* [RFC PATCH 1/2] tracing - signal tracer
2009-09-14 10:14 [RFC PATCH 0/2] tracing - signal tracer, support multiple pids in set_pid_ftrace jolsa
@ 2009-09-14 10:14 ` jolsa
2009-09-14 10:14 ` [RFC PATCH 2/2] tracing - support multiple pids in set_pid_ftrace file jolsa
` (2 subsequent siblings)
3 siblings, 0 replies; 6+ messages in thread
From: jolsa @ 2009-09-14 10:14 UTC (permalink / raw)
To: mingo, rostedt; +Cc: linux-kernel
Implements the tracer for the signals. It is possible to narrow the trace
using the "set_ftrace_pid" pid filter file.
Usage (running some of the pthread-tests pkg's binaries):
sh-4.0# echo signal > current_tracer
sh-4.0# /tests/signal-loss
sh-4.0# /tests/ptrace_event_clone
sh-4.0# /tests/ptrace-on-job-control-stopped
sh-4.0# /tests/clone-ptrace
sh-4.0# cat trace
# tracer: signal
#
# TIMESTAMP CPU# FROM-PID TO-PID SIGNAL-NUM
# | | | | | | | |
217.117000 [000] modprobe-8741 khelper-8740 SIGCHLD-17
217.142000 [001] signal-loss-8742 signal-loss-8743 SIGSTOP-19
217.143000 [001] signal-loss-8742 signal-loss-8743 SIGINT-2
218.145000 [001] <idle>-0 signal-loss-8742 SIGALRM-14
218.149000 [001] signal-loss-8742 signal-loss-8743 SIGKILL-9
218.159000 [001] signal-loss-8742 sh-283 SIGCHLD-17
221.108000 [001] modprobe-8745 khelper-8744 SIGCHLD-17
221.145000 [001] cat-8746 sh-283 SIGCHLD-17
254.790000 [000] modprobe-8748 khelper-8747 SIGCHLD-17
254.820000 [001] ptrace_event_cl-8750 ptrace_event_cl-8750 SIGSTOP-19
254.824000 [001] ptrace_event_cl-8749 ptrace_event_cl-8750 SIGKILL-9
254.824000 [001] ptrace_event_cl-8749 ptrace_event_cl-8751 SIGKILL-9
254.827000 [001] ptrace_event_cl-8749 sh-283 SIGCHLD-17
256.399000 [000] modprobe-8753 khelper-8752 SIGCHLD-17
256.448000 [000] cat-8754 sh-283 SIGCHLD-17
333.634000 [000] modprobe-8756 khelper-8755 SIGCHLD-17
333.663000 [000] ptrace-on-job-c-8757 ptrace-on-job-c-8758 SIGSTOP-19
333.664000 [000] ptrace-on-job-c-8757 ptrace-on-job-c-8758 SIGKILL-9
333.666000 [000] ptrace-on-job-c-8757 init-1 SIGCHLD-17
333.666000 [000] ptrace-on-job-c-8757 sh-283 SIGCHLD-17
335.323000 [000] modprobe-8760 khelper-8759 SIGCHLD-17
448.054000 [001] clone-ptrace-8808 clone-ptrace-8808 SIGSTOP-19
448.057000 [001] clone-ptrace-8807 clone-ptrace-8808 SIGKILL-9
448.058000 [001] clone-ptrace-8807 clone-ptrace-8809 SIGKILL-9
448.063000 [001] clone-ptrace-8807 init-1 SIGCHLD-17
448.063000 [001] clone-ptrace-8807 sh-283 SIGCHLD-17
448.064000 [000] clone-ptrace-8809 clone-ptrace-8809 SIGTRAP-5
448.066000 [000] clone-ptrace-8809 init-1 SIGCHLD-17
449.321000 [001] modprobe-8811 khelper-8810 SIGCHLD-17
sh-4.0#
wbr,
jirka
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
---
include/linux/signaltrace.h | 22 +++++++
include/linux/tracehook.h | 14 +++++
kernel/signal.c | 3 +
kernel/trace/Kconfig | 11 ++++
kernel/trace/Makefile | 1 +
kernel/trace/trace.h | 9 +++
kernel/trace/trace_signal.c | 132 +++++++++++++++++++++++++++++++++++++++++++
7 files changed, 192 insertions(+), 0 deletions(-)
create mode 100644 include/linux/signaltrace.h
create mode 100644 kernel/trace/trace_signal.c
diff --git a/include/linux/signaltrace.h b/include/linux/signaltrace.h
new file mode 100644
index 0000000..5254478
--- /dev/null
+++ b/include/linux/signaltrace.h
@@ -0,0 +1,22 @@
+/*
+ * Copyright (C) 2009 Jiri Olsa <jolsa@redhat.com>
+ *
+ * This file is released under GPL version 2.
