Merge branch 'tip/tracing/ftrace' of...

Merge branch 'tip/tracing/ftrace' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/ftrace

include/linux/interrupt.h

@@ -258,6 +258,11 @@ enum
 	NR_SOFTIRQS
 };
 
+/* map softirq index to softirq name. update 'softirq_to_name' in
+ * kernel/softirq.c when adding a new softirq.
+ */
+extern char *softirq_to_name[NR_SOFTIRQS];
+
 /* softirq mask and active fields moved to irq_cpustat_t in
  * asm/hardirq.h to get better cache usage.  KAO
  */

include/linux/kernel.h

@@ -452,31 +452,45 @@ do {									\
 
 #define trace_printk(fmt, args...)					\
 do {									\
-	static const char *trace_printk_fmt				\
-	__attribute__((section("__trace_printk_fmt")));			\
-									\
-	if (!trace_printk_fmt)						\
-		trace_printk_fmt = fmt;					\
-									\
 	__trace_printk_check_format(fmt, ##args);			\
-	__trace_printk(_THIS_IP_, trace_printk_fmt, ##args);		\
+	if (__builtin_constant_p(fmt)) {				\
+		static const char *trace_printk_fmt			\
+		  __attribute__((section("__trace_printk_fmt"))) =	\
+			__builtin_constant_p(fmt) ? fmt : NULL;		\
+									\
+		__trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args);	\
+	} else								\
+		__trace_printk(_THIS_IP_, fmt, ##args);		\
 } while (0)
 
+extern int
+__trace_bprintk(unsigned long ip, const char *fmt, ...)
+	__attribute__ ((format (printf, 2, 3)));
+
 extern int
 __trace_printk(unsigned long ip, const char *fmt, ...)
 	__attribute__ ((format (printf, 2, 3)));
 
+/*
+ * The double __builtin_constant_p is because gcc will give us an error
+ * if we try to allocate the static variable to fmt if it is not a
+ * constant. Even with the outer if statement.
+ */
 #define ftrace_vprintk(fmt, vargs)					\
 do {									\
-	static const char *trace_printk_fmt				\
-	__attribute__((section("__trace_printk_fmt")));			\
-									\
-	if (!trace_printk_fmt)						\
-		trace_printk_fmt = fmt;					\
+	if (__builtin_constant_p(fmt)) {				\
+		static const char *trace_printk_fmt			\
+		  __attribute__((section("__trace_printk_fmt"))) =	\
+			__builtin_constant_p(fmt) ? fmt : NULL;		\
 									\
-	__ftrace_vprintk(_THIS_IP_, trace_printk_fmt, vargs);		\
+		__ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs);	\
+	} else								\
+		__ftrace_vprintk(_THIS_IP_, fmt, vargs);		\
 } while (0)
 
+extern int
+__ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
+
 extern int
 __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
 

include/trace/irq_event_types.h

@@ -40,4 +40,16 @@ TRACE_EVENT(irq_handler_exit,
 		  __entry->irq, __entry->ret ? "handled" : "unhandled")
 );
 
+TRACE_FORMAT(softirq_entry,
+	TP_PROTO(struct softirq_action *h, struct softirq_action *vec),
+	TP_ARGS(h, vec),
+	TP_FMT("softirq=%d action=%s", (int)(h - vec), softirq_to_name[h-vec])
+	);
+
+TRACE_FORMAT(softirq_exit,
+	TP_PROTO(struct softirq_action *h, struct softirq_action *vec),
+	TP_ARGS(h, vec),
+	TP_FMT("softirq=%d action=%s", (int)(h - vec), softirq_to_name[h-vec])
+	);
+
 #undef TRACE_SYSTEM

kernel/softirq.c

@@ -24,6 +24,7 @@
 #include <linux/ftrace.h>
 #include <linux/smp.h>
 #include <linux/tick.h>
+#include <trace/irq.h>
 
 #include <asm/irq.h>
 /*
@@ -53,6 +54,12 @@ static struct softirq_action softirq_vec[NR_SOFTIRQS] __cacheline_aligned_in_smp
 
 static DEFINE_PER_CPU(struct task_struct *, ksoftirqd);
 
