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* rcu: Add CPU-stall capability to rcutorturePaul E. McKenney2012-02-211-0/+66
| | | | | | | | | | | | | Add module parameters to rcutorture that induce a CPU stall. The stall_cpu parameter specifies how long to stall in seconds, defaulting to zero, which indicates no stalling is to be undertaken. The stall_cpu_holdoff parameter specifies how many seconds after insmod (or boot, if rcutorture is built into the kernel) that this stall is to start. The default value for stall_cpu_holdoff is ten seconds. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcutorture: Permit holding off CPU-hotplug operations during bootPaul E. McKenney2012-02-211-2/+10
| | | | | | | | | | | When rcutorture is started automatically at boot time, it might well also start CPU-hotplug operations at that time, which might not be desirable. This commit therefore adds an rcutorture parameter that allows CPU-hotplug operations to be held off for the specified number of seconds after the start of boot. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Print scheduling-clock information on RCU CPU stall-warning messagesPaul E. McKenney2012-02-213-14/+180
| | | | | | | | | | | There have been situations where RCU CPU stall warnings were caused by issues in scheduling-clock timer initialization. To make it easier to track these down, this commit causes the RCU CPU stall-warning messages to print out the number of scheduling-clock interrupts taken in the current grace period for each stalled CPU. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Set RCU CPU stall times via sysfsPaul E. McKenney2012-02-212-11/+26
| | | | | | | | | | | | | | The default CONFIG_RCU_CPU_STALL_TIMEOUT value of 60 seconds has served Linux users well for production use for quite some time. However, for debugging, there will be more than three minutes between subsequent stall-warning messages. This can be an annoyingly long wait if you are trying to work out where the offending infinite loop is hiding. Therefore, this commit provides a rcu_cpu_stall_timeout sysfs parameter that may be adjusted at boot time and at runtime to speed up debugging. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Remove #ifdef CONFIG_SMP from TREE_RCUPaul E. McKenney2012-02-212-31/+0
| | | | | | | | | Now that both TINY_RCU and TINY_PREEMPT_RCU have been in place for awhile, it is time to remove UP support from TREE_RCU, which is what this commit does. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Check for idle-loop entry while in RCU read-side critical sectionPaul E. McKenney2012-02-211-0/+11
| | | | | | | | | | | The inner idle loop is an extended quiescent state for all flavors of RCU, but there have been recent bug involving use of RCU read-side primitives from within the idle loop. Therefore, this commit enlists lockdep-RCU to detect attempts to enter the inner idle loop while in an RCU read-side critical section, emitting a lockdep-RCU splat if so. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Clean up straggling rcu_preempt_needs_cpu() namePaul E. McKenney2012-02-213-6/+6
| | | | | | | | | | The recent updates to RCU_CPU_FAST_NO_HZ have an rcu_needs_cpu() that does more than just check for callbacks, so get the name for rcu_preempt_needs_cpu() consistent with that change, now calling it rcu_preempt_cpu_has_callbacks(). Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Simplify unboosting checksPaul E. McKenney2012-02-211-4/+6
| | | | | | | | | | | | | | | | | | | This is a port of commit #82e78d80 from TREE_PREEMPT_RCU to TINY_PREEMPT_RCU. This commit uses the fact that current->rcu_boost_mutex is set any time that the RCU_READ_UNLOCK_BOOSTED flag is set in the current->rcu_read_unlock_special bitmask. This allows tests of the bit to be changed to tests of the pointer, which in turn allows the RCU_READ_UNLOCK_BOOSTED flag to be eliminated. Please note that the check of current->rcu_read_unlock_special need not change because any time that RCU_READ_UNLOCK_BOOSTED was set, so was RCU_READ_UNLOCK_BLOCKED. Therefore, __rcu_read_unlock() can continue testing current->rcu_read_unlock_special for non-zero, as before. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Inform RCU of irq_exit() activityPaul E. McKenney2012-02-211-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is a port to TINY_RCU of Peter Zijlstra's commit #ec433f0c5 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 */ <preempt> |= UNLOCK_BLOCKED rcu_read_unlock() --t->rcu_read_lock_nesting irq_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); This can be triggered 'easily' 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. It is also necessary to delay the ->rcu_read_lock_nesting decrement until after rcu_read_unlock_special(). This delay is handled by the commit "Protect __rcu_read_unlock() against scheduler-using irq handlers". Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Prevent RCU callbacks from executing before scheduler initializedPaul E. McKenney2012-02-211-3/+12
