Steven Rostedt 03889384ce tracing: Add trace_dump_stack() ... I've been asked a few times about how to find out what is calling some location in the kernel. One way is to use dynamic function tracing and implement the func_stack_trace. But this only finds out who is calling a particular function. It does not tell you who is calling that function and entering a specific if conditional. I have myself implemented a quick version of trace_dump_stack() for this purpose a few times, and just needed it now. This is when I realized that this would be a good tool to have in the kernel like trace_printk(). Using trace_dump_stack() is similar to dump_stack() except that it writes to the trace buffer instead and can be used in critical locations. For example: @@ -5485,8 +5485,12 @@ need_resched_nonpreemptible: if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { if (unlikely(signal_pending_state(prev->state, prev))) prev->state = TASK_RUNNING; - else + else { deactivate_task(rq, prev, 1); + trace_printk("Deactivating task %s:%d\n", + prev->comm, prev->pid); + trace_dump_stack(); + } switch_count = &prev->nvcsw; } Produces: <...>-3249 [001] 296.105269: schedule: Deactivating task ntpd:3249 <...>-3249 [001] 296.105270: <stack trace> => schedule => schedule_hrtimeout_range => poll_schedule_timeout => do_select => core_sys_select => sys_select => system_call_fastpath Signed-off-by: Steven Rostedt <rostedt@goodmis.org>		2009-12-11 10:38:47 -05:00
..
gcov	microblaze: Enable GCOV_PROFILE_ALL	2009-09-21 14:29:21 +02:00
irq	Merge branches 'timers-for-linus-ntp' and 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-12-08 19:30:19 -08:00
power	PM / Runtime: Export the PM runtime workqueue	2009-12-06 16:17:56 +01:00
time	Merge branch 'timers-for-linus-urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-12-08 19:28:09 -08:00
trace	tracing: Add trace_dump_stack()	2009-12-11 10:38:47 -05:00
.gitignore
acct.c	bsdacct: switch credentials for writing to the accounting file	2009-08-24 11:33:40 +10:00
async.c	async: Fix lack of boot-time console due to insufficient synchronization	2009-06-08 12:31:53 -07:00
audit_tree.c	Fix rule eviction order for AUDIT_DIR	2009-06-24 00:02:38 -04:00
audit_watch.c	Audit: reorganize struct audit_watch to save 8 bytes	2009-09-24 03:50:25 -04:00
audit.c	Audit: send signal info if selinux is disabled	2009-09-24 03:50:26 -04:00
audit.h	Fix rule eviction order for AUDIT_DIR	2009-06-24 00:02:38 -04:00
auditfilter.c	Audit: clean up all op= output to include string quoting	2009-06-24 00:00:52 -04:00
auditsc.c	Audit: rearrange audit_context to save 16 bytes per struct	2009-09-24 03:50:26 -04:00
backtracetest.c
bounds.c
capability.c	remove CONFIG_SECURITY_FILE_CAPABILITIES compile option	2009-11-24 15:06:47 +11:00
cgroup_freezer.c	cgroups: let ss->can_attach and ss->attach do whole threadgroups at a time	2009-09-24 07:20:58 -07:00
cgroup.c	cgroup: fix strstrip() misuse	2009-10-29 07:39:25 -07:00
compat.c	signals: implement sys_rt_tgsigqueueinfo	2009-04-30 19:24:24 +02:00
configs.c
cpu.c	timers, init: Limit the number of per cpu calibration bootup messages	2009-11-26 10:18:42 +01:00
cpuset.c	cpumask: Partition_sched_domains takes array of cpumask_var_t	2009-11-04 13:16:40 +01:00
cred-internals.h
cred.c	creds_are_invalid() needs to be exported for use by modules:	2009-09-23 11:02:26 -07:00
delayacct.c	headers: taskstats_kern.h trim	2009-09-18 09:48:52 -07:00
dma.c
exec_domain.c	Get rid of indirect include of fs_struct.h	2009-03-31 23:00:27 -04:00
exit.c	Merge branch 'for-2.6.33' of git://git.kernel.dk/linux-2.6-block	2009-12-08 08:19:16 -08:00
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	Merge branch 'for-2.6.33' of git://git.kernel.dk/linux-2.6-block	2009-12-08 08:19:16 -08:00
freezer.c	sched: fix nr_uninterruptible accounting of frozen tasks really	2009-07-18 14:19:53 +02:00
