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2012-04-04Merge commit 'v3.2.14' into rt-3.2.14-rt23v3.2.14-rt23Clark Williams
2012-04-04correct rt patch version to be -rt23Clark Williams
Signed-off-by: Clark Williams <williams@redhat.com>
2012-04-04kconfig-preempt-rt-full.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04kconfig-disable-a-few-options-rt.patchThomas Gleixner
Disable stuff which is known to have issues on RT Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04net: Use cpu_chill() instead of cpu_relax()Thomas Gleixner
Retry loops on RT might loop forever when the modifying side was preempted. Use cpu_chill() instead of cpu_relax() to let the system make progress. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable-rt@vger.kernel.org
2012-04-04fs: dcache: Use cpu_chill() in trylock loopsThomas Gleixner
Retry loops on RT might loop forever when the modifying side was preempted. Use cpu_chill() instead of cpu_relax() to let the system make progress. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable-rt@vger.kernel.org
2012-04-04rt: Introduce cpu_chill()Thomas Gleixner
Retry loops on RT might loop forever when the modifying side was preempted. Add cpu_chill() to replace cpu_relax(). cpu_chill() defaults to cpu_relax() for non RT. On RT it puts the looping task to sleep for a tick so the preempted task can make progress. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable-rt@vger.kernel.org
2012-04-04softirq: Check preemption after reenabling interruptsThomas Gleixner
raise_softirq_irqoff() disables interrupts and wakes the softirq daemon, but after reenabling interrupts there is no preemption check, so the execution of the softirq thread might be delayed arbitrarily. In principle we could add that check to local_irq_enable/restore, but that's overkill as the rasie_softirq_irqoff() sections are the only ones which show this behaviour. Reported-by: Carsten Emde <cbe@osadl.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable-rt@vger.kernel.org
2012-04-04cpu: Make hotplug.lock a "sleeping" spinlock on RTSteven Rostedt
Tasks can block on hotplug.lock in pin_current_cpu(), but their state might be != RUNNING. So the mutex wakeup will set the state unconditionally to RUNNING. That might cause spurious unexpected wakeups. We could provide a state preserving mutex_lock() function, but this is semantically backwards. So instead we convert the hotplug.lock() to a spinlock for RT, which has the state preserving semantics already. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Cc: Carsten Emde <C.Emde@osadl.org> Cc: John Kacur <jkacur@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Clark Williams <clark.williams@gmail.com> Cc: stable-rt@vger.kernel.org Link: http://lkml.kernel.org/r/1330702617.25686.265.camel@gandalf.stny.rr.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04lglock/rt: Use non-rt for_each_cpu() in -rt codeSteven Rostedt
Currently the RT version of the lglocks() does a for_each_online_cpu() in the name##_global_lock_online() functions. Non-rt uses its own mask for this, and for good reason. A task may grab a *_global_lock_online(), and in the mean time, one of the CPUs goes offline. Now when that task does a *_global_unlock_online() it releases all the locks *except* the one that went offline. Now if that CPU were to come back on line, its lock is now owned by a task that never released it when it should have. This causes all sorts of fun errors. Like owners of a lock no longer existing, or sleeping on IO, waiting to be woken up by a task that happens to be blocked on the lock it never released. Convert the RT versions to use the lglock specific cpumasks. As once a CPU comes on line, the mask is set, and never cleared even when the CPU goes offline. The locks for that CPU will still be taken and released. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Cc: Carsten Emde <C.Emde@osadl.org> Cc: John Kacur <jkacur@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Clark Williams <clark.williams@gmail.com> Cc: stable-rt@vger.kernel.org Link: http://lkml.kernel.org/r/20120301190345.374756214@goodmis.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04sched/rt: Fix wait_task_interactive() to test rt_spin_lock stateSteven Rostedt