| | | | | | | | | | | | | | | | | | | This is a port of commit #b0d3041 from TREE_RCU to TREE_PREEMPT_RCU. 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. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Streamline code produced by __rcu_read_unlock()Paul E. McKenney2012-02-211-1/+1
| | | | | | | | This is a port of commit #be0e1e21 to TINY_PREEMPT_RCU. This uses noinline to prevent rcu_read_unlock_special() from being inlined into __rcu_read_unlock(). Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Protect __rcu_read_unlock() against scheduler-using irq handlersPaul E. McKenney2012-02-211-8/+35
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This commit ports commit #10f39bb1b2 (rcu: protect __rcu_read_unlock() against scheduler-using irq handlers) from TREE_PREEMPT_RCU to TINY_PREEMPT_RCU. The following is a corresponding port of that commit message. The addition of RCU read-side critical sections within runqueue and priority-inheritance critical sections introduced some deadlocks, 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. Of course, in a UP kernel, there are not really any deadlocks, but the upper-level critical section can still be be fatally confused by the lower-level critical section changing things out from under it. 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. 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 (OK, OK, fatal confusion) if that RCU read-side critical section happened to be in the scheduler where the runqueue or priority-inheritance locks were held. To prevent the possibility of fatal confusion that might result from preemption during the time that ->rcu_read_lock_nesting is negative, this commit also makes 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 both preemption and 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 <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Remove single-rcu_node optimization in rcu_start_gp()Paul E. McKenney2012-02-211-18/+0
| | | | | | | | | | | | | | | | The grace-period initialization sequence in rcu_start_gp() has a special case for systems where the rcu_node tree is a single rcu_node structure. This made sense some years ago when systems were smaller and up to 64 CPUs could share a single rcu_node structure, but now that large systems are common and a given leaf rcu_node structure can support only 16 CPUs (due to lock contention on the rcu_node's ->lock field), this optimization is almost never taken. And even the small mobile platforms that might make use of it might rather have the kernel text reduction. Therefore, this commit removes the check for single-rcu_node trees. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
* rcu: Don't make callbacks go through second full grace periodPaul E. McKenney2012-02-211-6/+46
| | | | | | | | | | | | | | | | | RCU's current CPU-offline code path dumps all of the outgoing CPU's callbacks onto the RCU_NEXT_TAIL portion of the surviving CPU's callback list. This means that all the ready-to-invoke callbacks from the outgoing CPU must wait for another full RCU grace period. This was just fine when CPU-hotplug events were rare, but there is increasing evidence that users are planning to make increasing use of CPU hotplug. Therefore, this commit changes the callback-dumping procedure so that callbacks that are ready to invoke are moved to the RCU_DONE_TAIL portion of the surviving CPU's callback list. This avoids running these callbacks through a second unnecessary grace period. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Check for callback invocation from offline CPUsPaul E. McKenney2012-02-211-0/+1
| | | | | | | | | | | | | | | Because quiescent states are now reported from offline CPUs in CPU_DYING state, there is some possibility that such a CPU might note the end of a grace period and attempt to start invoking callbacks. This would be a very bad thing, and is supposed to be prevented by the fact that the CPU_DYING CPU gets rid of all its callbacks before reporting the quiescent state. However, there is other CPU-offline code in the kernel, and it is quite possible that someone will invoke RCU core processing from that code. Therefore, this commit adds a warning for this case. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Limit lazy-callback durationPaul E. McKenney2012-02-211-1/+11
| | | | | | | | | | Currently, a given CPU is permitted to remain in dyntick-idle mode indefinitely if it has only lazy RCU callbacks queued. This is vulnerable to corner cases in NUMA systems, so limit the time to six seconds by default. (Currently controlled by a cpp macro.) Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Make rcutorture flag online/offline failuresPaul E. McKenney2012-02-211-0/+4
| | | | | | | | Make rcutorture check for CPU-hotplug failures and complain if there were any. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Simplify offline processingPaul E. McKenney2012-02-213-99/+90
| | | | | | | | | | | Move ->qsmaskinit and blkd_tasks[] manipulation to the CPU_DYING notifier. This simplifies the code by eliminating a potential deadlock and by reducing the responsibilities of force_quiescent_state(). Also rename functions to make their connection to the CPU-hotplug stages explicit. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Avoid waking up CPUs having only kfree_rcu() callbacksPaul E. McKenney2012-02-216-22/+105
