Use TX control flag IEEE80211_TX_CTL_ASSIGN_SEQ as a request to update
the seq# for the frames. This will likely require some further cleanup
to get seq# correctly for Beacons vs. other frames and also potentially
for multiple BSSes. Anyway, this is better than ending up sending out
most frames with seq# 0.
(This is a backport of patch w/ same title already in net-next-2.6.
It is verified to fix http://bugzilla.kernel.org/show_bug.cgi?id=11394
and it should be acceptable for -rc due to the driver being new
in 2.6.27.)
Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This fixes kernel bugzilla 11469: "TUN with 1024 neighbours:
ip6_dst_lookup_tail NULL crash"
dst->neighbour is not necessarily hooked up at this point
in the processing path, so blindly dereferencing it is
the wrong thing to do. This NULL check exists in other
similar paths and this case was just an oversight.
Also fix the completely wrong and confusing indentation
here while we're at it.
Based upon a patch by Evgeniy Polyakov.
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The commit commit 4c563f7669 ("[XFRM]:
Speed up xfrm_policy and xfrm_state walking") inadvertently removed
larval states and socket policies from netlink dumps. This patch
restores them.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
The Security Mode 4 of the Bluetooth 2.1 specification has strict
authentication and encryption requirements. It is the initiators job
to create a secure ACL link. However in case of malicious devices, the
acceptor has to make sure that the ACL is encrypted before allowing
any kind of L2CAP connection. The only exception here is the PSM 1 for
the service discovery protocol, because that is allowed to run on an
insecure ACL link.
Previously it was enough to reject a L2CAP connection during the
connection setup phase, but with Bluetooth 2.1 it is forbidden to
do any L2CAP protocol exchange on an insecure link (except SDP).
The new hci_conn_check_link_mode() function can be used to check the
integrity of an ACL link. This functions also takes care of the cases
where Security Mode 4 is disabled or one of the devices is based on
an older specification.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
With the introduction of Security Mode 4 and Simple Pairing from the
Bluetooth 2.1 specification it became mandatory that the initiator
requires authentication and encryption before any L2CAP channel can
be established. The only exception here is PSM 1 for the service
discovery protocol (SDP). It is meant to be used without any encryption
since it contains only public information. This is how Bluetooth 2.0
and before handle connections on PSM 1.
For Bluetooth 2.1 devices the pairing procedure differentiates between
no bonding, general bonding and dedicated bonding. The L2CAP layer
wrongly uses always general bonding when creating new connections, but it
should not do this for SDP connections. In this case the authentication
requirement should be no bonding and the just-works model should be used,
but in case of non-SDP connection it is required to use general bonding.
If the new connection requires man-in-the-middle (MITM) protection, it
also first wrongly creates an unauthenticated link key and then later on
requests an upgrade to an authenticated link key to provide full MITM
protection. With Simple Pairing the link key generation is an expensive
operation (compared to Bluetooth 2.0 and before) and doing this twice
during a connection setup causes a noticeable delay when establishing
a new connection. This should be avoided to not regress from the expected
Bluetooth 2.0 connection times. The authentication requirements are known
up-front and so enforce them.
To fulfill these requirements the hci_connect() function has been extended
with an authentication requirement parameter that will be stored inside
the connection information and can be retrieved by userspace at any
time. This allows the correct IO capabilities exchange and results in
the expected behavior.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
The ACL config stage keeps holding a reference count on incoming
connections when requesting the extended features. This results in
keeping an ACL link up without any users. The problem here is that
the Bluetooth specification doesn't define an ownership of the ACL
link and thus it can happen that the implementation on the initiator
side doesn't care about disconnecting unused links. In this case the
acceptor needs to take care of this.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
* 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/hskinnemoen/avr32-2.6:
avr32: pm_standby low-power ram bug fix
avr32: Fix lockup after Java stack underflow in user mode
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc:
powerpc: Fix rare boot build breakage
powerpc/spufs: Fix possible scheduling of a context to multiple SPEs
powerpc/spufs: Fix race for a free SPU
powerpc/spufs: Fix multiple get_spu_context()
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
sched: arch_reinit_sched_domains() must destroy domains to force rebuild
sched, cpuset: rework sched domains and CPU hotplug handling (v4)
* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev:
ahci: RAID mode SATA patch for Intel Ibex Peak DeviceIDs
pata_sil680: remove duplicate pcim_enable_device
libata-sff: kill spurious WARN_ON() in ata_hsm_move()
sata_nv: disable hardreset for generic
ahci: disable PMP for marvell ahcis
sata_mv: add RocketRaid 1720 PCI ID to driver
ahci, pata_marvell: play nicely together
... one entry lacked a colon which broke one of my scripts.
