The issue below was found in 2.6.34-rt rather than mainline rt
kernel, but the issue still exists upstream as well.
So please let me describe how it was noticed on 2.6.34-rt:
On this version, each softirq has its own thread, it means there
is at least one RT FIFO task per cpu. The priority of these
tasks is set to 49 by default. If user launches an RT FIFO task
with priority lower than 49 of softirq RT tasks, it's possible
there are two RT FIFO tasks enqueued one cpu runqueue at one
moment. By current strategy of balancing RT tasks, when it comes
to RT tasks, we really need to put them off to a CPU that they
can run on as soon as possible. Even if it means a bit of cache
line flushing, we want RT tasks to be run with the least latency.
When the user RT FIFO task which just launched before is
running, the sched timer tick of the current cpu happens. In this
tick period, the timeout value of the user RT task will be
updated once. Subsequently, we try to wake up one softirq RT
task on its local cpu. As the priority of current user RT task
is lower than the softirq RT task, the current task will be
preempted by the higher priority softirq RT task. Before
preemption, we check to see if current can readily move to a
different cpu. If so, we will reschedule to allow the RT push logic
to try to move current somewhere else. Whenever the woken
softirq RT task runs, it first tries to migrate the user FIFO RT
task over to a cpu that is running a task of lesser priority. If
migration is done, it will send a reschedule request to the found
cpu by IPI interrupt. Once the target cpu responds the IPI
interrupt, it will pick the migrated user RT task to preempt its
current task. When the user RT task is running on the new cpu,
the sched timer tick of the cpu fires. So it will tick the user
RT task again. This also means the RT task timeout value will be
updated again. As the migration may be done in one tick period,
it means the user RT task timeout value will be updated twice
within one tick.
If we set a limit on the amount of cpu time for the user RT task
by setrlimit(RLIMIT_RTTIME), the SIGXCPU signal should be posted
upon reaching the soft limit.
But exactly when the SIGXCPU signal should be sent depends on the
RT task timeout value. In fact the timeout mechanism of sending
the SIGXCPU signal assumes the RT task timeout is increased once
every tick.
However, currently the timeout value may be added twice per
tick. So it results in the SIGXCPU signal being sent earlier
than expected.
To solve this issue, we prevent the timeout value from increasing
twice within one tick time by remembering the jiffies value of
last updating the timeout. As long as the RT task's jiffies is
different with the global jiffies value, we allow its timeout to
be updated.
Signed-off-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Fan Du <fan.du@windriver.com>
Reviewed-by: Yong Zhang <yong.zhang0@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1342508623-2887-1-git-send-email-ying.xue@windriver.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull libata fixes from Jeff Garzik:
1) ahci: Fix typo that caused erronenous error handling.
Thought: I wonder if sparse could have caught this, somehow.
2) ahci: support a slightly odd Enmotus variant
3) core: fix a drive detection problem by correcting the logic by which
the DevSlp timing variables are obtained and used.
* tag 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev:
[libata] replace sata_settings with devslp_timing
[libata] ahci: Add support for Enmotus Bobcat device.
[libata] ahci: Fix lack of command retry after a success error handler.
Cleanup and preparation for the next change.
signal_wake_up(resume => true) is overused. None of ptrace/jctl callers
actually want to wakeup a TASK_WAKEKILL task, but they can't specify the
necessary mask.
Turn signal_wake_up() into signal_wake_up_state(state), reintroduce
signal_wake_up() as a trivial helper, and add ptrace_signal_wake_up()
which adds __TASK_TRACED.
This way ptrace_signal_wake_up() can work "inside" ptrace_request()
even if the tracee doesn't have the TASK_WAKEKILL bit set.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull module fixes and a virtio block fix from Rusty Russell:
"Various minor fixes, but a slightly more complex one to fix the
per-cpu overload problem introduced recently by kvm id changes."
* tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
module: put modules in list much earlier.
module: add new state MODULE_STATE_UNFORMED.
module: prevent warning when finit_module a 0 sized file
virtio-blk: Don't free ida when disk is in use
The ia64 function "thread_matches()" has no users since commit
e868a55c2a ("[IA64] remove find_thread_for_addr()"). Remove it.