The wait_task_interactive() will have a task sleep waiting for another task to have a certain state. But it ignores the rt_spin_locks state and can return with an incorrect result if the task it is waiting for is blocked on a rt_spin_lock() and is waking up. The rt_spin_locks save the tasks state in the saved_state field and the wait_task_interactive() must also test that state. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Cc: Carsten Emde <C.Emde@osadl.org> Cc: John Kacur <jkacur@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Clark Williams <clark.williams@gmail.com> Cc: stable-rt@vger.kernel.org Link: http://lkml.kernel.org/r/20120301190345.979435764@goodmis.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04ring-buffer/rt: Check for irqs disabled before grabbing reader lockSteven Rostedt
In RT the reader lock is a mutex and we can not grab it when preemption is disabled. The in_atomic() check that is there does not check if irqs are disabled. Add that check as well. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Cc: Carsten Emde <C.Emde@osadl.org> Cc: John Kacur <jkacur@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Clark Williams <clark.williams@gmail.com> Cc: stable-rt@vger.kernel.org Link: http://lkml.kernel.org/r/20120301190345.786365803@goodmis.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04futex/rt: Fix possible lockup when taking pi_lock in proxy handlerSteven Rostedt
When taking the pi_lock, we must disable interrupts because the pi_lock can also be taken in an interrupt handler. Use raw_spin_lock_irq() instead of raw_spin_lock(). Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Cc: Carsten Emde <C.Emde@osadl.org> Cc: John Kacur <jkacur@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Clark Williams <clark.williams@gmail.com> Cc: stable-rt@vger.kernel.org Link: http://lkml.kernel.org/r/20120301190345.165160680@goodmis.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04timer: Fix hotplug for -rtSteven Rostedt
Revert the RT patch: Author: Ingo Molnar <mingo@elte.hu> Date: Fri Jul 3 08:30:32 2009 -0500 timers: fix timer hotplug on -rt Here we are in the CPU_DEAD notifier, and we must not sleep nor enable interrupts. There's no problem with sleeping in this notifier. But the get_cpu_var() had to be converted to a get_local_var(). Replace the previous fix with the get_local_var() convert. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Cc: Carsten Emde <C.Emde@osadl.org> Cc: John Kacur <jkacur@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Clark Williams <clark.williams@gmail.com> Cc: stable-rt@vger.kernel.org Link: http://lkml.kernel.org/r/20120301190344.948157137@goodmis.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04seqlock: Prevent rt starvationThomas Gleixner
If a low prio writer gets preempted while holding the seqlock write locked, a high prio reader spins forever on RT. To prevent this let the reader grab the spinlock, so it blocks and eventually boosts the writer. This way the writer can proceed and endless spinning is prevented. For seqcount writers we disable preemption over the update code path. Thaanks to Al Viro for distangling some VFS code to make that possible. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable-rt@vger.kernel.org
2012-04-04cpumask: Disable CONFIG_CPUMASK_OFFSTACK for RTThomas Gleixner
We can't deal with the cpumask allocations which happen in atomic context (see arch/x86/kernel/apic/io_apic.c) on RT right now. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04dm: Make rt awareThomas Gleixner
Use the BUG_ON_NORT variant for the irq_disabled() checks. RT has interrupts legitimately enabled here as we cant deadlock against the irq thread due to the "sleeping spinlocks" conversion. Reported-by: Luis Claudio R. Goncalves <lclaudio@uudg.org> Cc: stable-rt@vger.kernel.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04x86: crypto: Reduce preempt disabled regionsPeter Zijlstra
