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Paul E. McKenney cd95851785 rcu: fix classic RCU locking cleanup lockdep problem 
On Fri, Aug 15, 2008 at 04:24:30PM +0200, Ingo Molnar wrote:
>
> Paul,
>
> one of your two recent RCU patches caused this lockdep splat in -tip
> testing:
>
> ------------------->
> Brought up 2 CPUs
> Total of 2 processors activated (6850.87 BogoMIPS).
> PM: Adding info for No Bus:platform
> khelper used greatest stack depth: 3124 bytes left
>
> =================================
> [ INFO: inconsistent lock state ]
> 2.6.27-rc3-tip #1
> ---------------------------------
> inconsistent {softirq-on-W} -> {in-softirq-W} usage.
> ksoftirqd/0/4 [HC0[0]:SC1[1]:HE1:SE0] takes:
>  (&rcu_ctrlblk.lock){-+..}, at: [<c016d91c>] __rcu_process_callbacks+0x1ac/0x1f0
> {softirq-on-W} state was registered at:
>   [<c01528e4>] __lock_acquire+0x3f4/0x5b0
>   [<c0152b29>] lock_acquire+0x89/0xc0
>   [<c076142b>] _spin_lock+0x3b/0x70
>   [<c016d649>] rcu_init_percpu_data+0x29/0x80
>   [<c075e43f>] rcu_cpu_notify+0xaf/0xd0
>   [<c076458d>] notifier_call_chain+0x2d/0x60
>   [<c0145ede>] __raw_notifier_call_chain+0x1e/0x30
>   [<c075db29>] _cpu_up+0x79/0x110
>   [<c075dc0d>] cpu_up+0x4d/0x70
>   [<c0a769e1>] kernel_init+0xb1/0x200
>   [<c01048a3>] kernel_thread_helper+0x7/0x10
>   [<ffffffff>] 0xffffffff
> irq event stamp: 14
> hardirqs last  enabled at (14): [<c01534db>] trace_hardirqs_on+0xb/0x10
> hardirqs last disabled at (13): [<c014dbeb>] trace_hardirqs_off+0xb/0x10
> softirqs last  enabled at (0): [<c012b186>] copy_process+0x276/0x1190
> softirqs last disabled at (11): [<c0105c0a>] call_on_stack+0x1a/0x30
>
> other info that might help us debug this:
> no locks held by ksoftirqd/0/4.
>
> stack backtrace:
> Pid: 4, comm: ksoftirqd/0 Not tainted 2.6.27-rc3-tip #1
>  [<c01504dc>] print_usage_bug+0x16c/0x1b0
>  [<c0152455>] mark_lock+0xa75/0xb10
>  [<c0108b75>] ? sched_clock+0x15/0x30
>  [<c015289d>] __lock_acquire+0x3ad/0x5b0
>  [<c0152b29>] lock_acquire+0x89/0xc0
>  [<c016d91c>] ? __rcu_process_callbacks+0x1ac/0x1f0
>  [<c076142b>] _spin_lock+0x3b/0x70
>  [<c016d91c>] ? __rcu_process_callbacks+0x1ac/0x1f0
>  [<c016d91c>] __rcu_process_callbacks+0x1ac/0x1f0
>  [<c016d986>] rcu_process_callbacks+0x26/0x50
>  [<c0132305>] __do_softirq+0x95/0x120
>  [<c0132270>] ? __do_softirq+0x0/0x120
>  [<c0105c0a>] call_on_stack+0x1a/0x30
>  [<c0132426>] ? ksoftirqd+0x96/0x110
>  [<c0132390>] ? ksoftirqd+0x0/0x110
>  [<c01411f7>] ? kthread+0x47/0x80
>  [<c01411b0>] ? kthread+0x0/0x80
>  [<c01048a3>] ? kernel_thread_helper+0x7/0x10
>  =======================
> calling  init_cpufreq_transition_notifier_list+0x0/0x20
> initcall init_cpufreq_transition_notifier_list+0x0/0x20 returned 0 after 0 msecs
> calling  net_ns_init+0x0/0x190
> net_namespace: 676 bytes
> initcall net_ns_init+0x0/0x190 returned 0 after 0 msecs
> calling  cpufreq_tsc+0x0/0x20
> initcall cpufreq_tsc+0x0/0x20 returned 0 after 0 msecs
> calling  reboot_init+0x0/0x20
> initcall reboot_init+0x0/0x20 returned 0 after 0 msecs
> calling  print_banner+0x0/0x10
> Booting paravirtualized kernel on bare hardware
>
> <-----------------------
>
> my guess is on:
>
>  commit 1f7b94cd3d
>  Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
>  Date:   Tue Aug 5 09:21:44 2008 -0700
>
>     rcu: classic RCU locking and memory-barrier cleanups
>
> 	Ingo

Fixes a problem detected by lockdep in which rcu->lock was acquired
both in irq context and in process context, but without disabling from
process context.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-17 17:38:01 +02:00
..