+char *softirq_to_name[NR_SOFTIRQS] = {
+	"HI_SOFTIRQ", "TIMER_SOFTIRQ", "NET_TX_SOFTIRQ", "NET_RX_SOFTIRQ",
+	"BLOCK_SOFTIRQ", "TASKLET_SOFTIRQ", "SCHED_SOFTIRQ", "HRTIMER_SOFTIRQ",
+	"RCU_SOFTIRQ"
+};
+
 /*
  * we cannot loop indefinitely here to avoid userspace starvation,
  * but we also don't want to introduce a worst case 1/HZ latency
@@ -180,6 +187,9 @@ EXPORT_SYMBOL(local_bh_enable_ip);
  */
 #define MAX_SOFTIRQ_RESTART 10
 
+DEFINE_TRACE(softirq_entry);
+DEFINE_TRACE(softirq_exit);
+
 asmlinkage void __do_softirq(void)
 {
 	struct softirq_action *h;
@@ -206,12 +216,14 @@ asmlinkage void __do_softirq(void)
 		if (pending & 1) {
 			int prev_count = preempt_count();
 
+			trace_softirq_entry(h, softirq_vec);
 			h->action(h);
-
+			trace_softirq_exit(h, softirq_vec);
 			if (unlikely(prev_count != preempt_count())) {
-				printk(KERN_ERR "huh, entered softirq %td %p"
+				printk(KERN_ERR "huh, entered softirq %td %s %p"
 				       "with preempt_count %08x,"
 				       " exited with %08x?\n", h - softirq_vec,
+				       softirq_to_name[h - softirq_vec],
 				       h->action, prev_count, preempt_count());
 				preempt_count() = prev_count;
 			}

kernel/trace/trace.h

@@ -20,6 +20,7 @@ enum trace_type {
 	TRACE_WAKE,
 	TRACE_STACK,
 	TRACE_PRINT,
+	TRACE_BPRINT,
 	TRACE_SPECIAL,
 	TRACE_MMIO_RW,
 	TRACE_MMIO_MAP,
@@ -117,7 +118,7 @@ struct userstack_entry {
 /*
  * trace_printk entry:
  */
-struct print_entry {
+struct bprint_entry {
 	struct trace_entry	ent;
 	unsigned long		ip;
 	int			depth;
@@ -125,6 +126,13 @@ struct print_entry {
 	u32			buf[];
 };
 
+struct print_entry {
+	struct trace_entry	ent;
+	unsigned long		ip;
+	int			depth;
+	char			buf[];
+};
+
 #define TRACE_OLD_SIZE		88
 
 struct trace_field_cont {
@@ -286,6 +294,7 @@ extern void __ftrace_bad_type(void);
 		IF_ASSIGN(var, ent, struct stack_entry, TRACE_STACK);	\
 		IF_ASSIGN(var, ent, struct userstack_entry, TRACE_USER_STACK);\
 		IF_ASSIGN(var, ent, struct print_entry, TRACE_PRINT);	\
+		IF_ASSIGN(var, ent, struct bprint_entry, TRACE_BPRINT);	\
 		IF_ASSIGN(var, ent, struct special_entry, 0);		\
 		IF_ASSIGN(var, ent, struct trace_mmiotrace_rw,		\
 			  TRACE_MMIO_RW);				\
@@ -570,6 +579,8 @@ extern int trace_selftest_startup_branch(struct tracer *trace,
 extern void *head_page(struct trace_array_cpu *data);
 extern long ns2usecs(cycle_t nsec);
 extern int
+trace_vbprintk(unsigned long ip, int depth, const char *fmt, va_list args);
+extern int
 trace_vprintk(unsigned long ip, int depth, const char *fmt, va_list args);
 
 extern unsigned long trace_flags;
@@ -737,6 +748,9 @@ static inline void trace_branch_disable(void)
 }
 #endif /* CONFIG_BRANCH_TRACER */
 
+/* set ring buffers to default size if not already done so */
+int tracing_update_buffers(void);
+
 /* trace event type bit fields, not numeric */
 enum {
 	TRACE_EVENT_TYPE_PRINTF		= 1,
@@ -759,4 +773,21 @@ void event_trace_printk(unsigned long ip, const char *fmt, ...);
 extern struct ftrace_event_call __start_ftrace_events[];
 extern struct ftrace_event_call __stop_ftrace_events[];
 
