- 11 Dec, 2011 22 commits
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Frederic Weisbecker authored
On the irq exit path, tick_nohz_irq_exit() may raise a softirq, which action leads to the wake up path and select_task_rq_fair() that makes use of rcu to iterate the domains. This is an illegal use of RCU because we may be in RCU extended quiescent state if we interrupted an RCU-idle window in the idle loop: [ 132.978883] =============================== [ 132.978883] [ INFO: suspicious RCU usage. ] [ 132.978883] ------------------------------- [ 132.978883] kernel/sched_fair.c:1707 suspicious rcu_dereference_check() usage! [ 132.978883] [ 132.978883] other info that might help us debug this: [ 132.978883] [ 132.978883] [ 132.978883] rcu_scheduler_active = 1, debug_locks = 0 [ 132.978883] RCU used illegally from extended quiescent state! [ 132.978883] 2 locks held by swapper/0: [ 132.978883] #0: (&p->pi_lock){-.-.-.}, at: [<ffffffff8105a729>] try_to_wake_up+0x39/0x2f0 [ 132.978883] #1: (rcu_read_lock){.+.+..}, at: [<ffffffff8105556a>] select_task_rq_fair+0x6a/0xec0 [ 132.978883] [ 132.978883] stack backtrace: [ 132.978883] Pid: 0, comm: swapper Tainted: G W 3.0.0+ #178 [ 132.978883] Call Trace: [ 132.978883] <IRQ> [<ffffffff810a01f6>] lockdep_rcu_suspicious+0xe6/0x100 [ 132.978883] [<ffffffff81055c49>] select_task_rq_fair+0x749/0xec0 [ 132.978883] [<ffffffff8105556a>] ? select_task_rq_fair+0x6a/0xec0 [ 132.978883] [<ffffffff812fe494>] ? do_raw_spin_lock+0x54/0x150 [ 132.978883] [<ffffffff810a1f2d>] ? trace_hardirqs_on+0xd/0x10 [ 132.978883] [<ffffffff8105a7c3>] try_to_wake_up+0xd3/0x2f0 [ 132.978883] [<ffffffff81094f98>] ? ktime_get+0x68/0xf0 [ 132.978883] [<ffffffff8105aa35>] wake_up_process+0x15/0x20 [ 132.978883] [<ffffffff81069dd5>] raise_softirq_irqoff+0x65/0x110 [ 132.978883] [<ffffffff8108eb65>] __hrtimer_start_range_ns+0x415/0x5a0 [ 132.978883] [<ffffffff812fe3ee>] ? do_raw_spin_unlock+0x5e/0xb0 [ 132.978883] [<ffffffff8108ed08>] hrtimer_start+0x18/0x20 [ 132.978883] [<ffffffff8109c9c3>] tick_nohz_stop_sched_tick+0x393/0x450 [ 132.978883] [<ffffffff810694f2>] irq_exit+0xd2/0x100 [ 132.978883] [<ffffffff81829e96>] do_IRQ+0x66/0xe0 [ 132.978883] [<ffffffff81820d53>] common_interrupt+0x13/0x13 [ 132.978883] <EOI> [<ffffffff8103434b>] ? native_safe_halt+0xb/0x10 [ 132.978883] [<ffffffff810a1f2d>] ? trace_hardirqs_on+0xd/0x10 [ 132.978883] [<ffffffff810144ea>] default_idle+0xba/0x370 [ 132.978883] [<ffffffff810147fe>] amd_e400_idle+0x5e/0x130 [ 132.978883] [<ffffffff8100a9f6>] cpu_idle+0xb6/0x120 [ 132.978883] [<ffffffff817f217f>] rest_init+0xef/0x150 [ 132.978883] [<ffffffff817f20e2>] ? rest_init+0x52/0x150 [ 132.978883] [<ffffffff81ed9cf3>] start_kernel+0x3da/0x3e5 [ 132.978883] [<ffffffff81ed9346>] x86_64_start_reservations+0x131/0x135 [ 132.978883] [<ffffffff81ed944d>] x86_64_start_kernel+0x103/0x112 Fix this by calling rcu_idle_enter() after tick_nohz_irq_exit(). Signed-off-by:Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by:
Josh Triplett <josh@joshtriplett.org>
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Frederic Weisbecker authored
Interrupts notify the idle exit state before calling irq_enter(). But the notifier code calls rcu_read_lock() and this is not allowed while rcu is in an extended quiescent state. We need to wait for irq_enter() -> rcu_idle_exit() to be called before doing so otherwise this results in a grumpy RCU: [ 0.099991] WARNING: at include/linux/rcupdate.h:194 __atomic_notifier_call_chain+0xd2/0x110() [ 0.099991] Hardware name: AMD690VM-FMH [ 0.099991] Modules linked in: [ 0.099991] Pid: 0, comm: swapper Not tainted 3.0.0-rc6+ #255 [ 0.099991] Call Trace: [ 0.099991] <IRQ> [<ffffffff81051c8a>] warn_slowpath_common+0x7a/0xb0 [ 0.099991] [<ffffffff81051cd5>] warn_slowpath_null+0x15/0x20 [ 0.099991] [<ffffffff817d6fa2>] __atomic_notifier_call_chain+0xd2/0x110 [ 0.099991] [<ffffffff817d6ff1>] atomic_notifier_call_chain+0x11/0x20 [ 0.099991] [<ffffffff81001873>] exit_idle+0x43/0x50 [ 0.099991] [<ffffffff81020439>] smp_apic_timer_interrupt+0x39/0xa0 [ 0.099991] [<ffffffff817da253>] apic_timer_interrupt+0x13/0x20 [ 0.099991] <EOI> [<ffffffff8100ae67>] ? default_idle+0xa7/0x350 [ 0.099991] [<ffffffff8100ae65>] ? default_idle+0xa5/0x350 [ 0.099991] [<ffffffff8100b19b>] amd_e400_idle+0x8b/0x110 [ 0.099991] [<ffffffff810cb01f>] ? rcu_enter_nohz+0x8f/0x160 [ 0.099991] [<ffffffff810019a0>] cpu_idle+0xb0/0x110 [ 0.099991] [<ffffffff817a7505>] rest_init+0xe5/0x140 [ 0.099991] [<ffffffff817a7468>] ? rest_init+0x48/0x140 [ 0.099991] [<ffffffff81cc5ca3>] start_kernel+0x3d1/0x3dc [ 0.099991] [<ffffffff81cc5321>] x86_64_start_reservations+0x131/0x135 [ 0.099991] [<ffffffff81cc5412>] x86_64_start_kernel+0xed/0xf4 Signed-off-by:
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Frederic Weisbecker authored
The idle notifier, called by enter_idle(), enters into rcu read side critical section but at that time we already switched into the RCU-idle window (rcu_idle_enter() has been called). And it's illegal to use rcu_read_lock() in that state. This results in rcu reporting its bad mood: [ 1.275635] WARNING: at include/linux/rcupdate.h:194 __atomic_notifier_call_chain+0xd2/0x110() [ 1.275635] Hardware name: AMD690VM-FMH [ 1.275635] Modules linked in: [ 1.275635] Pid: 0, comm: swapper Not tainted 3.0.0-rc6+ #252 [ 1.275635] Call Trace: [ 1.275635] [<ffffffff81051c8a>] warn_slowpath_common+0x7a/0xb0 [ 1.275635] [<ffffffff81051cd5>] warn_slowpath_null+0x15/0x20 [ 1.275635] [<ffffffff817d6f22>] __atomic_notifier_call_chain+0xd2/0x110 [ 1.275635] [<ffffffff817d6f71>] atomic_notifier_call_chain+0x11/0x20 [ 1.275635] [<ffffffff810018a0>] enter_idle+0x20/0x30 [ 1.275635] [<ffffffff81001995>] cpu_idle+0xa5/0x110 [ 1.275635] [<ffffffff817a7465>] rest_init+0xe5/0x140 [ 1.275635] [<ffffffff817a73c8>] ? rest_init+0x48/0x140 [ 1.275635] [<ffffffff81cc5ca3>] start_kernel+0x3d1/0x3dc [ 1.275635] [<ffffffff81cc5321>] x86_64_start_reservations+0x131/0x135 [ 1.275635] [<ffffffff81cc5412>] x86_64_start_kernel+0xed/0xf4 [ 1.275635] ---[ end trace a22d306b065d4a66 ]--- Fix this by entering rcu extended quiescent state later, just before the CPU goes to sleep. Signed-off-by:
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Frederic Weisbecker authored
It is assumed that rcu won't be used once we switch to tickless mode and until we restart the tick. However this is not always true, as in x86-64 where we dereference the idle notifiers after the tick is stopped. To prepare for fixing this, add two new APIs: tick_nohz_idle_enter_norcu() and tick_nohz_idle_exit_norcu(). If no use of RCU is made in the idle loop between tick_nohz_enter_idle() and tick_nohz_exit_idle() calls, the arch must instead call the new *_norcu() version such that the arch doesn't need to call rcu_idle_enter() and rcu_idle_exit(). Otherwise the arch must call tick_nohz_enter_idle() and tick_nohz_exit_idle() and also call explicitly: - rcu_idle_enter() after its last use of RCU before the CPU is put to sleep. - rcu_idle_exit() before the first use of RCU after the CPU is woken up. Signed-off-by:
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Frederic Weisbecker authored
