Paul Mackerras ad3a37de81 perf_counter: Don't swap contexts containing locked mutex ... Peter Zijlstra pointed out that under some circumstances, we can take the mutex in a context or a counter and then swap that context or counter to another task, potentially leading to lock order inversions or the mutexes not protecting what they are supposed to protect. This fixes the problem by making sure that we never take a mutex in a context or counter which could get swapped to another task. Most of the cases where we take a mutex is on a top-level counter or context, i.e. a counter which has an fd associated with it or a context that contains such a counter. This adds WARN_ON_ONCE statements to verify that. The two cases where we need to take the mutex on a context that is a clone of another are in perf_counter_exit_task and perf_counter_init_task. The perf_counter_exit_task case is solved by uncloning the context before starting to remove the counters from it. The perf_counter_init_task is a little trickier; we temporarily disable context swapping for the parent (forking) task by setting its ctx->parent_gen to the all-1s value after locking the context, if it is a cloned context, and restore the ctx->parent_gen value at the end if the context didn't get uncloned in the meantime. This also moves the increment of the context generation count to be within the same critical section, protected by the context mutex, that adds the new counter to the context. That way, taking the mutex is sufficient to ensure that both the counter list and the generation count are stable. [ Impact: fix hangs, races with inherited and PID counters ] Signed-off-by: Paul Mackerras <paulus@samba.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <18975.31580.520676.619896@drongo.ozlabs.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>		2009-05-29 11:02:46 +02:00
..
irq	Revert "genirq: assert that irq handlers are indeed running in hardirq context"	2009-05-01 15:16:04 +02:00
power	PM/Hibernate: Fix waiting for image device to appear on resume	2009-04-24 15:31:30 -07:00
time	clockevents: prevent endless loop in tick_handle_periodic()	2009-05-02 10:22:27 +02:00
trace	tracing: fix ref count in splice pages	2009-04-29 08:02:44 +02:00
.gitignore
acct.c	[CVE-2009-0029] System call wrappers part 04	2009-01-14 14:15:19 +01:00
async.c	async: remove the temporary (2.6.29) "async is off by default" code	2009-03-28 13:05:30 -07:00
audit.c	Audit: remove spaces from audit_log_d_path	2009-04-05 13:49:04 -04:00
audit.h	fixing audit rule ordering mess, part 1	2009-01-04 15:14:41 -05:00
audit_tree.c	No need for crossing to mountpoint in audit_tag_tree()	2009-04-20 23:01:15 -04:00
auditfilter.c	inotify: use GFP_NOFS in kernel_event() to work around a lockdep false-positive	2009-05-06 16:36:09 -07:00
auditsc.c	Audit: remove spaces from audit_log_d_path	2009-04-05 13:49:04 -04:00
backtracetest.c
bounds.c
capability.c	[CVE-2009-0029] System call wrappers part 04	2009-01-14 14:15:19 +01:00
cgroup.c	Convert obvious places to deactivate_locked_super()	2009-05-09 10:49:40 -04:00
cgroup_debug.c	debug cgroup: remove unneeded cgroup_lock	2009-04-02 19:04:54 -07:00
cgroup_freezer.c
compat.c	signals: implement sys_rt_tgsigqueueinfo	2009-04-30 19:24:24 +02:00
configs.c
cpu.c	cpumask: use set_cpu_active in init/main.c	2009-03-30 22:05:12 +10:30
cpuset.c	cpusets: prevent PF_THREAD_BOUND tasks from attaching to non-root cpusets	2009-04-02 19:04:57 -07:00
cred-internals.h
cred.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6	2009-01-09 13:59:25 -08:00
delayacct.c
dma-coherent.c	dma-coherent: Restore dma_alloc_from_coherent() large alloc fall back policy.	2009-01-21 18:51:53 +09:00
dma.c
