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* kgdb: call touch_softlockup_watchdog on resumeJason Wessel2008-10-06
| | | | | | | | The softlockup watchdog needs to be touched when resuming the from the kgdb stopped state to avoid the printk that a CPU is stuck if the debugger was active for longer than the softlockup threshold. Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
* clockevents: check broadcast tick device not the clock events deviceThomas Gleixner2008-10-04
| | | | | | | | | | | Impact: jiffies increment too fast. Hugh Dickins noted that with NOHZ=n and HIGHRES=n jiffies get incremented too fast. The reason is a wrong check in the broadcast enter/exit code, which keeps the local apic timer in periodic mode when the switch happens. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* fix error-path NULL deref in alloc_posix_timer()Dan Carpenter2008-10-02
| | | | | | | | | Found by static checker (http://repo.or.cz/w/smatch.git). Signed-off-by: Dan Carpenter <error27@gmail.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'timers-fixes-for-linus' of ↵Linus Torvalds2008-09-30
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: hrtimer: prevent migration of per CPU hrtimers hrtimer: mark migration state hrtimer: fix migration of CB_IRQSAFE_NO_SOFTIRQ hrtimers hrtimer: migrate pending list on cpu offline Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| * hrtimer: prevent migration of per CPU hrtimersThomas Gleixner2008-09-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: per CPU hrtimers can be migrated from a dead CPU The hrtimer code has no knowledge about per CPU timers, but we need to prevent the migration of such timers and warn when such a timer is active at migration time. Explicitely mark the timers as per CPU and use a more understandable mode descriptor for the interrupts safe unlocked callback mode, which is used by hrtimer_sleeper and the scheduler code. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * hrtimer: mark migration stateThomas Gleixner2008-09-29
| | | | | | | | | | | | | | | | | | | | | | | | | | Impact: during migration active hrtimers can be seen as inactive The migration code removes the hrtimers from the queues of the dead CPU and sets the state temporary to INACTIVE. The enqueue code sets it to ACTIVE/PENDING again. Prevent that the wrong state can be seen by using a separate migration state bit. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * hrtimer: fix migration of CB_IRQSAFE_NO_SOFTIRQ hrtimersThomas Gleixner2008-09-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: Stale timers after a CPU went offline. commit 37bb6cb4097e29ffee970065b74499cbf10603a3 hrtimer: unlock hrtimer_wakeup changed the hrtimer sleeper callback mode to CB_IRQSAFE_NO_SOFTIRQ due to locking problems. A result of this change is that when enqueue is called for an already expired hrtimer the callback function is not longer called directly from the enqueue code. The normal callers have been fixed in the code, but the migration code which moves hrtimers from a dead CPU to a live CPU was not made aware of this. This can be fixed by checking the timer state after the call to enqueue in the migration code. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * hrtimer: migrate pending list on cpu offlineThomas Gleixner2008-09-29
| | | | | | | | | | | | | | | | | | Impact: hrtimers which are on the pending list are not migrated at cpu offline and can be stale forever Add the pending list migration when CONFIG_HIGH_RES_TIMERS is enabled Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | mm owner: fix race between swapoff and exitBalbir Singh2008-09-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There's a race between mm->owner assignment and swapoff, more easily seen when task slab poisoning is turned on. The condition occurs when try_to_unuse() runs in parallel with an exiting task. A similar race can occur with callers of get_task_mm(), such as /proc/<pid>/<mmstats> or ptrace or page migration. CPU0 CPU1 try_to_unuse looks at mm = task0->mm increments mm->mm_users task 0 exits mm->owner needs to be updated, but no new owner is found (mm_users > 1, but no other task has task->mm = task0->mm) mm_update_next_owner() leaves mmput(mm) decrements mm->mm_users task0 freed dereferencing mm->owner fails The fix is to notify the subsystem via mm_owner_changed callback(), if no new owner is found, by specifying the new task