21 Jul, 2011
7 commits
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The rcu callback __put_tree() just calls a kfree(),
so we use kfree_rcu() instead of the call_rcu(__put_tree).Signed-off-by: Lai Jiangshan
Signed-off-by: Paul E. McKenney
Cc: Al Viro
Cc: Eric Paris
Reviewed-by: Josh Triplett -
The rcu callback whitelist_item_free() just calls a kfree(),
so we use kfree_rcu() instead of the call_rcu(whitelist_item_free).Signed-off-by: Lai Jiangshan
Signed-off-by: Paul E. McKenney
Acked-by: James Morris
Reviewed-by: Josh Triplett -
The rcu callback free_conf() just calls a kfree(),
so we use kfree_rcu() instead of the call_rcu(free_conf).Signed-off-by: Lai Jiangshan
Signed-off-by: Paul E. McKenney
Acked-by: NeilBrown
Reviewed-by: Josh Triplett -
The __lock_task_sighand() function calls rcu_read_lock() with interrupts
and preemption enabled, but later calls rcu_read_unlock() with interrupts
disabled. It is therefore possible that this RCU read-side critical
section will be preempted and later RCU priority boosted, which means that
rcu_read_unlock() will call rt_mutex_unlock() in order to deboost itself, but
with interrupts disabled. This results in lockdep splats, so this commit
nests the RCU read-side critical section within the interrupt-disabled
region of code. This prevents the RCU read-side critical section from
being preempted, and thus prevents the attempt to deboost with interrupts
disabled.It is quite possible that a better long-term fix is to make rt_mutex_unlock()
disable irqs when acquiring the rt_mutex structure's ->wait_lock.Signed-off-by: Paul E. McKenney
Signed-off-by: Paul E. McKenney -
The rcu_read_unlock_special() function relies on in_irq() to exclude
scheduler activity from interrupt level. This fails because exit_irq()
can invoke the scheduler after clearing the preempt_count() bits that
in_irq() uses to determine that it is at interrupt level. This situation
can result in failures as follows:$task IRQ SoftIRQ
rcu_read_lock()
/* do stuff */
|= UNLOCK_BLOCKED
rcu_read_unlock()
--t->rcu_read_lock_nestingirq_enter();
/* do stuff, don't use RCU */
irq_exit();
sub_preempt_count(IRQ_EXIT_OFFSET);
invoke_softirq()ttwu();
spin_lock_irq(&pi->lock)
rcu_read_lock();
/* do stuff */
rcu_read_unlock();
rcu_read_unlock_special()
rcu_report_exp_rnp()
ttwu()
spin_lock_irq(&pi->lock) /* deadlock */rcu_read_unlock_special(t);
Ed can simply trigger this 'easy' because invoke_softirq() immediately
does a ttwu() of ksoftirqd/# instead of doing the in-place softirq stuff
first, but even without that the above happens.Cure this by also excluding softirqs from the
rcu_read_unlock_special() handler and ensuring the force_irqthreads
ksoftirqd/# wakeup is done from full softirq context.[ Alternatively, delaying the ->rcu_read_lock_nesting decrement
until after the special handling would make the thing more robust
in the face of interrupts as well. And there is a separate patch
for that. ]Cc: Thomas Gleixner
Reported-and-tested-by: Ed Tomlinson
Signed-off-by: Peter Zijlstra
Signed-off-by: Paul E. McKenney -
Ensure scheduler_ipi() calls irq_{enter,exit} when it does some actual
work. Traditionally we never did any actual work from the resched IPI
and all magic happened in the return from interrupt path.Now that we do do some work, we need to ensure irq_{enter,exit} are
called so that we don't confuse things.This affects things like timekeeping, NO_HZ and RCU, basically
everything with a hook in irq_enter/exit.Explicit examples of things going wrong are:
sched_clock_cpu() -- has a callback when leaving NO_HZ state to take
a new reading from GTOD and TSC. Without this
callback, time is stuck in the past.RCU -- needs in_irq() to work in order to avoid some nasty deadlocks
Signed-off-by: Peter Zijlstra
Signed-off-by: Paul E. McKenney -
The addition of RCU read-side critical sections within runqueue and
priority-inheritance lock critical sections introduced some deadlock
cycles, for example, involving interrupts from __rcu_read_unlock()
where the interrupt handlers call wake_up(). This situation can cause
the instance of __rcu_read_unlock() invoked from interrupt to do some
of the processing that would otherwise have been carried out by the
task-level instance of __rcu_read_unlock(). When the interrupt-level
instance of __rcu_read_unlock() is called with a scheduler lock held
from interrupt-entry/exit situations where in_irq() returns false,
deadlock can result.This commit resolves these deadlocks by using negative values of
the per-task ->rcu_read_lock_nesting counter to indicate that an
instance of __rcu_read_unlock() is in flight, which in turn prevents
instances from interrupt handlers from doing any special processing.