exec_domain.c	Get rid of indirect include of fs_struct.h	2009-03-31 23:00:27 -04:00
exit.c	perf_counter: Dynamically allocate tasks' perf_counter_context struct	2009-05-22 12:18:19 +02:00
extable.c	Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-04-05 11:04:19 -07:00
fork.c	perf_counter: Propagate inheritance failures down the fork() path	2009-05-25 14:55:01 +02:00
freezer.c
futex.c	futex: comment requeue key reference semantics	2009-04-02 23:39:53 +02:00
futex_compat.c
hrtimer.c	hrtimer: fix rq->lock inversion (again)	2009-03-31 14:52:52 +02:00
hung_task.c	softlockup: ensure the task has been switched out once	2009-02-11 11:04:16 +01:00
itimer.c	timers: split process wide cpu clocks/timers	2009-02-05 13:04:33 +01:00
kallsyms.c	Ksplice: Add functions for walking kallsyms symbols	2009-03-31 13:05:32 +10:30
Kconfig.freezer
Kconfig.hz
Kconfig.preempt
kexec.c	kexec: vmcoreinfo_data[] can become static	2009-04-02 19:05:04 -07:00
kfifo.c
kgdb.c	sysrq, intel_fb: fix sysrq g collision	2009-05-15 07:56:24 -05:00
kmod.c	module: create a request_module_nowait()	2009-03-31 13:05:35 +10:30
kprobes.c	kprobes: fix to use text_mutex around arm/disarm kprobe	2009-05-08 16:23:48 -07:00
ksysfs.c	kernel/ksysfs.c:fix dependence on CONFIG_NET	2009-01-06 10:44:31 -08:00
kthread.c	kthread: move sched-realeted initialization from kthreadd context	2009-04-09 09:50:37 +09:30
latencytop.c	sched, latencytop: incorporate review feedback from Andrew Morton	2009-02-11 10:18:04 +01:00
lockdep.c	lockdep: more robust lockdep_map init sequence	2009-04-17 18:00:00 +02:00
lockdep_internals.h	lockdep: get_user_chars() redo	2009-02-14 23:28:22 +01:00
lockdep_proc.c	lockstat: warn about disabled lock debugging	2009-02-14 23:28:28 +01:00
lockdep_states.h	lockdep: move state bit definitions around	2009-02-14 23:27:59 +01:00
Makefile	Merge commit 'v2.6.30-rc1' into perfcounters/core	2009-04-08 10:35:30 +02:00
marker.c
module.c	async: Fix module loading async-work regression	2009-04-11 12:44:49 -07:00
mutex-debug.c	mutex: implement adaptive spinning	2009-01-14 18:09:02 +01:00
mutex-debug.h	mutex: implement adaptive spinning	2009-01-14 18:09:02 +01:00
mutex.c	Merge branch 'core/locking' into perfcounters/core	2009-05-06 08:47:26 +02:00
mutex.h	mutex: implement adaptive spinning	2009-01-14 18:09:02 +01:00
notifier.c
ns_cgroup.c	cgroups: relax ns_can_attach checks to allow attaching to grandchild cgroups	2009-04-02 19:04:53 -07:00
nsproxy.c
panic.c	Eliminate thousands of warnings with gcc 3.2 build	2009-05-06 16:36:09 -07:00
params.c	param: fix charp parameters set via sysfs	2009-03-31 13:05:30 +10:30
perf_counter.c	perf_counter: Don't swap contexts containing locked mutex	2009-05-29 11:02:46 +02:00
pid.c	pids: refactor vnr/nr_ns helpers to make them safe	2009-04-02 19:05:02 -07:00
pid_namespace.c	signals: zap_pid_ns_process() should use force_sig()	2009-04-02 19:04:58 -07:00
pm_qos_params.c
posix-cpu-timers.c	kernel/posix-cpu-timers.c: fix sparse warning	2009-04-30 08:08:31 +02:00
posix-timers.c	[CVE-2009-0029] System call wrappers part 05	2009-01-14 14:15:20 +01:00
printk.c	Merge branch 'printk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-04-05 10:23:25 -07:00
profile.c	profiling: fix broken profiling regression	2009-02-10 00:50:37 +01:00
ptrace.c	ptrace: ptrace_attach: fix the usage of ->cred_exec_mutex	2009-04-27 20:30:51 +10:00
rcuclassic.c	kmemtrace, rcu: fix linux/rcutree.h and linux/rcuclassic.h dependencies	2009-04-03 12:23:02 +02:00
rcupdate.c	RCU: Don't try and predeclare inline funcs as it upsets some versions of gcc	2009-04-15 13:55:14 -07:00
rcupreempt.c	kmemtrace, rcu: fix rcupreempt.c data structure dependencies	2009-04-03 12:23:04 +02:00
rcupreempt_trace.c
rcutorture.c	cpumask: convert rcutorture.c	2009-03-30 22:05:16 +10:30
