Peter Zijlstra
a69b0ca4ac
perf: Fix cloning
...
Alexander reported that when the 'original' context gets destroyed, no
new clones happen.
This can happen irrespective of the ctx switch optimization, any task
can die, even the parent, and we want to continue monitoring the task
hierarchy until we either close the event or no tasks are left in the
hierarchy.
perf_event_init_context() will attempt to pin the 'parent' context
during clone(). At that point current is the parent, and since current
cannot have exited while executing clone(), its context cannot have
passed through perf_event_exit_task_context(). Therefore
perf_pin_task_context() cannot observe ctx->task == TASK_TOMBSTONE.
However, since inherit_event() does:
if (parent_event->parent)
parent_event = parent_event->parent;
it looks at the 'original' event when it does: is_orphaned_event().
This can return true if the context that contains the this event has
passed through perf_event_exit_task_context(). And thus we'll fail to
clone the perf context.
Fix this by adding a new state: STATE_DEAD, which is set by
perf_release() to indicate that the filedesc (or kernel reference) is
dead and there are no observers for our data left.
Only for STATE_DEAD will is_orphaned_event() be true and inhibit
cloning.
STATE_EXIT is otherwise preserved such that is_event_hup() remains
functional and will report when the observed task hierarchy becomes
empty.
Reported-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Tested-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dvyukov@google.com
Cc: eranian@google.com
Cc: oleg@redhat.com
Cc: panand@redhat.com
Cc: sasha.levin@oracle.com
Cc: vince@deater.net
Fixes: c6e5b73242 ("perf: Synchronously clean up child events")
Link: http://lkml.kernel.org/r/20160224174947.919845295@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-02-25 08:42:33 +01:00
..
bpf
bpf: fix branch offset adjustment on backjumps after patching ctx expansion
2016-02-10 16:56:47 -05:00
configs
debug
module: use a structure to encapsulate layout.
2015-12-04 22:46:25 +01:00
events
perf: Fix cloning
2016-02-25 08:42:33 +01:00
gcov
gcov: use within_module() helper.
2015-12-04 22:46:25 +01:00
irq
Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2016-01-31 14:48:58 -08:00
livepatch
livepatch: Cleanup module page permission changes
2015-12-04 22:51:07 +01:00
locking
Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2016-02-14 12:02:05 -08:00
power
PM: APM_EMULATION does not depend on PM
2016-01-27 23:20:14 +01:00
printk
kernel: printk: specify alignment for struct printk_log
2016-01-20 17:09:18 -08:00
rcu
Merge branches 'doc.2015.12.05a', 'exp.2015.12.07a', 'fixes.2015.12.07a', 'list.2015.12.04b' and 'torture.2015.12.05a' into HEAD
2015-12-07 17:02:54 -08:00
sched
Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2016-01-31 15:44:04 -08:00
time
Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2016-01-31 15:49:06 -08:00
trace
Two more small fixes.
2016-02-22 14:09:18 -08:00
.gitignore
certs: add .gitignore to stop git nagging about x509_certificate_list
2015-10-21 15:18:35 +01:00
acct.c
async.c
async: export current_is_async()
2015-11-19 17:51:48 +01:00
audit.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
2016-01-17 19:13:15 -08:00
audit.h
security: Make inode argument of inode_getsecid non-const
2015-12-24 11:09:39 -05:00
audit_fsnotify.c
wrappers for ->i_mutex access
2016-01-22 18:04:28 -05:00
audit_tree.c
audit: audit_tree_match can be boolean
2015-11-04 08:23:51 -05:00
audit_watch.c
wrappers for ->i_mutex access
2016-01-22 18:04:28 -05:00
auditfilter.c
audit: fix comment block whitespace
2015-11-04 08:23:51 -05:00
auditsc.c
security: Make inode argument of inode_getsecid non-const
2015-12-24 11:09:39 -05:00
backtracetest.c
bounds.c
capability.c
cgroup.c
cgroup: make sure a parent css isn't freed before its children
2016-01-22 10:42:58 -05:00
cgroup_freezer.c
cgroup: kill cgrp_ss_priv[CGROUP_CANFORK_COUNT] and friends
2015-12-03 10:24:08 -05:00
cgroup_pids.c
cgroup_pids: fix a typo.