futex_compat.c	futex: Fix compat_futex to be same as futex for REQUEUE_PI	2009-08-10 15:41:12 +02:00
futex.c	futex: Fix spurious wakeup for requeue_pi really	2009-10-28 20:34:34 +01:00
groups.c	groups: move code to kernel/groups.c	2009-06-16 19:47:48 -07:00
hrtimer.c	Merge branch 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-12-08 19:27:08 -08:00
hung_task.c	softlockup: Fix hung_task_check_count sysctl	2009-11-27 06:21:57 +01:00
hw_breakpoint.c	hw-breakpoints: Use struct perf_event_attr to define kernel breakpoints	2009-11-27 06:22:59 +01:00
itimer.c	itimers: Fix racy writes to cpu_itimer fields	2009-11-18 16:32:12 +01:00
kallsyms.c	hw-breakpoints: Fix broken hw-breakpoint sample module	2009-11-10 11:23:29 +01:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks	mutex: Better control mutex adaptive spinning config	2009-12-03 11:50:11 +01:00
Kconfig.preempt
kexec.c	kexec: fix omitting offset in extended crashkernel syntax	2009-07-29 19:10:34 -07:00
kfifo.c	kfifo: Use "const" definitions	2009-09-19 13:13:17 -07:00
kgdb.c	sched: Remove unused __schedule() declaration	2009-11-04 11:43:42 +01:00
kmod.c	security: report the module name to security_module_request	2009-11-10 09:33:46 +11:00
kprobes.c	Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-12-05 15:30:21 -08:00
ksysfs.c
kthread.c	sched: Fix kthread_bind() by moving the body of kthread_bind() to sched.c	2009-11-03 07:25:00 +01:00
latencytop.c
lockdep_internals.h	lockdep: BFS cleanup	2009-07-24 10:53:29 +02:00
lockdep_proc.c	seq_file: constify seq_operations	2009-09-23 07:39:29 -07:00
lockdep_states.h
lockdep.c	tracing: Rename 'lockdep' event subsystem into 'lock'	2009-11-13 10:48:27 +01:00
Makefile	Merge branch 'kvm-updates/2.6.33' of git://git.kernel.org/pub/scm/virt/kvm/kvm	2009-12-08 08:02:38 -08:00
module.c	modules: don't export section names of empty sections via sysfs	2009-12-02 15:38:25 -08:00
mutex-debug.c	headers: remove sched.h from interrupt.h	2009-10-11 11:20:58 -07:00
mutex-debug.h
mutex.c	mutex: Better control mutex adaptive spinning config	2009-12-03 11:50:11 +01:00
mutex.h
notifier.c	kprobes: Fix to add __kprobes to notify_die	2009-08-30 03:08:26 +02:00
ns_cgroup.c	cgroups: let ss->can_attach and ss->attach do whole threadgroups at a time	2009-09-24 07:20:58 -07:00
nsproxy.c	nsproxy: extract create_nsproxy()	2009-06-18 13:03:56 -07:00
panic.c	Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-10-08 12:16:35 -07:00
params.c	param: fix setting arrays of bool	2009-10-29 08:56:20 +10:30
perf_event.c	perf: Don't free perf_mmap_data until work has been done	2009-12-02 09:30:18 +01:00
pid_namespace.c	pidns: deny CLONE_PARENT|CLONE_NEWPID combination	2009-09-24 07:21:04 -07:00
pid.c	mm: also use alloc_large_system_hash() for the PID hash table	2009-09-22 07:17:38 -07:00
pm_qos_params.c
posix-cpu-timers.c	posix-cpu-timers: optimize and document timer_create callback	2009-11-18 12:36:05 +01:00
posix-timers.c	time: Introduce CLOCK_REALTIME_COARSE	2009-08-21 21:43:46 +02:00
printk.c	Merge branch 'core-printk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-12-05 09:50:22 -08:00
profile.c	kernel/profile.c: Switch /proc/irq/prof_cpu_mask to seq_file	2009-09-20 20:15:40 +02:00
ptrace.c	ptrace: __ptrace_detach: do __wake_up_parent() if we reap the tracee	2009-09-24 07:20:59 -07:00
rcupdate.c	rcu: Re-arrange code to reduce #ifdef pain	2009-11-22 18:58:16 +01:00
rcutiny.c	rcu: Eliminate unneeded function wrapping	2009-11-22 18:58:16 +01:00
rcutorture.c	rcu: Add expedited grace-period support for preemptible RCU	2009-12-03 11:35:25 +01:00
rcutree_plugin.h	rcu: Add expedited grace-period support for preemptible RCU	2009-12-03 11:35:25 +01:00
rcutree_trace.c	rcu: Add expedited grace-period support for preemptible RCU	2009-12-03 11:35:25 +01:00
rcutree.c	rcu: Add expedited grace-period support for preemptible RCU	2009-12-03 11:35:25 +01:00
