[for-next][PATCH 0/8] tracing: More updates for 4.11

[for-next][PATCH 0/8] tracing: More updates for 4.11

[Steven Rostedt]

  git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
for-next

Head SHA1: 8f0994bb8cbde5452e58ce0cacdbf6cb58079d01


Arnd Bergmann (1):
      tracing: Use modern function declaration

Jason Baron (1):
      jump_label: Reduce the size of struct static_key

Luiz Capitulino (1):
      tracing/hwlat: Update old comment about migration

Masami Hiramatsu (1):
      tracing/probe: Show subsystem name in messages

Steven Rostedt (VMware) (2):
      tracing: Have COMM event filter key be treated as a string
      tracing: Have traceprobe_probes_write() not access userspace unnecessarily

Thomas Gleixner (1):
      timers: Make flags output in the timer_start tracepoint useful

Wei Yongjun (1):
      tracing: Fix return value check in trace_benchmark_reg()

----
 Documentation/static-keys.txt  |   4 +-
 include/linux/jump_label.h     |  23 ++++---
 include/linux/timer.h          |   2 +
 include/trace/events/timer.h   |  14 +++-
 kernel/jump_label.c            | 153 ++++++++++++++++++++++++++++++++++-------
 kernel/trace/trace.h           |   5 +-
 kernel/trace/trace_benchmark.c |   4 +-
 kernel/trace/trace_hwlat.c     |   5 +-
 kernel/trace/trace_kprobe.c    |   1 +
 kernel/trace/trace_probe.c     |  49 ++++++++-----
 kernel/trace/trace_uprobe.c    |   1 +
 11 files changed, 197 insertions(+), 64 deletions(-)

[for-next][PATCH 1/8] tracing: Have COMM event filter key be treated as a string

[Steven Rostedt]

[-- Attachment #1: 0001-tracing-Have-COMM-event-filter-key-be-treated-as-a-s.patch --]
[-- Type: text/plain, Size: 962 bytes --]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

The GLOB operation "~" should be able to work with the COMM filter key in
order to trace programs with a glob. For example

  echo 'COMM ~ "systemd*"' > events/syscalls/filter

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index afbec961eab1..d2d068b36341 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1312,7 +1312,8 @@ static inline bool is_string_field(struct ftrace_event_field *field)
 {
 	return field->filter_type == FILTER_DYN_STRING ||
 	       field->filter_type == FILTER_STATIC_STRING ||
-	       field->filter_type == FILTER_PTR_STRING;
+	       field->filter_type == FILTER_PTR_STRING ||
+	       field->filter_type == FILTER_COMM;
 }
 
 static inline bool is_function_field(struct ftrace_event_field *field)
-- 
2.10.2

[for-next][PATCH 2/8] tracing: Have traceprobe_probes_write() not access userspace unnecessarily

[Steven Rostedt]

[-- Attachment #1: 0002-tracing-Have-traceprobe_probes_write-not-access-user.patch --]
[-- Type: text/plain, Size: 2697 bytes --]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

The code in traceprobe_probes_write() reads up to 4096 bytes from userpace
for each line. If userspace passes in several lines to execute, the code
will do a large read for each line, even though, it is highly likely that
the first read from userspace received all of the lines at once.

I changed the logic to do a single read from userspace, and to only read
from userspace again if not all of the read from userspace made it in.

I tested this by adding printk()s and writing files that would test -1, ==,
and +1 the buffer size, to make sure that there's no overflows and that if a
single line is written with +1 the buffer size, that it fails properly.

