Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel…

…/git/tip/linux-2.6-tip * 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: lockdep: Avoid out of bounds array reference in save_trace() futex: Take mmap_sem for get_user_pages in fault_in_user_writeable lockstat: Add usage info to Documentation/lockstat.txt lockstat: Fix min, max times in /proc/lock_stats

Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel…
…/git/tip/linux-2.6-tip * 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: lockdep: Avoid out of bounds array reference in save_trace() futex: Take mmap_sem for get_user_pages in fault_in_user_writeable lockstat: Add usage info to Documentation/lockstat.txt lockstat: Fix min, max times in /proc/lock_stats
Linus Torvalds
2 parents 756300983f ea5b41f9d5
Showing 3 changed files Side-by-side Diff
Documentation/lockstat.txt
kernel/futex.c
kernel/lockdep.c
@@ -62,7 +62,19 @@
 It also tracks 4 contention points per class. A contention point is a call site
 that had to wait on lock acquisition.
  
+ - CONFIGURATION
+
+Lock statistics are enabled via CONFIG_LOCK_STATS.
+
  - USAGE
+
+Enable collection of statistics:
+
+# echo 1 >/proc/sys/kernel/lock_stat
+
+Disable collection of statistics:
+
+# echo 0 >/proc/sys/kernel/lock_stat
  
 Look at the current lock statistics:
  
@@ -304,8 +304,14 @@
  */
 static int fault_in_user_writeable(u32 __user *uaddr)
 {
-	int ret = get_user_pages(current, current->mm, (unsigned long)uaddr,
-				 1, 1, 0, NULL, NULL);
+	struct mm_struct *mm = current->mm;
+	int ret;
+
+	down_read(&mm->mmap_sem);
+	ret = get_user_pages(current, mm, (unsigned long)uaddr,
+			     1, 1, 0, NULL, NULL);
+	up_read(&mm->mmap_sem);
+
 	return ret < 0 ? ret : 0;
 }
  
@@ -168,7 +168,7 @@
 	if (time > lt->max)
 		lt->max = time;
  
-	if (time < lt->min || !lt->min)
+	if (time < lt->min || !lt->nr)
 		lt->min = time;
  
 	lt->total += time;
@@ -177,8 +177,15 @@
  
 static inline void lock_time_add(struct lock_time *src, struct lock_time *dst)
 {
-	dst->min += src->min;
-	dst->max += src->max;
+	if (!src->nr)
+		return;
+
+	if (src->max > dst->max)
+		dst->max = src->max;
+
+	if (src->min < dst->min || !dst->nr)
+		dst->min = src->min;
+
 	dst->total += src->total;
 	dst->nr += src->nr;
 }
@@ -379,7 +386,8 @@
 	 * complete trace that maxes out the entries provided will be reported
 	 * as incomplete, friggin useless </rant>
 	 */
-	if (trace->entries[trace->nr_entries-1] == ULONG_MAX)
+	if (trace->nr_entries != 0 &&
+	    trace->entries[trace->nr_entries-1] == ULONG_MAX)
 		trace->nr_entries--;
  
 	trace->max_entries = trace->nr_entries;
...	...	@@ -62,7 +62,19 @@
62	62	It also tracks 4 contention points per class. A contention point is a call site
63	63	that had to wait on lock acquisition.
64	64
	65	+ - CONFIGURATION
	66	+
	67	+Lock statistics are enabled via CONFIG_LOCK_STATS.
	68	+
65	69	- USAGE
	70	+
	71	+Enable collection of statistics:
	72	+
	73	+# echo 1 >/proc/sys/kernel/lock_stat
	74	+
	75	+Disable collection of statistics:
	76	+
	77	+# echo 0 >/proc/sys/kernel/lock_stat
66	78
67	79	Look at the current lock statistics:
68	80
...	...	@@ -304,8 +304,14 @@
304	304	*/
305	305	static int fault_in_user_writeable(u32 __user *uaddr)
306	306	{
307		- int ret = get_user_pages(current, current->mm, (unsigned long)uaddr,
308		- 1, 1, 0, NULL, NULL);
	307	+ struct mm_struct *mm = current->mm;
	308	+ int ret;
	309	+
	310	+ down_read(&mm->mmap_sem);
	311	+ ret = get_user_pages(current, mm, (unsigned long)uaddr,
	312	+ 1, 1, 0, NULL, NULL);
	313	+ up_read(&mm->mmap_sem);
	314	+
309	315	return ret < 0 ? ret : 0;
310	316	}
311	317
...	...	@@ -168,7 +168,7 @@
168	168	if (time > lt->max)
169	169	lt->max = time;
170	170
171		- if (time < lt->min \|\| !lt->min)
	171	+ if (time < lt->min \|\| !lt->nr)
172	172	lt->min = time;
173	173
174	174	lt->total += time;
...	...	@@ -177,8 +177,15 @@
177	177
178	178	static inline void lock_time_add(struct lock_time src, struct lock_time dst)
179	179	{
180		- dst->min += src->min;
181		- dst->max += src->max;
	180	+ if (!src->nr)
	181	+ return;
	182	+
	183	+ if (src->max > dst->max)
	184	+ dst->max = src->max;
	185	+
	186	+ if (src->min < dst->min \|\| !dst->nr)
	187	+ dst->min = src->min;
	188	+
182	189	dst->total += src->total;
183	190	dst->nr += src->nr;
184	191	}
...	...	@@ -379,7 +386,8 @@
379	386	* complete trace that maxes out the entries provided will be reported
380	387	* as incomplete, friggin useless </rant>
381	388	*/
382		- if (trace->entries[trace->nr_entries-1] == ULONG_MAX)
	389	+ if (trace->nr_entries != 0 &&
	390	+ trace->entries[trace->nr_entries-1] == ULONG_MAX)
383	391	trace->nr_entries--;
384	392
385	393	trace->max_entries = trace->nr_entries;