+extern const char *__start___trace_bprintk_fmt[];
+extern const char *__stop___trace_bprintk_fmt[];
+
+#define event_trace_printk(ip, fmt, args...)				\
+do {									\
+	__trace_printk_check_format(fmt, ##args);			\
+	tracing_record_cmdline(current);				\
+	if (__builtin_constant_p(fmt)) {				\
+		static const char *trace_printk_fmt			\
+		  __attribute__((section("__trace_printk_fmt"))) =	\
+			__builtin_constant_p(fmt) ? fmt : NULL;		\
+									\
+		__trace_bprintk(ip, trace_printk_fmt, ##args);		\
+	} else								\
+		__trace_printk(ip, fmt, ##args);			\
+} while (0)
+
 #endif /* _LINUX_KERNEL_TRACE_H */

kernel/trace/trace_event_types.h

@@ -102,7 +102,7 @@ TRACE_EVENT_FORMAT(user_stack, TRACE_USER_STACK, userstack_entry, ignore,
 		 "\t=> (%08lx)\n\t=> (%08lx)\n\t=> (%08lx)\n\t=> (%08lx)\n")
 );
 
-TRACE_EVENT_FORMAT(print, TRACE_PRINT, print_entry, ignore,
+TRACE_EVENT_FORMAT(bprint, TRACE_BPRINT, bprint_entry, ignore,
 	TRACE_STRUCT(
 		TRACE_FIELD(unsigned long, ip, ip)
 		TRACE_FIELD(unsigned int, depth, depth)
@@ -112,6 +112,15 @@ TRACE_EVENT_FORMAT(print, TRACE_PRINT, print_entry, ignore,
 	TP_RAW_FMT("%08lx (%d) fmt:%p %s")
 );
 
+TRACE_EVENT_FORMAT(print, TRACE_PRINT, print_entry, ignore,
+	TRACE_STRUCT(
+		TRACE_FIELD(unsigned long, ip, ip)
+		TRACE_FIELD(unsigned int, depth, depth)
+		TRACE_FIELD_ZERO_CHAR(buf)
+	),
+	TP_RAW_FMT("%08lx (%d) fmt:%p %s")
+);
+
 TRACE_EVENT_FORMAT(branch, TRACE_BRANCH, trace_branch, ignore,
 	TRACE_STRUCT(
 		TRACE_FIELD(unsigned int, line, line)

kernel/trace/trace_events.c

@@ -24,16 +24,6 @@ static DEFINE_MUTEX(event_mutex);
 	     (unsigned long)event < (unsigned long)__stop_ftrace_events; \
 	     event++)
 
-void event_trace_printk(unsigned long ip, const char *fmt, ...)
-{
-	va_list ap;
-
-	va_start(ap, fmt);
-	tracing_record_cmdline(current);
-	trace_vprintk(ip, task_curr_ret_stack(current), fmt, ap);
-	va_end(ap);
-}
-
 static void ftrace_clear_events(void)
 {
 	struct ftrace_event_call *call = (void *)__start_ftrace_events;
@@ -141,6 +131,10 @@ ftrace_event_write(struct file *file, const char __user *ubuf,
 	if (!cnt || cnt < 0)
 		return 0;
 
+	ret = tracing_update_buffers();
+	if (ret < 0)
+		return ret;
+
 	ret = get_user(ch, ubuf++);
 	if (ret)
 		return ret;
@@ -331,6 +325,10 @@ event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
 	if (ret < 0)
 		return ret;
 
+	ret = tracing_update_buffers();
+	if (ret < 0)
+		return ret;
+
 	switch (val) {
 	case 0:
 	case 1:

kernel/trace/trace_events_stage_2.h

@@ -57,7 +57,7 @@ ftrace_raw_output_##call(struct trace_iterator *iter, int flags)	\
 									\
 	field = (typeof(field))entry;					\
 									\
-	ret = trace_seq_printf(s, print);				\
+	ret = trace_seq_printf(s, #call ": " print);			\
 	if (!ret)							\
 		return TRACE_TYPE_PARTIAL_LINE;				\
 									\