The tick_nohz_stop_sched_tick() function, which tries to delay the next timer tick as long as possible, can be called from two places: - From the idle loop to start the dytick idle mode - From interrupt exit if we have interrupted the dyntick idle mode, so that we reprogram the next tick event in case the irq changed some internal state that requires this action. There are only few minor differences between both that are handled by that function, driven by the ts->inidle cpu variable and the inidle parameter. The whole guarantees that we only update the dyntick mode on irq exit if we actually interrupted the dyntick idle mode, and that we enter in RCU extended quiescent state from idle loop entry only. Split this function into: - tick_nohz_idle_enter(), which sets ts->inidle to 1, enters dynticks idle mode unconditionally if it can, and enters into RCU extended quiescent state. - tick_nohz_irq_exit() which only updates the dynticks idle mode when ts->inidle is set (ie: if tick_nohz_idle_enter() has been called). To maintain symmetry, tick_nohz_restart_sched_tick() has been renamed into tick_nohz_idle_exit(). This simplifies the code and micro-optimize the irq exit path (no need for local_irq_save there). This also prepares for the split between dynticks and rcu extended quiescent state logics. We'll need this split to further fix illegal uses of RCU in extended quiescent states in the idle loop. Signed-off-by:
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Paul E. McKenney authored
A common debug_lockdep_rcu_enabled() function is used to check whether RCU lockdep splats should be reported, but srcu_read_lock() does not use it. This commit therefore brings srcu_read_lock_held() up to date. Signed-off-by:
Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by:
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Paul E. McKenney authored
Catch SRCU up to the other variants of RCU by making PROVE_RCU complain if either srcu_read_lock() or srcu_read_lock_held() are used from within RCU-idle mode. Frederic reworked this to allow for the new versions of his patches that check for extended quiescent states. Signed-off-by:
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Paul E. McKenney authored
Simplify things a bit by substituting the definitions of the single-line rcu_read_acquire(), rcu_read_release(), rcu_read_acquire_bh(), rcu_read_release_bh(), rcu_read_acquire_sched(), and rcu_read_release_sched() functions at their call points. Signed-off-by:
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Frederic Weisbecker authored
We are currently able to detect uses of rcu_dereference_check() inside extended quiescent states (such as the RCU-free window in idle). But rcu_read_lock() and friends can be used without rcu_dereference(), so that the earlier commit checking for use of rcu_dereference() and friends while in RCU idle mode miss some error conditions. This commit therefore adds extended quiescent state checking to rcu_read_lock() and friends. Uses of RCU from within RCU-idle mode are totally ignored by RCU, hence the importance of these checks. Signed-off-by:
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Frederic Weisbecker authored
Inform the user if an RCU usage error is detected by lockdep while in an extended quiescent state (in this case, the RCU-free window in idle). This is accomplished by adding a line to the RCU lockdep splat indicating whether or not the splat occurred in extended quiescent state. Uses of RCU from within extended quiescent state mode are totally ignored by RCU, hence the importance of this diagnostic. Signed-off-by:
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Frederic Weisbecker authored
Report that none of the rcu read lock maps are held while in an RCU extended quiescent state (the section between rcu_idle_enter() and rcu_idle_exit()). This helps detect any use of rcu_dereference() and friends from within the section in idle where RCU is not allowed. This way we can guarantee an extended quiescent window where the CPU can be put in dyntick idle mode or can simply aoid to be part of any global grace period completion while in the idle loop. Uses of RCU from such mode are totally ignored by RCU, hence the importance of these checks. Signed-off-by:
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Thomas Gleixner authored
Empty void functions do not need "return", so this commit removes it from rcu_report_exp_rnp(). Signed-off-by:
Thomas Gleixner <tglx@linutronix.de> Signed-off-by:
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Thomas Gleixner authored
When setting up an expedited grace period, if there were no readers, the task will awaken itself. This commit removes this useless self-awakening. Signed-off-by:
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Paul E. McKenney authored
Because rcu_is_cpu_idle() is to be used to check for extended quiescent states in RCU-preempt read-side critical sections, it cannot assume that preemption is disabled. And preemption must be disabled when accessing the dyntick-idle state, because otherwise the following sequence of events could occur: 1. Task A on CPU 1 enters rcu_is_cpu_idle() and picks up the pointer to CPU 1's per-CPU variables. 2. Task B preempts Task A and starts running on CPU 1. 3. Task A migrates to CPU 2. 4. Task B blocks, leaving CPU 1 idle. 5. Task A continues execution on CPU 2, accessing CPU 1's dyntick-idle information using the pointer fetched in step 1 above, and finds that CPU 1 is idle. 6. Task A therefore incorrectly concludes that it is executing in an extended quiescent state, possibly issuing a spurious splat. Therefore, this commit disables preemption within the rcu_is_cpu_idle() function. Signed-off-by:
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Paul E. McKenney authored
One of lclaudio's systems was seeing RCU CPU stall warnings from idle. These turned out to be caused by a bug that stopped scheduling-clock tick interrupts from being sent to a given CPU for several hundred seconds. This commit therefore updates the documentation to call this out as a possible cause for RCU CPU stall warnings. Signed-off-by:
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Paul E. McKenney authored
Trace the rcutorture RCU accesses and dump the trace buffer when the first failure is detected. Signed-off-by:
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Paul E. McKenney authored
Add an EXPORT_SYMBOL_GPL() so that rcutorture can dump the trace buffer upon detection of an RCU error. Signed-off-by:
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Paul E. McKenney authored
Earlier versions of RCU used the scheduling-clock tick to detect idleness by checking for the idle task, but handled idleness differently for CONFIG_NO_HZ=y. But there are now a number of uses of RCU read-side critical sections in the idle task, for example, for tracing. A more fine-grained detection of idleness is therefore required. This commit presses the old dyntick-idle code into full-time service, so that rcu_idle_enter(), previously known as rcu_enter_nohz(), is always invoked at the beginning of an idle loop iteration. Similarly, rcu_idle_exit(), previously known as rcu_exit_nohz(), is always invoked at the end of an idle-loop iteration. This allows the idle task to use RCU everywhere except between consecutive rcu_idle_enter() and rcu_idle_exit() calls, in turn allowing architecture maintainers to specify exactly where in the idle loop that RCU may be used. Because some of the userspace upcall uses can result in what looks to RCU like half of an interrupt, it is not possible to expect that the irq_enter() and irq_exit() hooks will give exact counts. This patch therefore expands the ->dynticks_nesting counter to 64 bits and uses two separate bitfields to count process/idle transitions and interrupt entry/exit transitions. It is presumed that userspace upcalls do not happen in the idle loop or from usermode execution (though usermode might do a system call that results in an upcall). The counter is hard-reset on each process/idle transition, which avoids the interrupt entry/exit error from accumulating. Overflow is avoided by the 64-bitness of the ->dyntick_nesting counter. This commit also adds warnings if a non-idle task asks RCU to enter idle state (and these checks will need some adjustment before applying Frederic's OS-jitter patches (http://lkml.org/lkml/2011/10/7/246). In addition, validation of ->dynticks and ->dynticks_nesting is added. Signed-off-by:
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Paul E. McKenney authored
There are a number of bugs that can leak or overuse lock classes, which can cause the maximum number of lock classes (currently 8191) to be exceeded. However, the documentation does not tell you how to track down these problems. This commit addresses this shortcoming. Signed-off-by: -
Paul E. McKenney authored
When synchronize_sched_expedited() takes its second and subsequent snapshots of sync_sched_expedited_started, it subtracts 1. This means that the concurrent caller of synchronize_sched_expedited() that incremented to that value sees our successful completion, it will not be able to take advantage of it. This restriction is pointless, given that our full expedited grace period would have happened after the other guy started, and thus should be able to serve as a proxy for the other guy successfully executing try_stop_cpus(). This commit therefore removes the subtraction of 1. Signed-off-by:
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Paul E. McKenney authored
Because rcu_read_unlock_special() samples rcu_preempted_readers_exp(rnp) after dropping rnp->lock, the following sequence of events is possible: 1. Task A exits its RCU read-side critical section, and removes itself from the ->blkd_tasks list, releases rnp->lock, and is then preempted. Task B remains on the ->blkd_tasks list, and blocks the current expedited grace period. 2. Task B exits from its RCU read-side critical section and removes itself from the ->blkd_tasks list. Because it is the last task blocking the current expedited grace period, it ends that expedited grace period. 3. Task A resumes, and samples rcu_preempted_readers_exp(rnp) which of course indicates that nothing is blocking the nonexistent expedited grace period. Task A is again preempted. 4. Some other CPU starts an expedited grace period. There are several tasks blocking this expedited grace period queued on the same rcu_node structure that Task A was using in step 1 above. 5. Task A examines its state and incorrectly concludes that it was the last task blocking the expedited grace period on the current rcu_node structure. It therefore reports completion up the rcu_node tree. 6. The expedited grace period can then incorrectly complete before the tasks blocked on this same rcu_node structure exit their RCU read-side critical sections. Arbitrarily bad things happen. This commit therefore takes a snapshot of rcu_preempted_readers_exp(rnp) prior to dropping the lock, so that only the last task thinks that it is the last task, thus avoiding the failure scenario laid out above. Signed-off-by:
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Paul E. McKenney authored
The ->signaled field was named before complications in the form of dyntick-idle mode and offlined CPUs. These complications have required that force_quiescent_state() be implemented as a state machine, instead of simply unconditionally sending reschedule IPIs. Therefore, this commit renames ->signaled to ->fqs_state to catch up with the new force_quiescent_state() reality. Signed-off-by:
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- 09 Dec, 2011 18 commits
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Linus Torvalds authored