This allows us to make ptrace_check_attach() static to kernel/ptrace.c,
which is good since we'll need to change the semantics of it and fix up
all the callers.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull ACPI and power management fixes from Rafael Wysocki:
- cpuidle regression fix related to the initialization of state
kobjects from Krzysztof Mazur.
- cpuidle fix removing some not very useful code and making some
user-visible problems go away at the same time. From Daniel Lezcano.
- ACPI build fix from Yinghai Lu.
* tag 'pm+acpi-for-3.8-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
cpuidle: remove the power_specified field in the driver
ACPI / glue: Fix build with ACPI_GLUE_DEBUG set
cpuidle: fix number of initialized/destroyed states
Commit 1b963c81b1 ("lockdep, rwsem: provide down_write_nest_lock()")
contains a bug in a codepath when CONFIG_DEBUG_LOCK_ALLOC is disabled,
which causes down_read() to be called instead of down_write() by mistake
on such configurations. Fix that.
Reported-and-tested-by: Andrew Clayton <andrew@digital-domain.net>
Reported-and-tested-by: Zlatko Calusic <zlatko.calusic@iskon.hr>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If the default iosched is built as module, the kernel may deadlock
while trying to load the iosched module on device probe if the probing
was running off async. This is because async_synchronize_full() at
the end of module init ends up waiting for the async job which
initiated the module loading.
async A modprobe
1. finds a device
2. registers the block device
3. request_module(default iosched)
4. modprobe in userland
5. load and init module
6. async_synchronize_full()
Async A waits for modprobe to finish in request_module() and modprobe
waits for async A to finish in async_synchronize_full().
Because there's no easy to track dependency once control goes out to
userland, implementing properly nested flushing is difficult. For
now, make module init perform async_synchronize_full() iff module init
has queued async jobs as suggested by Linus.
This avoids the described deadlock because iosched module doesn't use
async and thus wouldn't invoke async_synchronize_full(). This is
hacky and incomplete. It will deadlock if async module loading nests;
however, this works around the known problem case and seems to be the
best of bad options.
For more details, please refer to the following thread.
http://thread.gmane.org/gmane.linux.kernel/1420814
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Alex Riesen <raa.lkml@gmail.com>
Tested-by: Ming Lei <ming.lei@canonical.com>
Tested-by: Alex Riesen <raa.lkml@gmail.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We realized that the power usage field is never filled and when it
is filled for tegra, the power_specified flag is not set causing all
of these values to be reset when the driver is initialized with
set_power_state().
However, the power_specified flag can be simply removed under the
assumption that the states are always backward sorted, which is the
case with the current code.
This change allows the menu governor select function and the
cpuidle_play_dead() to be simplified. Moreover, the
set_power_states() function can removed as it does not make sense
any more.
Drop the power_specified flag from struct cpuidle_driver and make
the related changes as described above.
As a consequence, this also fixes the bug where on the dynamic
C-states system, the power fields are not initialized.
[rjw: Changelog]
References: https://bugzilla.kernel.org/show_bug.cgi?id=42870
References: https://bugzilla.kernel.org/show_bug.cgi?id=43349
References: https://lkml.org/lkml/2012/10/16/518
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
NCQ capability was used to check availability of SATA Settings page
from Identify Device Data Log, which contains DevSlp timing variables.
It does not work on some HDDs and leads to error messages.
IDENTIFY word 78 bit 5(Hardware Feature Control) can't work either
because it is only the sufficient condition of Identify Device data
log, not the necessary condition.
This patch replaced ata_device->sata_settings with ->devslp_timing
to only save DevSlp timing variables(8 bytes), instead of the whole
SATA Settings page(512 bytes).
Addresses https://bugzilla.kernel.org/show_bug.cgi?id=51881
Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Shane Huang <shane.huang@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Pull driver core fixes from Greg Kroah-Hartman:
"Here are two patches for 3.8-rc3.
One removes the __dev* defines from init.h now that all usages of it
are gone from your tree. The other fix is for debugfs's paramater
that was using the wrong base for the option.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>"
* tag 'driver-core-3.8-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
debugfs: convert gid= argument from decimal, not octal
Remove __dev* markings from init.h
Pull networking fixes from David Miller:
1) Fix regression allowing IP_TTL setting of zero, fix from Cong Wang.
2) Fix leak regressions in tunap, from Jason Wang.
3) be2net driver always returns IRQ_HANDLED in INTx handler, fix from
Sathya Perla.