| | | | | | | | | | | | | | | | When CONFIG_RCU_FAST_NO_HZ is enabled, RCU will allow a given CPU to enter dyntick-idle mode even if it still has RCU callbacks queued. RCU avoids system hangs in this case by scheduling a timer for several jiffies in the future. However, if all of the callbacks on that CPU are from kfree_rcu(), there is no reason to wake the CPU up, as it is not a problem to defer freeing of memory. This commit therefore tracks the number of callbacks on a given CPU that are from kfree_rcu(), and avoids scheduling the timer if all of a given CPU's callbacks are from kfree_rcu(). Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Add diagnostic for misaligned rcu_head structuresPaul E. McKenney2012-02-211-0/+1
| | | | | | | | | | | | The push for energy efficiency will require that RCU tag rcu_head structures to indicate whether or not their invocation is time critical. This tagging is best carried out in the bottom bits of the ->next pointers in the rcu_head structures. This tagging requires that the rcu_head structures be properly aligned, so this commit adds the required diagnostics. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Add lockdep-RCU checks for simple self-deadlockPaul E. McKenney2012-02-215-0/+27
| | | | | | | | | | It is illegal to have a grace period within a same-flavor RCU read-side critical section, so this commit adds lockdep-RCU checks to splat when such abuse is encountered. This commit does not detect more elaborate RCU deadlock situations. These situations might be a job for lockdep enhancements. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* Merge tag 'for-linus' of git://github.com/rustyrussell/linuxLinus Torvalds2012-02-131-1/+2
|\ | | | | | | | | | | * tag 'for-linus' of git://github.com/rustyrussell/linux: module: fix broken isapnp handling in file2alias module: make module param bint handle nul value
| * module: make module param bint handle nul valueDave Young2012-02-141-1/+2
| | | | | | | | | | | | | | | | Allow bint param accept nul values, just do same as bool param. Signed-off-by: Dave Young <dyoung@redhat.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* | Merge branch 'for-linus' of git://git.kernel.dk/linux-blockLinus Torvalds2012-02-112-3/+9
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Says Jens: "Time to push off some of the pending items. I really wanted to wait until we had the regression nailed, but alas it's not quite there yet. But I'm very confident that it's "just" a missing expire on exit, so fix from Tejun should be fairly trivial. I'm headed out for a week on the slopes. - Killing the barrier part of mtip32xx. It doesn't really support barriers, and it doesn't need them (writes are fully ordered). - A few fixes from Dan Carpenter, preventing overflows of integer multiplication. - A fixup for loop, fixing a previous commit that didn't quite solve the partial read problem from Dave Young. - A bio integer overflow fix from Kent Overstreet. - Improvement/fix of the door "keep locked" part of the cdrom shared code from Paolo Benzini. - A few cfq fixes from Shaohua Li. - A fix for bsg sysfs warning when removing a file it did not create from Stanislaw Gruszka. - Two fixes for floppy from Vivek, preventing a crash. - A few block core fixes from Tejun. One killing the over-optimized ioc exit path, cleaning that up nicely. Two others fixing an oops on elevator switch, due to calling into the scheduler merge check code without holding the queue lock." * 'for-linus' of git://git.kernel.dk/linux-block: block: fix lockdep warning on io_context release put_io_context() relay: prevent integer overflow in relay_open() loop: zero fill bio instead of return -EIO for partial read bio: don't overflow in bio_get_nr_vecs() floppy: Fix a crash during rmmod floppy: Cleanup disk->queue before caling put_disk() if add_disk() was never called cdrom: move shared static to cdrom_device_info bsg: fix sysfs link remove warning block: don't call elevator callbacks for plug merges block: separate out blk_rq_merge_ok() and blk_try_merge() from elevator functions mtip32xx: removed the irrelevant argument of mtip_hw_submit_io() and the unused member of struct driver_data block: strip out locking optimization in put_io_context() cdrom: use copy_to_user() without the underscores block: fix ioc locking warning block: fix NULL icq_cache reference block,cfq: change code order