Link: http://lkml.kernel.org/r/20170209180458.5c829ab2@gandalf.local.home

Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_probe.c | 48 ++++++++++++++++++++++++++++------------------
 1 file changed, 29 insertions(+), 19 deletions(-)

diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 8c0553d9afd3..2a06f1fa7001 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -647,7 +647,7 @@ ssize_t traceprobe_probes_write(struct file *file, const char __user *buffer,
 				size_t count, loff_t *ppos,
 				int (*createfn)(int, char **))
 {
-	char *kbuf, *tmp;
+	char *kbuf, *buf, *tmp;
 	int ret = 0;
 	size_t done = 0;
 	size_t size;
@@ -667,27 +667,37 @@ ssize_t traceprobe_probes_write(struct file *file, const char __user *buffer,
 			goto out;
 		}
 		kbuf[size] = '\0';
-		tmp = strchr(kbuf, '\n');
+		buf = kbuf;
+		do {
+			tmp = strchr(buf, '\n');
+			if (tmp) {
+				*tmp = '\0';
+				size = tmp - buf + 1;
+			} else {
+				size = strlen(buf);
+				if (done + size < count) {
+					if (buf != kbuf)
+						break;
+					pr_warn("Line length is too long: Should be less than %d\n",
+						WRITE_BUFSIZE);
+					ret = -EINVAL;
+					goto out;
+				}
+			}
+			done += size;
 
-		if (tmp) {
-			*tmp = '\0';
-			size = tmp - kbuf + 1;
-		} else if (done + size < count) {
-			pr_warn("Line length is too long: Should be less than %d\n",
-				WRITE_BUFSIZE);
-			ret = -EINVAL;
-			goto out;
-		}
-		done += size;
-		/* Remove comments */
-		tmp = strchr(kbuf, '#');
+			/* Remove comments */
+			tmp = strchr(buf, '#');
 
-		if (tmp)
-			*tmp = '\0';
+			if (tmp)
+				*tmp = '\0';
 
-		ret = traceprobe_command(kbuf, createfn);
-		if (ret)
-			goto out;
+			ret = traceprobe_command(buf, createfn);
+			if (ret)
+				goto out;
+			buf += size;
+
+		} while (done < count);
 	}
 	ret = done;
 
-- 
2.10.2

[for-next][PATCH 3/8] timers: Make flags output in the timer_start tracepoint useful

[Steven Rostedt]

[-- Attachment #1: 0003-timers-Make-flags-output-in-the-timer_start-tracepoi.patch --]
[-- Type: text/plain, Size: 2384 bytes --]

From: Thomas Gleixner <tglx@linutronix.de>

The timer flags in the timer_start trace event contain lots of useful
information, but the meaning is not clear in the trace output. Making tools
rely on the bit positions is bad as they might change over time.

Decode the flags in the print out. Tools can retrieve the bits and their
meaning from the trace format file.

Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1702101639290.4036@nanos

Requested-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 include/linux/timer.h        |  2 ++
 include/trace/events/timer.h | 14 ++++++++++++--
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/include/linux/timer.h b/include/linux/timer.h
index 51d601f192d4..a17f915f9456 100644
--- a/include/linux/timer.h
+++ b/include/linux/timer.h
@@ -66,6 +66,8 @@ struct timer_list {
 #define TIMER_ARRAYSHIFT	22
 #define TIMER_ARRAYMASK		0xFFC00000
 
+#define TIMER_TRACE_FLAGMASK	(TIMER_MIGRATING | TIMER_DEFERRABLE | TIMER_PINNED | TIMER_IRQSAFE)
+
 #define __TIMER_INITIALIZER(_function, _expires, _data, _flags) { \
 		.entry = { .next = TIMER_ENTRY_STATIC },	\
 		.function = (_function),			\
diff --git a/include/trace/events/timer.h b/include/trace/events/timer.h
index 1448637616d6..f6d8fea6df77 100644
--- a/include/trace/events/timer.h
+++ b/include/trace/events/timer.h
@@ -36,6 +36,13 @@ DEFINE_EVENT(timer_class, timer_init,
 	TP_ARGS(timer)
 );
 
+#define decode_timer_flags(flags)			\
+	__print_flags(flags, "|",			\
+		{  TIMER_MIGRATING,	"M" },		\
+		{  TIMER_DEFERRABLE,	"D" },		\
+		{  TIMER_PINNED,	"P" },		\
+		{  TIMER_IRQSAFE,	"I" })
+
 /**
  * timer_start - called when the timer is started
  * @timer:	pointer to struct timer_list
@@ -65,9 +72,12 @@ TRACE_EVENT(timer_start,
 		__entry->flags		= flags;
 	),
 