4) qlge doesn't really support NETIF_F_TSO6, don't set that flag. Fix
from Amerigo Wang.
5) Add 802.11ad Atheros wil6210 driver, from Vladimir Kondratiev.
6) Fix MTU calculations in mac80211 layer, from T Krishna Chaitanya.
7) Station info layer of mac80211 needs to use del_timer_sync(), from
Johannes Berg.
8) tcp_read_sock() can loop forever, because we don't immediately stop
when recv_actor() returns zero. Fix from Eric Dumazet.
9) Fix WARN_ON() in tcp_cleanup_rbuf(). We have to use sk_eat_skb() in
tcp_recv_skb() to handle the case where a large GRO packet is split
up while it is use by a splice() operation. Fix also from Eric
Dumazet.
10) addrconf_get_prefix_route() in ipv6 tests flags incorrectly, it
does:
if (X && (p->flags & Y) != 0)
when it really meant to go:
if (X && (p->flags & X) != 0)
fix from Romain Kuntz.
11) Fix lost Kconfig dependency for bfin_mac driver hardware
timestamping. From Lars-Peter Clausen.
12) Fix regression in handling of RST without ACK in TCP, from Eric
Dumazet.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (37 commits)
be2net: fix unconditionally returning IRQ_HANDLED in INTx
tuntap: fix leaking reference count
tuntap: forbid calling TUNSETIFF when detached
tuntap: switch to use rtnl_dereference()
net, wireless: overwrite default_ethtool_ops
qlge: remove NETIF_F_TSO6 flag
tcp: accept RST without ACK flag
net: ethernet: xilinx: Do not use NO_IRQ in axienet
net: ethernet: xilinx: Do not use axienet on PPC
bnx2x: Allow management traffic after boot from SAN
bnx2x: Fix fastpath structures when memory allocation fails
bfin_mac: Restore hardware time-stamping dependency on BF518
tun: avoid owner checks on IFF_ATTACH_QUEUE
bnx2x: move debugging code before the return
tuntap: refuse to re-attach to different tun_struct
ipv6: use addrconf_get_prefix_route for prefix route lookup [v2]
ipv6: fix the noflags test in addrconf_get_prefix_route
tcp: fix splice() and tcp collapsing interaction
tcp: splice: fix an infinite loop in tcp_read_sock()
net: prevent setting ttl=0 via IP_TTL
...
You should never look at such a module, so it's excised from all paths
which traverse the modules list.
We add the state at the end, to avoid gratuitous ABI break (ksplice).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Since:
commit 2c60db0370
Author: Eric Dumazet <edumazet@google.com>
Date: Sun Sep 16 09:17:26 2012 +0000
net: provide a default dev->ethtool_ops
wireless core does not correctly assign ethtool_ops.
After alloc_netdev*() call, some cfg80211 drivers provide they own
ethtool_ops, but some do not. For them, wireless core provide generic
cfg80211_ethtool_ops, which is assigned in NETDEV_REGISTER notify call:
if (!dev->ethtool_ops)
dev->ethtool_ops = &cfg80211_ethtool_ops;
But after Eric's commit, dev->ethtool_ops is no longer NULL (on cfg80211
drivers without custom ethtool_ops), but points to &default_ethtool_ops.
In order to fix the problem, provide function which will overwrite
default_ethtool_ops and use it by wireless core.
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
lib/rbtree.c declared __rb_erase_color() as __always_inline void, and
then exported it with EXPORT_SYMBOL.
This was because __rb_erase_color() must be exported for augmented
rbtree users, but it must also be inlined into rb_erase() so that the
dummy callback can get optimized out of that call site.
(Actually with a modern compiler, none of the dummy callback functions
should even be generated as separate text functions).
The above usage is legal C, but it was unusual enough for some compilers
to warn about it. This change makes things more explicit, with a static
__always_inline ____rb_erase_color function for use in rb_erase(), and a
separate non-inline __rb_erase_color function for use in
rb_erase_augmented call sites.
Signed-off-by: Michel Lespinasse <walken@google.com>
Reported-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Eric Wong reported on 3.7 and 3.8-rc2 that ppoll() got stuck when
waiting for POLLIN on a local TCP socket. It was easier to trigger if
there was disk IO and dirty pages at the same time and he bisected it to
commit 1fb3f8ca0e ("mm: compaction: capture a suitable high-order page
immediately when it is made available").