| * | relay: prevent integer overflow in relay_open()Dan Carpenter2012-02-101-2/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | "subbuf_size" and "n_subbufs" come from the user and they need to be capped to prevent an integer overflow. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: stable@kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: strip out locking optimization in put_io_context()Tejun Heo2012-02-071-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | put_io_context() performed a complex trylock dancing to avoid deferring ioc release to workqueue. It was also broken on UP because trylock was always assumed to succeed which resulted in unbalanced preemption count. While there are ways to fix the UP breakage, even the most pathological microbench (forced ioc allocation and tight fork/exit loop) fails to show any appreciable performance benefit of the optimization. Strip it out. If there turns out to be workloads which are affected by this change, simpler optimization from the discussion thread can be applied later. Signed-off-by: Tejun Heo <tj@kernel.org> LKML-Reference: <1328514611.21268.66.camel@sli10-conroe> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | | Merge branch 'perf-urgent-for-linus' of ↵Linus Torvalds2012-02-101-5/+14
|\ \ \ | |_|/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf: Fix double start/stop in x86_pmu_start() perf evsel: Fix an issue where perf report fails to show the proper percentage perf tools: Fix prefix matching for kernel maps perf tools: Fix perf stack to non executable on x86_64 perf: Remove deprecated WARN_ON_ONCE()
| * | perf: Fix double start/stop in x86_pmu_start()Stephane Eranian2012-02-071-5/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The following patch fixes a bug introduced by the following commit: e050e3f0a71b ("perf: Fix broken interrupt rate throttling") The patch caused the following warning to pop up depending on the sampling frequency adjustments: ------------[ cut here ]------------ WARNING: at arch/x86/kernel/cpu/perf_event.c:995 x86_pmu_start+0x79/0xd4() It was caused by the following call sequence: perf_adjust_freq_unthr_context.part() { stop() if (delta > 0) { perf_adjust_period() { if (period > 8*...) { stop() ... start() } } } start() } Which caused a double start and a double stop, thus triggering the assert in x86_pmu_start(). The patch fixes the problem by avoiding the double calls. We pass a new argument to perf_adjust_period() to indicate whether or not the event is already stopped. We can't just remove the start/stop from that function because it's called from __perf_event_overflow where the event needs to be reloaded via a stop/start back-toback call. The patch reintroduces the assertion in x86_pmu_start() which was removed by commit: 84f2b9b ("perf: Remove deprecated WARN_ON_ONCE()") In this second version, we've added calls to disable/enable PMU during unthrottling or frequency adjustment based on bug report of spurious NMI interrupts from Eric Dumazet. Reported-and-tested-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Stephane Eranian <eranian@google.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: markus@trippelsdorf.de Cc: paulus@samba.org Link: http://lkml.kernel.org/r/20120207133956.GA4932@quad [ Minor edits to the changelog and to the code ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | Merge tag 'pm-fixes-for-3.3-rc3' of ↵Linus Torvalds2012-02-043-6/+31
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Power management fixes for 3.3-rc3 Three power management regression fixes, one for a recent regression introcuded by the freezer changes during the 3.3 merge window and two for regressions in cpuidle (resulting from PM QoS changes) and in the hibernate user space interface, both introduced during the 3.2 development cycle. They include: * Two hibernate (s2disk) regression fixes from Srivatsa S. Bhat (for regressions introduced during the 3.3 merge window and during the 3.2 development cycle). * A cpuidle fix from Venki Pallipadi for a regression resulting from PM QoS changes during the 3.2 development cycle causing cpuidle to work incorrectly for CONFIG_PM unset. * tag 'pm-fixes-for-3.3-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: PM / QoS: CPU C-state breakage with PM Qos change PM / Freezer: Thaw only kernel threads if freezing of kernel threads fails PM / Hibernate: Thaw kernel threads in SNAPSHOT_CREATE_IMAGE ioctl path
| * | | PM / Freezer: Thaw only kernel threads if freezing of kernel threads failsSrivatsa S. Bhat2012-02-042-4/+27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If freezing of kernel threads fails, we are expected to automatically thaw tasks in the error recovery path. However, at times, we encounter situations in which we would like the automatic error recovery path to thaw only the kernel threads, because we want to be able to do some more cleanup before we thaw userspace. Something like: error = freeze_kernel_threads(); if (error) { /* Do some cleanup */ /* Only then thaw userspace tasks*/ thaw_processes(); } An example of such a situation is where we freeze/thaw filesystems during suspend/hibernation. There, if freezing of kernel threads fails, we would like to thaw the frozen filesystems before thawing the userspace tasks. So, modify freeze_kernel_threads() to thaw only kernel threads in case of freezing failure. And change suspend_freeze_processes() accordingly. (At the same time, let us also get rid of the rather cryptic usage of the conditional operator (:?) in that function.) [rjw: In fact, this patch fixes a regression introduced during the 3.3 merge window, because without it thaw_processes() may be called before swsusp_free() in some situations and that may lead to massive memory allocation failures.] Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Acked-by: Tejun Heo <tj@kernel.org> Acked-by: Nigel Cunningham <nigel@tuxonice.net> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