rcutree.c	rcu: Make hierarchical RCU less IPI-happy	2009-04-14 11:31:50 +02:00
rcutree.h	kmemtrace, rcu: fix rcu_tree_trace.c data structure dependencies	2009-04-03 12:23:03 +02:00
rcutree_trace.c	rcu: Make hierarchical RCU less IPI-happy	2009-04-14 11:31:50 +02:00
relay.c	Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-04-05 11:04:19 -07:00
res_counter.c	memcg: memory cgroup resource counters for hierarchy	2009-01-08 08:31:05 -08:00
resource.c	Remove 'recurse into child resources' logic from 'reserve_region_with_split()'	2009-04-18 21:44:24 -07:00
rtmutex-debug.c
rtmutex-debug.h
rtmutex-tester.c
rtmutex.c	locking, rtmutex.c: Documentation cleanup	2009-04-29 23:20:17 +02:00
rtmutex.h
rtmutex_common.h
rwsem.c
sched.c	perf_counter: Fix dynamic irq_period logging	2009-05-23 19:37:44 +02:00
sched_clock.c	Merge branch 'tracing/core-v2' into tracing-for-linus	2009-04-02 00:49:02 +02:00
sched_cpupri.c	sched_rt: don't allocate cpumask in fastpath	2009-04-01 13:24:51 +02:00
sched_cpupri.h	cpumask: remove cpumask_t from core	2009-03-30 22:05:17 +10:30
sched_debug.c	sched: remove unused fields from struct rq	2009-03-24 23:16:51 +01:00
sched_fair.c	Merge branch 'sched/urgent'; commit 'v2.6.29-rc5' into sched/core	2009-02-15 21:15:16 +01:00
sched_features.h	Merge branch 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-03-30 17:17:35 -07:00
sched_idletask.c
sched_rt.c	Merge commit 'v2.6.30-rc1' into sched/urgent	2009-04-08 17:26:00 +02:00
sched_stats.h	sched: remove unused fields from struct rq	2009-03-24 23:16:51 +01:00
seccomp.c	x86-64: seccomp: fix 32/64 syscall hole	2009-03-02 15:41:30 -08:00
semaphore.c
signal.c	signals: implement sys_rt_tgsigqueueinfo	2009-04-30 19:24:24 +02:00
slow-work.c	Delete slow-work timers properly	2009-04-24 07:47:59 -07:00
smp.c	generic-ipi: eliminate WARN_ON()s during oops/panic	2009-03-13 10:47:34 +01:00
softirq.c	kernel/softirq.c: fix sparse warning	2009-04-17 01:57:54 +02:00
softlockup.c	softlockup: decouple hung tasks check from softlockup detection	2009-01-16 14:06:04 +01:00
spinlock.c	Allow rwlocks to re-enable interrupts	2009-04-02 19:05:11 -07:00
srcu.c
stacktrace.c
stop_machine.c	cpumask: remove cpumask_t from core	2009-03-30 22:05:17 +10:30
sys.c	Merge branch 'linus' into perfcounters/core	2009-04-29 14:47:05 +02:00
sys_ni.c	Merge commit 'v2.6.29-rc2' into perfcounters/core	2009-01-21 16:37:27 +01:00
sysctl.c	perf_counter: Generic per counter interrupt throttle	2009-05-25 21:41:12 +02:00
sysctl_check.c	net: add ARP notify option for devices	2009-02-01 01:04:33 -08:00
taskstats.c	cpumask: convert rest of files in kernel/	2009-01-01 10:12:28 +10:30
test_kprobes.c	kprobes: add tests for register_kprobes	2009-01-06 15:59:20 -08:00
time.c	[CVE-2009-0029] System call wrappers part 01	2009-01-14 14:15:18 +01:00
timeconst.pl
timer.c	Merge branch 'linus' into perfcounters/core	2009-04-29 14:47:05 +02:00
tracepoint.c	tracepoints: dont update zero-sized tracepoint sections	2009-03-18 19:55:00 +01:00
tsacct.c	Fix fixpoint divide exception in acct_update_integrals	2009-03-09 08:13:35 -07:00
uid16.c	[CVE-2009-0029] System call wrappers part 19	2009-01-14 14:15:26 +01:00
up.c	smp_call_function_single(): be slightly less stupid, fix #2	2009-01-12 16:04:37 +01:00
user.c	Merge branch 'master' into next	2009-03-24 10:52:46 +11:00
user_namespace.c	Fix recursive lock in free_uid()/free_user_ns()	2009-02-27 16:26:21 -08:00
utsname.c
utsname_sysctl.c	proc_sysctl: use CONFIG_PROC_SYSCTL around ipc and utsname proc_handlers	2009-04-02 19:05:01 -07:00
wait.c	wait: prevent exclusive waiter starvation	2009-02-05 12:56:48 -08:00
workqueue.c	work_on_cpu(): rewrite it to create a kernel thread on demand	2009-04-09 09:50:37 +09:30