+ */
+
+#ifndef _LINUX_SIGNALTRACE_H
+#define _LINUX_SIGNALTRACE_H
+
+#ifdef __KERNEL__
+
+#ifdef CONFIG_SIGNAL_TRACER
+void trace_signal(struct task_struct *to, int sig);
+#else
+static inline void trace_signal(struct task_struct *to, int sig)
+{
+}
+#endif
+
+#endif /* __KERNEL__ */
+
+#endif /* _LINUX_SIGNALTRACE_H */
diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h
index 17ba82e..315b828 100644
--- a/include/linux/tracehook.h
+++ b/include/linux/tracehook.h
@@ -49,6 +49,7 @@
#include <linux/sched.h>
#include <linux/ptrace.h>
#include <linux/security.h>
+#include <linux/signaltrace.h>
struct linux_binprm;
/**
@@ -462,6 +463,19 @@ static inline int tracehook_get_signal(struct task_struct *task,
}
/**
+ * tracehook_send_signal
+ * @to: @current
+ * @sig: number of signal being sent
+ */
+static inline int tracehook_send_signal(struct task_struct *to, int sig)
+{
+#ifdef CONFIG_SIGNAL_TRACER
+ trace_signal(to, sig);
+#endif
+ return 0;
+}
+
+/**
* tracehook_notify_jctl - report about job control stop/continue
* @notify: nonzero if this is the last thread in the group to stop
* @why: %CLD_STOPPED or %CLD_CONTINUED
diff --git a/kernel/signal.c b/kernel/signal.c
index 64c5dee..8d3072b 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -842,6 +842,9 @@ static int __send_signal(int sig, struct siginfo *info, struct task_struct *t,
return 0;
pending = group ? &t->signal->shared_pending : &t->pending;
+
+ tracehook_send_signal(t, sig);
+
/*
* Short-circuit ignored signals and support queuing
* exactly one non-rt signal, so that we can get more
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index d05a661..be47a1a 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -396,6 +396,17 @@ config HW_BRANCH_TRACER
This tracer records all branches on the system in a circular
buffer giving access to the last N branches for each cpu.
+config SIGNAL_TRACER
+ bool "Trace signals"
+ select TRACING
+ help
+ This tracer records sent signals in a circular buffer.
+ It is possible to narrow the trace using the "set_ftrace_pid"
+ pid filter file.
+
+ If unsure, say N.