| * | | PM / Hibernate: Thaw kernel threads in SNAPSHOT_CREATE_IMAGE ioctl pathSrivatsa S. Bhat2012-02-011-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In the SNAPSHOT_CREATE_IMAGE ioctl, if the call to hibernation_snapshot() fails, the frozen tasks are not thawed. And in the case of success, if we happen to exit due to a successful freezer test, all tasks (including those of userspace) are thawed, whereas actually we should have thawed only the kernel threads at that point. Fix both these issues. Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: stable@vger.kernel.org
* | | | kprobes: fix a memory leak in function pre_handler_kretprobe()Jiang Liu2012-02-031-1/+5
| |/ / |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In function pre_handler_kretprobe(), the allocated kretprobe_instance object will get leaked if the entry_handler callback returns non-zero. This may cause all the preallocated kretprobe_instance objects exhausted. This issue can be reproduced by changing samples/kprobes/kretprobe_example.c to probe "mutex_unlock". And the fix is straightforward: just put the allocated kretprobe_instance object back onto the free_instances list. [akpm@linux-foundation.org: use raw_spin_lock/unlock] Signed-off-by: Jiang Liu <jiang.liu@huawei.com> Acked-by: Jim Keniston <jkenisto@us.ibm.com> Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | Fix race in process_vm_rw_coreChristopher Yeoh2012-02-021-0/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This fixes the race in process_vm_core found by Oleg (see http://article.gmane.org/gmane.linux.kernel/1235667/ for details). This has been updated since I last sent it as the creation of the new mm_access() function did almost exactly the same thing as parts of the previous version of this patch did. In order to use mm_access() even when /proc isn't enabled, we move it to kernel/fork.c where other related process mm access functions already are. Signed-off-by: Chris Yeoh <yeohc@au1.ibm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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*-----. \ \ Merge branches 'core-urgent-for-linus', 'perf-urgent-for-linus', ↵Linus Torvalds2012-02-026-56/+124
|\ \ \ \ \ \ | |_|_|_|/ / |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 'sched-urgent-for-linus' and 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: bugs, x86: Fix printk levels for panic, softlockups and stack dumps * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf top: Fix number of samples displayed perf tools: Fix strlen() bug in perf_event__synthesize_event_type() perf tools: Fix broken build by defining _GNU_SOURCE in Makefile x86/dumpstack: Remove unneeded check in dump_trace() perf: Fix broken interrupt rate throttling * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/rt: Fix task stack corruption under __ARCH_WANT_INTERRUPTS_ON_CTXSW sched: Fix ancient race in do_exit() sched/nohz: Fix nohz cpu idle load balancing state with cpu hotplug sched/s390: Fix compile error in sched/core.c sched: Fix rq->nr_uninterruptible update race * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/reboot: Remove VersaLogic Menlow reboot quirk x86/reboot: Skip DMI checks if reboot set by user x86: Properly parenthesize cmpxchg() macro arguments
| | | * | | sched/rt: Fix task stack corruption under __ARCH_WANT_INTERRUPTS_ON_CTXSWChanho Min2012-01-271-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This issue happens under the following conditions: 1. preemption is off 2. __ARCH_WANT_INTERRUPTS_ON_CTXSW is defined 3. RT scheduling class 4. SMP system Sequence is as follows: 1.suppose current task is A. start schedule() 2.task A is enqueued pushable task at the entry of schedule() __schedule prev = rq->curr; ... put_prev_task put_prev_task_rt enqueue_pushable_task 4.pick the task B as next task. next = pick_next_task(rq); 3.rq->curr set to task B and context_switch is started. rq->curr = next; 4.At the entry of context_swtich, release this cpu's rq->lock. context_switch prepare_task_switch prepare_lock_switch raw_spin_unlock_irq(&rq->lock); 5.Shortly after rq->lock is released, interrupt is occurred and start IRQ context 6.try_to_wake_up() which called by ISR acquires rq->lock try_to_wake_up ttwu_remote rq = __task_rq_lock(p) ttwu_do_wakeup(rq, p, wake_flags); task_woken_rt 7.push_rt_task picks the task A which is enqueued before. task_woken_rt push_rt_tasks(rq) next_task = pick_next_pushable_task(rq) 8.At find_lock_lowest_rq(), If double_lock_balance() returns 0, lowest_rq can be the remote rq. (But,If preemption is on, double_lock_balance always return 1 and it does't happen.) push_rt_task find_lock_lowest_rq if (double_lock_balance(rq, lowest_rq)).. 