as NULL. Jiri Slaby: mm->owner was set to NULL prior to calling cgroup_mm_owner_callbacks(), but must be set after that, so as not to pass NULL as old owner causing oops. Daisuke Nishimura: mm_update_next_owner() may set mm->owner to NULL, but mem_cgroup_from_task() and its callers need to take account of this situation to avoid oops. Hugh Dickins: Lockdep warning and hang below exec_mmap() when testing these patches. exit_mm() up_reads mmap_sem before calling mm_update_next_owner(), so exec_mmap() now needs to do the same. And with that repositioning, there's now no point in mm_need_new_owner() allowing for NULL mm. Reported-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: Jiri Slaby <jirislaby@gmail.com> Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Hugh Dickins <hugh@veritas.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | kgdb, x86, arm, mips, powerpc: ignore user space single steppingJason Wessel2008-09-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On the x86 arch, user space single step exceptions should be ignored if they occur in the kernel space, such as ptrace stepping through a system call. First check if it is kgdb that is executing a single step, then ensure it is not an accidental traversal into the user space, while in kgdb, any other time the TIF_SINGLESTEP is set, kgdb should ignore the exception. On x86, arm, mips and powerpc, the kgdb_contthread usage was inconsistent with the way single stepping is implemented in the kgdb core. The arch specific stub should always set the kgdb_cpu_doing_single_step correctly if it is single stepping. This allows kgdb to correctly process an instruction steps if ptrace happens to be requesting an instruction step over a system call. Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
* | kgdb: could not write to the last of valid memory with kgdbAtsuo Igarashi2008-09-26
|/ | | | | | | | | On the ARM architecture, kgdb will crash the kernel if the last byte of valid memory is written due to a flush_icache_range flushing beyond the memory boundary. Signed-off-by: Atsuo Igarashi <atsuo_igarashi@tripeaks.co.jp> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
* Merge branch 'timers-fixes-for-linus' of ↵Linus Torvalds2008-09-23
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: timers: fix build error in !oneshot case x86: c1e_idle: don't mark TSC unstable if CPU has invariant TSC x86: prevent C-states hang on AMD C1E enabled machines clockevents: prevent mode mismatch on cpu online clockevents: check broadcast device not tick device clockevents: prevent stale tick_next_period for onlining CPUs x86: prevent stale state of c1e_mask across CPU offline/online clockevents: prevent cpu online to interfere with nohz
| * timers: fix build error in !oneshot caseIngo Molnar2008-09-23
| | | | | | | | | | | | | | kernel/time/tick-common.c: In function ‘tick_setup_periodic’: kernel/time/tick-common.c:113: error: implicit declaration of function ‘tick_broadcast_oneshot_active’ Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * clockevents: prevent mode mismatch on cpu onlineThomas Gleixner2008-09-23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: timer hang on CPU online observed on AMD C1E systems When a CPU is brought online then the broadcast machinery can be in the one shot state already. Check this and setup the timer device of the new CPU in one shot mode so the broadcast code can pick up the next_event value correctly. Another AMD C1E oddity, as we switch to broadcast immediately and not after the full bring up via the ACPI cpu idle code. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * clockevents: check broadcast device not tick deviceThomas Gleixner2008-09-23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: Possible hang on CPU online observed on AMD C1E machines. The broadcast setup code looks at the mode of the tick device to determine whether it needs to be shut down or setup. This is wrong when the broadcast mode is set to one shot already. This can happen when a CPU is brought online as it goes through the periodic setup first. The problem went unnoticed as sane systems do not call into that code before the switch to one shot for the clock event device happens. The AMD C1E idle routine switches over immediately and thereby shuts down the just setup device before the first interrupt happens. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * clockevents: prevent stale tick_next_period for onlining CPUsThomas Gleixner2008-09-23