+
+
config KMEMTRACE
bool "Trace SLAB allocations"
select GENERIC_TRACER
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index ce3b1cd..a76c214 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -55,5 +55,6 @@ obj-$(CONFIG_FTRACE_SYSCALLS) += trace_syscalls.o
obj-$(CONFIG_EVENT_PROFILE) += trace_event_profile.o
obj-$(CONFIG_EVENT_TRACING) += trace_events_filter.o
obj-$(CONFIG_KSYM_TRACER) += trace_ksym.o
+obj-$(CONFIG_SIGNAL_TRACER) += trace_signal.o
libftrace-y := ftrace.o
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index e747162..5c7873a 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -44,6 +44,7 @@ enum trace_type {
TRACE_POWER,
TRACE_BLK,
TRACE_KSYM,
+ TRACE_SIGNAL,
__TRACE_LAST_TYPE,
};
@@ -218,6 +219,7 @@ extern void __ftrace_bad_type(void);
IF_ASSIGN(var, ent, struct kmemtrace_free_entry, \
TRACE_KMEM_FREE); \
IF_ASSIGN(var, ent, struct ksym_trace_entry, TRACE_KSYM);\
+ IF_ASSIGN(var, ent, struct signal_trace_entry, TRACE_SIGNAL);\
__ftrace_bad_type(); \
} while (0)
@@ -254,6 +256,13 @@ struct ksym_trace_entry {
char cmd[TASK_COMM_LEN];
};
+/* Signal trace entry. */
+struct signal_trace_entry {
+ struct trace_entry ent;
+ int pid;
+ int sig;
+};
+
/**
* struct tracer - a specific tracer and its callbacks to interact with debugfs
* @name: the name chosen to select it on the available_tracers file
diff --git a/kernel/trace/trace_signal.c b/kernel/trace/trace_signal.c
new file mode 100644
index 0000000..4b386de
--- /dev/null
+++ b/kernel/trace/trace_signal.c
@@ -0,0 +1,132 @@
+/*
+ * signal tracer
+ *
+ * Copyright (C) 2009 Jiri Olsa <jolsa@redhat.com>
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/debugfs.h>
+#include <linux/ftrace.h>
+#include <linux/signaltrace.h>
+
+#include "trace.h"
+
+static char* signal_str[SIGRTMIN + 1] =
+{
+ "UNKNOWN", "SIGHUP", "SIGINT", "SIGQUIT", "SIGILL", "SIGTRAP",
+ "SIGABRT", "SIGBUS", "SIGFPE", "SIGKILL", "SIGUSR1", "SIGSEGV",
+ "SIGUSR2", "SIGPIPE", "SIGALRM", "SIGTERM", "SIGSTKFLT", "SIGCHLD",
+ "SIGCONT", "SIGSTOP", "SIGTSTP", "SIGTTIN", "SIGTTOU", "SIGURG",
+ "SIGXCPU", "SIGXFSZ", "SIGVTALRM", "SIGPROF", "SIGWINCH", "SIGIO",
+ "SIGPWR", "SIGSYS"
+};
+
+static struct trace_array *ctx_trace;
+static int signal_trace_enabled = 0;
+
+void trace_signal(struct task_struct *to, int sig)
+{
+ struct ring_buffer_event *event;
+ struct signal_trace_entry *entry;
+ struct trace_array *tr = ctx_trace;
+
+ if (!ftrace_trace_task(current))
+ return;
+
+ if (!signal_trace_enabled)
+ return;
+
+ event = trace_buffer_lock_reserve(tr->buffer, TRACE_SIGNAL,
+ sizeof(*entry), 0, 0);
+ if (!event)
+ return;
+
+ tracing_record_cmdline(current);
+ tracing_record_cmdline(to);
+
+ entry = ring_buffer_event_data(event);
+ entry->pid = to->pid;
+ entry->sig = sig;
+
+ trace_buffer_unlock_commit(tr->buffer, event, 0, 0);
+}
+
+static void start_signal_trace(void)
+{
+ signal_trace_enabled = 1;
+}
+
+static void stop_signal_trace(void)
+{
+ signal_trace_enabled = 0;
+}
+
+static int signal_trace_init(struct trace_array *tr)
+{
+ ctx_trace = tr;
+ start_signal_trace();
+ return 0;
+}
+
+static void signal_trace_reset(struct trace_array *tr)
+{
+ stop_signal_trace();
+}
+
+static void trace_signal_print_header(struct seq_file *m)
+{
+ seq_printf(m, "# %12s %5s %16s-%-5s %16s-%-5s %14s-%-4s\n",