9.find_lock_lowest_rq return the available rq. task A is migrated to the remote cpu/rq. push_rt_task ... deactivate_task(rq, next_task, 0); set_task_cpu(next_task, lowest_rq->cpu); activate_task(lowest_rq, next_task, 0); 10. But, task A is on irq context at this cpu. So, task A is scheduled by two cpus at the same time until restore from IRQ. Task A's stack is corrupted. To fix it, don't migrate an RT task if it's still running. Signed-off-by: Chanho Min <chanho.min@lge.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: <stable@kernel.org> Link: http://lkml.kernel.org/r/CAOAMb1BHA=5fm7KTewYyke6u-8DP0iUuJMpgQw54vNeXFsGpoQ@mail.gmail.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | | * | | sched: Fix ancient race in do_exit()Yasunori Goto2012-01-271-0/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | try_to_wake_up() has a problem which may change status from TASK_DEAD to TASK_RUNNING in race condition with SMI or guest environment of virtual machine. As a result, exited task is scheduled() again and panic occurs. Here is the sequence how it occurs: ----------------------------------+----------------------------- | CPU A | CPU B ----------------------------------+----------------------------- TASK A calls exit().... do_exit() exit_mm() down_read(mm->mmap_sem); rwsem_down_failed_common() set TASK_UNINTERRUPTIBLE set waiter.task <= task A list_add to sem->wait_list : raw_spin_unlock_irq() (I/O interruption occured) __rwsem_do_wake(mmap_sem) list_del(&waiter->list); waiter->task = NULL wake_up_process(task A) try_to_wake_up() (task is still TASK_UNINTERRUPTIBLE) p->on_rq is still 1.) ttwu_do_wakeup() (*A) : (I/O interruption handler finished) if (!waiter.task) schedule() is not called due to waiter.task is NULL. tsk->state = TASK_RUNNING : check_preempt_curr(); : task->state = TASK_DEAD (*B) <--- set TASK_RUNNING (*C) schedule() (exit task is running again) BUG_ON() is called! -------------------------------------------------------- The execution time between (*A) and (*B) is usually very short, because the interruption is disabled, and setting TASK_RUNNING at (*C) must be executed before setting TASK_DEAD. HOWEVER, if SMI is interrupted between (*A) and (*B), (*C) is able to execute AFTER setting TASK_DEAD! Then, exited task is scheduled again, and BUG_ON() is called.... If the system works on guest system of virtual machine, the time between (*A) and (*B) may be also long due to scheduling of hypervisor, and same phenomenon can occur. By this patch, do_exit() waits for releasing task->pi_lock which is used in try_to_wake_up(). It guarantees the task becomes TASK_DEAD after waking up. Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20120117174031.3118.E1E9C6FF@jp.fujitsu.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | | * | | sched/nohz: Fix nohz cpu idle load balancing state with cpu hotplugSuresh Siddha2012-01-261-5/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With the recent nohz scheduler changes, rq's nohz flag 'NOHZ_TICK_STOPPED' and its associated state doesn't get cleared immediately after the cpu exits idle. This gets cleared as part of the next tick seen on that cpu. For the cpu offline support, we need to clear this state manually. Fix it by registering a cpu notifier, which clears the nohz idle load balance state for this rq explicitly during the CPU_DYING notification. There won't be any nohz updates for that cpu, after the CPU_DYING notification. But lets be extra paranoid and skip updating the nohz state in the select_nohz_load_balancer() if the cpu is not in active state anymore. Reported-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Reviewed-and-tested-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Tested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1327026538.16150.40.camel@sbsiddha-desk.sc.intel.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | | * | | sched/s390: Fix compile error in sched/core.cChristian Borntraeger2012-01-261-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 029632fbb7b7c9d85063cc9eb470de6c54873df3 ("sched: Make separate sched*.c translation units") removed the include of asm/mutex.h from sched.c. This breaks the combination of: CONFIG_MUTEX_SPIN_ON_OWNER=yes CONFIG_HAVE_ARCH_MUTEX_CPU_RELAX=yes like s390 without mutex debugging: CC kernel/sched/core.o kernel/sched/core.c: In function ‘mutex_spin_on_owner’: kernel/sched/core.c:3287: error: implicit declaration of function ‘arch_mutex_cpu_relax’ Lets re-add the include to kernel/sched/core.c Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1326268696-30904-1-git-send-email-borntraeger@de.ibm.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | | * | | sched: Fix rq->nr_uninterruptible update racePeter Zijlstra2012-01-261-12/+6
