Commit 1e57c218 authored by Linus Torvalds's avatar Linus Torvalds

Merge branch 'core-fixes-for-linus' of...

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
parents 75630098 ea5b41f9
......@@ -62,8 +62,20 @@ applicable).
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:
( line numbers not part of actual output, done for clarity in the explanation
......
......@@ -304,8 +304,14 @@ void put_futex_key(int fshared, union futex_key *key)
*/
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 @@ static void lock_time_inc(struct lock_time *lt, u64 time)
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 void lock_time_inc(struct lock_time *lt, u64 time)
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 @@ static int save_trace(struct stack_trace *trace)
* 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;
......
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