Restrict the preempt disabled regions to the actual floating point operations and enable preemption for the administrative actions. This is necessary on RT to avoid that kfree and other operations are called with preemption disabled. Reported-and-tested-by: Carsten Emde <cbe@osadl.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: stable-rt@vger.kernel.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04scsi-fcoe-rt-aware.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04x86-kvm-require-const-tsc-for-rt.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04sysrq: Allow immediate Magic SysRq output for PREEMPT_RT_FULLFrank Rowand
Add a CONFIG option to allow the output from Magic SysRq to be output immediately, even if this causes large latencies. If PREEMPT_RT_FULL, printk() will not try to acquire the console lock when interrupts or preemption are disabled. If the console lock is not acquired the printk() output will be buffered, but will not be output immediately. Some drivers call into the Magic SysRq code with interrupts or preemption disabled, so the output of Magic SysRq will be buffered instead of printing immediately if this option is not selected. Even with this option selected, Magic SysRq output will be delayed if the attempt to acquire the console lock fails. Signed-off-by: Frank Rowand <frank.rowand@am.sony.com> Link: http://lkml.kernel.org/r/4E7CEF60.5020508@am.sony.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04ipc/sem: Rework semaphore wakeupsPeter Zijlstra
Current sysv sems have a weird ass wakeup scheme that involves keeping preemption disabled over a potential O(n^2) loop and busy waiting on that on other CPUs. Kill this and simply wake the task directly from under the sem_lock. This was discovered by a migrate_disable() debug feature that disallows: spin_lock(); preempt_disable(); spin_unlock() preempt_enable(); Cc: Manfred Spraul <manfred@colorfullife.com> Suggested-by: Thomas Gleixner <tglx@linutronix.de> Reported-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Manfred Spraul <manfred@colorfullife.com> Link: http://lkml.kernel.org/r/1315994224.5040.1.camel@twins Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04mm, rt: kmap_atomic schedulingPeter Zijlstra
In fact, with migrate_disable() existing one could play games with kmap_atomic. You could save/restore the kmap_atomic slots on context switch (if there are any in use of course), this should be esp easy now that we have a kmap_atomic stack. Something like the below.. it wants replacing all the preempt_disable() stuff with pagefault_disable() && migrate_disable() of course, but then you can flip kmaps around like below. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> [dvhart@linux.intel.com: build fix] Link: http://lkml.kernel.org/r/1311842631.5890.208.camel@twins
2012-04-04add /sys/kernel/realtime entryClark Williams
Add a /sys/kernel entry to indicate that the kernel is a realtime kernel. Clark says that he needs this for udev rules, udev needs to evaluate if its a PREEMPT_RT kernel a few thousand times and parsing uname output is too slow or so. Are there better solutions? Should it exist and return 0 on !-rt? Signed-off-by: Clark Williams <williams@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
2012-04-04kgdb/serial: Short term workaroundJason Wessel
On 07/27/2011 04:37 PM, Thomas Gleixner wrote: > - KGDB (not yet disabled) is reportedly unusable on -rt right now due > to missing hacks in the console locking which I dropped on purpose. > To work around this in the short term you can use this patch, in addition to the clocksource watchdog patch that Thomas brewed up. Comments are welcome of course. Ultimately the right solution is to change separation between the console and the HW to have a polled mode + work queue so as not to introduce any kind of latency. Thanks, Jason.
2012-04-04ping-sysrq.patchCarsten Emde
There are (probably rare) situations when a system crashed and the system console becomes unresponsive but the network icmp layer still is alive. Wouldn't it be wonderful, if we then could submit a sysreq command via ping? This patch provides this facility. Please consult the updated documentation Documentation/sysrq.txt for details. Signed-off-by: Carsten Emde <C.Emde@osadl.org>
2012-04-04net: Avoid livelock in net_tx_action() on RTSteven Rostedt