This patch is inspired by Steven Rostedt's earlier patch that similarly
made __rcu_read_unlock() guard against interrupt-mediated recursion
(see https://lkml.org/lkml/2011/7/15/326), but this commit refines
Steven's approach to avoid the need for preemption disabling on the
__rcu_read_unlock() fastpath and to also avoid the need for manipulating
a separate per-CPU variable.This patch avoids need for preempt_disable() by instead using negative
values of the per-task ->rcu_read_lock_nesting counter. Note that nested
rcu_read_lock()/rcu_read_unlock() pairs are still permitted, but they will
never see ->rcu_read_lock_nesting go to zero, and will therefore never
invoke rcu_read_unlock_special(), thus preventing them from seeing the
RCU_READ_UNLOCK_BLOCKED bit should it be set in ->rcu_read_unlock_special.
This patch also adds a check for ->rcu_read_unlock_special being negative
in rcu_check_callbacks(), thus preventing the RCU_READ_UNLOCK_NEED_QS
bit from being set should a scheduling-clock interrupt occur while
__rcu_read_unlock() is exiting from an outermost RCU read-side critical
section.Of course, __rcu_read_unlock() can be preempted during the time that
->rcu_read_lock_nesting is negative. This could result in the setting
of the RCU_READ_UNLOCK_BLOCKED bit after __rcu_read_unlock() checks it,
and would also result it this task being queued on the corresponding
rcu_node structure's blkd_tasks list. Therefore, some later RCU read-side
critical section would enter rcu_read_unlock_special() to clean up --
which could result in deadlock if that critical section happened to be in
the scheduler where the runqueue or priority-inheritance locks were held.This situation is dealt with by making rcu_preempt_note_context_switch()
check for negative ->rcu_read_lock_nesting, thus refraining from
queuing the task (and from setting RCU_READ_UNLOCK_BLOCKED) if we are
already exiting from the outermost RCU read-side critical section (in
other words, we really are no longer actually in that RCU read-side
critical section). In addition, rcu_preempt_note_context_switch()
invokes rcu_read_unlock_special() to carry out the cleanup in this case,
which clears out the ->rcu_read_unlock_special bits and dequeues the task
(if necessary), in turn avoiding needless delay of the current RCU grace
period and needless RCU priority boosting.It is still illegal to call rcu_read_unlock() while holding a scheduler
lock if the prior RCU read-side critical section has ever had either
preemption or irqs enabled. However, the common use case is legal,
namely where then entire RCU read-side critical section executes with
irqs disabled, for example, when the scheduler lock is held across the
entire lifetime of the RCU read-side critical section.Signed-off-by: Paul E. McKenney
Signed-off-by: Paul E. McKenney
20 Jul, 2011
3 commits
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Given some common flag combinations, particularly -Os, gcc will inline
rcu_read_unlock_special() despite its being in an unlikely() clause.
Use noinline to prohibit this misoptimization.In addition, move the second barrier() in __rcu_read_unlock() so that
it is not on the common-case code path. This will allow the compiler to
generate better code for the common-case path through __rcu_read_unlock().Suggested-by: Linus Torvalds
Signed-off-by: Paul E. McKenney
Acked-by: Mathieu Desnoyers -
The RCU_BOOST commits for TREE_PREEMPT_RCU introduced an other-task
write to a new RCU_READ_UNLOCK_BOOSTED bit in the task_struct structure's
->rcu_read_unlock_special field, but, as noted by Steven Rostedt, without
correctly synchronizing all accesses to ->rcu_read_unlock_special.