rcutree.h	rcu: Add expedited grace-period support for preemptible RCU	2009-12-03 11:35:25 +01:00
relay.c	const: mark struct vm_struct_operations	2009-09-27 11:39:25 -07:00
res_counter.c	memcg: some modification to softlimit under hierarchical memory reclaim.	2009-10-01 16:11:13 -07:00
resource.c	walk system ram range	2009-09-23 07:39:41 -07:00
rtmutex_common.h	rt_mutex: add proxy lock routines	2009-04-06 11:14:02 +02:00
rtmutex-debug.c
rtmutex-debug.h
rtmutex-tester.c
rtmutex.c	rtmutex: Avoid deadlock in rt_mutex_start_proxy_lock()	2009-08-06 05:50:21 +02:00
rtmutex.h
rwsem.c
sched_clock.c	sched_clock: Fix atomicity/continuity bug by using cmpxchg64()	2009-09-30 22:56:10 +02:00
sched_cpupri.c	sched: Add new prio to cpupri before removing old prio	2009-08-02 14:26:09 +02:00
sched_cpupri.h	cpumask: remove cpumask_t from core	2009-03-30 22:05:17 +10:30
sched_debug.c	sched: Rate-limit newidle	2009-11-04 19:13:48 +01:00
sched_fair.c	Merge branch 'sched/urgent' into sched/core	2009-11-26 10:50:42 +01:00
sched_features.h	sched: Add new wakeup preemption mode: WAKEUP_RUNNING	2009-09-17 10:17:25 +02:00
sched_idletask.c	sched: Simplify sys_sched_rr_get_interval() system call	2009-09-21 09:53:55 +02:00
sched_rt.c	cpumask: Simplify sched_rt.c	2009-11-04 13:16:38 +01:00
sched_stats.h	sched: remove unused fields from struct rq	2009-03-24 23:16:51 +01:00
sched.c	Merge git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/sysctl-2.6	2009-12-08 07:38:50 -08:00
seccomp.c
semaphore.c
signal.c	Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-12-05 15:30:21 -08:00
slow-work-debugfs.c	SLOW_WORK: Move slow_work's proc file to debugfs	2009-12-01 08:20:31 -08:00
slow-work.c	Merge git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/sysctl-2.6	2009-12-08 07:38:50 -08:00
slow-work.h	SLOW_WORK: Move slow_work's proc file to debugfs	2009-12-01 08:20:31 -08:00
smp.c	generic-ipi: Add smp_call_function_any()	2009-11-18 14:52:25 +01:00
softirq.c	rcu: Cleanup: balance rcu_irq_enter()/rcu_irq_exit() calls	2009-11-02 16:06:37 +01:00
softlockup.c	sysctl: remove "struct file *" argument of ->proc_handler	2009-09-24 07:21:04 -07:00
spinlock.c	locking: Reduce ifdefs in kernel/spinlock.c	2009-11-13 20:53:28 +01:00
srcu.c	rcu: Add synchronize_srcu_expedited()	2009-10-26 09:40:30 +01:00
stacktrace.c
stop_machine.c	cpumask: remove cpumask_t from core	2009-03-30 22:05:17 +10:30
sys_ni.c	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6	2009-12-08 07:55:01 -08:00
sys.c	sched, cputime: Introduce thread_group_times()	2009-12-02 17:32:40 +01:00
sysctl_binary.c	sysctl binary: Reorder the tests to process wild card entries first.	2009-11-12 01:42:31 -08:00
sysctl_check.c	ipv4 05/05: add sysctl to accept packets with local source addresses	2009-12-03 12:14:38 -08:00
sysctl.c	Merge git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/sysctl-2.6	2009-12-08 07:38:50 -08:00
taskstats.c	genetlink: make netns aware	2009-07-12 14:03:27 -07:00
test_kprobes.c
time.c	Merge branch 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-12-08 19:27:08 -08:00
timeconst.pl
timer.c	Merge branch 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-09-23 09:46:15 -07:00
tracepoint.c	trivial: fix typo "to to" in multiple files	2009-09-21 15:14:55 +02:00
tsacct.c
uid16.c	headers: utsname.h redux	2009-09-23 18:13:10 -07:00
up.c
user_namespace.c
user-return-notifier.c	core: Clean up user return notifers use of per_cpu	2009-12-02 10:22:59 +01:00
user.c	uids: Prevent tear down race	2009-11-02 16:02:39 +01:00
utsname_sysctl.c	sysctl kernel: Remove binary sysctl logic	2009-11-12 02:04:55 -08:00
utsname.c	utsns: extract creeate_uts_ns()	2009-06-18 13:03:55 -07:00
wait.c	locking, sched: Give waitqueue spinlocks their own lockdep classes	2009-08-10 14:43:09 +02:00
workqueue.c	workqueue: fix race condition in schedule_on_each_cpu()	2009-11-17 17:40:33 -08:00