Signed-off-by: Uwe Kleine-König <ukleinek@informatik.uni-freiburg.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6:
bridge: don't allow setting hello time to zero
netns : fix kernel panic in timewait socket destruction
pkt_sched: Fix qdisc state in net_tx_action()
netfilter: nf_conntrack_irc: make sure string is terminated before calling simple_strtoul
netfilter: nf_conntrack_gre: nf_ct_gre_keymap_flush() fixlet
netfilter: nf_conntrack_gre: more locking around keymap list
netfilter: nf_conntrack_sip: de-static helper pointers
The hw interface drivers for the usb serial devices deference the tty
structure to set up the parameters for the initial console. The tty
structure should be passed as a parameter to the set_termios() call.
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Automounter maps can contain mount options valid for other NFS
implementations but not for Linux. The Linux automounter uses the
mount command's "-s" command line option ("s" for "sloppy") so that
mount requests containing such options are not rejected.
Commit f45663ce5f attempted to address a
known regression with text-based NFS mount option parsing. Unrecognized
mount options would cause mount requests to fail, even if the "-s"
option was used on the mount command line.
Unfortunately, this commit was not complete as submitted. It adds a
new mount option, "sloppy". But it is missing a hunk, so it now allows
NFS mounts with unrecognized mount options, even if the "sloppy" option
is not present. This could be a problem if a required critical mount
option such as "sync" is misspelled, for example, and is considered a
regression from 2.6.26.
This patch restores the missing hunk. Now, the default behavior of
text-based NFS mount options is as before: any unrecognized mount option
will cause the mount to fail.
Please include this in 2.6.27-rc.
Thanks to Neil Brown for reporting this.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Acked-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Dushan Tcholich reports that on his system ksoftirqd can consume
between %6 to %10 of cpu time, and cause ~200 context switches per
second.
He then correlated this with a report by bdupree@techfinesse.com:
http://marc.info/?l=linux-kernel&m=119613299024398&w=2
and the culprit cause seems to be starting the bridge interface.
In particular, when starting the bridge interface, his scripts
are specifying a hello timer interval of "0".
The bridge hello time can't be safely set to values less than 1
second, otherwise it is possible to end up with a runaway timer.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
How to reproduce ?
- create a network namespace
- use tcp protocol and get timewait socket
- exit the network namespace
- after a moment (when the timewait socket is destroyed), the kernel
panics.
# BUG: unable to handle kernel NULL pointer dereference at
0000000000000007
IP: [<ffffffff821e394d>] inet_twdr_do_twkill_work+0x6e/0xb8
PGD 119985067 PUD 11c5c0067 PMD 0
Oops: 0000 [1] SMP
CPU 1
Modules linked in: ipv6 button battery ac loop dm_mod tg3 libphy ext3 jbd
edd fan thermal processor thermal_sys sg sata_svw libata dock serverworks
sd_mod scsi_mod ide_disk ide_core [last unloaded: freq_table]
Pid: 0, comm: swapper Not tainted 2.6.27-rc2 #3
RIP: 0010:[<ffffffff821e394d>] [<ffffffff821e394d>]
inet_twdr_do_twkill_work+0x6e/0xb8
RSP: 0018:ffff88011ff7fed0 EFLAGS: 00010246
RAX: ffffffffffffffff RBX: ffffffff82339420 RCX: ffff88011ff7ff30
RDX: 0000000000000001 RSI: ffff88011a4d03c0 RDI: ffff88011ac2fc00
RBP: ffffffff823392e0 R08: 0000000000000000 R09: ffff88002802a200
R10: ffff8800a5c4b000 R11: ffffffff823e4080 R12: ffff88011ac2fc00
R13: 0000000000000001 R14: 0000000000000001 R15: 0000000000000000
FS: 0000000041cbd940(0000) GS:ffff8800bff839c0(0000)
knlGS:0000000000000000
CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b
CR2: 0000000000000007 CR3: 00000000bd87c000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process swapper (pid: 0, threadinfo ffff8800bff9e000, task