irq genirq: better warning on irqchip->set_type() failure 2008-08-05 14:33:47 -07:00
power kexec jump: save/restore device state 2008-07-26 12:00:04 -07:00
time cpumask: change cpumask_of_cpu_ptr to use new cpumask_of_cpu 2008-07-26 16:40:33 +02:00
trace Merge branch 'linus' into cpus4096 2008-07-28 23:32:00 +02:00
.gitignore
acct.c bsdacct: fix and add comments around acct_process() 2008-07-25 10:53:47 -07:00
audit_tree.c [PATCH] list_for_each_rcu must die: audit 2008-05-17 03:30:23 -04:00
audit.c [PATCH] Fix the bug of using AUDIT_STATUS_RATE_LIMIT when set fail, no error output. 2008-08-01 12:15:16 -04:00
audit.h [PATCH 1/2] audit: move extern declarations to audit.h 2008-04-28 06:28:04 -04:00
auditfilter.c Re: [PATCH] the loginuid field should be output in all AUDIT_CONFIG_CHANGE audit messages 2008-08-01 12:15:03 -04:00
auditsc.c Re: [PATCH] Fix the kernel panic of audit_filter_task when key field is set 2008-08-04 06:13:50 -04:00
backtracetest.c backtrace: replace timer with tasklet + completions 2008-06-27 18:09:16 +02:00
bounds.c Add kbuild.h that contains common definitions for kbuild users 2008-04-29 08:06:29 -07:00
capability.c security: filesystem capabilities refactor kernel code 2008-07-24 10:47:22 -07:00
cgroup_debug.c CGroup API files: move "releasable" to cgroup_debug subsystem 2008-04-29 08:06:09 -07:00
cgroup.c cgroup: uninline cgroup_has_css_refs() 2008-07-30 09:41:44 -07:00
compat.c ntp: support for TAI 2008-05-01 08:03:59 -07:00
configs.c kernel: use non-racy method for proc entries creation 2008-04-29 08:06:22 -07:00
cpu.c Merge branch 'linus' into cpus4096 2008-07-28 23:32:00 +02:00
cpuset.c cpuset: clean up cpuset hierarchy traversal code 2008-07-30 09:41:44 -07:00
delayacct.c per-task-delay-accounting: update taskstats for memory reclaim delay 2008-07-25 10:53:47 -07:00
dma-coherent.c dma: fix order calculation in dma_mark_declared_memory_occupied() 2008-08-05 14:33:49 -07:00
dma.c kernel: use non-racy method for proc entries creation 2008-04-29 08:06:22 -07:00
exec_domain.c [PATCH] kill altroot 2008-07-26 20:53:20 -04:00
exit.c tracehook: fix exit_signal=0 case 2008-08-01 12:01:11 -07:00
extable.c
fork.c mmu-notifiers: core 2008-07-28 16:30:21 -07:00
futex_compat.c
futex.c futexes: fix fault handling in futex_lock_pi 2008-06-23 13:31:15 +02:00
hrtimer.c Merge branch 'generic-ipi' into generic-ipi-for-linus 2008-07-15 21:55:59 +02:00
itimer.c
kallsyms.c kallsyms: fix potential overflow in binary search 2008-07-25 10:53:27 -07:00
Kconfig.hz sched: fix hrtick & generic-ipi dependency 2008-07-23 11:18:28 +02:00
Kconfig.preempt
kexec.c kexec jump: save/restore device state 2008-07-26 12:00:04 -07:00
kfifo.c
kgdb.c kgdb: fix gdb serial thread queries 2008-08-01 08:39:35 -05:00
kmod.c call_usermodehelper(): increase reliability 2008-07-25 10:53:28 -07:00
kprobes.c kprobes: remove redundant config check 2008-07-25 10:53:30 -07:00
ksysfs.c
kthread.c tracehook: wait_task_inactive 2008-07-26 12:00:09 -07:00