| | | | | | | | | | | | | | | | | | | | Impact: possible hang on CPU onlining in timer one shot mode. The tick_next_period variable is only used during boot on nohz/highres enabled systems, but for CPU onlining it needs to be maintained when the per cpu clock events device operates in one shot mode. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * clockevents: prevent cpu online to interfere with nohzThomas Gleixner2008-09-23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: rare hang which can be triggered on CPU online. tick_do_timer_cpu keeps track of the CPU which updates jiffies via do_timer. The value -1 is used to signal, that currently no CPU is doing this. There are two cases, where the variable can have this state: boot: necessary for systems where the boot cpu id can be != 0 nohz long idle sleep: When the CPU which did the jiffies update last goes into a long idle sleep it drops the update jiffies duty so another CPU which is not idle can pick it up and keep jiffies going. Using the same value for both situations is wrong, as the CPU online code can see the -1 state when the timer of the newly onlined CPU is setup. The setup for a newly onlined CPU goes through periodic mode and can pick up the do_timer duty without being aware of the nohz / highres mode of the already running system. Use two separate states and make them constants to avoid magic numbers confusion. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | Merge branch 'sched-fixes-for-linus' of ↵Linus Torvalds2008-09-23
|\ \ | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: sched: fix init_hrtick() section mismatch warning
| * | sched: fix init_hrtick() section mismatch warningRakib Mullick2008-09-23
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | LD kernel/built-in.o WARNING: kernel/built-in.o(.text+0x326): Section mismatch in reference from the function init_hrtick() to the variable .cpuinit.data:hotplug_hrtick_nb.8 The function init_hrtick() references the variable __cpuinitdata hotplug_hrtick_nb.8. This is often because init_hrtick lacks a __cpuinitdata annotation or the annotation of hotplug_hrtick_nb.8 is wrong. Signed-off-by: Md.Rakib H. Mullick <rakib.mullick@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* / kexec: fix segmentation fault in kimage_add_entryJonathan Steel2008-09-23
|/ | | | | | | | | | | | | | | | | | | | | | A segmentation fault can occur in kimage_add_entry in kexec.c when loading a kernel image into memory. The fault occurs because a page is requested by calling kimage_alloc_page with gfp_mask GFP_KERNEL and the function may actually return a page with gfp_mask GFP_HIGHUSER. The high mem page is returned because it was swapped with the kernel page due to the kernel page being a page that will shortly be copied to. This patch ensures that kimage_alloc_page returns a page that was created with the correct gfp flags. I have verified the change and fixed the whitespace damage of the original patch. Jonathan did a great job of tracking this down after he hit the problem. -- Eric Signed-off-by: Jonathan Steel <jon.steel@esentire.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Acked-by: Simon Horman <horms@verge.net.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'sched-fixes-for-linus' of ↵Linus Torvalds2008-09-19
|\ | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: sched: fix deadlock in setting scheduler parameter to zero sched: fix 2.6.27-rc5 couldn't boot on tulsa machine randomly
| * sched: fix deadlock in setting scheduler parameter to zeroHiroshi Shimamoto2008-09-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Andrei Gusev wrote: > I played witch scheduler settings. After doing something like: > echo -n 1000000 >sched_rt_period_us > > command is locked. I found in kernel.log: > > Sep 11 00:39:34 zaratustra > Sep 11 00:39:34 zaratustra Pid: 4495, comm: bash Tainted: G W > (2.6.26.3 #12) > Sep 11 00:39:34 zaratustra EIP: 0060:[<c0213fc7>] EFLAGS: 00210246 CPU: 0 > Sep 11 00:39:34 zaratustra EIP is at div64_u64+0x57/0x80 > Sep 11 00:39:34 zaratustra EAX: 0000389f EBX: 00000000 ECX: 00000000 > EDX: 00000000 > Sep 11 00:39:34 zaratustra ESI: d9800000 EDI: d9800000 EBP: 0000389f > ESP: ea7a6edc > Sep 11 00:39:34 zaratustra DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 0068 > Sep 11 00:39:34 zaratustra Process bash (pid: 4495, ti=ea7a6000 > task=ea744000 