ffff88011ff76690)
Stack: ffffffff823392e0 0000000000000100 ffffffff821e3a3a
0000000000000008
0000000000000000 ffffffff821e3a61 ffff8800bff7c000 ffffffff8203c7e7
ffff88011ff7ff10 ffff88011ff7ff10 0000000000000021 ffffffff82351108
Call Trace:
<IRQ> [<ffffffff821e3a3a>] ? inet_twdr_hangman+0x0/0x9e
[<ffffffff821e3a61>] ? inet_twdr_hangman+0x27/0x9e
[<ffffffff8203c7e7>] ? run_timer_softirq+0x12c/0x193
[<ffffffff820390d1>] ? __do_softirq+0x5e/0xcd
[<ffffffff8200d08c>] ? call_softirq+0x1c/0x28
[<ffffffff8200e611>] ? do_softirq+0x2c/0x68
[<ffffffff8201a055>] ? smp_apic_timer_interrupt+0x8e/0xa9
[<ffffffff8200cad6>] ? apic_timer_interrupt+0x66/0x70
<EOI> [<ffffffff82011f4c>] ? default_idle+0x27/0x3b
[<ffffffff8200abbd>] ? cpu_idle+0x5f/0x7d
Code: e8 01 00 00 4c 89 e7 41 ff c5 e8 8d fd ff ff 49 8b 44 24 38 4c 89 e7
65 8b 14 25 24 00 00 00 89 d2 48 8b 80 e8 00 00 00 48 f7 d0 <48> 8b 04 d0
48 ff 40 58 e8 fc fc ff ff 48 89 df e8 c0 5f 04 00
RIP [<ffffffff821e394d>] inet_twdr_do_twkill_work+0x6e/0xb8
RSP <ffff88011ff7fed0>
CR2: 0000000000000007
This patch provides a function to purge all timewait sockets related
to a network namespace. The timewait sockets life cycle is not tied with
the network namespace, that means the timewait sockets stay alive while
the network namespace dies. The timewait sockets are for avoiding to
receive a duplicate packet from the network, if the network namespace is
freed, the network stack is removed, so no chance to receive any packets
from the outside world. Furthermore, having a pending destruction timer
on these sockets with a network namespace freed is not safe and will lead
to an oops if the timer callback which try to access data belonging to
the namespace like for example in:
inet_twdr_do_twkill_work
-> NET_INC_STATS_BH(twsk_net(tw), LINUX_MIB_TIMEWAITED);
Purging the timewait sockets at the network namespace destruction will:
1) speed up memory freeing for the namespace
2) fix kernel panic on asynchronous timewait destruction
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Acked-by: Denis V. Lunev <den@openvz.org>
Acked-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Remove duplicate call to pcim_enable_device in sil680_init_one.
Signed-off-by: David Milburn <dmilburn@redhat.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
On HSM_ST_ERR, ata_hsm_move() triggers WARN_ON() if AC_ERR_DEV or
AC_ERR_HSM is not set. PHY events may trigger HSM_ST_ERR with other
error codes and, with or without it, there just isn't much reason to
do WARN_ON() on it. Even if error code is not set there, core EH
logic won't have any problem dealing with the error condition.
OSDL bz#11065 reports this problem.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
of them being unifying probing, hotplug and EH reset paths uniform.
Previously, broken hardreset could go unnoticed as it wasn't used
during probing but when something goes wrong or after hotplug the
problem will surface and bite hard.
OSDL bug 11195 reports that sata_nv generic flavor falls into this
category. Hardreset itself succeeds but PHY stays offline after
hardreset. I tried longer debounce timing but the result was the
same.
http://bugzilla.kernel.org/show_bug.cgi?id=11195
So, it seems we'll have to drop hardreset from the generic flavor.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Peer Chen <pchen@nvidia.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Marvell ahcis don't play nicely with PMPs. Disable it.
Reported by KueiHuan Chen in the following thread.
http://thread.gmane.org/gmane.linux.ide/33296
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: KueiHuan Chen <kueihuan.chen@gmail.com>
Cc: Mark Lord <mlord@pobox.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
I've been chasing Jeff about this for months. Jeff added the Marvell
device identifiers to the ahci driver without making the AHCI driver
handle the PATA port. This means a lot of users can't use current
kernels and in most distro cases can't even install.