qdisc_lock is taken w/o disabling interrupts or bottom halfs. So code holding a qdisc_lock() can be interrupted and softirqs can run on the return of interrupt in !RT. The spin_trylock() in net_tx_action() makes sure, that the softirq does not deadlock. When the lock can't be acquired q is requeued and the NET_TX softirq is raised. That causes the softirq to run over and over. That works in mainline as do_softirq() has a retry loop limit and leaves the softirq processing in the interrupt return path and schedules ksoftirqd. The task which holds qdisc_lock cannot be preempted, so the lock is released and either ksoftirqd or the next softirq in the return from interrupt path can proceed. Though it's a bit strange to actually run MAX_SOFTIRQ_RESTART (10) loops before it decides to bail out even if it's clear in the first iteration :) On RT all softirq processing is done in a FIFO thread and we don't have a loop limit, so ksoftirqd preempts the lock holder forever and unqueues and requeues until the reset button is hit. Due to the forced threading of ksoftirqd on RT we actually cannot deadlock on qdisc_lock because it's a "sleeping lock". So it's safe to replace the spin_trylock() with a spin_lock(). When contended, ksoftirqd is scheduled out and the lock holder can proceed. [ tglx: Massaged changelog and code comments ] Solved-by: Thomas Gleixner <tglx@linuxtronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Tested-by: Carsten Emde <cbe@osadl.org> Cc: Clark Williams <williams@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Luis Claudio R. Goncalves <lclaudio@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04mips-disable-highmem-on-rt.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04ARM: at91: tclib: Default to tclib timer for RTThomas Gleixner
RT is not too happy about the shared timer interrupt in AT91 devices. Default to tclib timer for RT. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04arm-disable-highmem-on-rt.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04power-disable-highmem-on-rt.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04power-use-generic-rwsem-on-rtThomas Gleixner
2012-04-04printk: Disable migration instead of preemptionRichard Weinberger
There is no need do disable preemption in vprintk(), disable_migrate() is sufficient. This fixes the following bug in -rt: [ 14.759233] BUG: sleeping function called from invalid context at /home/rw/linux-rt/kernel/rtmutex.c:645 [ 14.759235] in_atomic(): 1, irqs_disabled(): 0, pid: 547, name: bash [ 14.759244] Pid: 547, comm: bash Not tainted 3.0.12-rt29+ #3 [ 14.759246] Call Trace: [ 14.759301] [<ffffffff8106fade>] __might_sleep+0xeb/0xf0 [ 14.759318] [<ffffffff810ad784>] rt_spin_lock_fastlock.constprop.9+0x21/0x43 [ 14.759336] [<ffffffff8161fef0>] rt_spin_lock+0xe/0x10 [ 14.759354] [<ffffffff81347ad1>] serial8250_console_write+0x81/0x121 [ 14.759366] [<ffffffff8107ecd3>] __call_console_drivers+0x7c/0x93 [ 14.759369] [<ffffffff8107ef31>] _call_console_drivers+0x5c/0x60 [ 14.759372] [<ffffffff8107f7e5>] console_unlock+0x147/0x1a2 [ 14.759374] [<ffffffff8107fd33>] vprintk+0x3ea/0x462 [ 14.759383] [<ffffffff816160e0>] printk+0x51/0x53 [ 14.759399] [<ffffffff811974e4>] ? proc_reg_poll+0x9a/0x9a [ 14.759403] [<ffffffff81335b42>] __handle_sysrq+0x50/0x14d [ 14.759406] [<ffffffff81335c8a>] write_sysrq_trigger+0x4b/0x53 [ 14.759408] [<ffffffff81335c3f>] ? __handle_sysrq+0x14d/0x14d [ 14.759410] [<ffffffff81197583>] proc_reg_write+0x9f/0xbe [ 14.759426] [<ffffffff811497ec>] vfs_write+0xac/0xf3 [ 14.759429] [<ffffffff8114a9b3>] ? fget_light+0x3a/0x9b [ 14.759431] [<ffffffff811499db>] sys_write+0x4a/0x6e [ 14.759438] [<ffffffff81625d52>] system_call_fastpath+0x16/0x1b Signed-off-by: Richard Weinberger <rw@linutronix.de> Link: http://lkml.kernel.org/r/1323696956-11445-1-git-send-email-rw@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04console-make-rt-friendly.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04x86-no-perf-irq-work-rt.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04skbufhead-raw-lock.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04jump-label-rt.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04debugobjects-rt.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04hotplug-stuff.patchThomas Gleixner
Do not take lock for non handled cases (might be atomic context) Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04workqueue: Use get_cpu_light() in flush_gcwq()Yong Zhang