latencytop.c kernel: use non-racy method for proc entries creation 2008-04-29 08:06:22 -07:00
lockdep_internals.h lockdep: add lock_class information to lock_chain and output it 2008-06-24 01:28:20 +02:00
lockdep_proc.c lockdep: add lock_class information to lock_chain and output it 2008-06-24 01:28:20 +02:00
lockdep.c Merge branch 'core/locking' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2008-07-14 14:55:13 -07:00
Makefile Merge branch 'linus' into core/generic-dma-coherent 2008-07-29 00:07:55 +02:00
marker.c markers: fix markers read barrier for multiple probes 2008-07-30 09:41:45 -07:00
module.c stop_machine: Wean existing callers off stop_machine_run() 2008-07-28 12:16:31 +10:00
mutex-debug.c mutex-debug: check mutex magic before owner 2008-05-16 16:53:35 +02:00
mutex-debug.h
mutex.c locking: fix mutex @key parameter kernel-doc notation 2008-07-28 18:12:36 +02:00
mutex.h
notifier.c ipc: re-enable msgmni automatic recomputing msgmni if set to negative 2008-04-29 08:06:13 -07:00
ns_cgroup.c cgroup_clone: use pid of newly created task for new cgroup 2008-07-25 10:53:37 -07:00
nsproxy.c cgroup_clone: use pid of newly created task for new cgroup 2008-07-25 10:53:37 -07:00
panic.c Add a WARN() macro; this is WARN_ON() + printk arguments 2008-07-25 10:53:29 -07:00
params.c
pid_namespace.c bsdacct: switch from global bsd_acct_struct instance to per-pidns one 2008-07-25 10:53:47 -07:00
pid.c pidns: remove now unused find_pid function. 2008-07-25 10:53:45 -07:00
pm_qos_params.c pm_qos: spelling fixes 2008-08-05 14:33:50 -07:00
posix-cpu-timers.c posix-timers: print RT watchdog message 2008-05-24 18:49:22 +02:00
posix-timers.c posix timers: release_posix_timer: kill the bogus put_task_struct(->it_process); 2008-07-25 10:53:38 -07:00
printk.c printk: fix comment for printk ratelimiting 2008-07-30 09:41:45 -07:00
profile.c build kernel/profile.o only when requested 2008-07-25 10:53:27 -07:00
ptrace.c tracehook: wait_task_inactive 2008-07-26 12:00:09 -07:00
rcuclassic.c rcu: fix classic RCU locking cleanup lockdep problem 2008-08-17 17:38:01 +02:00
rcupdate.c Merge branch 'generic-ipi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2008-07-15 14:12:03 -07:00
rcupreempt_trace.c rcu: trace fix possible mem-leak 2008-08-15 17:54:40 +02:00
rcupreempt.c Merge branch 'linus' into cpus4096 2008-07-16 00:29:07 +02:00
rcutorture.c rcu: make rcutorture even more vicious: invoke RCU readers from irq handlers (timers) 2008-06-26 09:24:33 +02:00
relay.c relay: fix "full buffer with exactly full last subbuffer" accounting problem 2008-08-05 14:33:46 -07:00
res_counter.c cgroup files: convert res_counter_write() to be a cgroups write_string() handler 2008-07-25 10:53:36 -07:00
resource.c resource: add resource_size() 2008-07-30 09:41:43 -07:00
rtmutex_common.h
rtmutex-debug.c
rtmutex-debug.h
rtmutex-tester.c sysdev: Pass the attribute to the low level sysdev show/store function 2008-07-21 21:55:02 -07:00