| | | |/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | KOSAKI Motohiro noticed the following race: > CPU0 CPU1 > -------------------------------------------------------- > deactivate_task() > task->state = TASK_UNINTERRUPTIBLE; > activate_task() > rq->nr_uninterruptible--; > > schedule() > deactivate_task() > rq->nr_uninterruptible++; > Kosaki-San's scenario is possible when CPU0 runs __sched_setscheduler() against CPU1's current @task. __sched_setscheduler() does a dequeue/enqueue in order to move the task to its new queue (position) to reflect the newly provided scheduling parameters. However it should be completely invariant to nr_uninterruptible accounting, sched_setscheduler() doesn't affect readyness to run, merely policy on when to run. So convert the inappropriate activate/deactivate_task usage to enqueue/dequeue_task, which avoids the nr_uninterruptible accounting. Also convert the two other sites: __migrate_task() and normalize_task() that still use activate/deactivate_task. These sites aren't really a problem since __migrate_task() will only be called on non-running task (and therefore are immume to the described problem) and normalize_task() isn't ever used on regular systems. Also remove the comments from activate/deactivate_task since they're misleading at best. Reported-by: KOSAKI Motohiro <kosaki.motohiro@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1327486224.2614.45.camel@laptop Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | | perf: Fix broken interrupt rate throttlingStephane Eranian2012-01-271-38/+66
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fixes the sampling interrupt throttling mechanism. It was broken in v3.2. Events were not being unthrottled. The unthrottling mechanism required that events be checked at each timer tick. This patch solves this problem and also separates: - unthrottling - multiplexing - frequency-mode period adjustments Not all of them need to be executed at each timer tick. This third version of the patch is based on my original patch + PeterZ proposal (https://lkml.org/lkml/2012/1/7/87). At each timer tick, for each context: - if the current CPU has throttled events, we unthrottle events - if context has frequency-based events, we adjust sampling periods - if we have reached the jiffies interval, we multiplex (rotate) We decoupled rotation (multiplexing) from frequency-mode sampling period adjustments. They should not necessarily happen at the same rate. Multiplexing is subject to jiffies_interval (currently at 1 but could be higher once the tunable is exposed via sysfs). We have grouped frequency-mode adjustment and unthrottling into the same routine to minimize code duplication. When throttled while in frequency mode, we scan the events only once. We have fixed the threshold enforcement code in __perf_event_overflow(). There was a bug whereby it would allow more than the authorized rate because an increment of hwc->interrupts was not executed at the right place. The patch was tested with low sampling limit (2000) and fixed periods, frequency mode, overcommitted PMU. On a 2.1GHz AMD CPU: $ cat /proc/sys/kernel/perf_event_max_sample_rate 2000 We set a rate of 3000 samples/sec (2.1GHz/3000 = 700000): $ perf record -e cycles,cycles -c 700000 noploop 10 $ perf report -D | tail -21 Aggregated stats: TOTAL events: 80086 MMAP events: 88 COMM events: 2 EXIT events: 4 THROTTLE events: 19996 UNTHROTTLE events: 19996 SAMPLE events: 40000 cycles stats: TOTAL events: 40006 MMAP events: 5 COMM events: 1 EXIT events: 4 THROTTLE events: 9998 UNTHROTTLE events: 9998 SAMPLE events: 20000 cycles stats: TOTAL events: 39996 THROTTLE events: 9998 UNTHROTTLE events: 9998 SAMPLE events: 20000 For 10s, the cap is 2x2000x10 = 40000 samples. We get exactly that: 20000 samples/event. Signed-off-by: Stephane Eranian <eranian@google.com> Cc: <stable@kernel.org> # v3.2+ Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20120126160319.GA5655@quad Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | | bugs, x86: Fix printk levels for panic, softlockups and stack dumpsPrarit Bhargava2012-01-261-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | rsyslog will display KERN_EMERG messages on a connected terminal. However, these messages are useless/undecipherable for a general user. For example, after a softlockup we get: Message from syslogd@intel-s3e37-04 at Jan 25 14:18:06 ... kernel:Stack: Message from syslogd@intel-s3e37-04 at Jan 25 14:18:06 ... kernel:Call Trace: Message from syslogd@intel-s3e37-04 at Jan 25 14:18:06 ... kernel:Code: ff ff a8 08 75 25 31 d2 48 8d 86 38 e0 ff ff 48 89 d1 0f 01 c8 0f ae f0 48 8b 86 38 e0 ff ff a8 08 75 08 b1 01 4c 89 e0 0f 01 c9 <e8> ea 69 dd ff 4c 29 e8 48 89 c7 e8 0f bc da ff 49 89 c4 49 89 This happens because the printk levels for these messages are incorrect. Only an informational message should be displayed on a terminal. I modified the printk levels for various messages in the kernel and tested the output by using the drivers/misc/lkdtm.c kernel modules (ie, softlockups, panics, hard lockups, etc.) and confirmed that the console output was still the same and that the output to the terminals was correct. For example, in the case of a softlockup we now see the much more informative: Message from syslogd@intel-s3e37-04 at Jan 25 10:18:06 ... BUG: soft lockup - CPU4 stuck for 60s! instead of the above confusing messages. AFAICT, the messages no longer have to be KERN_EMERG. In the most important case of a panic we set console_verbose(). As for the other less severe cases the correct data is output to the console and /var/log/messages. Successfully tested by me using the drivers/misc/lkdtm.c module. Signed-off-by: Prarit Bhargava <prarit@redhat.com> Cc: dzickus@redhat.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/1327586134-11926-1-git-send-email-prarit@redhat.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | | PM / Hibernate: Fix s2disk regression related to freezing workqueuesRafael J. Wysocki2012-01-292-0/+28
