Frederic Weisbecker
45a73372ef
hw_breakpoints: Fix per task breakpoint tracking ...
Freeing a perf event can happen in several ways. A task
calls perf_event_exit_task() right before exiting. This helper
will detach all the events from the task context and queue their
removal through free_event() if they are child tasks. The task
also loses its context reference there.
Releasing the breakpoint slot from the constraint table is made
from free_event() that calls release_bp_slot(). We count the number
of breakpoints this task is running by looking at the task's
perf_event_ctxp and iterating through its attached events.
But at this time, the reference to this context has been cleaned up
already.
So looking at the event->ctx instead of task->perf_event_ctxp
to count the remaining breakpoints should solve the problem.
At least it would for child breakpoints, but not for parent ones.
If the parent exits before the child, it will remove all its
events from the context but free_event() will be called later,
on fd release time. And checking the number of breakpoints the
task has attached to its context at this time is unreliable as all
events have been removed from the context.
To solve this, we keep track of the list of per task breakpoints.
On top of it, we maintain our array of numbers of breakpoints used
by the tasks. We use the context address as a task id.
So, instead of looking at the number of events attached to a context,
we walk through our list of per task breakpoints and count the number
of breakpoints that use the same ctx than the one to be reserved or
released from the constraint table, and update the count on top of this
result.
In the meantime it solves a bad refcounting, it also solves a warning,
reported by Paul.
Badness at /home/paulus/kernel/perf/kernel/hw_breakpoint.c:114
NIP: c0000000000cb470 LR: c0000000000cb46c CTR: c00000000032d9b8
REGS: c000000118e7b570 TRAP: 0700 Not tainted (2.6.35-rc3-perf-00008-g76b0f13
)
MSR: 9000000000029032 <EE,ME,CE,IR,DR> CR: 44004424 XER: 000fffff
TASK = c0000001187dcad0[3143] 'perf' THREAD: c000000118e78000 CPU: 1
GPR00: c0000000000cb46c c000000118e7b7f0 c0000000009866a0 0000000000000020
GPR04: 0000000000000000 000000000000001d 0000000000000000 0000000000000001
GPR08: c0000000009bed68 c00000000086dff8 c000000000a5bf10 0000000000000001
GPR12: 0000000024004422 c00000000ffff200 0000000000000000 0000000000000000
GPR16: 0000000000000000 0000000000000000 0000000000000018 00000000101150f4
GPR20: 0000000010206b40 0000000000000000 0000000000000000 00000000101150f4
GPR24: c0000001199090c0 0000000000000001 0000000000000000 0000000000000001
GPR28: 0000000000000000 0000000000000000 c0000000008ec290 0000000000000000
NIP [c0000000000cb470] .task_bp_pinned+0x5c/0x12c
LR [c0000000000cb46c] .task_bp_pinned+0x58/0x12c
Call Trace:
[c000000118e7b7f0] [c0000000000cb46c] .task_bp_pinned+0x58/0x12c (unreliable)
[c000000118e7b8a0] [c0000000000cb584] .toggle_bp_task_slot+0x44/0xe4
[c000000118e7b940] [c0000000000cb6c8] .toggle_bp_slot+0xa4/0x164
[c000000118e7b9f0] [c0000000000cbafc] .release_bp_slot+0x44/0x6c
[c000000118e7ba80] [c0000000000c4178] .bp_perf_event_destroy+0x10/0x24
[c000000118e7bb00] [c0000000000c4aec] .free_event+0x180/0x1bc
[c000000118e7bbc0] [c0000000000c54c4] .perf_event_release_kernel+0x14c/0x170
Reported-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Prasad <prasad@linux.vnet.ibm.com>
Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
2010-06-24 23:33:40 +02:00
module: fix kdb's illicit use of struct module_use.
2010-06-05 11:17:36 +09:30
microblaze: Enable GCOV_PROFILE_ALL
2009-09-21 14:29:21 +02:00
genirq: Clear CPU mask in affinity_hint when none is provided
2010-05-12 11:23:34 +02:00
PM / Hibernate: Fix block_io.c printk warning
2010-05-10 23:08:18 +02:00
Merge branch 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
2010-05-19 17:11:10 -07:00
Merge branch 'perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing into perf/core
2010-06-09 18:55:57 +02:00
Merge branch 'next' into for-linus
2010-05-18 08:57:00 +10:00
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
audit: preface audit printk with audit
2010-04-05 13:19:45 -07:00
kbuild: move bounds.h to include/generated
2009-12-12 13:08:14 +01:00
sched: Remove remaining USER_SCHED code
2010-04-02 20:12:00 +02:00
cgroups: alloc_css_id() increments hierarchy depth
2010-06-04 15:21:45 -07:00
Freezer / cgroup freezer: Update stale locking comments
2010-05-10 23:18:47 +02:00
cpumask: fix compat getaffinity
2010-05-19 11:48:18 -07:00
fix cpu_chain section mismatch...
