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authorLinus Torvalds <torvalds@linux-foundation.org>2009-10-14 15:25:35 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-10-14 15:25:35 -0700
commitee67e6cbe1121da1ae4eceb7b2bcb535c5cbf65e (patch)
tree8ceefe56b6f325a4b8dbf0ee2dcda0d9216a52a3
parent220a6258b1bac1f0b050a99aa8233330d6c8c416 (diff)
parentc7cedb125ba20cc531671dc667ad704baa667d97 (diff)
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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: oprofile: warn on freeing event buffer too early oprofile: fix race condition in event_buffer free lockdep: Use cpu_clock() for lockstat
-rw-r--r--drivers/oprofile/event_buffer.c35
-rw-r--r--kernel/lockdep.c20
2 files changed, 38 insertions, 17 deletions
diff --git a/drivers/oprofile/event_buffer.c b/drivers/oprofile/event_buffer.c
index 2b7ae366ceb1..5df60a6b6776 100644
--- a/drivers/oprofile/event_buffer.c
+++ b/drivers/oprofile/event_buffer.c
@@ -35,12 +35,23 @@ static size_t buffer_pos;
/* atomic_t because wait_event checks it outside of buffer_mutex */
static atomic_t buffer_ready = ATOMIC_INIT(0);
-/* Add an entry to the event buffer. When we
- * get near to the end we wake up the process
- * sleeping on the read() of the file.
+/*
+ * Add an entry to the event buffer. When we get near to the end we
+ * wake up the process sleeping on the read() of the file. To protect
+ * the event_buffer this function may only be called when buffer_mutex
+ * is set.
*/
void add_event_entry(unsigned long value)
{
+ /*
+ * This shouldn't happen since all workqueues or handlers are
+ * canceled or flushed before the event buffer is freed.
+ */
+ if (!event_buffer) {
+ WARN_ON_ONCE(1);
+ return;
+ }
+
if (buffer_pos == buffer_size) {
atomic_inc(&oprofile_stats.event_lost_overflow);
return;
@@ -69,7 +80,6 @@ void wake_up_buffer_waiter(void)
int alloc_event_buffer(void)
{
- int err = -ENOMEM;
unsigned long flags;
spin_lock_irqsave(&oprofilefs_lock, flags);
@@ -80,21 +90,22 @@ int alloc_event_buffer(void)
if (buffer_watershed >= buffer_size)
return -EINVAL;
+ buffer_pos = 0;
event_buffer = vmalloc(sizeof(unsigned long) * buffer_size);
if (!event_buffer)
- goto out;
+ return -ENOMEM;
- err = 0;
-out:
- return err;
+ return 0;
}
void free_event_buffer(void)
{
+ mutex_lock(&buffer_mutex);
vfree(event_buffer);
-
+ buffer_pos = 0;
event_buffer = NULL;
+ mutex_unlock(&buffer_mutex);
}
@@ -167,6 +178,12 @@ static ssize_t event_buffer_read(struct file *file, char __user *buf,
mutex_lock(&buffer_mutex);
+ /* May happen if the buffer is freed during pending reads. */
+ if (!event_buffer) {
+ retval = -EINTR;
+ goto out;
+ }
+
atomic_set(&buffer_ready, 0);
retval = -EFAULT;
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 3815ac1d58b2..9af56723c096 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -142,6 +142,11 @@ static inline struct lock_class *hlock_class(struct held_lock *hlock)
#ifdef CONFIG_LOCK_STAT
static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], lock_stats);
+static inline u64 lockstat_clock(void)
+{
+ return cpu_clock(smp_processor_id());
+}
+
static int lock_point(unsigned long points[], unsigned long ip)
{
int i;
@@ -158,7 +163,7 @@ static int lock_point(unsigned long points[], unsigned long ip)
return i;
}
-static void lock_time_inc(struct lock_time *lt, s64 time)
+static void lock_time_inc(struct lock_time *lt, u64 time)
{
if (time > lt->max)
lt->max = time;
@@ -234,12 +239,12 @@ static void put_lock_stats(struct lock_class_stats *stats)
static void lock_release_holdtime(struct held_lock *hlock)
{
struct lock_class_stats *stats;
- s64 holdtime;
+ u64 holdtime;
if (!lock_stat)
return;
- holdtime = sched_clock() - hlock->holdtime_stamp;
+ holdtime = lockstat_clock() - hlock->holdtime_stamp;
stats = get_lock_stats(hlock_class(hlock));
if (hlock->read)
@@ -2792,7 +2797,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
hlock->references = references;
#ifdef CONFIG_LOCK_STAT
hlock->waittime_stamp = 0;
- hlock->holdtime_stamp = sched_clock();
+ hlock->holdtime_stamp = lockstat_clock();
#endif
if (check == 2 && !mark_irqflags(curr, hlock))
@@ -3322,7 +3327,7 @@ found_it:
if (hlock->instance != lock)
return;
- hlock->waittime_stamp = sched_clock();
+ hlock->waittime_stamp = lockstat_clock();
contention_point = lock_point(hlock_class(hlock)->contention_point, ip);
contending_point = lock_point(hlock_class(hlock)->contending_point,
@@ -3345,8 +3350,7 @@ __lock_acquired(struct lockdep_map *lock, unsigned long ip)
struct held_lock *hlock, *prev_hlock;
struct lock_class_stats *stats;
unsigned int depth;
- u64 now;
- s64 waittime = 0;
+ u64 now, waittime = 0;
int i, cpu;
depth = curr->lockdep_depth;
@@ -3374,7 +3378,7 @@ found_it:
cpu = smp_processor_id();
if (hlock->waittime_stamp) {
- now = sched_clock();
+ now = lockstat_clock();
waittime = now - hlock->waittime_stamp;
hlock->holdtime_stamp = now;
}