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git://git.samba.org/sfrench/cifs-2.6Linus Torvalds authored
* git://git.samba.org/sfrench/cifs-2.6: cifs: check for NULL last_entry before calling cifs_save_resume_key cifs: attempt to freeze while looping on a receive attempt cifs: Fix sparse warning when calling cifs_strtoUCS CIFS: Add descriptions to the brlock cache functions
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86, efi: Calling __pa() with an ioremap()ed address is invalid x86, hpet: Immediately disable HPET timer 1 if rtc irq is masked x86/intel_mid: Kconfig select fix x86/intel_mid: Fix the Kconfig for MID selection
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git://git.pengutronix.de/git/wsa/linux-2.6Linus Torvalds authored
* 'spi/for-3.2' of git://git.pengutronix.de/git/wsa/linux-2.6: spi/gpio: fix section mismatch warning spi/fsl-espi: disable CONFIG_SPI_FSL_ESPI=m build spi/nuc900: Include linux/module.h spi/ath79: fix compile error due to missing include
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git://neil.brown.name/mdLinus Torvalds authored
* 'for-linus' of git://neil.brown.name/md: md: raid5 crash during degradation md/raid5: never wait for bad-block acks on failed device. md: ensure new badblocks are handled promptly. md: bad blocks shouldn't cause a Blocked status on a Faulty device. md: take a reference to mddev during sysfs access. md: refine interpretation of "hold_active == UNTIL_IOCTL". md/lock: ensure updates to page_attrs are properly locked.
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git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tileLinus Torvalds authored
* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile: arch/tile: use new generic {enable,disable}_percpu_irq() routines drivers/net/ethernet/tile: use skb_frag_page() API asm-generic/unistd.h: support new process_vm_{readv,write} syscalls arch/tile: fix double-free bug in homecache_free_pages() arch/tile: add a few #includes and an EXPORT to catch up with kernel changes.
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git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommuLinus Torvalds authored
* 'iommu/fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu: MAINTAINERS: Update amd-iommu F: patterns iommu/amd: Fix typo in kernel-parameters.txt iommu/msm: Fix compile error in mach-msm/devices-iommu.c Fix comparison using wrong pointer variable in dma debug code
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git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/soundLinus Torvalds authored
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: ALSA: hda/realtek - Fix lost speaker volume controls ALSA: hda/realtek - Create "Bass Speaker" for two speaker pins ALSA: hda/realtek - Don't create extra controls with channel suffix ALSA: hda - Fix remaining VREF mute-LED NID check in post-3.1 changes ALSA: hda - Fix GPIO LED setup for IDT 92HD75 codecs ASoC: Provide a more complete DMA driver stub ASoC: Remove references to corgi and spitz from machine driver document ASoC: Make SND_SOC_MX27VIS_AIC32X4 depend on I2C ASoC: Fix dependency for SND_SOC_RAUMFELD and SND_PXA2XX_SOC_HX4700 ASoC: uda1380: Return proper error in uda1380_modinit failure path ASoC: kirkwood: Make SND_KIRKWOOD_SOC_OPENRD and SND_KIRKWOOD_SOC_T5325 depend on I2C ASoC: Mark WM8994 ADC muxes as virtual ALSA: hda/realtek - Fix Oops in alc_mux_select() ALSA: sis7019 - give slow codecs more time to reset
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf: Do no try to schedule task events if there are none lockdep, kmemcheck: Annotate ->lock in lockdep_init_map() perf header: Use event_name() to get an event name perf stat: Failure with "Operation not supported"
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Mandeep Singh Baines authored