-	TP_printk("timer=%p function=%pf expires=%lu [timeout=%ld] flags=0x%08x",
+	TP_printk("timer=%p function=%pf expires=%lu [timeout=%ld] cpu=%u idx=%u flags=%s",
 		  __entry->timer, __entry->function, __entry->expires,
-		  (long)__entry->expires - __entry->now, __entry->flags)
+		  (long)__entry->expires - __entry->now,
+		  __entry->flags & TIMER_CPUMASK,
+		  __entry->flags >> TIMER_ARRAYSHIFT,
+		  decode_timer_flags(__entry->flags & TIMER_TRACE_FLAGMASK))
 );
 
 /**
-- 
2.10.2

[for-next][PATCH 4/8] tracing/hwlat: Update old comment about migration

[Steven Rostedt]

[-- Attachment #1: 0004-tracing-hwlat-Update-old-comment-about-migration.patch --]
[-- Type: text/plain, Size: 1154 bytes --]

From: Luiz Capitulino <lcapitulino@redhat.com>

The ftrace hwlat does support a cpumask.

Link: http://lkml.kernel.org/r/20170213122517.6e211955@redhat.com

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_hwlat.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c
index 775569ec50d0..bf209d2657ab 100644
--- a/kernel/trace/trace_hwlat.c
+++ b/kernel/trace/trace_hwlat.c
@@ -322,10 +322,7 @@ static void move_to_next_cpu(void)
  * need to ensure nothing else might be running (and thus preempting).
  * Obviously this should never be used in production environments.
  *
- * Currently this runs on which ever CPU it was scheduled on, but most
- * real-world hardware latency situations occur across several CPUs,
- * but we might later generalize this if we find there are any actualy
- * systems with alternate SMI delivery or other hardware latencies.
+ * Executes one loop interaction on each CPU in tracing_cpumask sysfs file.
  */
 static int kthread_fn(void *data)
 {
-- 
2.10.2

[for-next][PATCH 5/8] tracing/probe: Show subsystem name in messages

[Steven Rostedt]

[-- Attachment #1: 0005-tracing-probe-Show-subsystem-name-in-messages.patch --]
[-- Type: text/plain, Size: 1780 bytes --]

From: Masami Hiramatsu <mhiramat@kernel.org>

Show "trace_probe:", "trace_kprobe:" and "trace_uprobe:"
headers for each warning/error/info message. This will
help people to notice that kprobe/uprobe events caused
those messages.

Link: http://lkml.kernel.org/r/148646647813.24658.16705315294927615333.stgit@devbox

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_kprobe.c | 1 +
 kernel/trace/trace_probe.c  | 1 +
 kernel/trace/trace_uprobe.c | 1 +
 3 files changed, 3 insertions(+)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index a133ecd741e4..5c9bd0550542 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -16,6 +16,7 @@
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
+#define pr_fmt(fmt)	"trace_kprobe: " fmt
 
 #include <linux/module.h>
 #include <linux/uaccess.h>
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 2a06f1fa7001..11b63328d6fb 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -21,6 +21,7 @@
  * Copyright (C) IBM Corporation, 2010-2011
  * Author:     Srikar Dronamraju
  */
+#define pr_fmt(fmt)	"trace_probe: " fmt
 
 #include "trace_probe.h"
 
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 4f2ba2bb11e0..f4379e772171 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -17,6 +17,7 @@
  * Copyright (C) IBM Corporation, 2010-2012
  * Author:	Srikar Dronamraju <srikar@linux.vnet.ibm.com>
  */
+#define pr_fmt(fmt)	"trace_kprobe: " fmt
 
 #include <linux/module.h>
 #include <linux/uaccess.h>
-- 
2.10.2

[for-next][PATCH 6/8] jump_label: Reduce the size of struct static_key

[Steven Rostedt]

[-- Attachment #1: 0006-jump_label-Reduce-the-size-of-struct-static_key.patch --]
[-- Type: text/plain, Size: 11691 bytes --]

From: Jason Baron <jbaron@akamai.com>

The static_key->next field goes mostly unused. The field is used for
associating module uses with a static key. Most uses of struct static_key
define a static key in the core kernel and make use of it entirely within
the core kernel, or define the static key in a module and make use of it
only from within that module. In fact, of the ~3,000 static keys defined,
I found only about 5 or so that did not fit this pattern.