2015-12-14 14:54:37 -05:00
compat.c
configs.c
context_tracking.c
context_tracking: Switch to new static_branch API
2015-11-24 09:56:43 +01:00
cpu.c
kernel/cpu.c: make set_cpu_* static inlines
2016-01-20 17:09:18 -08:00
cpu_pm.c
kernel/cpu_pm: fix cpu_cluster_pm_exit comment
2015-09-03 02:42:20 +02:00
cpuset.c
cpuset: make mm migration asynchronous
2016-01-22 10:22:46 -05:00
crash_dump.c
cred.c
kmemcg: account certain kmem allocations to memcg
2016-01-14 16:00:49 -08:00
delayacct.c
kmemcg: account certain kmem allocations to memcg
2016-01-14 16:00:49 -08:00
dma.c
elfcore.c
exec_domain.c
exit.c
exit: remove unneeded declaration of exit_mm()
2016-01-20 17:09:18 -08:00
extable.c
kernel/extable.c: remove duplicated include
2015-09-10 13:29:01 -07:00
fork.c
mm: rework virtual memory accounting
2016-01-14 16:00:49 -08:00
freezer.c
futex.c
rtmutex: Make wait_lock irq safe
2016-01-26 11:08:35 +01:00
futex_compat.c
ptrace: use fsuid, fsgid, effective creds for fs access checks
2016-01-20 17:09:18 -08:00
groups.c
hung_task.c
irq_work.c
treewide: Remove old email address
2015-11-23 09:44:58 +01:00
jump_label.c
treewide: Remove old email address
2015-11-23 09:44:58 +01:00
kallsyms.c
kcmp.c
ptrace: use fsuid, fsgid, effective creds for fs access checks
2016-01-20 17:09:18 -08:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kexec.c
kexec: set KEXEC_TYPE_CRASH before sanity_check_segment_list()
2016-01-20 17:09:18 -08:00
kexec_core.c
kernel/kexec_core.c: use list_for_each_entry_safe in kimage_free_page_list
2016-01-20 17:09:18 -08:00
kexec_file.c
kexec: move some memembers and definitions within the scope of CONFIG_KEXEC_FILE
2016-01-20 17:09:18 -08:00
kexec_internal.h
kexec: move some memembers and definitions within the scope of CONFIG_KEXEC_FILE
2016-01-20 17:09:18 -08:00
kmod.c
kmod: don't run async usermode helper as a child of kworker thread
2015-10-23 17:55:10 +09:00
kprobes.c
ksysfs.c
rcu: Remove TINY_RCU bloat from pointless boot parameters
2015-12-07 16:59:37 -08:00
kthread.c
kernel/kthread.c:kthread_create_on_node(): clarify documentation
2015-09-04 16:54:41 -07:00
latencytop.c
Makefile
sys_membarrier(): system-wide memory barrier (generic, x86)
2015-09-11 15:21:34 -07:00
membarrier.c
sys_membarrier(): system-wide memory barrier (generic, x86)
2015-09-11 15:21:34 -07:00
memremap.c
devm_memremap_release(): fix memremap'd addr handling
2016-02-18 16:23:24 -08:00
module-internal.h
module.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching
2016-02-18 16:34:15 -08:00
module_signing.c
KEYS: Merge the type-specific data with the payload data
2015-10-21 15:18:36 +01:00
notifier.c
Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2015-09-01 08:40:25 -07:00
nsproxy.c
padata.c
panic.c
printk: do cond_resched() between lines while outputting to consoles
2016-01-16 11:17:25 -08:00
params.c
Nothing exciting, minor tweaks and cleanups.
2015-11-09 15:53:39 -08:00
pid.c
Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2016-01-31 15:44:04 -08:00
pid_namespace.c
profile.c
mm: rename alloc_pages_exact_node() to __alloc_pages_node()
2015-09-08 15:35:28 -07:00
ptrace.c
ptrace: use fsuid, fsgid, effective creds for fs access checks
2016-01-20 17:09:18 -08:00
range.c
reboot.c
kexec: split kexec_load syscall from kexec core code
2015-09-10 13:29:01 -07:00
relay.c
wrappers for ->i_mutex access
2016-01-22 18:04:28 -05:00
resource.c
kernel/resource.c: fix muxed resource handling in __request_region()
2016-02-20 08:57:52 -08:00
seccomp.c
seccomp: always propagate NO_NEW_PRIVS on tsync
2016-01-27 07:38:25 -08:00
signal.c
signals: avoid random wakeups in sigsuspend()
2016-02-05 18:10:40 -08:00
smp.c
mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd
2015-11-06 17:50:42 -08:00
smpboot.c
stop_machine: Kill smp_hotplug_thread->pre_unpark, introduce stop_machine_unpark()
2015-10-20 10:23:55 +02:00
smpboot.h
softirq.c
stacktrace.c
stop_machine.c
kernel/stop_machine.c: remove CONFIG_SMP dependencies
2016-01-16 11:17:24 -08:00
sys.c
prctl: take mmap sem for writing to protect against others
2016-01-20 17:09:18 -08:00
sys_ni.c
vfs: add copy_file_range syscall and vfs helper
2015-12-01 14:00:53 -05:00
sysctl.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
2016-01-22 10:24:03 -08:00
sysctl_binary.c
task_work.c
task_work: remove fifo ordering guarantee
2015-09-05 13:46:58 -07:00
taskstats.c
test_kprobes.c
torture.c
torture: Consolidate cond_resched_rcu_qs() into stutter_wait()
2015-10-06 11:25:01 -07:00
tracepoint.c
tracepoint: Give priority to probes of tracepoints
2015-10-25 21:33:54 -04:00
tsacct.c
uid16.c
up.c
user-return-notifier.c
user.c
user_namespace.c
kernel/*: switch to memdup_user_nul()
2016-01-04 10:27:55 -05:00
utsname.c
utsname_sysctl.c
watchdog.c
Merge branch 'for-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
2016-01-11 18:53:13 -08:00
workqueue.c
workqueue: handle NUMA_NO_NODE for unbound pool_workqueue lookup
2016-02-10 12:13:05 -05:00
workqueue_internal.h