In order to safely dereference current->real_parent inside an rcu_read_lock, we need an rcu_dereference. Signed-off-by:
Mandeep Singh Baines <msb@chromium.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Kees Cook <keescook@chromium.org> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Alexandre Bounine authored
Modify initialization of PCIe capability registers in Tsi721 mport driver: - change Completion Timeout value to avoid unexpected data transfer aborts during intensive traffic. - replace hardcoded offset of PCIe capability block by making it use the common function. This patch is applicable to kernel versions starting from 3.2-rc1. Signed-off-by:
Alexandre Bounine <alexandre.bounine@idt.com> Cc: Matt Porter <mporter@kernel.crashing.org> Signed-off-by:
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Alexandre Bounine authored
Bug fix for Tsi721 RapidIO mport driver: Tsi721 supports four RapidIO mailboxes (MBOX0 - MBOX3) as defined by RapidIO specification. Mailbox resources has to be properly reported to allow use of all available mailboxes (initial version reports only MBOX0). This patch is applicable to kernel versions staring from 3.2-rc1. Signed-off-by:
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Alexandre Bounine authored
Replace the pair dma_alloc_coherent()+memset() with the new dma_zalloc_coherent() added by Andrew Morton for kernel version 3.2 Signed-off-by:
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Michal Hocko authored
Since commit a25cac51 ("proc: Consider NO_HZ when printing idle and iowait times") we are reporting idle/io_wait time also while a CPU is tickless. We rely on get_{idle,iowait}_time functions to retrieve proper data. These functions, however, use usecs_to_cputime to translate micro seconds time to cputime64_t. This is just an alias to usecs_to_jiffies which reduces the data type from u64 to unsigned int and also checks whether the given parameter overflows jiffies_to_usecs(MAX_JIFFY_OFFSET) and returns MAX_JIFFY_OFFSET in that case. When we overflow depends on CONFIG_HZ but especially for CONFIG_HZ_300 it is quite low (1431649781) so we are getting MAX_JIFFY_OFFSET for >3000s! until we overflow unsigned int. Just for reference CONFIG_HZ_100 has an overflow window around 20s, CONFIG_HZ_250 ~8s and CONFIG_HZ_1000 ~2s. This results in a bug when people saw [h]top going mad reporting 100% CPU usage even though there was basically no CPU load. The reason was simply that /proc/stat stopped reporting idle/io_wait changes (and reported MAX_JIFFY_OFFSET) and so the only change happening was for user system time. Let's use nsecs_to_jiffies64 instead which doesn't reduce the precision to 32b type and it is much more appropriate for cumulative time values (unlike usecs_to_jiffies which intended for timeout calculations). Signed-off-by:
Michal Hocko <mhocko@suse.cz> Tested-by:
Artem S. Tashkinov <t.artem@mailcity.com> Cc: Dave Jones <davej@redhat.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by:
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Mel Gorman authored
Commit f5252e00 ("mm: avoid null pointer access in vm_struct via /proc/vmallocinfo") adds newly allocated vm_structs to the vmlist after it is fully initialised. Unfortunately, it did not check that __vmalloc_area_node() successfully populated the area. In the event of allocation failure, the vmalloc area is freed but the pointer to freed memory is inserted into the vmlist leading to a a crash later in get_vmalloc_info(). This patch adds a check for ____vmalloc_area_node() failure within __vmalloc_node_range. It does not use "goto fail" as in the previous error path as a warning was already displayed by __vmalloc_area_node() before it called vfree in its failure path. Credit goes to Luciano Chavez for doing all the real work of identifying exactly where the problem was. Signed-off-by:
Mel Gorman <mgorman@suse.de> Reported-by:
Luciano Chavez <lnx1138@linux.vnet.ibm.com> Tested-by:
Rik van Riel <riel@redhat.com> Acked-by:
David Rientjes <rientjes@google.com> Cc: <stable@vger.kernel.org> [3.1.x+] Signed-off-by:
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Michal Hocko authored
setup_zone_migrate_reserve() expects that zone->start_pfn starts at pageblock_nr_pages aligned pfn otherwise we could access beyond an existing memblock resulting in the following panic if CONFIG_HOLES_IN_ZONE is not configured and we do not check pfn_valid: IP: [<c02d331d>] setup_zone_migrate_reserve+0xcd/0x180 *pdpt = 0000000000000000 *pde = f000ff53f000ff53 Oops: 0000 [#1] SMP Pid: 1, comm: swapper Not tainted 3.0.7-0.7-pae #1 VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform EIP: 0060:[<c02d331d>] EFLAGS: 00010006 CPU: 0 EIP is at setup_zone_migrate_reserve+0xcd/0x180 EAX: 000c0000 EBX: f5801fc0 ECX: 000c0000 EDX: 00000000 ESI: 000c01fe EDI: 000c01fe EBP: 00140000 ESP: f2475f58 DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 Process swapper (pid: 1, ti=f2474000 task=f2472cd0 task.ti=f2474000) Call Trace: [<c02d389c>] __setup_per_zone_wmarks+0xec/0x160 [<c02d3a1f>] setup_per_zone_wmarks+0xf/0x20 [<c08a771c>] init_per_zone_wmark_min+0x27/0x86 [<c020111b>] do_one_initcall+0x2b/0x160 [<c086639d>] kernel_init+0xbe/0x157 [<c05cae26>] kernel_thread_helper+0x6/0xd Code: a5 39 f5 89 f7 0f 46 fd 39 cf 76 40 8b 03 f6 c4 08 74 32 eb 91 90 89 c8 c1 e8 0e 0f be 80 80 2f 86 c0 8b 14 85 60 2f 86 c0 89 c8 <2b> 82 b4 12 00 00 c1 e0 05 03 82 ac 12 00 00 8b 00 f6 c4 08 0f EIP: [<c02d331d>] setup_zone_migrate_reserve+0xcd/0x180 SS:ESP 0068:f2475f58 CR2: 00000000000012b4 We crashed in pageblock_is_reserved() when accessing pfn 0xc0000 because highstart_pfn = 0x36ffe. The issue was introduced in 3.0-rc1 by 6d3163ce ("mm: check if any page in a pageblock is reserved before marking it MIGRATE_RESERVE"). Make sure that start_pfn is always aligned to pageblock_nr_pages to ensure that pfn_valid s always called at the start of each pageblock. Architectures with holes in pageblocks will be correctly handled by pfn_valid_within in pageblock_is_reserved. Signed-off-by:
Dang Bo <bdang@vmware.com> Reviewed-by:
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Arve Hjnnevg <arve@android.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Cc: <stable@vger.kernel.org> [3.0+] Signed-off-by:
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Hillf Danton authored
Avoid unlocking and unlocked page if we failed to lock it. Signed-off-by:
Hillf Danton <dhillf@gmail.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by:
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Youquan Song authored
Commit 70b50f94 ("mm: thp: tail page refcounting fix") keeps all page_tail->_count zero at all times. But the current kernel does not set page_tail->_count to zero if a 1GB page is utilized. So when an IOMMU 1GB page is used by KVM, it wil result in a kernel oops because a tail page's _count does not equal zero. kernel BUG at include/linux/mm.h:386! invalid opcode: 0000 [#1] SMP Call Trace: gup_pud_range+0xb8/0x19d get_user_pages_fast+0xcb/0x192 ? trace_hardirqs_off+0xd/0xf hva_to_pfn+0x119/0x2f2 gfn_to_pfn_memslot+0x2c/0x2e kvm_iommu_map_pages+0xfd/0x1c1 kvm_iommu_map_memslots+0x7c/0xbd kvm_iommu_map_guest+0xaa/0xbf kvm_vm_ioctl_assigned_device+0x2ef/0xa47 kvm_vm_ioctl+0x36c/0x3a2 do_vfs_ioctl+0x49e/0x4e4 sys_ioctl+0x5a/0x7c system_call_fastpath+0x16/0x1b RIP gup_huge_pud+0xf2/0x159 Signed-off-by:
Youquan Song <youquan.song@intel.com> Reviewed-by:
Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by:
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