+ "TIMESTAMP", "CPU#", "FROM", "PID", "TO", "PID", "SIGNAL", "NUM");
+ seq_printf(m, "# %12s %5s %16s %-5s %16s %-5s %14s %-4s\n",
+ " | ", " | ", " |", "| ", " |", "| ", " |", "| ");
+}
+
+static enum print_line_t trace_signal_print_line(struct trace_iterator *iter)
+{
+ char to_comm[TASK_COMM_LEN], from_comm[TASK_COMM_LEN];
+ struct trace_seq *s = &iter->seq;
+ struct trace_entry *tr_entry = iter->ent;
+ struct signal_trace_entry *sig_entry = NULL;
+ int sig;
+ unsigned long long t = ns2usecs(iter->ts);
+ unsigned long usec_rem = do_div(t, USEC_PER_SEC);
+ unsigned long secs = (unsigned long)t;
+
+ trace_assign_type(sig_entry, iter->ent);
+ if (!sig_entry)
+ return TRACE_TYPE_UNHANDLED;
+
+ sig = sig_entry->sig < 0 ? 0 : sig_entry->sig;
+ if (sig > SIGRTMIN)
+ sig = 0;
+
+ trace_find_cmdline(tr_entry->pid, from_comm);
+ trace_find_cmdline(sig_entry->pid, to_comm);
+
+ trace_seq_printf(s, " %5lu.%06lu [%03d] %16s-%-5d %16s-%-5d %14s-%-4d\n",
+ secs, usec_rem, iter->cpu,
+ from_comm, tr_entry->pid,
+ to_comm, sig_entry->pid,
+ signal_str[sig], sig);
+
+ return TRACE_TYPE_HANDLED;
+}
+
+struct tracer signal_trace __read_mostly =
+{
+ .name = "signal",
+ .init = signal_trace_init,
+ .reset = signal_trace_reset,
+ .wait_pipe = poll_wait_pipe,
+ .print_header = trace_signal_print_header,
+ .print_line = trace_signal_print_line,
+};
+
+static __init int init_signal_trace(void)
+{
+ return register_tracer(&signal_trace);
+}
+
+device_initcall(init_signal_trace);
--
1.6.2.5
^ permalink raw reply related [flat|nested] 6+ messages in thread* [RFC PATCH 2/2] tracing - support multiple pids in set_pid_ftrace file
2009-09-14 10:14 [RFC PATCH 0/2] tracing - signal tracer, support multiple pids in set_pid_ftrace jolsa
2009-09-14 10:14 ` [RFC PATCH 1/2] tracing - signal tracer jolsa
@ 2009-09-14 10:14 ` jolsa
2009-09-14 12:20 ` [RFC PATCH 0/2] tracing - signal tracer, support multiple pids in set_pid_ftrace Steven Rostedt
2009-09-14 13:59 ` Daniel Walker
3 siblings, 0 replies; 6+ messages in thread
From: jolsa @ 2009-09-14 10:14 UTC (permalink / raw)
To: mingo, rostedt; +Cc: linux-kernel
Adding the possibility to set more than 1 pid in the set_pid_ftrace file,
thus allowing to trace more than 1 independent processes.
Usage:
sh-4.0# echo 284 > ./set_ftrace_pid
sh-4.0# cat ./set_ftrace_pid
284
sh-4.0# echo 1 >> ./set_ftrace_pid
sh-4.0# echo 0 >> ./set_ftrace_pid
sh-4.0# cat ./set_ftrace_pid
swapper tasks
1
284
sh-4.0# echo 4 > ./set_ftrace_pid
sh-4.0# cat ./set_ftrace_pid
4
sh-4.0# echo > ./set_ftrace_pid
sh-4.0# cat ./set_ftrace_pid
no pid
sh-4.0#
wbr,
jirka
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
---
kernel/trace/ftrace.c | 226 +++++++++++++++++++++++++++++++++++--------------
kernel/trace/trace.h | 4 +-
2 files changed, 164 insertions(+), 66 deletions(-)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 8b23d56..89ad5c8 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -60,6 +60,13 @@ static int last_ftrace_enabled;
/* Quick disabling of function tracer. */
int function_trace_stop;
+/* List for set_ftrace_pid's pids */
+LIST_HEAD(ftrace_pids);
+struct ftrace_pid {
+ struct list_head list;
+ struct pid *pid;
+};
+
/*
* ftrace_disabled is set when an anomaly is discovered.
* ftrace_disabled is much stronger than ftrace_enabled.