Thus, we can remove the static_key->next field entirely and overload
the static_key->entries field. That is, when all the static_key uses
are contained within the same module, static_key->entries continues
to point to those uses. However, if the static_key uses are not contained
within the module where the static_key is defined, then we allocate a
struct static_key_mod, store a pointer to the uses within that
struct static_key_mod, and have the static key point at the static_key_mod.
This does incur some extra memory usage when a static_key is used in a
module that does not define it, but since there are only a handful of such
cases there is a net savings.

In order to identify if the static_key->entries pointer contains a
struct static_key_mod or a struct jump_entry pointer, bit 1 of
static_key->entries is set to 1 if it points to a struct static_key_mod and
is 0 if it points to a struct jump_entry. We were already using bit 0 in a
similar way to store the initial value of the static_key. This does mean
that allocations of struct static_key_mod and that the struct jump_entry
tables need to be at least 4-byte aligned in memory. As far as I can tell
all arches meet this criteria.

For my .config, the patch increased the text by 778 bytes, but reduced
the data + bss size by 14912, for a net savings of 14,134 bytes.

   text	   data	    bss	    dec	    hex	filename
8092427	5016512	 790528	13899467	 d416cb	vmlinux.pre
8093205	5001600	 790528	13885333	 d3df95	vmlinux.post

Link: http://lkml.kernel.org/r/1486154544-4321-1-git-send-email-jbaron@akamai.com

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Jason Baron <jbaron@akamai.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 Documentation/static-keys.txt |   4 +-
 include/linux/jump_label.h    |  23 ++++---
 kernel/jump_label.c           | 153 +++++++++++++++++++++++++++++++++++-------
 3 files changed, 145 insertions(+), 35 deletions(-)

diff --git a/Documentation/static-keys.txt b/Documentation/static-keys.txt
index ea8d7b4e53f0..32a25fad0c1b 100644
--- a/Documentation/static-keys.txt
+++ b/Documentation/static-keys.txt
@@ -155,7 +155,9 @@ or:
 
 There are a few functions and macros that architectures must implement in order
 to take advantage of this optimization. If there is no architecture support, we
-simply fall back to a traditional, load, test, and jump sequence.
+simply fall back to a traditional, load, test, and jump sequence. Also, the
+struct jump_entry table must be at least 4-byte aligned because the
+static_key->entry field makes use of the two least significant bits.
 
 * select HAVE_ARCH_JUMP_LABEL, see: arch/x86/Kconfig
 
diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h
index a0547c571800..680c98b2f41c 100644
--- a/include/linux/jump_label.h
+++ b/include/linux/jump_label.h
@@ -89,11 +89,17 @@ extern bool static_key_initialized;
 
 struct static_key {
 	atomic_t enabled;
-/* Set lsb bit to 1 if branch is default true, 0 ot */
-	struct jump_entry *entries;
-#ifdef CONFIG_MODULES
-	struct static_key_mod *next;
-#endif
+/*
+ * bit 0 => 1 if key is initially true
+ *	    0 if initially false
+ * bit 1 => 1 if points to struct static_key_mod
+ *	    0 if points to struct jump_entry
+ */
+	union {
+		unsigned long type;
+		struct jump_entry *entries;
+		struct static_key_mod *next;
+	};
 };
 
 #else
@@ -118,9 +124,10 @@ struct module;
 