This has been going on since March 2008 for the 6121 Marvell, and late 2007
for the 6145!!!
This was all pointed out at the time and repeatedly ignored. Bugs assigned
to Jeff about this are ignored also.
To quote Jeff in email
> "Just switch the order of 'ahci' and 'pata_marvell' in
> /etc/modprobe.conf, then use Fedora's tools regenerate the initrd.
> See? It's not rocket science, and the current configuration can be
> easily made to work for Fedora users."
(Which isn't trivial, isn't end user, shouldn't be needed, and as it usually
breaks at install time is in fact impossible)
To quote Jeff in August 2007
> " mv-ahci-pata
> Marvell 6121/6141 PATA support. Needs fixing in the 'PATA controller
> command' area before it is usable, and can go upstream."
Only he add the ids anyway later and caused regressions, adding a further
id in March causing more regresions.
The actual fix for the moment is very simple. If the user has included
the pata_marvell driver let it drive the ports. If they've only selected
for SATA support give them the AHCI driver which will run the port a fraction
faster. Allow the user to control this decision via ahci.marvell_enable as
a module parameter so that distributions can ship 'it works' defaults and
smarter users (or config tools) can then flip it over it desired.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
A make -j20 powerpc kernel build broke a couple of months ago saying:
In file included from arch/powerpc/boot/gunzip_util.h:13,
from arch/powerpc/boot/prpmc2800.c:21:
arch/powerpc/boot/zlib.h:85: error: expected ‘:’, ‘,’, ‘;’, ‘}’ or ‘__attribute__’ before ‘*’ token
arch/powerpc/boot/zlib.h:630: warning: type defaults to ‘int’ in declaration of ‘Byte’
arch/powerpc/boot/zlib.h:630: error: expected ‘;’, ‘,’ or ‘)’ before ‘*’ token
It happened again yesterday: too rare for me to confirm the fix, but
it looks like the list of dependants on gunzip_util.h was incomplete.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This reverts commit bd699f2df6,
which causes camellia to fail the included self-test vectors.
It has also been confirmed that it breaks existing encrypted
disks using camellia.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
net_tx_action() can skip __QDISC_STATE_SCHED bit clearing while qdisc
is neither ran nor rescheduled, which may cause endless loop in
dev_deactivate().
Reported-by: Denys Fedoryshchenko <denys@visp.net.lb>
Tested-by: Denys Fedoryshchenko <denys@visp.net.lb>
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Alexey Dobriyan points out:
1. simple_strtoul() silently accepts all characters for given base even
if result won't fit into unsigned long. This is amazing stupidity in
itself, but
2. nf_conntrack_irc helper use simple_strtoul() for DCC request parsing.
Data first copied into 64KB buffer, so theoretically nothing prevents
reading past the end of it, since data comes from network given 1).
This is not actually a problem currently since we're guaranteed to have
a 0 byte in skb_shared_info or in the buffer the data is copied to, but
to make this more robust, make sure the string is actually terminated.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
It does "kfree(list_head)" which looks wrong because entity that was
allocated is definitely not list_head.
However, this all works because list_head is first item in
struct nf_ct_gre_keymap.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
gre_keymap_list should be protected in all places.
(unless I'm misreading something)
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Helper's ->help hook can run concurrently with itself, so iterating over
SIP helpers with static pointer won't work reliably.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
We currently have a race when scheduling a context to a SPE -
after we have found a runnable context in spusched_tick, the same
context may have been scheduled by spu_activate().
This may result in a panic if we try to unschedule a context that has
been freed in the meantime.
This change exits spu_schedule() if the context has already been
scheduled, so we don't end up scheduling it twice.
Signed-off-by: Andre Detsch <adetsch@br.ibm.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86: cpu_init(): fix memory leak when using CPU hotplug
x86: pda_init(): fix memory leak when using CPU hotplug
x86, xen: Use native_pte_flags instead of native_pte_val for .pte_flags
x86: move mtrr cpu cap setting early in early_init_xxxx
x86: delay early cpu initialization until cpuid is done
x86: use X86_FEATURE_NOPL in alternatives
x86: add NOPL as a synthetic CPU feature bit
x86: boot: stub out unimplemented CPU feature words
Exception stacks are allocated each time a CPU is set online.