kernel/trace/trace_functions_graph.c

@@ -684,7 +684,7 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
 }
 
 static enum print_line_t
-print_graph_comment(struct print_entry *trace, struct trace_seq *s,
+print_graph_comment(struct bprint_entry *trace, struct trace_seq *s,
 		   struct trace_entry *ent, struct trace_iterator *iter)
 {
 	int i;
@@ -781,8 +781,8 @@ print_graph_function(struct trace_iterator *iter)
 		trace_assign_type(field, entry);
 		return print_graph_return(&field->ret, s, entry, iter);
 	}
-	case TRACE_PRINT: {
-		struct print_entry *field;
+	case TRACE_BPRINT: {
+		struct bprint_entry *field;
 		trace_assign_type(field, entry);
 		return print_graph_comment(field, s, entry, iter);
 	}

kernel/trace/trace_mmiotrace.c

@@ -254,6 +254,7 @@ static enum print_line_t mmio_print_mark(struct trace_iterator *iter)
 {
 	struct trace_entry *entry = iter->ent;
 	struct print_entry *print = (struct print_entry *)entry;
+	const char *msg		= print->buf;
 	struct trace_seq *s	= &iter->seq;
 	unsigned long long t	= ns2usecs(iter->ts);
 	unsigned long usec_rem	= do_div(t, USEC_PER_SEC);
@@ -261,11 +262,7 @@ static enum print_line_t mmio_print_mark(struct trace_iterator *iter)
 	int ret;
 
 	/* The trailing newline must be in the message. */
-	ret = trace_seq_printf(s, "MARK %u.%06lu ", secs, usec_rem);
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
-
-	ret = trace_seq_bprintf(s, print->fmt, print->buf);
+	ret = trace_seq_printf(s, "MARK %u.%06lu %s", secs, usec_rem, msg);
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
 

kernel/trace/trace_output.c

@@ -832,13 +832,13 @@ static struct trace_event trace_user_stack_event = {
 	.binary		= trace_special_bin,
 };
 
-/* TRACE_PRINT */
+/* TRACE_BPRINT */
 static enum print_line_t
-trace_print_print(struct trace_iterator *iter, int flags)
+trace_bprint_print(struct trace_iterator *iter, int flags)
 {
 	struct trace_entry *entry = iter->ent;
 	struct trace_seq *s = &iter->seq;
-	struct print_entry *field;
+	struct bprint_entry *field;
 
 	trace_assign_type(field, entry);
 
@@ -858,9 +858,10 @@ trace_print_print(struct trace_iterator *iter, int flags)
 }
 
 
-static enum print_line_t trace_print_raw(struct trace_iterator *iter, int flags)
+static enum print_line_t
+trace_bprint_raw(struct trace_iterator *iter, int flags)
 {
-	struct print_entry *field;
+	struct bprint_entry *field;
 	struct trace_seq *s = &iter->seq;
 
 	trace_assign_type(field, iter->ent);
@@ -878,12 +879,55 @@ static enum print_line_t trace_print_raw(struct trace_iterator *iter, int flags)
 }
 
 
+static struct trace_event trace_bprint_event = {
+	.type		= TRACE_BPRINT,
+	.trace		= trace_bprint_print,
+	.raw		= trace_bprint_raw,
+};
+
+/* TRACE_PRINT */
+static enum print_line_t trace_print_print(struct trace_iterator *iter,
+					   int flags)
+{
+	struct print_entry *field;
+	struct trace_seq *s = &iter->seq;
+
+	trace_assign_type(field, iter->ent);
+
+	if (!seq_print_ip_sym(s, field->ip, flags))
+		goto partial;
+
+	if (!trace_seq_printf(s, ": %s", field->buf))
+		goto partial;
+
+	return TRACE_TYPE_HANDLED;
+
+ partial:
+	return TRACE_TYPE_PARTIAL_LINE;
+}
+
+static enum print_line_t trace_print_raw(struct trace_iterator *iter, int flags)
+{
+	struct print_entry *field;
+
+	trace_assign_type(field, iter->ent);
+
+	if (!trace_seq_printf(&iter->seq, "# %lx %s", field->ip, field->buf))
+		goto partial;
+
+	return TRACE_TYPE_HANDLED;
+
+ partial:
+	return TRACE_TYPE_PARTIAL_LINE;
+}
+
 static struct trace_event trace_print_event = {
-	.type		= TRACE_PRINT,
+	.type	 	= TRACE_PRINT,
 	.trace		= trace_print_print,
 	.raw		= trace_print_raw,
 };
 