rtmutex.c
rtmutex.h
rwsem.c
sched_clock.c Merge branch 'sched/clock' into sched/devel 2008-07-14 12:19:13 +02:00
sched_cpupri.c sched: use a 2-d bitmap for searching lowest-pri CPU 2008-06-06 15:19:28 +02:00
sched_cpupri.h sched: fix the cpuprio count really 2008-06-06 15:19:44 +02:00
sched_debug.c sched: add full schedstats to /proc/sched_debug 2008-06-27 14:31:31 +02:00
sched_fair.c Merge branch 'sched/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2008-07-23 19:36:53 -07:00
sched_features.h sched: bias effective_load() error towards failing wake_affine(). 2008-06-27 14:31:47 +02:00
sched_idletask.c sched: make rt_sched_class, idle_sched_class static 2008-05-05 23:56:17 +02:00
sched_rt.c Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2008-07-24 12:53:51 -07:00
sched_stats.h sched: fix accounting in task delay accounting & migration 2008-07-04 12:50:23 +02:00
sched.c __sched_setscheduler: don't do any policy checks when not "user" 2008-08-04 17:16:20 -07:00
seccomp.c
semaphore.c semaphore: __down_common: use signal_pending_state() 2008-08-05 14:33:47 -07:00
signal.c tracehook: force signal_pending() 2008-07-26 12:00:09 -07:00
smp.c Full conversion to early_initcall() interface, remove old interface 2008-07-26 12:00:04 -07:00
softirq.c Full conversion to early_initcall() interface, remove old interface 2008-07-26 12:00:04 -07:00
softlockup.c Full conversion to early_initcall() interface, remove old interface 2008-07-26 12:00:04 -07:00
spinlock.c ftrace: lockdep notrace annotations 2008-05-23 20:39:40 +02:00
srcu.c
stacktrace.c stacktrace: fix modular build, export print_stack_trace and save_stack_trace 2008-06-30 09:20:55 +02:00
stop_machine.c stop_machine(): stop_machine_run() changed to use cpu mask 2008-07-28 12:16:30 +10:00
sys_ni.c signalfd: fix undefined reference to `compat_sys_signalfd4' when !CONFIG_SIGNALFD 2008-07-25 11:35:41 -07:00
sys.c kexec jump 2008-07-26 12:00:04 -07:00
sysctl_check.c sysctl: check for bogus modes 2008-07-25 10:53:45 -07:00
sysctl.c lost sysctl fix 2008-07-27 09:45:34 -07:00
taskstats.c taskstats: remove initialization of static per-cpu variable 2008-07-25 10:53:47 -07:00
test_kprobes.c
time.c Make constants in kernel/timeconst.h fixed 64 bits 2008-05-02 16:18:42 -07:00
timeconst.pl Make constants in kernel/timeconst.h fixed 64 bits 2008-05-02 16:18:42 -07:00
timer.c Merge branch 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm 2008-07-14 16:06:58 -07:00
tsacct.c task IO accounting: move all IO statistics in struct task_io_accounting 2008-07-27 16:12:28 -07:00
uid16.c
user_namespace.c eCryptfs: make key module subsystem respect namespaces 2008-04-29 08:06:07 -07:00
user.c alloc_uid: cleanup 2008-04-30 08:29:53 -07:00
utsname_sysctl.c
utsname.c kernel: explicitly include required header files under kernel/ 2008-04-29 08:06:04 -07:00
wait.c
workqueue.c workqueues: add comments to __create_workqueue_key() 2008-07-30 09:41:47 -07:00