But the allocated space is never freed. Thus with one CPU hotplug
offline/online cycle there is a memory leak of 24K (6 pages) for
a CPU.
Fix is to allocate exception stacks only once -- when the CPU is
set online for the first time.
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: akpm@linux-foundation.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
pda->irqstackptr is allocated whenever a CPU is set online.
But it is never freed. This results in a memory leak of 16K
for each CPU offline/online cycle.
Fix is to allocate pda->irqstackptr only once.
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: akpm@linux-foundation.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Using native_pte_val triggers the BUG_ON() in the paravirt_ops
version of pte_flags().
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
What I realized recently is that calling rebuild_sched_domains() in
arch_reinit_sched_domains() by itself is not enough when cpusets are enabled.
partition_sched_domains() code is trying to avoid unnecessary domain rebuilds
and will not actually rebuild anything if new domain masks match the old ones.
What this means is that doing
echo 1 > /sys/devices/system/cpu/sched_mc_power_savings
on a system with cpusets enabled will not take affect untill something changes
in the cpuset setup (ie new sets created or deleted).
This patch fixes restore correct behaviour where domains must be rebuilt in
order to enable MC powersaving flags.
Test on quad-core Core2 box with both CONFIG_CPUSETS and !CONFIG_CPUSETS.
Also tested on dual-core Core2 laptop. Lockdep is happy and things are working
as expected.
Signed-off-by: Max Krasnyansky <maxk@qualcomm.com>
Tested-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Krzysztof Helt found MTRR is not detected on k6-2
root cause:
we moved mtrr_bp_init() early for mtrr trimming,
and in early_detect we only read the CPU capability from cpuid,
so some cpu doesn't have that bit in cpuid.
So we need to add early_init_xxxx to preset those bit before mtrr_bp_init
for those earlier cpus.
this patch is for v2.6.27
Reported-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Move early cpu initialization after cpu early get cap so the
early cpu initialization can fix up cpu caps.
Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The current check for monotonicity is way too weak: Andreas Mohr reports (
http://lkml.org/lkml/2008/8/10/77 ) that on one of his test systems the
current check only triggers in 50% of all cases, leading to catastrophic
timer behaviour. To fix this issue, expand the check for monotonicity by
doing ten consecutive tests instead of one.
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
On all hardware (some Intel ICH4, PIIX4 and PIIX4E chipsets) affected by a
hardware errata there's about a 4.2% chance that initialization of the
ACPI PMTMR fails. On those chipsets, we need to read out the timer value
at least three times to get a correct result, for every once in a while
(i.e. within a 3 ns window every 69.8 ns) the read returns a bogus
result. During normal operation we work around this issue, but during
initialization reading a bogus value may lead to -EINVAL even though the
hardware is usable.
Thanks to Andreas Mohr for spotting this issue.
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
We have a bug in the calculation of the next jiffie to trigger the RTC
synchronisation. The aim here is to run sync_cmos_clock() as close as
possible to the middle of a second. Which means we want this function to
be called less than or equal to half a jiffie away from when now.tv_nsec
equals 5e8 (500000000).
If this is not the case for a given call to the function, for this purpose
instead of updating the RTC we calculate the offset in nanoseconds to the
next point in time where now.tv_nsec will be equal 5e8. The calculated
offset is then converted to jiffies as these are the unit used by the
timer.
Hovewer timespec_to_jiffies() used here uses a ceil()-type rounding mode,
where the resulting value is rounded up. As a result the range of
now.tv_nsec when the timer will trigger is from 5e8 to 5e8 + TICK_NSEC
rather than the desired 5e8 - TICK_NSEC / 2 to 5e8 + TICK_NSEC / 2.
As a result if for example sync_cmos_clock() happens to be called at the
time when now.tv_nsec is between 5e8 + TICK_NSEC / 2 and 5e8 to 5e8 +
TICK_NSEC, it will simply be rescheduled HZ jiffies later, falling in the
same range of now.tv_nsec again. Similarly for cases offsetted by an
integer multiple of TICK_NSEC.
This change addresses the problem by subtracting TICK_NSEC / 2 from the
nanosecond offset to the next point in time where now.tv_nsec will be
equal 5e8, effectively shifting the following rounding in
timespec_to_jiffies() so that it produces a rounded-to-nearest result.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