| |/ / / |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 2aede851ddf08666f68ffc17be446420e9d2a056 PM / Hibernate: Freeze kernel threads after preallocating memory introduced a mechanism by which kernel threads were frozen after the preallocation of hibernate image memory to avoid problems with frozen kernel threads not responding to memory freeing requests. However, it overlooked the s2disk code path in which the SNAPSHOT_CREATE_IMAGE ioctl was run directly after SNAPSHOT_FREE, which caused freeze_workqueues_begin() to BUG(), because it saw that worqueues had been already frozen. Although in principle this issue might be addressed by removing the relevant BUG_ON() from freeze_workqueues_begin(), that would reintroduce the very problem that commit 2aede851ddf08666f68ffc17be4 attempted to avoid into that particular code path. For this reason, to fix the issue at hand, introduce thaw_kernel_threads() and make the SNAPSHOT_FREE ioctl execute it. Special thanks to Srivatsa S. Bhat for detailed analysis of the problem. Reported-and-tested-by: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Cc: stable@kernel.org
* | | | Merge branch 'perf-urgent-for-linus' of ↵Linus Torvalds2012-01-262-3/+1
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf: Call perf_cgroup_event_time() directly perf: Don't call release_callchain_buffers() if allocation fails
| * | | | perf: Call perf_cgroup_event_time() directlyNamhyung Kim2012-01-211-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The perf_event_time() will call perf_cgroup_event_time() if @event is a cgroup event. Just do it directly and avoid the extra check.. Signed-off-by: Namhyung Kim <namhyung.kim@lge.com> Cc: Namhyung Kim <namhyung@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Link: http://lkml.kernel.org/r/1327021966-27688-2-git-send-email-namhyung.kim@lge.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | | perf: Don't call release_callchain_buffers() if allocation failsNamhyung Kim2012-01-211-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When alloc_callchain_buffers() fails, it frees all of entries before return. In addition, calling the release_callchain_buffers() will cause a NULL pointer dereference since callchain_cpu_entries is not set. Signed-off-by: Namhyung Kim <namhyung.kim@lge.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Namhyung Kim <namhyung@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Link: http://lkml.kernel.org/r/1327021966-27688-1-git-send-email-namhyung.kim@lge.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | | Merge branch 'core-urgent-for-linus' of ↵Linus Torvalds2012-01-261-4/+4
|\ \ \ \ \ | | |/ / / | |/| / / | |_|/ / |/| | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: rcu: Add missing __cpuinit annotation in rcutorture code sched: Add "const" to is_idle_task() parameter rcu: Make rcutorture bool parameters really bool (core code) memblock: Fix alloc failure due to dumb underflow protection in memblock_find_in_range_node()
| * | | Merge branch 'rcu/urgent' of ↵Ingo Molnar2012-01-171-4/+4
| |\ \ \ | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/urgent
| | * | | rcu: Add missing __cpuinit annotation in rcutorture codeHeiko Carstens2012-01-161-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | "rcu: Add rcutorture CPU-hotplug capability" adds cpu hotplug operations to the rcutorture code but produces a false positive warning about section mismatches: WARNING: vmlinux.o(.text+0x1e420c): Section mismatch in reference from the function rcu_torture_onoff() to the function .cpuinit.text:cpu_up() The function rcu_torture_onoff() references the function __cpuinit cpu_up(). This is often because rcu_torture_onoff lacks a __cpuinit annotation or the annotation of cpu_up is wrong. This commit therefore adds a __cpuinit annotation so the warning goes away. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| | * | | rcu: Make rcutorture bool parameters really bool (core code)Rusty Russell2012-01-161-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | module_param(bool) used to counter-intuitively take an int. In fddd5201 (mid-2009) we allowed bool or int/unsigned int using a messy trick. It's time to remove the int/unsigned int option. For this version it'll simply give a warning, but it'll break next kernel version. This commit makes this change to rcutorture. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| | * | | Merge branch 'rcu/fixes-for-v3.2' into rcu/urgentPaul E. McKenney2012-01-1617-243/+933
| | |\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge reason: Add these commits so that fixes on this branch do not conflict with already-mainlined code. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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