2010-06-01 09:22:50 -07:00
cpusets: new round-robin rotor for SLAB allocations
2010-05-27 09:12:44 -07:00
umh: creds: kill subprocess_info->cred logic
2010-05-27 09:12:45 -07:00
headers: taskstats_kern.h trim
2009-09-18 09:48:52 -07:00
x86: Do not free zero sized per cpu areas
2010-03-29 18:55:40 +02:00
elf coredump: add extended numbering support
2010-03-06 11:26:46 -08:00
sys_personality: change sys_personality() to accept "unsigned int" instead of u_long
2010-06-04 15:21:45 -07:00
proc: turn signal_struct->count into "int nr_threads"
2010-05-27 09:12:47 -07:00
Revert "cpusets: randomize node rotor used in cpuset_mem_spread_node()"
2010-05-30 09:00:03 -07:00
futex: Handle futex value corruption gracefully
2010-02-03 15:13:22 +01:00
futex: Protect pid lookup in compat code with RCU
2009-12-09 14:22:14 +01:00
security: remove dead hook task_setgroups
2010-04-12 12:19:18 +10:00
hrtimer: Avoid double seqlock
2010-05-26 16:15:37 +02:00
softlockup: Fix hung_task_check_count sysctl
2009-11-27 06:21:57 +01:00
hw_breakpoints: Fix per task breakpoint tracking
2010-06-24 23:33:40 +02:00
itimers: Fix racy writes to cpu_itimer fields
2009-11-18 16:32:12 +01:00
kdb: core for kgdb back end (2 of 2)
2010-05-20 21:04:21 -05:00
mutex: Better control mutex adaptive spinning config
2009-12-03 11:50:11 +01:00
kexec: fix OOPS in crash_kernel_shrink
2010-05-11 17:33:42 -07:00
kfifo: Don't use integer as NULL pointer
2010-02-16 15:11:08 -08:00
call_usermodehelper: UMH_WAIT_EXEC ignores kernel_thread() failure
2010-05-27 09:12:45 -07:00
kprobes: Move enable/disable_kprobe() out from debugfs code
2010-05-08 18:08:30 +02:00
sysfs: add struct file* to bin_attr callbacks
2010-05-21 09:37:31 -07:00
cpuset: fix the problem that cpuset_mem_spread_node() returns an offline node
2010-03-24 16:31:21 -07:00
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
lockdep: Add novalidate class for dev->mutex conversion
2010-05-21 09:37:30 -07:00
lockdep: No need to disable preemption in debug atomic ops
2010-05-04 05:38:16 +02:00
lockstat: Make lockstat counting per cpu
2010-04-06 00:15:37 +02:00
Move kernel/kgdb.c to kernel/debug/debug_core.c
2010-05-20 21:04:18 -05:00
module: fix bne2 "gave up waiting for init of module libcrc32c"
2010-06-05 11:17:37 +09:30
headers: remove sched.h from interrupt.h
2009-10-11 11:20:58 -07:00
locking: Implement new raw_spinlock
2009-12-14 23:55:32 +01:00
mutex: Fix optimistic spinning vs. BKL
2010-05-19 08:18:44 +02:00
sched: Use lockdep-based checking on rcu_dereference()
2010-02-25 10:34:26 +01:00
cgroups: let ss->can_attach and ss->attach do whole threadgroups at a time
2009-09-24 07:20:58 -07:00
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
kernel/: convert cpu notifier to return encapsulate errno value
2010-05-27 09:12:48 -07:00
panic: call console_verbose() in panic
2010-05-27 09:12:53 -07:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
2010-03-12 16:04:50 -08:00
Merge branch 'perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing into perf/core
2010-06-09 18:55:57 +02:00
pids: increase pid_max based on num_possible_cpus
2010-05-27 09:12:51 -07:00
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
PM: PM QOS update fix
2010-05-17 00:21:03 +02:00
posix-cpu-timers: avoid "task->signal != NULL" checks
2010-05-27 09:12:46 -07:00
posix_timer: Fix error path in timer_create
2010-05-27 22:38:15 +02:00
printk,kdb: capture printk() when in kdb shell
2010-05-20 21:04:27 -05:00
numa: in-kernel profiling: use cpu_to_mem() for per cpu allocations
2010-05-27 09:12:57 -07:00
ptrace: PTRACE_GETFDPIC: fix the unsafe usage of child->mm
2010-05-27 09:12:44 -07:00
x86: Change range end to start+size