@@ -155,7 +162,7 @@ static int __register_ftrace_function(struct ftrace_ops *ops)
else
func = ftrace_list_func;
- if (ftrace_pid_trace) {
+ if (!list_empty(&ftrace_pids)) {
set_ftrace_pid_function(func);
func = ftrace_pid_func;
}
@@ -203,7 +210,7 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops)
if (ftrace_list->next == &ftrace_list_end) {
ftrace_func_t func = ftrace_list->func;
- if (ftrace_pid_trace) {
+ if (!list_empty(&ftrace_pids)) {
set_ftrace_pid_function(func);
func = ftrace_pid_func;
}
@@ -227,7 +234,7 @@ static void ftrace_update_pid_func(void)
func = ftrace_trace_function;
- if (ftrace_pid_trace) {
+ if (!list_empty(&ftrace_pids)) {
set_ftrace_pid_function(func);
func = ftrace_pid_func;
} else {
@@ -818,7 +825,6 @@ static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
#endif /* CONFIG_FUNCTION_PROFILER */
/* set when tracing only a pid */
-struct pid *ftrace_pid_trace;
static struct pid * const ftrace_swapper_pid = &init_struct_pid;
#ifdef CONFIG_DYNAMIC_FTRACE
@@ -2795,23 +2801,6 @@ static inline void ftrace_startup_enable(int command) { }
# define ftrace_shutdown_sysctl() do { } while (0)
#endif /* CONFIG_DYNAMIC_FTRACE */
-static ssize_t
-ftrace_pid_read(struct file *file, char __user *ubuf,
- size_t cnt, loff_t *ppos)
-{
- char buf[64];
- int r;
-
- if (ftrace_pid_trace == ftrace_swapper_pid)
- r = sprintf(buf, "swapper tasks\n");
- else if (ftrace_pid_trace)
- r = sprintf(buf, "%u\n", pid_vnr(ftrace_pid_trace));
- else
- r = sprintf(buf, "no pid\n");
-
- return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
-}
-
static void clear_ftrace_swapper(void)
{
struct task_struct *p;
@@ -2880,11 +2869,141 @@ static void set_ftrace_pid_task(struct pid *pid)
set_ftrace_pid(pid);
}
+static int ftrace_pid_add(int p)
+{
+ struct pid *pid;
+ struct ftrace_pid *fpid;
+ int ret = -EINVAL;
+
+ mutex_lock(&ftrace_lock);
+
+ if (!p)
+ pid = ftrace_swapper_pid;
+ else
+ pid = find_get_pid(p);
+
+ if (!pid)
+ goto out;
+
+ list_for_each_entry(fpid, &ftrace_pids, list)
+ if (fpid->pid == pid)
+ goto out_put;
+
+ ret = -ENOMEM;
+
+ fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
+ if (!fpid)
+ goto out_put;
+
+ list_add(&fpid->list, &ftrace_pids);
+ fpid->pid = pid;
+
+ set_ftrace_pid_task(pid);
+
+ ftrace_update_pid_func();
+ ftrace_startup_enable(0);
+
+ mutex_unlock(&ftrace_lock);
+ return 0;
+
+out_put:
+ if (pid != ftrace_swapper_pid)
+ put_pid(pid);
+
+out:
+ mutex_unlock(&ftrace_lock);
+ return ret;
+}
+
+static void ftrace_pid_reset(void)
+{
+ struct ftrace_pid *fpid, *safe;
+
+ mutex_lock(&ftrace_lock);
+ list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
+ struct pid *pid = fpid->pid;
+
+ clear_ftrace_pid_task(&pid);
+
+ if (pid != ftrace_swapper_pid)
+ put_pid(pid);
+
+ list_del(&fpid->list);
+ kfree(fpid);
+ }
+
+ ftrace_update_pid_func();
+ ftrace_startup_enable(0);
+
+ mutex_unlock(&ftrace_lock);
+}
+
+static void *fpid_start(struct seq_file *m, loff_t *pos)
+{
+ mutex_lock(&ftrace_lock);
+
+ if (list_empty(&ftrace_pids) && (!*pos))
+ return (void* )1;
+
+ return seq_list_start(&ftrace_pids, *pos);
+}
+
+static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
+{