+
 static struct trace_event *events[] __initdata = {
 	&trace_fn_event,
 	&trace_ctx_event,
@@ -891,6 +935,7 @@ static struct trace_event *events[] __initdata = {
 	&trace_special_event,
 	&trace_stack_event,
 	&trace_user_stack_event,
+	&trace_bprint_event,
 	&trace_print_event,
 	NULL
 };

kernel/trace/trace_printk.c

@@ -4,18 +4,19 @@
  * Copyright (C) 2008 Lai Jiangshan <laijs@cn.fujitsu.com>
  *
  */
+#include <linux/seq_file.h>
+#include <linux/debugfs.h>
+#include <linux/uaccess.h>
 #include <linux/kernel.h>
 #include <linux/ftrace.h>
 #include <linux/string.h>
+#include <linux/module.h>
+#include <linux/marker.h>
+#include <linux/mutex.h>
 #include <linux/ctype.h>
 #include <linux/list.h>
-#include <linux/mutex.h>
 #include <linux/slab.h>
-#include <linux/module.h>
-#include <linux/seq_file.h>
 #include <linux/fs.h>
-#include <linux/marker.h>
-#include <linux/uaccess.h>
 
 #include "trace.h"
 
@@ -99,7 +100,7 @@ struct notifier_block module_trace_bprintk_format_nb = {
 	.notifier_call = module_trace_bprintk_format_notify,
 };
 
-int __trace_printk(unsigned long ip, const char *fmt, ...)
+int __trace_bprintk(unsigned long ip, const char *fmt, ...)
  {
 	int ret;
 	va_list ap;
@@ -111,13 +112,13 @@ int __trace_printk(unsigned long ip, const char *fmt, ...)
 		return 0;
 
 	va_start(ap, fmt);
-	ret = trace_vprintk(ip, task_curr_ret_stack(current), fmt, ap);
+	ret = trace_vbprintk(ip, task_curr_ret_stack(current), fmt, ap);
 	va_end(ap);
 	return ret;
 }
-EXPORT_SYMBOL_GPL(__trace_printk);
+EXPORT_SYMBOL_GPL(__trace_bprintk);
 
-int __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap)
+int __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap)
  {
 	if (unlikely(!fmt))
 		return 0;
@@ -125,10 +126,141 @@ int __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap)
 	if (!(trace_flags & TRACE_ITER_PRINTK))
 		return 0;
 
+	return trace_vbprintk(ip, task_curr_ret_stack(current), fmt, ap);
+}
+EXPORT_SYMBOL_GPL(__ftrace_vbprintk);
+
+int __trace_printk(unsigned long ip, const char *fmt, ...)
+{
+	int ret;
+	va_list ap;
+
+	if (!(trace_flags & TRACE_ITER_PRINTK))
+		return 0;
+
+	va_start(ap, fmt);
+	ret = trace_vprintk(ip, task_curr_ret_stack(current), fmt, ap);
+	va_end(ap);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(__trace_printk);
+
+int __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap)
+{
+	if (!(trace_flags & TRACE_ITER_PRINTK))
+		return 0;
+
 	return trace_vprintk(ip, task_curr_ret_stack(current), fmt, ap);
 }
 EXPORT_SYMBOL_GPL(__ftrace_vprintk);
 