task.ti=ea7a6000) > Sep 11 00:39:34 zaratustra Stack: 00000000 000003e8 d9800000 0000389f > c0119042 00000000 00000000 00000001 > Sep 11 00:39:34 zaratustra 00000000 00000000 ea7a6f54 00010000 00000000 > c04d2e80 00000001 000e7ef0 > Sep 11 00:39:34 zaratustra c01191a3 00000000 00000000 ea7a6fa0 00000001 > ffffffff c04d2e80 ea5b2480 > Sep 11 00:39:34 zaratustra Call Trace: > Sep 11 00:39:34 zaratustra [<c0119042>] __rt_schedulable+0x52/0x130 > Sep 11 00:39:34 zaratustra [<c01191a3>] sched_rt_handler+0x83/0x120 > Sep 11 00:39:34 zaratustra [<c01a76a6>] proc_sys_call_handler+0xb6/0xd0 > Sep 11 00:39:34 zaratustra [<c01a76c0>] proc_sys_write+0x0/0x20 > Sep 11 00:39:34 zaratustra [<c01a76d9>] proc_sys_write+0x19/0x20 > Sep 11 00:39:34 zaratustra [<c016cc68>] vfs_write+0xa8/0x140 > Sep 11 00:39:34 zaratustra [<c016cdd1>] sys_write+0x41/0x80 > Sep 11 00:39:34 zaratustra [<c0103051>] sysenter_past_esp+0x6a/0x91 > Sep 11 00:39:34 zaratustra ======================= > Sep 11 00:39:34 zaratustra Code: c8 41 0f ad f3 d3 ee f6 c1 20 0f 45 de > 31 f6 0f ad ef d3 ed f6 c1 20 0f 45 fd 0f 45 ee 31 c9 39 eb 89 fe 89 ea > 77 08 89 e8 31 d2 <f7> f3 89 c1 89 f0 8b 7c 24 08 f7 f3 8b 74 24 04 89 > ca 8b 1c 24 > Sep 11 00:39:34 zaratustra EIP: [<c0213fc7>] div64_u64+0x57/0x80 SS:ESP > 0068:ea7a6edc > Sep 11 00:39:34 zaratustra ---[ end trace 4eaa2a86a8e2da22 ]--- fix the boundary condition. sysctl_sched_rt_period=0 makes exception at to_ratio(). Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * sched: fix 2.6.27-rc5 couldn't boot on tulsa machine randomlyZhang, Yanmin2008-09-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On my tulsa x86-64 machine, kernel 2.6.25-rc5 couldn't boot randomly. Basically, function __enable_runtime forgets to reset rt_rq->rt_throttled to 0. When every cpu is up, per-cpu migration_thread is created and it runs very fast, sometimes to mark the corresponding rt_rq->rt_throttled to 1 very quickly. After all cpus are up, with below calling chain: sched_init_smp => arch_init_sched_domains => build_sched_domains => ... => cpu_attach_domain => rq_attach_root => set_rq_online => ... => _enable_runtime _enable_runtime is called against every rt_rq again, so rt_rq->rt_time is reset to 0, but rt_rq->rt_throttled might be still 1. Later on function do_sched_rt_period_timer couldn't reset it, and all RT tasks couldn't be scheduled to run on that cpu. here is RT task migration_thread which is woken up when a task is migrated to another cpu. Below patch fixes it against 2.6.27-rc5. Signed-off-by: Zhang Yanmin <yanmin_zhang@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | Merge branch 'timers-fixes-for-linus' of ↵Linus Torvalds2008-09-19
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: clockevents: make device shutdown robust clocksource, acpi_pm.c: fix check for monotonicity clockevents: remove WARN_ON which was used to gather information
| * | clockevents: make device shutdown robustThomas Gleixner2008-09-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The device shut down does not cleanup the next_event variable of the clock event device. So when the device is reactivated the possible stale next_event value can prevent the device to be reprogrammed as it claims to wait on a event already. This is the root cause of the resurfacing suspend/resume problem, where systems need key press to come back to life. Fix this by setting next_event to KTIME_MAX when the device is shut down. Use a separate function for shutdown which takes care of that and only keep the direct set mode call in the broadcast code, where we can not touch the next_event value. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | cpuset: avoid changing cpuset's cpus when -errno returnedLi Zefan2008-09-13
|/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After the patch: commit 0b2f630a28d53b5a2082a5275bc3334b10373508 Author: Miao Xie <miaox@cn.fujitsu.com> Date: Fri Jul 25 01:47:21 2008 -0700 cpusets: restructure the function update_cpumask() and update_nodemask() It might happen that 'echo 0 > /cpuset/sub/cpus' returned failure but 'cpus' has been changed, because cpus was changed before calling heap_init() which may return -ENOMEM. This patch restores the orginal behavior. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Cc: Paul Jackson <pj@sgi.com> Cc: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | clockevents: remove WARN_ON which was used to gather informationThomas Gleixner2008-09-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The issue of the endless reprogramming loop due to a too small min_delta_ns was fixed with the previous updates of the clock events code, but we had no information about the spread of this problem. I added a WARN_ON to get automated information via kerneloops.org and to get some direct reports, which allowed me to analyse the affected machines. The WARN_ON has served its purpose and would be annoying for a release kernel. Remove it and just keep the information about the increase of the min_delta_ns value. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | Merge branch 'sched-fixes-for-linus' of ↵Linus Torvalds2008-09-08
|\| | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: sched: arch_reinit_sched_domains() must destroy domains to force rebuild sched, cpuset: rework sched domains and CPU hotplug handling (v4)
| * Merge branch 'sched/cpuset' into sched/urgentIngo Molnar2008-09-06
| |\
| | * sched: arch_reinit_sched_domains() must destroy domains to force rebuildMax Krasnyansky2008-09-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | What I realized recently is that calling rebuild_sched_domains() in arch_reinit_sched_domains() by itself is not enough when cpusets are enabled. partition_sched_domains() code is trying to avoid unnecessary domain rebuilds and will not actually rebuild anything if new domain masks match the old ones. What this means is that doing echo 1 > /sys/devices/system/cpu/sched_mc_power_savings on a system with cpusets enabled will not take affect untill something changes in the cpuset setup (ie new sets created or deleted). This patch fixes restore correct behaviour where domains must be rebuilt in order to enable MC powersaving flags. Test on quad-core Core2 box with both CONFIG_CPUSETS and !CONFIG_CPUSETS. Also tested on dual-core Core2 laptop. Lockdep is happy and things are working as expected. Signed-off-by: Max Krasnyansky <maxk@qualcomm.com> Tested-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * sched, cpuset: rework sched domains and CPU hotplug handling (v4)Max Krasnyansky2008-08-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is an updated version of my previous cpuset patch on top of the latest mainline git. The patch fixes CPU hotplug handling issues in the current cpusets code. Namely circular locking in rebuild_sched_domains() and unsafe access to the cpu_online_map in the cpuset cpu hotplug handler. This version includes changes suggested by Paul Jackson (naming, comments, style, etc). I also got rid of the separate workqueue thread because it is now safe to call get_online_cpus() from workqueue callbacks. Here are some more details: rebuild_sched_domains() is the only way to rebuild sched domains correctly based on the current cpuset settings. What this means is that we need to be able to call it from different contexts, like cpu hotplug for example. Also latest scheduler code in -tip now calls rebuild_sched_domains() directly from functions like arch_reinit_sched_domains(). In order to support that properly we need to rework cpuset locking rules to avoid circular dependencies, which is what this patch does. New lock nesting rules are explained in the comments. We can now safely call rebuild_sched_domains() from virtually any context. The only requirement is that it needs to be called under get_online_cpus(). This allows cpu hotplug handlers and the scheduler to call rebuild_sched_domains() directly. The rest of the cpuset code now offloads sched domains rebuilds to a workqueue (async_rebuild_sched_domains()). This version of the patch addresses comments from the previous review. I fixed all miss-formated comments and trailing spaces. I also factored out the code that builds domain masks and split up CPU and memory hotplug handling. This was needed to simplify locking, to avoid unsafe access to the cpu_online_map from mem hotplug handler, and in general to make things cleaner. The patch passes moderate testing (building kernel with -j 16, creating & removing domains and bringing cpus off/online at the same time) on the quad-core2 based machine. It passes lockdep checks, even with preemptable RCU enabled. This time I also tested in with suspend/resume path and everything is working as expected. Signed-off-by: Max Krasnyansky <maxk@qualcomm.com> Acked-by: Paul Jackson <pj@sgi.com> Cc: menage@google.com Cc: a.p.zijlstra@chello.nl Cc: vegard.nossum@gmail.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | Merge branch 'timers-fixes-for-linus' of ↵Linus Torvalds2008-09-06