 #ifdef HAVE_JUMP_LABEL
 
-#define JUMP_TYPE_FALSE	0UL
-#define JUMP_TYPE_TRUE	1UL
-#define JUMP_TYPE_MASK	1UL
+#define JUMP_TYPE_FALSE		0UL
+#define JUMP_TYPE_TRUE		1UL
+#define JUMP_TYPE_LINKED	2UL
+#define JUMP_TYPE_MASK		3UL
 
 static __always_inline bool static_key_false(struct static_key *key)
 {
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index 93ad6c1fb9b6..953411f5ba7f 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -229,12 +229,28 @@ void __weak __init_or_module arch_jump_label_transform_static(struct jump_entry
 
 static inline struct jump_entry *static_key_entries(struct static_key *key)
 {
-	return (struct jump_entry *)((unsigned long)key->entries & ~JUMP_TYPE_MASK);
+	WARN_ON_ONCE(key->type & JUMP_TYPE_LINKED);
+	return (struct jump_entry *)(key->type & ~JUMP_TYPE_MASK);
 }
 
 static inline bool static_key_type(struct static_key *key)
 {
-	return (unsigned long)key->entries & JUMP_TYPE_MASK;
+	return key->type & JUMP_TYPE_TRUE;
+}
+
+static inline bool static_key_linked(struct static_key *key)
+{
+	return key->type & JUMP_TYPE_LINKED;
+}
+
+static inline void static_key_clear_linked(struct static_key *key)
+{
+	key->type &= ~JUMP_TYPE_LINKED;
+}
+
+static inline void static_key_set_linked(struct static_key *key)
+{
+	key->type |= JUMP_TYPE_LINKED;
 }
 
 static inline struct static_key *jump_entry_key(struct jump_entry *entry)
@@ -247,6 +263,26 @@ static bool jump_entry_branch(struct jump_entry *entry)
 	return (unsigned long)entry->key & 1UL;
 }
 
+/***
+ * A 'struct static_key' uses a union such that it either points directly
+ * to a table of 'struct jump_entry' or to a linked list of modules which in
+ * turn point to 'struct jump_entry' tables.
+ *
+ * The two lower bits of the pointer are used to keep track of which pointer
+ * type is in use and to store the initial branch direction, we use an access
+ * function which preserves these bits.
+ */
+static void static_key_set_entries(struct static_key *key,
+				   struct jump_entry *entries)
+{
+	unsigned long type;
+
+	WARN_ON_ONCE((unsigned long)entries & JUMP_TYPE_MASK);
+	type = key->type & JUMP_TYPE_MASK;
+	key->entries = entries;
+	key->type |= type;
+}
+
 static enum jump_label_type jump_label_type(struct jump_entry *entry)
 {
 	struct static_key *key = jump_entry_key(entry);
@@ -306,13 +342,7 @@ void __init jump_label_init(void)
 			continue;
 
 		key = iterk;
-		/*
-		 * Set key->entries to iter, but preserve JUMP_LABEL_TRUE_BRANCH.
-		 */
-		*((unsigned long *)&key->entries) += (unsigned long)iter;
-#ifdef CONFIG_MODULES
-		key->next = NULL;
-#endif
+		static_key_set_entries(key, iter);
 	}
 	static_key_initialized = true;
 	jump_label_unlock();
@@ -336,6 +366,29 @@ struct static_key_mod {
 	struct module *mod;
 };
 
+static inline struct static_key_mod *static_key_mod(struct static_key *key)
+{
+	WARN_ON_ONCE(!(key->type & JUMP_TYPE_LINKED));
+	return (struct static_key_mod *)(key->type & ~JUMP_TYPE_MASK);
+}
+
+/***
+ * key->type and key->next are the same via union.
+ * This sets key->next and preserves the type bits.
+ *
+ * See additional comments above static_key_set_entries().
+ */
+static void static_key_set_mod(struct static_key *key,
+			       struct static_key_mod *mod)
+{
+	unsigned long type;
+
+	WARN_ON_ONCE((unsigned long)mod & JUMP_TYPE_MASK);
+	type = key->type & JUMP_TYPE_MASK;
+	key->next = mod;
+	key->type |= type;
+}
+
 static int __jump_label_mod_text_reserved(void *start, void *end)
 {
 	struct module *mod;
@@ -358,11 +411,23 @@ static void __jump_label_mod_update(struct static_key *key)
 {
 	struct static_key_mod *mod;
 