BUG: sleeping function called from invalid context at kernel/rtmutex.c:645 in_atomic(): 1, irqs_disabled(): 0, pid: 1739, name: bash Pid: 1739, comm: bash Not tainted 3.0.6-rt17-00284-gb76d419 #3 Call Trace: [<c06e3b5d>] ? printk+0x1d/0x20 [<c01390b6>] __might_sleep+0xe6/0x110 [<c06e633c>] rt_spin_lock+0x1c/0x30 [<c01655a6>] flush_gcwq+0x236/0x320 [<c021c651>] ? kfree+0xe1/0x1a0 [<c05b7178>] ? __cpufreq_remove_dev+0xf8/0x260 [<c0183fad>] ? rt_down_write+0xd/0x10 [<c06cd91e>] workqueue_cpu_down_callback+0x26/0x2d [<c06e9d65>] notifier_call_chain+0x45/0x60 [<c0171cfe>] __raw_notifier_call_chain+0x1e/0x30 [<c014c9b4>] __cpu_notify+0x24/0x40 [<c06cbc6f>] _cpu_down+0xdf/0x330 [<c06cbef0>] cpu_down+0x30/0x50 [<c06cd6b0>] store_online+0x50/0xa7 [<c06cd660>] ? acpi_os_map_memory+0xec/0xec [<c04f2faa>] sysdev_store+0x2a/0x40 [<c02887a4>] sysfs_write_file+0xa4/0x100 [<c0229ab2>] vfs_write+0xa2/0x170 [<c0288700>] ? sysfs_poll+0x90/0x90 [<c0229d92>] sys_write+0x42/0x70 [<c06ecedf>] sysenter_do_call+0x12/0x2d CPU 1 is now offline SMP alternatives: switching to UP code SMP alternatives: switching to SMP code Booting Node 0 Processor 1 APIC 0x1 smpboot cpu 1: start_ip = 9b000 Initializing CPU#1 BUG: sleeping function called from invalid context at kernel/rtmutex.c:645 in_atomic(): 1, irqs_disabled(): 1, pid: 0, name: kworker/0:0 Pid: 0, comm: kworker/0:0 Not tainted 3.0.6-rt17-00284-gb76d419 #3 Call Trace: [<c06e3b5d>] ? printk+0x1d/0x20 [<c01390b6>] __might_sleep+0xe6/0x110 [<c06e633c>] rt_spin_lock+0x1c/0x30 [<c06cd85b>] workqueue_cpu_up_callback+0x56/0xf3 [<c06e9d65>] notifier_call_chain+0x45/0x60 [<c0171cfe>] __raw_notifier_call_chain+0x1e/0x30 [<c014c9b4>] __cpu_notify+0x24/0x40 [<c014c9ec>] cpu_notify+0x1c/0x20 [<c06e1d43>] notify_cpu_starting+0x1e/0x20 [<c06e0aad>] smp_callin+0xfb/0x10e [<c06e0ad9>] start_secondary+0x19/0xd7 NMI watchdog enabled, takes one hw-pmu counter. Switched to NOHz mode on CPU #1 Signed-off-by: Yong Zhang <yong.zhang0@gmail.com> Link: http://lkml.kernel.org/r/1318762607-2261-5-git-send-email-yong.zhang0@gmail.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04workqueue: Fix PF_THREAD_BOUND abusePeter Zijlstra
PF_THREAD_BOUND is set by kthread_bind() and means the thread is bound to a particular cpu for correctness. The workqueue code abuses this flag and blindly sets it for all created threads, including those that are free to migrate. Restore the original semantics now that the worst abuse in the cpu-hotplug path are gone. The only icky bit is the rescue thread for per-cpu workqueues, this cannot use kthread_bind() but will use set_cpus_allowed_ptr() to migrate itself to the desired cpu. Set and clear PF_THREAD_BOUND manually here. XXX: I think worker_maybe_bind_and_lock()/worker_unbind_and_unlock() should also do a get_online_cpus(), this would likely allow us to remove the while loop. XXX: should probably repurpose GCWQ_DISASSOCIATED to warn on adding works after CPU_DOWN_PREPARE -- its dual use to mark unbound gcwqs is a tad annoying though. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04workqueue: Fix cpuhotplug trainwreckPeter Zijlstra
The current workqueue code does crazy stuff on cpu unplug, it relies on forced affine breakage, thereby violating per-cpu expectations. Worse, it tries to re-attach to a cpu if the thing comes up again before all previously queued works are finished. This breaks (admittedly bonkers) cpu-hotplug use that relies on a down-up cycle to push all usage away. Introduce a new WQ_NON_AFFINE flag that indicates a per-cpu workqueue will not respect cpu affinity and use this to migrate all its pending works to whatever cpu is doing cpu-down. This also adds a warning for queue_on_cpu() users which warns when its used on WQ_NON_AFFINE workqueues for the API implies you care about what cpu things are ran on when such workqueues cannot guarantee this. For the rest, simply flush all per-cpu works and don't mess about. This also means that currently all workqueues that are manually flushing things on cpu-down in order to provide the per-cpu guarantee no longer need to do so. In short, we tell the WQ what we want it to do, provide validation for this and loose ~250 lines of code. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04mm-vmalloc.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04epoll.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04workqueue-use-get-cpu-light.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04x86: Disable IST stacks for debug/int 3/stack fault for PREEMPT_RTAndi Kleen