2010-02-10 17:47:17 -08:00
rcu: slim down rcutiny by removing rcu_scheduler_active and friends
2010-05-10 11:08:34 -07:00
rcu: remove all rcu head initializations, except on_stack initializations
2010-05-11 16:10:47 -07:00
rcu: slim down rcutiny by removing rcu_scheduler_active and friends
2010-05-10 11:08:34 -07:00
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
2010-05-18 08:27:54 -07:00
rcu: remove all rcu head initializations, except on_stack initializations
2010-05-11 16:10:47 -07:00
rcu: reduce the number of spurious RCU_SOFTIRQ invocations
2010-05-10 11:08:35 -07:00
rcu: remove all rcu head initializations, except on_stack initializations
2010-05-11 16:10:47 -07:00
rcu: reduce the number of spurious RCU_SOFTIRQ invocations
2010-05-10 11:08:35 -07:00
kernel/: convert cpu notifier to return encapsulate errno value
2010-05-27 09:12:48 -07:00
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
resource: shared I/O region support
2010-05-11 12:01:10 -07:00
sched: Convert pi_lock to raw_spinlock
2009-12-14 23:55:33 +01:00
rtmutes: Convert rtmutex.lock to raw_spinlock
2009-12-14 23:55:33 +01:00
Merge commit 'v2.6.35-rc3' into perf/core
2010-06-18 10:53:19 +02:00
blkio: fix for modular blk-cgroup build
2010-04-15 08:54:59 +02:00
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
sched: Convert cpupri lock to raw_spinlock
2009-12-14 23:55:33 +01:00
proc_sched_show_task(): use get_nr_threads()
2010-05-27 09:12:47 -07:00
sched: Fix wake_affine() vs RT tasks
2010-06-01 09:27:16 +02:00
sched: Remove ASYM_GRAN feature
2010-03-11 18:32:53 +01:00
sched: Cure load average vs NO_HZ woes
2010-04-23 11:02:02 +02:00
sched: Add enqueue/dequeue flags
2010-04-02 20:12:05 +02:00
exit: change zap_other_threads() to count sub-threads
2010-05-27 09:12:46 -07:00
SLOW_WORK: Move slow_work's proc file to debugfs
2009-12-01 08:20:31 -08:00
slow-work: use get_ref wrapper instead of directly calling get_ref
2010-03-29 09:13:30 -07:00
SLOW_WORK: CONFIG_SLOW_WORK_PROC should be CONFIG_SLOW_WORK_DEBUG
2010-03-29 09:14:47 -07:00
kernel/: convert cpu notifier to return encapsulate errno value
2010-05-27 09:12:48 -07:00
kernel/: fix BUG_ON checks for cpu notifier callbacks direct call
2010-06-04 15:21:45 -07:00
softlockup: Stop spurious softlockup messages due to overflow
2010-03-21 19:30:13 +01:00
locking: Cleanup the name space completely
2009-12-14 23:55:33 +01:00
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
sched: Make sure timers have migrated before killing the migration_thread
2010-05-31 08:37:44 +02:00
kmod: add init function to usermodehelper
2010-05-27 09:12:44 -07:00
Add generic sys_ipc wrapper
2010-03-12 15:52:32 -08:00
pipe: change /proc/sys/fs/pipe-max-pages to byte sized interface
2010-06-03 14:54:39 +02:00
sysctl: don't use own implementation of hex_to_bin()
2010-05-25 08:07:05 -07:00
ipv4 05/05: add sysctl to accept packets with local source addresses
2009-12-03 12:14:38 -08:00
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
timekeeping: Fix timezone update
2010-05-24 11:50:38 +02:00
kernel/: fix BUG_ON checks for cpu notifier callbacks direct call
2010-06-04 15:21:45 -07:00
tracing: Let tracepoints have data passed to tracepoint callbacks
2010-05-14 09:50:34 -04:00
mm: clean up mm_counter
2010-03-06 11:26:23 -08:00
headers: utsname.h redux
2009-09-23 18:13:10 -07:00
core: Clean up user return notifers use of per_cpu
2009-12-02 10:22:59 +01:00
sched: Remove a stale comment
2010-05-10 08:48:39 +02:00
kref: remove kref_set
2010-05-21 09:37:29 -07:00
sysctl kernel: Remove binary sysctl logic
2009-11-12 02:04:55 -08:00
kernel/: convert cpu notifier to return encapsulate errno value
2010-05-27 09:12:48 -07:00
45a73372ef