream commit e072b3fad5f3915102c94628b4971f52ff99dd05 ]

Bug: The VLAN bit of the MAC RX Status Word is unreliable in several older
supported chips. Sometimes the VLAN bit is not set for valid VLAN packets
and also sometimes the VLAN bit is set for non-VLAN packets that came after
a VLAN packet. This results in a receive length error when VLAN hardware
tagging is enabled.

Fix: Variation on original fix proposed by Mirko.
The VLAN information is decoded in the status loop, and can be
applied to the received SKB there. This eliminates the need for the
separate tag field in the interface data structure. The tag has to
be copied and cleared if packet is copied. This version checked out
with vlan and normal traffic.

Note: vlan_tx_tag_present should be renamed vlan_tag_present, but that
is outside scope of this.

Reported-by: Mirko Lindner <mlindner@marvell.com>
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tg3: Avoid panic from reserved statblk field access

[ Upstream commit f891ea1634ce41f5f47ae40d8594809f4cd2ca66 ]

When RSS is enabled, interrupt vector 0 does not receive any rx traffic.
The rx producer index fields for vector 0's status block should be
considered reserved in this case.  This patch changes the code to
respect these reserved fields, which avoids a kernel panic when these
fields take on non-zero values.

Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sungem: Fix WakeOnLan

[ Upstream commit 5a8887d39e1ba5ee2d4ccb94b14d6f2dce5ddfca ]

WakeOnLan was broken in this driver because gp->asleep_wol is a 1-bit
bitfield and it was being assigned WAKE_MAGIC, which is (1 << 5).
gp->asleep_wol remains 0 and the machine never wakes up.  Fixed by casting
gp->wake_on_lan to bool.  Tested on an iBook G4.

Signed-off-by: Gerard Lledo <gerard.lledo@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tcp: change tcp_adv_win_scale and tcp_rmem[2]

[ Upstream commit b49960a05e32121d29316cfdf653894b88ac9190 ]

tcp_adv_win_scale default value is 2, meaning we expect a good citizen
skb to have skb->len / skb->truesize ratio of 75% (3/4)

In 2.6 kernels we (mis)accounted for typical MSS=1460 frame :
1536 + 64 + 256 = 1856 'estimated truesize', and 1856 * 3/4 = 1392.
So these skbs were considered as not bloated.

With recent truesize fixes, a typical MSS=1460 frame truesize is now the
more precise :
2048 + 256 = 2304. But 2304 * 3/4 = 1728.
So these skb are not good citizen anymore, because 1460 < 1728

(GRO can escape this problem because it build skbs with a too low
truesize.)

This also means tcp advertises a too optimistic window for a given
allocated rcvspace : When receiving frames, sk_rmem_alloc can hit
sk_rcvbuf limit and we call tcp_prune_queue()/tcp_collapse() too often,
especially when application is slow to drain its receive queue or in
case of losses (netperf is fast, scp is slow). This is a major latency
source.

We should adjust the len/truesize ratio to 50% instead of 75%

This patch :

1) changes tcp_adv_win_scale default to 1 instead of 2

2) increase tcp_rmem[2] limit from 4MB to 6MB to take into account
better truesize tracking and to allow autotuning tcp receive window to
reach same value than before. Note that same amount of kernel memory is
consumed compared to 2.6 kernels.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Tom Herbert <therbert@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>