+ if (v == (void *)1)
+ return NULL;
+
+ return seq_list_next(v, &ftrace_pids, pos);
+}
+
+static void fpid_stop(struct seq_file *m, void *p)
+{
+ mutex_unlock(&ftrace_lock);
+}
+
+static int fpid_show(struct seq_file *m, void *v)
+{
+ const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
+
+ if (v == (void *)1) {
+ seq_printf(m, "no pid\n");
+ return 0;
+ }
+
+ if (fpid->pid == ftrace_swapper_pid)
+ seq_printf(m, "swapper tasks\n");
+ else
+ seq_printf(m, "%u\n", pid_vnr(fpid->pid));
+
+ return 0;
+}
+
+static struct seq_operations ftrace_pid_sops = {
+ .start = fpid_start,
+ .next = fpid_next,
+ .stop = fpid_stop,
+ .show = fpid_show,
+};
+
+static int
+ftrace_pid_open(struct inode *inode, struct file *file)
+{
+ int ret = 0;
+
+ if ((file->f_mode & FMODE_WRITE) &&
+ (file->f_flags & O_TRUNC))
+ ftrace_pid_reset();
+
+ if (file->f_mode & FMODE_READ)
+ ret = seq_open(file, &ftrace_pid_sops);
+
+ return ret;
+}
+
static ssize_t
ftrace_pid_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
- struct pid *pid;
char buf[64];
long val;
int ret;
@@ -2897,57 +3016,36 @@ ftrace_pid_write(struct file *filp, const char __user *ubuf,
buf[cnt] = 0;
+ /*
+ * Allow the "echo > set_ftrace_pid" to clean
+ * the pids quietly.
+ */
+ if (!*ppos && *buf == '\n' && cnt == 1)
+ return 1;
+
ret = strict_strtol(buf, 10, &val);
if (ret < 0)
return ret;
- mutex_lock(&ftrace_lock);
- if (val < 0) {
- /* disable pid tracing */
- if (!ftrace_pid_trace)
- goto out;
-
- clear_ftrace_pid_task(&ftrace_pid_trace);
-
- } else {
- /* swapper task is special */
- if (!val) {
- pid = ftrace_swapper_pid;
- if (pid == ftrace_pid_trace)
- goto out;
- } else {
- pid = find_get_pid(val);
-
- if (pid == ftrace_pid_trace) {
- put_pid(pid);
- goto out;
- }
- }
-
- if (ftrace_pid_trace)
- clear_ftrace_pid_task(&ftrace_pid_trace);
-
- if (!pid)
- goto out;
-
- ftrace_pid_trace = pid;
+ ret = ftrace_pid_add(val);
- set_ftrace_pid_task(ftrace_pid_trace);
- }
-
- /* update the function call */
- ftrace_update_pid_func();
- ftrace_startup_enable(0);
-
- out:
- mutex_unlock(&ftrace_lock);
+ return ret ? ret : cnt;
+}
- return cnt;
+static int
+ftrace_pid_release(struct inode *inode, struct file *file)
+{
+ if (file->f_mode & FMODE_READ)
+ seq_release(inode, file);
+ return 0;
}
static const struct file_operations ftrace_pid_fops = {
- .read = ftrace_pid_read,
- .write = ftrace_pid_write,
+ .open = ftrace_pid_open,
+ .write = ftrace_pid_write,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = ftrace_pid_release,
};
static __init int ftrace_init_debugfs(void)
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 5c7873a..a8470ac 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -530,12 +530,12 @@ print_graph_function(struct trace_iterator *iter)
}
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
-extern struct pid *ftrace_pid_trace;
+extern struct list_head ftrace_pids;
#ifdef CONFIG_FUNCTION_TRACER
static inline int ftrace_trace_task(struct task_struct *task)
{
- if (!ftrace_pid_trace)
+ if (list_empty(&ftrace_pids))
return 1;
return test_tsk_trace_trace(task);
--
1.6.2.5
^ permalink raw reply related [flat|nested] 6+ messages in thread