This could result in bits in ->rcu_read_unlock_special being spuriously
set and cleared due to conflicting accesses, which in turn could result
in deadlocks between the rcu_node structure's ->lock and the scheduler's
rq and pi locks. These deadlocks would result from RCU incorrectly
believing that the just-ended RCU read-side critical section had been
preempted and/or boosted. If that RCU read-side critical section was
executed with either rq or pi locks held, RCU's ensuing (incorrect)
calls to the scheduler would cause the scheduler to attempt to once
again acquire the rq and pi locks, resulting in deadlock. More complex
deadlock cycles are also possible, involving multiple rq and pi locks
as well as locks from multiple rcu_node structures.This commit fixes synchronization by creating ->rcu_boosted field in
task_struct that is accessed and modified only when holding the ->lock
in the rcu_node structure on which the task is queued (on that rcu_node
structure's ->blkd_tasks list). This results in tasks accessing only
their own current->rcu_read_unlock_special fields, making unsynchronized
access once again legal, and keeping the rcu_read_unlock() fastpath free
of atomic instructions and memory barriers.The reason that the rcu_read_unlock() fastpath does not need to access
the new current->rcu_boosted field is that this new field cannot
be non-zero unless the RCU_READ_UNLOCK_BLOCKED bit is set in the
current->rcu_read_unlock_special field. Therefore, rcu_read_unlock()
need only test current->rcu_read_unlock_special: if that is zero, then
current->rcu_boosted must also be zero.This bug does not affect TINY_PREEMPT_RCU because this implementation
of RCU accesses current->rcu_read_unlock_special with irqs disabled,
thus preventing races on the !SMP systems that TINY_PREEMPT_RCU runs on.Maybe-reported-by: Dave Jones
Maybe-reported-by: Sergey Senozhatsky
Reported-by: Steven Rostedt
Signed-off-by: Paul E. McKenney
Signed-off-by: Paul E. McKenney
Reviewed-by: Steven Rostedt -
PREEMPT_RCU read-side critical sections blocking an expedited grace
period invoke rcu_report_exp_rnp(). When the last such critical section
has completed, rcu_report_exp_rnp() invokes the scheduler to wake up the
task that invoked synchronize_rcu_expedited() -- needlessly holding the
root rcu_node structure's lock while doing so, thus needlessly providing
a way for RCU and the scheduler to deadlock.This commit therefore releases the root rcu_node structure's lock before
calling wake_up().Reported-by: Ed Tomlinson
Signed-off-by: Paul E. McKenney
13 Jul, 2011
1 commit
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Under some rare but real combinations of configuration parameters, RCU
callbacks are posted during early boot that use kernel facilities that
are not yet initialized. Therefore, when these callbacks are invoked,
hard hangs and crashes ensue. This commit therefore prevents RCU
callbacks from being invoked until after the scheduler is fully up and
running, as in after multiple tasks have been spawned.It might well turn out that a better approach is to identify the specific
RCU callbacks that are causing this problem, but that discussion will
wait until such time as someone really needs an RCU callback to be invoked
(as opposed to merely registered) during early boot.Reported-by: julie Sullivan
Reported-by: RKK
Signed-off-by: Paul E. McKenney
Tested-by: Konrad Rzeszutek Wilk
Tested-by: julie Sullivan
Tested-by: RKK
12 Jul, 2011
11 commits
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That file harkens back to the days of the big 2.4 -> 2.6 version jump,
and was based even then on older versions. Some of it is just obsolete,
and Jesper Juhl points out that it talks about kernel versions 2.6 and
should be updated to 3.0.Remove some obsolete text, and re-phrase some other to not be 2.6-specific.