|\ \ \ | |/ / |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: clocksource, acpi_pm.c: check for monotonicity clocksource, acpi_pm.c: use proper read function also in errata mode ntp: fix calculation of the next jiffie to trigger RTC sync x86: HPET: read back compare register before reading counter x86: HPET fix moronic 32/64bit thinko clockevents: broadcast fixup possible waiters HPET: make minimum reprogramming delta useful clockevents: prevent endless loop lockup clockevents: prevent multiple init/shutdown clockevents: enforce reprogram in oneshot setup clockevents: prevent endless loop in periodic broadcast handler clockevents: prevent clockevent event_handler ending up handler_noop
| * | ntp: fix calculation of the next jiffie to trigger RTC syncMaciej W. Rozycki2008-09-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We have a bug in the calculation of the next jiffie to trigger the RTC synchronisation. The aim here is to run sync_cmos_clock() as close as possible to the middle of a second. Which means we want this function to be called less than or equal to half a jiffie away from when now.tv_nsec equals 5e8 (500000000). If this is not the case for a given call to the function, for this purpose instead of updating the RTC we calculate the offset in nanoseconds to the next point in time where now.tv_nsec will be equal 5e8. The calculated offset is then converted to jiffies as these are the unit used by the timer. Hovewer timespec_to_jiffies() used here uses a ceil()-type rounding mode, where the resulting value is rounded up. As a result the range of now.tv_nsec when the timer will trigger is from 5e8 to 5e8 + TICK_NSEC rather than the desired 5e8 - TICK_NSEC / 2 to 5e8 + TICK_NSEC / 2. As a result if for example sync_cmos_clock() happens to be called at the time when now.tv_nsec is between 5e8 + TICK_NSEC / 2 and 5e8 to 5e8 + TICK_NSEC, it will simply be rescheduled HZ jiffies later, falling in the same range of now.tv_nsec again. Similarly for cases offsetted by an integer multiple of TICK_NSEC. This change addresses the problem by subtracting TICK_NSEC / 2 from the nanosecond offset to the next point in time where now.tv_nsec will be equal 5e8, effectively shifting the following rounding in timespec_to_jiffies() so that it produces a rounded-to-nearest result. Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | clockevents: broadcast fixup possible waitersThomas Gleixner2008-09-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | Until the C1E patches arrived there where no users of periodic broadcast before switching to oneshot mode. Now we need to trigger a possible waiter for a periodic broadcast when switching to oneshot mode. Otherwise we can starve them for ever. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | clockevents: prevent endless loop lockupThomas Gleixner2008-09-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The C1E/HPET bug reports on AMDX2/RS690 systems where tracked down to a too small value of the HPET minumum delta for programming an event. The clockevents code needs to enforce an interrupt event on the clock event device in some cases. The enforcement code was stupid and naive, as it just added the minimum delta to the current time and tried to reprogram the device. When the minimum delta is too small, then this loops forever. Add a sanity check. Allow reprogramming to fail 3 times, then print a warning and double the minimum delta value to make sure, that this does not happen again. Use the same function for both tick-oneshot and tick-broadcast code. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | clockevents: prevent multiple init/shutdownThomas Gleixner2008-09-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | While chasing the C1E/HPET bugreports I went through the clock events code inch by inch and found that the broadcast device can be initialized and shutdown multiple times. Multiple shutdowns are not critical, but useless waste of time. Multiple initializations are simply broken. Another CPU might have the device in use already after the first initialization and the second init could just render it unusable again. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | clockevents: enforce reprogram in oneshot setupThomas Gleixner2008-09-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In tick_oneshot_setup we program the device to the given next_event, but we do not check the return value. We need to make sure that the device is programmed enforced so the interrupt handler engine starts working. Split out the reprogramming function from tick_program_event() and call it with the device, which was handed in to tick_setup_oneshot(). Set the force argument, so the devices is firing an interrupt. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | clockevents: prevent endless loop in periodic broadcast handlerThomas Gleixner2008-09-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The reprogramming of the periodic broadcast handler was broken, when the first programming returned -ETIME. The clockevents code stores the new expiry value in the clock events device next_event field only when the programming time has not been elapsed yet. The loop in question calculates the new expiry value from the next_event value and therefor never increases. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | clockevents: prevent clockevent event_handler ending up handler_noopVenkatesh Pallipadi2008-09-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There is a ordering related problem with clockevents code, due to which clockevents_register_device() called after tickless/highres switch will not work. The new clockevent ends up with clockevents_handle_noop as event handler, resulting in no timer activity. The problematic path seems to be * old device already has hrtimer_interrupt as the event_handler * new clockevent device registers with a higher rating * tick_check_new_device() is called * clockevents_exchange_device() gets called * old->event_handler is set to clockevents_handle_noop * tick_setup_device() is called for the new device * which sets new->event_handler using the old->event_handler which is noop. Change the ordering so that new device inherits the proper handler. This does not have any issue in normal case as most likely all the clockevent devices are setup before the highres switch. But, can potentially be affecting some corner case where HPET force detect happens after the highres switch. This was a problem with HPET in MSI mode code that we have been experimenting with. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | sched: fix process time monotonicityBalbir Singh2008-09-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Spencer reported a problem where utime and stime were going negative despite the fixes in commit b27f03d4bdc145a09fb7b0c0e004b29f1ee555fa. The suspected reason for the problem is that signal_struct maintains it's own utime and stime (of exited tasks), these are not updated using the new task_utime() routine, hence sig->utime can go backwards and cause the same problem to occur (sig->utime, adds tsk->utime and not task_utime()). This patch fixes the problem TODO: using max(task->prev_utime, derived utime) works for now, but a more generic solution is to implement cputime_max() and use the cputime_gt() function for comparison. Reported-by: spencer@bluehost.com Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | sched_clock: fix NOHZ interactionPeter Zijlstra2008-09-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If HLT stops the TSC, we'll fail to account idle time, thereby inflating the actual process times. Fix this by re-calibrating the clock against GTOD when leaving nohz mode. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Tested-by: Avi Kivity <avi@qumranet.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | forgotten refcount on sysctl root tableAl Viro2008-09-04
|/ / | | | | | | | | | | | | | | | | | | We should've set refcount on the root sysctl table; otherwise we'll blow up the first time we get down to zero dynamically registered sysctl tables. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Tested-by: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | pm_qos_requirement might sleepJohn Kacur2008-09-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make PM_QOS and CPU_IDLE play nicer when run with the RT-Preempt kernel. The purpose of the patch is to remove the spin_lock around the read in the function pm_qos_requirement - since spinlocks can sleep in -rt and this function is called from idle. CPU_IDLE polls the target_value's of some of the pm_qos parameters from the idle loop causing sleeping locking warnings. Changing the target_value to an atomic avoids this issue. Remove the spinlock in pm_qos_requirement by making target_value an atomic type. Signed-off-by: mark gross <mgross@linux.intel.com> Signed-off-by: John Kacur <jkacur@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | pid_ns: (BUG 11391) change ->child_reaper when init->group_leader exitsOleg Nesterov2008-09-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We don't change pid_ns->child_reaper when the main thread of the subnamespace init exits. As Robert Rex <robert.rex@exasol.com> pointed out this is wrong. Yes, the re-parenting itself works correctly, but if the reparented task exits it needs ->parent->nsproxy->pid_ns in do_notify_parent(), and if the main thread is zombie its ->nsproxy was already cleared by exit_task_namespaces(). Introduce the new function, find_new_reaper(), which finds the new ->parent for the re-parenting and changes ->child_reaper if needed. Kill the now unneeded exit_child_reaper(). Also move the changing of ->child_reaper from zap_pid_ns_processes() to find_new_reaper(), this consolidates the games with ->child_reaper and makes it stable under tasklist_lock. Addresses http://bugzilla.kernel.org/show_bug.cgi?id=11391 Reported-by: Robert Rex <robert.rex@exasol.com> Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Serge Hallyn <serue@us.ibm.com> Acked-by: Pavel Emelyanov <xemul@openvz.org> Acked-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | pid_ns: zap_pid_ns_processes: fix the ->child_reaper changingOleg Nesterov2008-09-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | zap_pid_ns_processes() sets pid_ns->child_reaper = NULL, this is wrong. Yes, we have already killed all tasks in this namespace, and sys_wait4() doesn't see any child. But this doesn't mean ->children list is empty, we may have EXIT_DEAD tasks which are not visible to do_wait(). In that case the subsequent forget_original_parent() will crash the kernel because it will try to re-parent these tasks to the NULL reaper. Even if there are no childs, it is not good that forget_original_parent() uses reaper == NULL. Change the code to set ->child_reaper = init_pid_ns.child_reaper instead. We could use pid_ns->parent->child_reaper as well, I think this does not really matter. These EXIT_DEAD tasks are not visible to the new ->parent after re-parenting, they will silently do release_task() eventually. Note that we must change ->child_reaper, otherwise forget_original_parent() will use reaper == father, and in that case we will hit the (correct) BUG_ON(!list_empty(&father->children)). Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Serge Hallyn <serue@us.ibm.com> Acked-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Acked-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Merge branch 'audit.b57' of ↵Linus Torvalds2008-09-02
|\ \ | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current * 'audit.b57' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current: [PATCH] audit: Moved variable declaration to beginning of function
| * | [PATCH] audit: Moved variable declaration to beginning of functionCordelia2008-09-01
| | | | | | | | | | | | | | | | | | | | | | | | got rid of compilation warning: ISO C90 forbids mixed declarations and code Signed-off-by: Cordelia Sam <cordesam@gmail.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | | softlockup: minor cleanup, don't check task->state twiceOleg Nesterov2008-09-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The recent commit 16d9679f33caf7e683471647d1472bfe133d858 changed check_hung_task() to filter out the TASK_KILLABLE tasks. We can move this check to the caller which has to test t->state anyway. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | kernel/resource.c: fix new kernel-doc warningRandy Dunlap2008-09-02
|/ / | | | | | | | | | | | | | | | | Fix kernel-doc warning for new function: Warning(linux-2.6.27-rc5-git2//kernel/resource.c:448): No description found for parameter 'root' Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Resource handling: add 'insert_resource_expand_to_fit()' functionLinus Torvalds2008-08-29
| | | | | | | | | | | | | | | | | | Not used anywhere yet, but this complements the existing plain 'insert_resource()' functionality with a version that can expand the resource we are adding in order to fix up any conflicts it has with existing resources. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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