+static void *
+t_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	const char **fmt = m->private;
+	const char **next = fmt;
+
+	(*pos)++;
+
+	if ((unsigned long)fmt >= (unsigned long)__stop___trace_bprintk_fmt)
+		return NULL;
+
+	next = fmt;
+	m->private = ++next;
+
+	return fmt;
+}
+
+static void *t_start(struct seq_file *m, loff_t *pos)
+{
+	return t_next(m, NULL, pos);
+}
+
+static int t_show(struct seq_file *m, void *v)
+{
+	const char **fmt = v;
+	const char *str = *fmt;
+	int i;
+
+	seq_printf(m, "0x%lx : \"", (unsigned long)fmt);
+
+	/*
+	 * Tabs and new lines need to be converted.
+	 */
+	for (i = 0; str[i]; i++) {
+		switch (str[i]) {
+		case '\n':
+			seq_puts(m, "\\n");
+			break;
+		case '\t':
+			seq_puts(m, "\\t");
+			break;
+		case '\\':
+			seq_puts(m, "\\");
+			break;
+		case '"':
+			seq_puts(m, "\\\"");
+			break;
+		default:
+			seq_putc(m, str[i]);
+		}
+	}
+	seq_puts(m, "\"\n");
+
+	return 0;
+}
+
+static void t_stop(struct seq_file *m, void *p)
+{
+}
+
+static const struct seq_operations show_format_seq_ops = {
+	.start = t_start,
+	.next = t_next,
+	.show = t_show,
+	.stop = t_stop,
+};
+
+static int
+ftrace_formats_open(struct inode *inode, struct file *file)
+{
+	int ret;
+
+	ret = seq_open(file, &show_format_seq_ops);
+	if (!ret) {
+		struct seq_file *m = file->private_data;
+
+		m->private = __start___trace_bprintk_fmt;
+	}
+	return ret;
+}
+
+static const struct file_operations ftrace_formats_fops = {
+	.open = ftrace_formats_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = seq_release,
+};
+
+static __init int init_trace_printk_function_export(void)
+{
+	struct dentry *d_tracer;
+	struct dentry *entry;
+
+	d_tracer = tracing_init_dentry();
+	if (!d_tracer)
+		return 0;
+
+	entry = debugfs_create_file("printk_formats", 0444, d_tracer,
+				    NULL, &ftrace_formats_fops);
+	if (!entry)
+		pr_warning("Could not create debugfs "
+			   "'printk_formats' entry\n");
+
+	return 0;
+}
+
+fs_initcall(init_trace_printk_function_export);
 
 static __init int init_trace_printk(void)
 {

kernel/trace/trace_stack.c

@@ -245,16 +245,31 @@ static int trace_lookup_stack(struct seq_file *m, long i)
 #endif
 }
 
+static void print_disabled(struct seq_file *m)
+{
+	seq_puts(m, "#\n"
+		 "#  Stack tracer disabled\n"
+		 "#\n"
+		 "# To enable the stack tracer, either add 'stacktrace' to the\n"
+		 "# kernel command line\n"
+		 "# or 'echo 1 > /proc/sys/kernel/stack_tracer_enabled'\n"
+		 "#\n");
+}
+
 static int t_show(struct seq_file *m, void *v)
 {
 	long i;
 	int size;
 
 	if (v == SEQ_START_TOKEN) {
-		seq_printf(m, "        Depth   Size      Location"
+		seq_printf(m, "        Depth    Size      Location"
 			   "    (%d entries)\n"
-			   "        -----   ----      --------\n",
+			   "        -----    ----      --------\n",
 			   max_stack_trace.nr_entries);
+
+		if (!stack_tracer_enabled && !max_stack_size)
+			print_disabled(m);
+
 		return 0;
 	}
 

kernel/trace/trace_workqueue.c

@@ -193,12 +193,20 @@ static int workqueue_stat_show(struct seq_file *s, void *p)
 	struct cpu_workqueue_stats *cws = p;
 	unsigned long flags;
 	int cpu = cws->cpu;
-	struct task_struct *tsk = find_task_by_vpid(cws->pid);
-
-	seq_printf(s, "%3d %6d     %6u       %s\n", cws->cpu,
-		   atomic_read(&cws->inserted),
-		   cws->executed,
-		   tsk ? tsk->comm : "<...>");
+	struct pid *pid;
+	struct task_struct *tsk;
+
+	pid = find_get_pid(cws->pid);
+	if (pid) {
+		tsk = get_pid_task(pid, PIDTYPE_PID);
+		if (tsk) {
+			seq_printf(s, "%3d %6d     %6u       %s\n", cws->cpu,
+				   atomic_read(&cws->inserted), cws->executed,
+				   tsk->comm);
+			put_task_struct(tsk);
+		}
+		put_pid(pid);
+	}
 
 	spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags);
 	if (&cws->list == workqueue_cpu_stat(cpu)->list.next)