Reported-by: Jesper Juhl
Signed-off-by: Linus Torvalds -
* 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6:
[media] msp3400: fill in v4l2_tuner based on vt->type field
[media] tuner-core.c: don't change type field in g_tuner or g_frequency
[media] cx18/ivtv: fix g_tuner support
[media] tuner-core: power up tuner when called with s_power(1)
[media] v4l2-ioctl.c: check for valid tuner type in S_HW_FREQ_SEEK
[media] tuner-core: simplify the standard fixup
[media] tuner-core/v4l2-subdev: document that the type field has to be filled in
[media] v4l2-subdev.h: remove unused s_mode tuner op
[media] feature-removal-schedule: change in how radio device nodes are handled
[media] bttv: fix s_tuner for radio
[media] pvrusb2: fix g/s_tuner support
[media] v4l2-ioctl.c: prefill tuner type for g_frequency and g/s_tuner
[media] tuner-core: fix tuner_resume: use t->mode instead of t->type
[media] tuner-core: fix s_std and s_tuner -
* 'pm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6:
PM: Reintroduce dropped call to check_wakeup_irqs -
* git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6:
cifs: drop spinlock before calling cifs_put_tlink
cifs: fix expand_dfs_referral
cifs: move bdi_setup_and_register outside of CONFIG_CIFS_DFS_UPCALL
cifs: factor smb_vol allocation out of cifs_setup_volume_info
cifs: have cifs_cleanup_volume_info not take a double pointer
cifs: fix build_unc_path_to_root to account for a prefixpath
cifs: remove bogus call to cifs_cleanup_volume_info -
* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq:
[CPUFREQ] fix cpumask memory leak in acpi-cpufreq on cpu hotplug. -
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mjg59/platform-drivers-x86:
hp-wmi: fix use after free
dell-laptop - using buffer without mutex_lock
Revert: "dell-laptop: Toggle the unsupported hardware killswitch"
platform-drivers-x86: set backlight type to BACKLIGHT_PLATFORM
thinkpad-acpi: handle HKEY 0x4010, 0x4011 events
drivers/platform/x86: Fix memory leak
thinkpad-acpi: handle some new HKEY 0x60xx events
acer-wmi: fix bitwise bug when set device state
acer-wmi: Only update rfkill status for associated hotkey events -
* 'movieboard' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6:
firewire: ohci: do not bind to Pinnacle cards, avert panic -
Signed-off-by: Joe Perches
Acked-by: Pavel Roskin
Signed-off-by: Linus Torvalds -
Since we removed sti()/cli() and related, how about removing it from
Documentation/spinlocks.txt?Signed-off-by: Muthukumar R
Signed-off-by: Linus Torvalds -
...as that function can sleep.
Signed-off-by: Jeff Layton
Signed-off-by: Steve French
11 Jul, 2011
6 commits
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[ 191.310008] WARNING: kmemcheck: Caught 32-bit read from freed memory (f0d25f14)
[ 191.310011] c056d2f088000000105fd2f00000000050415353040000000000000000000000
[ 191.310020] i i i i f f f f f f f f f f f f f f f f f f f f f f f f f f f f
[ 191.310027] ^
[ 191.310029]
[ 191.310032] Pid: 737, comm: modprobe Not tainted 3.0.0-rc5+ #268 Hewlett-Packard HP Compaq 6005 Pro SFF PC/3047h
[ 191.310036] EIP: 0060:[] EFLAGS: 00010286 CPU: 0
[ 191.310039] EIP is at hp_wmi_perform_query+0x104/0x150 [hp_wmi]
[ 191.310041] EAX: f0d25601 EBX: f0d25f00 ECX: 000121cf EDX: 000121ce
[ 191.310043] ESI: f0d25f10 EDI: f0f97ea8 EBP: f0f97ec4 ESP: c173f34c
[ 191.310045] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
[ 191.310046] CR0: 8005003b CR2: f540c000 CR3: 30f30000 CR4: 000006d0
[ 191.310048] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
[ 191.310050] DR6: ffff4ff0 DR7: 00000400
[ 191.310051] [] hp_wmi_dock_state+0x2b/0x40 [hp_wmi]
[ 191.310054] [] hp_wmi_init+0x93/0x1a8 [hp_wmi]
[ 191.310057] [] do_one_initcall+0x30/0x170
[ 191.310061] [] sys_init_module+0xef/0x1a60
[ 191.310064] [] sysenter_do_call+0x12/0x28
[ 191.310067] [] 0xffffffffSigned-off-by: Eric Dumazet
Signed-off-by: Matthew Garrett -
Using buffer->output[1] without mutex_lock()
Signed-off-by: Jose Alonso
Signed-off-by: Matthew Garrett -
This reverts commit a3d77411e8b2ad661958c1fbee65beb476ec6d70,
as it causes a mess in the wireless rfkill status on some models.
It is probably a bad idea to toggle the rfkill for all dell models
without the respect to the claim that it is hardware-controlled.Cc: stable@kernel.org
Signed-off-by: Keng-Yu Lin
Signed-off-by: Matthew Garrett -
Patch 2e711c04dbbf7a7732a3f7073b1fc285d12b369d
(PM: Remove sysdev suspend, resume and shutdown operations)
deleted sysdev_suspend(), which was being relied on to call
check_wakeup_irqs() in suspend. If check_wakeup_irqs() is not
called, wake interrupts that are pending when suspend is
entered may be lost. It also breaks IRQCHIP_MASK_ON_SUSPEND,
which is handled in check_wakeup_irqs().This patch adds a call to check_wakeup_irqs() in syscore_suspend(),
similar to what was deleted in sysdev_suspend().Signed-off-by: Colin Cross
Signed-off-by: Rafael J. Wysocki -
I came across a memory leak during a cyclic cpu-online-offline test.