Normally the x86-64 trap handlers for debug/int 3/stack fault run on a special interrupt stack to make them more robust when dealing with kernel code. The PREEMPT_RT kernel can sleep in locks even while allocating GFP_ATOMIC memory. When one of these trap handlers needs to send real time signals for ptrace it allocates memory and could then try to to schedule. But it is not allowed to schedule on a IST stack. This can cause warnings and hangs. This patch disables the IST stacks for these handlers for PREEMPT_RT kernel. Instead let them run on the normal process stack. The kernel only really needs the ISTs here to make kernel debuggers more robust in case someone sets a break point somewhere where the stack is invalid. But there are no kernel debuggers in the standard kernel that do this. It also means kprobes cannot be set in situations with invalid stack; but that sounds like a reasonable restriction. The stack fault change could minimally impact oops quality, but not very much because stack faults are fairly rare. A better solution would be to use similar logic as the NMI "paranoid" path: check if signal is for user space, if yes go back to entry.S, switch stack, call sync_regs, then do the signal sending etc. But this patch is much simpler and should work too with minimal impact. Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04x86: Use generic rwsem_spinlocks on -rtThomas Gleixner
Simplifies the separation of anon_rw_semaphores and rw_semaphores for -rt. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04x86: stackprotector: Avoid random pool on rtThomas Gleixner
CPU bringup calls into the random pool to initialize the stack canary. During boot that works nicely even on RT as the might sleep checks are disabled. During CPU hotplug the might sleep checks trigger. Making the locks in random raw is a major PITA, so avoid the call on RT is the only sensible solution. This is basically the same randomness which we get during boot where the random pool has no entropy and we rely on the TSC randomnness. Reported-by: Carsten Emde <carsten.emde@osadl.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04x86: Convert mce timer to hrtimerThomas Gleixner
mce_timer is started in atomic contexts of cpu bringup. This results in might_sleep() warnings on RT. Convert mce_timer to a hrtimer to avoid this. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-04-04fs: ntfs: disable interrupt only on !RTMike Galbraith
On Sat, 2007-10-27 at 11:44 +0200, Ingo Molnar wrote: > * Nick Piggin <nickpiggin@yahoo.com.au> wrote: > > > > [10138.175796] [<c0105de3>] show_trace+0x12/0x14 > > > [10138.180291] [<c0105dfb>] dump_stack+0x16/0x18 > > > [10138.184769] [<c011609f>] native_smp_call_function_mask+0x138/0x13d > > > [10138.191117] [<c0117606>] smp_call_function+0x1e/0x24 > > > [10138.196210] [<c012f85c>] on_each_cpu+0x25/0x50 > > > [10138.200807] [<c0115c74>] flush_tlb_all+0x1e/0x20 > > > [10138.205553] [<c016caaf>] kmap_high+0x1b6/0x417 > > > [10138.210118] [<c011ec88>] kmap+0x4d/0x4f > > > [10138.214102] [<c026a9d8>] ntfs_end_buffer_async_read+0x228/0x2f9 > > > [10138.220163] [<c01a0e9e>] end_bio_bh_io_sync+0x26/0x3f > > > [10138.225352] [<c01a2b09>] bio_endio+0x42/0x6d > > > [10138.229769] [<c02c2a08>] __end_that_request_first+0x115/0x4ac > > > [10138.235682] [<c02c2da7>] end_that_request_chunk+0x8/0xa > > > [10138.241052] [<c0365943>] ide_end_request+0x55/0x10a > > > [10138.246058] [<c036dae3>] ide_dma_intr+0x6f/0xac > > > [10138.250727] [<c0366d83>] ide_intr+0x93/0x1e0 > > > [10138.255125] [<c015afb4>] handle_IRQ_event+0x5c/0xc9 > > > > Looks like ntfs is kmap()ing from interrupt context. Should be using > > kmap_atomic instead, I think. > > it's not atomic interrupt context but irq thread context - and -rt > remaps kmap_atomic() to kmap() internally. Hm. Looking at the change to mm/bounce.c, perhaps I should do this instead? Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>