-	for (mod = key->next; mod; mod = mod->next) {
-		struct module *m = mod->mod;
+	for (mod = static_key_mod(key); mod; mod = mod->next) {
+		struct jump_entry *stop;
+		struct module *m;
+
+		/*
+		 * NULL if the static_key is defined in a module
+		 * that does not use it
+		 */
+		if (!mod->entries)
+			continue;
 
-		__jump_label_update(key, mod->entries,
-				    m->jump_entries + m->num_jump_entries);
+		m = mod->mod;
+		if (!m)
+			stop = __stop___jump_table;
+		else
+			stop = m->jump_entries + m->num_jump_entries;
+		__jump_label_update(key, mod->entries, stop);
 	}
 }
 
@@ -397,7 +462,7 @@ static int jump_label_add_module(struct module *mod)
 	struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
 	struct jump_entry *iter;
 	struct static_key *key = NULL;
-	struct static_key_mod *jlm;
+	struct static_key_mod *jlm, *jlm2;
 
 	/* if the module doesn't have jump label entries, just return */
 	if (iter_start == iter_stop)
@@ -414,20 +479,32 @@ static int jump_label_add_module(struct module *mod)
 
 		key = iterk;
 		if (within_module(iter->key, mod)) {
-			/*
-			 * Set key->entries to iter, but preserve JUMP_LABEL_TRUE_BRANCH.
-			 */
-			*((unsigned long *)&key->entries) += (unsigned long)iter;
-			key->next = NULL;
+			static_key_set_entries(key, iter);
 			continue;
 		}
 		jlm = kzalloc(sizeof(struct static_key_mod), GFP_KERNEL);
 		if (!jlm)
 			return -ENOMEM;
+		if (!static_key_linked(key)) {
+			jlm2 = kzalloc(sizeof(struct static_key_mod),
+				       GFP_KERNEL);
+			if (!jlm2) {
+				kfree(jlm);
+				return -ENOMEM;
+			}
+			preempt_disable();
+			jlm2->mod = __module_address((unsigned long)key);
+			preempt_enable();
+			jlm2->entries = static_key_entries(key);
+			jlm2->next = NULL;
+			static_key_set_mod(key, jlm2);
+			static_key_set_linked(key);
+		}
 		jlm->mod = mod;
 		jlm->entries = iter;
-		jlm->next = key->next;
-		key->next = jlm;
+		jlm->next = static_key_mod(key);
+		static_key_set_mod(key, jlm);
+		static_key_set_linked(key);
 
 		/* Only update if we've changed from our initial state */
 		if (jump_label_type(iter) != jump_label_init_type(iter))
@@ -454,16 +531,34 @@ static void jump_label_del_module(struct module *mod)
 		if (within_module(iter->key, mod))
 			continue;
 
+		/* No memory during module load */
+		if (WARN_ON(!static_key_linked(key)))
+			continue;
+
 		prev = &key->next;
-		jlm = key->next;
+		jlm = static_key_mod(key);
 
 		while (jlm && jlm->mod != mod) {
 			prev = &jlm->next;
 			jlm = jlm->next;
 		}
 