Signed-off-by: Yu Luming
Cc: Len Brown
Signed-off-by: Andrew Morton
Signed-off-by: Dave Jones -
* 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/staging:
hwmon: (pmbus) Improve auto-detection of temperature status register
hwmon: (lm95241) Fix negative temperature results
hwmon: (lm95241) Fix chip detection code
10 Jul, 2011
9 commits
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It is possible that a PMBus device supports the READ_TEMPERATURE2 and/or
READ_TEMPERATURE3 registers but does not support READ_TEMPERATURE1.
Improve temperature status register detection to address this condition.Reported-by: Jean Delvare
Signed-off-by: Guenter Roeck
Acked-by: Jean Delvare
Cc: stable@kernel.org # 2.6.39+ -
Negative temperatures were returned in degrees C instead of milli-Degrees C.
Also, negative temperatures were reported for remote temperature sensors even
if the chip was configured for positive-only results.Fix by detecting temperature modes, and by treating negative temperatures
similar to positive temperatures, with appropriate sign extension.Signed-off-by: Guenter Roeck
Acked-by: Jean Delvare
Cc: stable@kernel.org # 2.6.30+ -
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6:
ALSA: hda - Fix a copmile warning
ASoC: ak4642: fixup snd_soc_update_bits mask for PW_MGMT2
ALSA: hda - Change all ADCs for dual-adc switching mode for Realtek
ASoC: Manage WM8731 ACTIVE bit as a supply widget
ASoC: Don't set invalid name string to snd_card->driver field
ASoC: Ensure we delay long enough for WM8994 FLL to lock when starting
ASoC: Tegra: I2S: Ensure clock is enabled when writing regs
ASoC: Fix Blackfin I2S _pointer() implementation return in bounds values
ASoC: tlv320aic3x: Do soft reset to codec when going to bias off state
ASoC: tlv320aic3x: Don't sync first two registers from register cache
audio: tlv320aic26: fix PLL register configuration -
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6:
PCI: conditional resource-reallocation through kernel parameter pci=realloc -
* 'fixes' of master.kernel.org:/home/rmk/linux-2.6-arm:
ARM: 6994/1: smp_twd: Fix typo in 'twd_timer_rate' printing
ARM: 6987/1: l2x0: fix disabling function to avoid deadlock
ARM: 6966/1: ep93xx: fix inverted RTS/DTR signals on uart1
ARM: 6980/1: mmci: use StartBitErr to detect bad connections
ARM: 6979/1: mach-vt8500: add forgotten irq_data conversion
ARM: move memory layout sanity checking before meminfo initialization
ARM: 6990/1: MAINTAINERS: add entry for ARM PMU profiling and debugging
ARM: 6989/1: perf: do not start the PMU when no events are present
ARM: dmabounce: fix map_single() error return value -
* 'drm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6:
drm/radeon/kms: clean up multiple crtc handling for evergreen+ (v2) -
When firewire-ohci is bound to a Pinnacle MovieBoard, eventually a
"Register access failure" is logged and an interrupt storm or a kernel
panic happens. https://bugzilla.kernel.org/show_bug.cgi?id=36622Until this is sorted out (if that is going to succeed at all), let's
just prevent firewire-ohci from touching these devices.Signed-off-by: Stefan Richter
Cc: -
Regression introduced in commit 724d9f1cfba.
Prior to that, expand_dfs_referral would regenerate the mount data string
and then call cifs_parse_mount_options to re-parse it (klunky, but it
worked). The above commit moved cifs_parse_mount_options out of cifs_mount,
so the re-parsing of the new mount options no longer occurred. Fix it by
making expand_dfs_referral re-parse the mount options.Signed-off-by: Jeff Layton
Signed-off-by: Steve French -
This needs to be done regardless of whether that KConfig option is set
or not.Reported-by: Sven-Haegar Koch
Signed-off-by: Jeff Layton
Signed-off-by: Steve French
09 Jul, 2011
3 commits
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It's harmless but annyoing.
sound/pci/hda/patch_realtek.c: In function ‘alc_cap_getput_caller’:
sound/pci/hda/patch_realtek.c:2722:9: warning: ‘err’ may be used uninitialized in this functionSigned-off-by: Takashi Iwai
-
…sound-2.6 into fix/asoc