The intention of that patch was to improve high-order allocations under
memory pressure after changes made to reclaim in 3.6 drastically hurt
THP allocations but the approach was flawed. For Eric, the problem was
that page->pfmemalloc was not being cleared for captured pages leading
to a poor interaction with swap-over-NFS support causing the packets to
be dropped. However, I identified a few more problems with the patch
including the fact that it can increase contention on zone->lock in some
cases which could result in async direct compaction being aborted early.
In retrospect the capture patch took the wrong approach. What it should
have done is mark the pageblock being migrated as MIGRATE_ISOLATE if it
was allocating for THP and avoided races that way. While the patch was
showing to improve allocation success rates at the time, the benefit is
marginal given the relative complexity and it should be revisited from
scratch in the context of the other reclaim-related changes that have
taken place since the patch was first written and tested. This patch
partially reverts commit 1fb3f8ca0e ("mm: compaction: capture a
suitable high-order page immediately when it is made available").
Reported-and-tested-by: Eric Wong <normalperson@yhbt.net>
Tested-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
While the kernel internals want pt_regs (and so it includes
linux/ptrace.h), the user version of audit.h does not need it. So move
the include out of the uapi version.
This avoids issues where people want the audit defines and userland
ptrace api. Including both the kernel ptrace and the userland ptrace
headers can easily lead to failure.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Cc: Eric Paris <eparis@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The seccomp path was using AUDIT_ANOM_ABEND from when seccomp mode 1
could only kill a process. While we still want to make sure an audit
record is forced on a kill, this should use a separate record type since
seccomp mode 2 introduces other behaviors.
In the case of "handled" behaviors (process wasn't killed), only emit a
record if the process is under inspection. This change also fixes
userspace examination of seccomp audit events, since it was considered
malformed due to missing fields of the AUDIT_ANOM_ABEND event type.
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric Paris <eparis@redhat.com>
Cc: Jeff Layton <jlayton@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Julien Tinnes <jln@google.com>
Acked-by: Will Drewry <wad@chromium.org>
Acked-by: Steve Grubb <sgrubb@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In some cases, free_irq_cpu_rmap() is called while holding a lock (eg
rtnl). This can lead to deadlocks, because it invokes
flush_scheduled_work() which ends up waiting for whole system workqueue
to flush, but some pending works might try to acquire the lock we are
already holding.
This commit uses reference-counting to replace
irq_run_affinity_notifiers(). It also removes
irq_run_affinity_notifiers() altogether.
[akpm@linux-foundation.org: eliminate free_cpu_rmap, rename cpu_rmap_reclaim() to cpu_rmap_release(), propagate kref_put() retval from cpu_rmap_put()]
Signed-off-by: David Decotigny <decot@googlers.com>
Reviewed-by: Ben Hutchings <bhutchings@solarflare.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Acked-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now that all in-kernel users of __dev* are gone, let's remove them from
init.h to keep them from popping up again and again.
Thanks to Bill Pemberton for doing all of the hard work to make removal
of this possible.
Cc: Bill Pemberton <wfp5p@virginia.edu>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 3a50597de8 ("KEYS: Make the session and process keyrings
per-thread") removed the definition of the thread_group_cred structure,
but left a now unused pointer in struct cred.
Signed-off-by: Marc Dionne <marc.c.dionne@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull namei.h missing include fix from Al Viro.
The new use of ESTALE in namei.h can cause compile failures on ARM with
certain configurations due to lack of errno.h.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
namei.h: include errno.h
Commit 702d1a6e07 ("memory-hotplug: fix kswapd looping forever
problem") added an isolated pageblocks counter (nr_pageblock_isolate in
struct zone) and used it to adjust free pages counter in
zone_watermark_ok_safe() to prevent kswapd looping forever problem.
Then later, commit 2139cbe627 ("cma: fix counting of isolated pages")
fixed accounting of isolated pages in global free pages counter. It
made the previous zone_watermark_ok_safe() fix unnecessary and
potentially harmful (cause now isolated pages may be accounted twice
making free pages counter incorrect).
This patch removes the special isolated pageblocks counter altogether
which fixes zone_watermark_ok_safe() free pages check.
Reported-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Aaditya Kumar <aaditya.kumar.30@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