-		if (jlm) {
+		/* No memory during module load */
+		if (WARN_ON(!jlm))
+			continue;
+
+		if (prev == &key->next)
+			static_key_set_mod(key, jlm->next);
+		else
 			*prev = jlm->next;
+
+		kfree(jlm);
+
+		jlm = static_key_mod(key);
+		/* if only one etry is left, fold it back into the static_key */
+		if (jlm->next == NULL) {
+			static_key_set_entries(key, jlm->entries);
+			static_key_clear_linked(key);
 			kfree(jlm);
 		}
 	}
@@ -492,8 +587,10 @@ jump_label_module_notify(struct notifier_block *self, unsigned long val,
 	case MODULE_STATE_COMING:
 		jump_label_lock();
 		ret = jump_label_add_module(mod);
-		if (ret)
+		if (ret) {
+			WARN(1, "Failed to allocatote memory: jump_label may not work properly.\n");
 			jump_label_del_module(mod);
+		}
 		jump_label_unlock();
 		break;
 	case MODULE_STATE_GOING:
@@ -554,11 +651,14 @@ int jump_label_text_reserved(void *start, void *end)
 static void jump_label_update(struct static_key *key)
 {
 	struct jump_entry *stop = __stop___jump_table;
-	struct jump_entry *entry = static_key_entries(key);
+	struct jump_entry *entry;
 #ifdef CONFIG_MODULES
 	struct module *mod;
 
-	__jump_label_mod_update(key);
+	if (static_key_linked(key)) {
+		__jump_label_mod_update(key);
+		return;
+	}
 
 	preempt_disable();
 	mod = __module_address((unsigned long)key);
@@ -566,6 +666,7 @@ static void jump_label_update(struct static_key *key)
 		stop = mod->jump_entries + mod->num_jump_entries;
 	preempt_enable();
 #endif
+	entry = static_key_entries(key);
 	/* if there are no users, entry can be NULL */
 	if (entry)
 		__jump_label_update(key, entry, stop);
-- 
2.10.2

[for-next][PATCH 7/8] tracing: Use modern function declaration

[Steven Rostedt]

[-- Attachment #1: 0007-tracing-Use-modern-function-declaration.patch --]
[-- Type: text/plain, Size: 1162 bytes --]

From: Arnd Bergmann <arnd@arndb.de>

We get a lot of harmless warnings about this header file at W=1 level
because of an unusual function declaration:

kernel/trace/trace.h:766:1: error: 'inline' is not at beginning of declaration [-Werror=old-style-declaration]

This moves the inline statement where it normally belongs, avoiding the
warning.

Link: http://lkml.kernel.org/r/20170123122521.3389010-1-arnd@arndb.de

Fixes: 4046bf023b06 ("ftrace: Expose ftrace_hash_empty and ftrace_lookup_ip")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index d2d068b36341..ae1cce91fead 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -763,7 +763,7 @@ struct ftrace_hash {
 struct ftrace_func_entry *
 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip);
 
-static bool __always_inline ftrace_hash_empty(struct ftrace_hash *hash)
+static __always_inline bool ftrace_hash_empty(struct ftrace_hash *hash)
 {
 	return !hash || !hash->count;
 }
-- 
2.10.2

[for-next][PATCH 8/8] tracing: Fix return value check in trace_benchmark_reg()

[Steven Rostedt]

[-- Attachment #1: 0008-tracing-Fix-return-value-check-in-trace_benchmark_re.patch --]
[-- Type: text/plain, Size: 1127 bytes --]

From: Wei Yongjun <weiyongjun1@huawei.com>

In case of error, the function kthread_run() returns ERR_PTR() and never
returns NULL. The NULL test in the return value check should be replaced
with IS_ERR().

Link: http://lkml.kernel.org/r/20170112135502.28556-1-weiyj.lk@gmail.com

Cc: stable@vger.kernel.org
Fixes: 81dc9f0e ("tracing: Add tracepoint benchmark tracepoint")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_benchmark.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace_benchmark.c b/kernel/trace/trace_benchmark.c
index e3b488825ae3..e49fbe901cfc 100644
--- a/kernel/trace/trace_benchmark.c
+++ b/kernel/trace/trace_benchmark.c
@@ -175,9 +175,9 @@ int trace_benchmark_reg(void)
 
 	bm_event_thread = kthread_run(benchmark_event_kthread,
 				      NULL, "event_benchmark");
-	if (!bm_event_thread) {
+	if (IS_ERR(bm_event_thread)) {
 		pr_warning("trace benchmark failed to create kernel thread\n");
-		return -ENOMEM;
+		return PTR_ERR(bm_event_thread);
 	}
 
 	return 0;
-- 
2.10.2